diff --git a/audio/core/all-versions/vts/functional/7.0/Generators.cpp b/audio/core/all-versions/vts/functional/7.0/Generators.cpp
index d2ba339..8c92cbd 100644
--- a/audio/core/all-versions/vts/functional/7.0/Generators.cpp
+++ b/audio/core/all-versions/vts/functional/7.0/Generators.cpp
@@ -102,6 +102,9 @@
             if (mixPort.getRole() != xsd::Role::source) continue;  // not an output profile
             auto [flags, isOffload] = generateOutFlags(mixPort);
             for (const auto& profile : mixPort.getProfile()) {
+                if (!profile.hasFormat() || !profile.hasSamplingRates() ||
+                    !profile.hasChannelMasks())
+                    continue;
                 auto configs = combineAudioConfig(profile.getChannelMasks(),
                                                   profile.getSamplingRates(), profile.getFormat());
                 for (auto& config : configs) {
@@ -231,6 +234,9 @@
                                std::back_inserter(flags), [](auto flag) { return toString(flag); });
             }
             for (const auto& profile : mixPort.getProfile()) {
+                if (!profile.hasFormat() || !profile.hasSamplingRates() ||
+                    !profile.hasChannelMasks())
+                    continue;
                 auto configs = combineAudioConfig(profile.getChannelMasks(),
                                                   profile.getSamplingRates(), profile.getFormat());
                 for (const auto& config : configs) {
diff --git a/audio/core/all-versions/vts/functional/Android.bp b/audio/core/all-versions/vts/functional/Android.bp
index 7c25c23..b99ed43 100644
--- a/audio/core/all-versions/vts/functional/Android.bp
+++ b/audio/core/all-versions/vts/functional/Android.bp
@@ -245,6 +245,7 @@
     data: [
         "tests/apm_config_no_vx_7_0.xml",
         "tests/apm_config_with_vx_7_0.xml",
+        "tests/apm_config_b_204314749_7_0.xml",
     ],
     test_config: "tests/HalAudioV7_0GeneratorTest.xml",
 }
diff --git a/audio/core/all-versions/vts/functional/tests/HalAudioV7_0GeneratorTest.xml b/audio/core/all-versions/vts/functional/tests/HalAudioV7_0GeneratorTest.xml
index 2e79455..3dc5b33 100644
--- a/audio/core/all-versions/vts/functional/tests/HalAudioV7_0GeneratorTest.xml
+++ b/audio/core/all-versions/vts/functional/tests/HalAudioV7_0GeneratorTest.xml
@@ -24,6 +24,7 @@
         <option name="cleanup" value="true" />
         <option name="push" value="apm_config_no_vx_7_0.xml->/data/local/tmp/apm_config_no_vx.xml" />
         <option name="push" value="apm_config_with_vx_7_0.xml->/data/local/tmp/apm_config_with_vx.xml" />
+        <option name="push" value="apm_config_b_204314749_7_0.xml->/data/local/tmp/apm_config_b_204314749_7_0.xml" />
         <option name="push" value="HalAudioV7_0GeneratorTest->/data/local/tmp/HalAudioV7_0GeneratorTest" />
     </target_preparer>
 
diff --git a/audio/core/all-versions/vts/functional/tests/apm_config_b_204314749_7_0.xml b/audio/core/all-versions/vts/functional/tests/apm_config_b_204314749_7_0.xml
new file mode 100644
index 0000000..5bdca9a
--- /dev/null
+++ b/audio/core/all-versions/vts/functional/tests/apm_config_b_204314749_7_0.xml
@@ -0,0 +1,263 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<!-- Copyright (C) 2015 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<audioPolicyConfiguration version="7.0" xmlns:xi="http://www.w3.org/2001/XInclude">
+    <!-- version section contains a “version” tag in the form “major.minor” e.g. version=”1.0” -->
+
+    <!-- Global configuration Decalaration -->
+    <globalConfiguration speaker_drc_enabled="false"/>
+
+
+    <!-- Modules section:
+        There is one section per audio HW module present on the platform.
+        Each module section will contains two mandatory tags for audio HAL “halVersion” and “name”.
+        The module names are the same as in current .conf file:
+                “primary”, “A2DP”, “remote_submix”, “USB”
+        Each module will contain the following sections:
+        “devicePorts”: a list of device descriptors for all input and output devices accessible via this
+        module.
+        This contains both permanently attached devices and removable devices.
+        “mixPorts”: listing all output and input streams exposed by the audio HAL
+        “routes”: list of possible connections between input and output devices or between stream and
+        devices.
+            "route": is defined by an attribute:
+                -"type": <mux|mix> means all sources are mutual exclusive (mux) or can be mixed (mix)
+                -"sink": the sink involved in this route
+                -"sources": all the sources than can be connected to the sink via vis route
+        “attachedDevices”: permanently attached devices.
+        The attachedDevices section is a list of devices names. The names correspond to device names
+        defined in <devicePorts> section.
+        “defaultOutputDevice”: device to be used by default when no policy rule applies
+    -->
+    <modules>
+        <!-- Primary Audio HAL -->
+        <module name="primary" halVersion="3.0">
+            <attachedDevices>
+                <item>Speaker</item>
+                <item>Built-In Mic</item>
+                <item>Built-In Back Mic</item>
+                <item>Echo Reference</item>
+                <item>Tuner</item>
+            </attachedDevices>
+            <defaultOutputDevice>Speaker</defaultOutputDevice>
+            <mixPorts>
+                <mixPort name="primary output" role="source" flags="AUDIO_OUTPUT_FLAG_PRIMARY">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="48000" channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
+                </mixPort>
+                <mixPort name="tunnel pcm" role="source" flags="AUDIO_OUTPUT_FLAG_DIRECT AUDIO_OUTPUT_FLAG_HW_AV_SYNC">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="32000 44100 48000" channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
+                </mixPort>
+                <mixPort name="direct pcm" role="source" flags="AUDIO_OUTPUT_FLAG_DIRECT">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="32000 44100 48000" channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
+                </mixPort>
+                <mixPort name="direct output" role="source" flags="AUDIO_OUTPUT_FLAG_DIRECT">
+                    <profile name=""/>
+                </mixPort>
+                <mixPort name="tunnel direct output" role="source" flags="AUDIO_OUTPUT_FLAG_DIRECT AUDIO_OUTPUT_FLAG_HW_AV_SYNC">
+                    <profile name=""/>
+                </mixPort>
+                <mixPort name="mmap_no_irq_out" role="source" flags="AUDIO_OUTPUT_FLAG_DIRECT AUDIO_OUTPUT_FLAG_MMAP_NOIRQ">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                            samplingRates="48000"
+                            channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
+                </mixPort>
+                <mixPort name="primary input" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="8000 11025 12000 16000 22050 24000 32000 44100 48000"
+                             channelMasks="AUDIO_CHANNEL_IN_MONO AUDIO_CHANNEL_IN_STEREO"/>
+                </mixPort>
+                <mixPort name="tunnel a2dp" role="source" flags="AUDIO_OUTPUT_FLAG_DIRECT AUDIO_OUTPUT_FLAG_HW_AV_SYNC">
+                    <profile name=""/>
+                </mixPort>
+                <mixPort name="direct a2dp" role="source" flags="AUDIO_OUTPUT_FLAG_DIRECT">
+                    <profile name=""/>
+                </mixPort>
+                <mixPort name="echo reference" role="sink">
+                    <profile name="echo_reference" format="AUDIO_FORMAT_PCM_32_BIT"
+                             samplingRates="48000"
+                             channelMasks="AUDIO_CHANNEL_IN_MONO AUDIO_CHANNEL_IN_STEREO"/>
+                </mixPort>
+                <mixPort name="built-in mic" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_32_BIT"
+                             samplingRates="16000"
+                             channelMasks="AUDIO_CHANNEL_IN_MONO AUDIO_CHANNEL_IN_STEREO"/>
+                </mixPort>
+                <mixPort name="ble_in" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="16000" channelMasks="AUDIO_CHANNEL_IN_MONO"/>
+                </mixPort>
+            </mixPorts>
+            <devicePorts>
+                <!-- Output devices declaration, i.e. Sink DEVICE PORT -->
+                <devicePort tagName="Speaker" role="sink" type="AUDIO_DEVICE_OUT_SPEAKER">
+                    <gains>
+                        <gain name="gain_1" mode="AUDIO_GAIN_MODE_JOINT"
+                              minValueMB="-10000"
+                              maxValueMB="0"
+                              defaultValueMB="-6000"
+                              stepValueMB="100"/>
+                    </gains>
+                </devicePort>
+                <devicePort tagName="HDMI Out" type="AUDIO_DEVICE_OUT_AUX_DIGITAL" role="sink">
+                </devicePort>
+                <devicePort tagName="Tuner" role="source" type="AUDIO_DEVICE_IN_TV_TUNER">
+                    <gains>
+                        <gain name="gain_1" mode="AUDIO_GAIN_MODE_JOINT"
+                              minValueMB="-10000"
+                              maxValueMB="0"
+                              defaultValueMB="-6000"
+                              stepValueMB="100"/>
+                    </gains>
+                </devicePort>
+                <devicePort tagName="Wired Headset" type="AUDIO_DEVICE_OUT_WIRED_HEADSET" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="48000" channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
+                </devicePort>
+                <devicePort tagName="Wired Headphones" type="AUDIO_DEVICE_OUT_WIRED_HEADPHONE" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="48000" channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
+                </devicePort>
+                <devicePort tagName="BT SCO" type="AUDIO_DEVICE_OUT_BLUETOOTH_SCO" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="8000 16000" channelMasks="AUDIO_CHANNEL_OUT_MONO"/>
+                </devicePort>
+                <devicePort tagName="BT SCO Headset" type="AUDIO_DEVICE_OUT_BLUETOOTH_SCO_HEADSET" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="8000 16000" channelMasks="AUDIO_CHANNEL_OUT_MONO"/>
+                </devicePort>
+                <devicePort tagName="BT A2DP Out" type="AUDIO_DEVICE_OUT_BLUETOOTH_A2DP" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="44100"
+                             channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
+                </devicePort>
+                <devicePort tagName="BT A2DP Headphones" type="AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="44100"
+                             channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
+                </devicePort>
+                <devicePort tagName="BT A2DP Speaker" type="AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER" role="sink">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="44100"
+                             channelMasks="AUDIO_CHANNEL_OUT_STEREO"/>
+                </devicePort>
+
+                <devicePort tagName="Built-In Mic" type="AUDIO_DEVICE_IN_BUILTIN_MIC" role="source" address="top">
+                    <profile name="" format="AUDIO_FORMAT_PCM_32_BIT"
+                             samplingRates="8000 11025 12000 16000 22050 24000 32000 44100 48000"
+                             channelMasks="AUDIO_CHANNEL_IN_MONO AUDIO_CHANNEL_IN_STEREO AUDIO_CHANNEL_IN_FRONT_BACK"/>
+                </devicePort>
+                <devicePort tagName="Built-In Back Mic" type="AUDIO_DEVICE_IN_BACK_MIC" role="source">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="8000 11025 12000 16000 22050 24000 32000 44100 48000"
+                             channelMasks="AUDIO_CHANNEL_IN_MONO AUDIO_CHANNEL_IN_STEREO AUDIO_CHANNEL_IN_FRONT_BACK"/>
+                </devicePort>
+                <devicePort tagName="Wired Headset Mic" type="AUDIO_DEVICE_IN_WIRED_HEADSET" role="source">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="8000 11025 12000 16000 22050 24000 32000 44100 48000"
+                             channelMasks="AUDIO_CHANNEL_IN_MONO AUDIO_CHANNEL_IN_STEREO AUDIO_CHANNEL_IN_FRONT_BACK"/>
+                </devicePort>
+                <devicePort tagName="BT SCO Headset Mic" type="AUDIO_DEVICE_IN_BLUETOOTH_SCO_HEADSET" role="source">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="8000 16000" channelMasks="AUDIO_CHANNEL_IN_MONO"/>
+                </devicePort>
+                <devicePort tagName="Echo Reference" type="AUDIO_DEVICE_IN_ECHO_REFERENCE" role="source">
+                    <profile name="echo_reference" format="AUDIO_FORMAT_PCM_32_BIT"
+                             samplingRates="48000"
+                             channelMasks="AUDIO_CHANNEL_IN_STEREO"/>
+                </devicePort>
+                <devicePort tagName="BLE-In" type="AUDIO_DEVICE_IN_BLUETOOTH_BLE" role="source">
+                    <profile name="" format="AUDIO_FORMAT_PCM_16_BIT"
+                             samplingRates="16000" channelMasks="AUDIO_CHANNEL_IN_MONO"/>
+                </devicePort>
+            </devicePorts>
+            <!-- route declaration, i.e. list all available sources for a given sink -->
+            <routes>
+                <route type="mix" sink="HDMI Out"
+                       sources="primary output,tunnel pcm,direct output,Tuner,mmap_no_irq_out,tunnel direct output"/>
+                <route type="mix" sink="Speaker"
+                       sources="primary output,tunnel pcm,direct pcm,BT SCO Headset Mic,Tuner,mmap_no_irq_out"/>
+                <route type="mix" sink="BT SCO"
+                       sources="primary output,BT SCO Headset Mic,Tuner,mmap_no_irq_out"/>
+                <route type="mix" sink="BT SCO Headset"
+                       sources="primary output,BT SCO Headset Mic,Tuner,mmap_no_irq_out"/>
+                <route type="mix" sink="Wired Headset"
+                       sources="primary output,tunnel pcm,BT SCO Headset Mic,Tuner,mmap_no_irq_out"/>
+                <route type="mix" sink="Wired Headphones"
+                       sources="primary output,tunnel pcm,BT SCO Headset Mic,Tuner,mmap_no_irq_out"/>
+                <route type="mix" sink="primary input"
+                       sources="Built-In Back Mic,Wired Headset Mic,BT SCO Headset Mic,Tuner"/>
+                <route type="mix" sink="BT A2DP Out"
+                       sources="primary output,tunnel a2dp,direct a2dp,Tuner,mmap_no_irq_out"/>
+                <route type="mix" sink="BT A2DP Headphones"
+                       sources="primary output,tunnel a2dp,direct a2dp,Tuner,mmap_no_irq_out"/>
+                <route type="mix" sink="BT A2DP Speaker"
+                       sources="primary output,tunnel a2dp,direct a2dp,Tuner,mmap_no_irq_out"/>
+                <route type="mix" sink="echo reference"
+                       sources="Echo Reference"/>
+                <route type="mix" sink="built-in mic"
+                       sources="Built-In Mic"/>
+                <route type="mix" sink="ble_in"
+                       sources="BLE-In"/>
+            </routes>
+
+        </module>
+
+        <!-- A2dp Audio HAL -->
+        <!-- <xi:include href="a2dp_audio_policy_configuration.xml"/> -->
+
+        <!-- Usb Audio HAL -->
+        <!-- <xi:include href="usb_audio_policy_configuration.xml"/> -->
+
+        <!-- Remote Submix Audio HAL -->
+        <!-- <xi:include href="r_submix_audio_policy_configuration.xml"/> -->
+
+        <!-- Hearing aid Audio HAL -->
+        <!-- <xi:include href="hearing_aid_audio_policy_configuration.xml"/> -->
+
+        <!-- MSD Audio HAL (optional) -->
+        <!-- <xi:include href="msd_audio_policy_configuration.xml"/> -->
+
+    </modules>
+    <!-- End of Modules section -->
+
+    <!-- Volume section -->
+
+    <!-- <xi:include href="audio_policy_volumes.xml"/> -->
+    <!-- <xi:include href="default_volume_tables.xml"/> -->
+
+    <!-- End of Volume section -->
+
+    <!-- Surround Sound configuration -->
+
+    <surroundSound>
+    <!-- Each of the listed formats gets an entry in Surround Settings dialog on TV devices.
+        There must be a corresponding Java ENCODING_... constant defined in AudioFormat.java,
+        and a display name defined in AudioFormat.toDisplayName. For the formats that don't
+        need a dedicated Surrond Settings dialog entry, a subformats list has to be used. -->
+        <formats>
+            <format name="AUDIO_FORMAT_AC3" />
+            <format name="AUDIO_FORMAT_E_AC3" />
+            <format name="AUDIO_FORMAT_E_AC3_JOC" />
+            <format name="AUDIO_FORMAT_DTS" />
+        </formats>
+    </surroundSound>
+
+    <!-- End of Surround Sound configuration -->
+
+</audioPolicyConfiguration>
diff --git a/audio/core/all-versions/vts/functional/tests/generators_tests.cpp b/audio/core/all-versions/vts/functional/tests/generators_tests.cpp
index 583ff01..7caa712 100644
--- a/audio/core/all-versions/vts/functional/tests/generators_tests.cpp
+++ b/audio/core/all-versions/vts/functional/tests/generators_tests.cpp
@@ -128,5 +128,11 @@
 }
 
 // Target file names are the same for all versions, see 'HalAudioVx_0GeneratorTest.xml' test configs
+// clang-format off
 INSTANTIATE_TEST_SUITE_P(Generators, GeneratorsTest,
-                         ::testing::Values("apm_config_no_vx.xml", "apm_config_with_vx.xml"));
+                         ::testing::Values("apm_config_no_vx.xml", "apm_config_with_vx.xml"
+#if MAJOR_VERSION == 7
+                                         , "apm_config_b_204314749_7_0.xml"
+#endif
+                                           ));
+// clang-format on
diff --git a/automotive/vehicle/TEST_MAPPING b/automotive/vehicle/TEST_MAPPING
index f55016f..3696351 100644
--- a/automotive/vehicle/TEST_MAPPING
+++ b/automotive/vehicle/TEST_MAPPING
@@ -17,6 +17,9 @@
     },
     {
       "name": "FakeObd2FrameTest"
+    },
+    {
+      "name": "FakeUserHalTest"
     }
   ]
 }
diff --git a/automotive/vehicle/aidl/impl/fake_impl/hardware/Android.bp b/automotive/vehicle/aidl/impl/fake_impl/hardware/Android.bp
index 210f316..dfc2efc 100644
--- a/automotive/vehicle/aidl/impl/fake_impl/hardware/Android.bp
+++ b/automotive/vehicle/aidl/impl/fake_impl/hardware/Android.bp
@@ -34,6 +34,8 @@
     static_libs: [
         "VehicleHalUtils",
         "FakeVehicleHalValueGenerators",
+        "FakeObd2Frame",
+        "FakeUserHal",
     ],
     shared_libs: [
         "libjsoncpp",
diff --git a/automotive/vehicle/aidl/impl/fake_impl/hardware/include/FakeVehicleHardware.h b/automotive/vehicle/aidl/impl/fake_impl/hardware/include/FakeVehicleHardware.h
index b2d813f..46a526c 100644
--- a/automotive/vehicle/aidl/impl/fake_impl/hardware/include/FakeVehicleHardware.h
+++ b/automotive/vehicle/aidl/impl/fake_impl/hardware/include/FakeVehicleHardware.h
@@ -18,9 +18,12 @@
 #define android_hardware_automotive_vehicle_aidl_impl_fake_impl_hardware_include_FakeVehicleHardware_H_
 
 #include <DefaultConfig.h>
+#include <FakeObd2Frame.h>
+#include <FakeUserHal.h>
 #include <IVehicleHardware.h>
 #include <VehicleHalTypes.h>
 #include <VehiclePropertyStore.h>
+#include <android-base/result.h>
 #include <android-base/thread_annotations.h>
 
 #include <map>
@@ -85,14 +88,16 @@
     // Expose private methods to unit test.
     friend class FakeVehicleHardwareTestHelper;
 
-    std::unique_ptr<VehiclePropertyStore> mServerSidePropStore;
     // mValuePool is also used in mServerSidePropStore.
-    std::shared_ptr<VehiclePropValuePool> mValuePool;
+    const std::shared_ptr<VehiclePropValuePool> mValuePool;
+    const std::shared_ptr<VehiclePropertyStore> mServerSidePropStore;
+    const std::unique_ptr<obd2frame::FakeObd2Frame> mFakeObd2Frame;
+    const std::unique_ptr<FakeUserHal> mFakeUserHal;
     std::mutex mCallbackLock;
     OnPropertyChangeCallback mOnPropertyChangeCallback GUARDED_BY(mCallbackLock);
     OnPropertySetErrorCallback mOnPropertySetErrorCallback GUARDED_BY(mCallbackLock);
 
-    void init(std::shared_ptr<VehiclePropValuePool> valuePool);
+    void init();
     // Stores the initial value to property store.
     void storePropInitialValue(const defaultconfig::ConfigDeclaration& config);
     // The callback that would be called when a vehicle property value change happens.
@@ -104,13 +109,21 @@
     // Override the properties using config files in 'overrideDir'.
     void overrideProperties(const char* overrideDir);
 
-    ::aidl::android::hardware::automotive::vehicle::StatusCode maybeSetSpecialValue(
+    ::android::base::Result<void> maybeSetSpecialValue(
             const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value,
             bool* isSpecialValue);
-    ::aidl::android::hardware::automotive::vehicle::StatusCode setApPowerStateReport(
+    ::android::base::Result<VehiclePropValuePool::RecyclableType> maybeGetSpecialValue(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value,
+            bool* isSpecialValue) const;
+    ::android::base::Result<void> setApPowerStateReport(
             const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value);
     VehiclePropValuePool::RecyclableType createApPowerStateReq(
             ::aidl::android::hardware::automotive::vehicle::VehicleApPowerStateReq state);
+    ::android::base::Result<void> setUserHalProp(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value);
+    ::android::base::Result<VehiclePropValuePool::RecyclableType> getUserHalProp(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value) const;
+    bool isHvacPropAndHvacNotAvailable(int32_t propId);
 };
 
 }  // namespace fake
diff --git a/automotive/vehicle/aidl/impl/fake_impl/hardware/src/FakeVehicleHardware.cpp b/automotive/vehicle/aidl/impl/fake_impl/hardware/src/FakeVehicleHardware.cpp
index 94791da..104147a 100644
--- a/automotive/vehicle/aidl/impl/fake_impl/hardware/src/FakeVehicleHardware.cpp
+++ b/automotive/vehicle/aidl/impl/fake_impl/hardware/src/FakeVehicleHardware.cpp
@@ -17,7 +17,9 @@
 #include "FakeVehicleHardware.h"
 
 #include <DefaultConfig.h>
+#include <FakeObd2Frame.h>
 #include <JsonFakeValueGenerator.h>
+#include <PropertyUtils.h>
 #include <VehicleHalTypes.h>
 #include <VehicleUtils.h>
 #include <android-base/properties.h>
@@ -28,6 +30,7 @@
 #include <sys/types.h>
 #include <fstream>
 #include <regex>
+#include <unordered_set>
 #include <vector>
 
 namespace android {
@@ -53,9 +56,33 @@
 using ::aidl::android::hardware::automotive::vehicle::VehiclePropertyType;
 using ::aidl::android::hardware::automotive::vehicle::VehiclePropValue;
 
+using ::android::base::Error;
+using ::android::base::Result;
+
 const char* VENDOR_OVERRIDE_DIR = "/vendor/etc/automotive/vhaloverride/";
 const char* OVERRIDE_PROPERTY = "persist.vendor.vhal_init_value_override";
 
+template <class T>
+StatusCode getErrorCode(const Result<T>& result) {
+    if (result.ok()) {
+        return StatusCode::OK;
+    }
+    return static_cast<StatusCode>(result.error().code());
+}
+
+template <class T>
+int getIntErrorCode(const Result<T>& result) {
+    return toInt(getErrorCode(result));
+}
+
+template <class T>
+std::string getErrorMsg(const Result<T>& result) {
+    if (result.ok()) {
+        return "";
+    }
+    return result.error().message();
+}
+
 }  // namespace
 
 void FakeVehicleHardware::storePropInitialValue(const defaultconfig::ConfigDeclaration& config) {
@@ -93,32 +120,53 @@
         auto result =
                 mServerSidePropStore->writeValue(mValuePool->obtain(prop), /*updateStatus=*/true);
         if (!result.ok()) {
-            ALOGE("failed to write default config value, error: %s",
-                  result.error().message().c_str());
+            ALOGE("failed to write default config value, error: %s, status: %d",
+                  getErrorMsg(result).c_str(), getIntErrorCode(result));
         }
     }
 }
 
-FakeVehicleHardware::FakeVehicleHardware() {
-    mValuePool = std::make_shared<VehiclePropValuePool>();
-    init(mValuePool);
+FakeVehicleHardware::FakeVehicleHardware()
+    : mValuePool(new VehiclePropValuePool),
+      mServerSidePropStore(new VehiclePropertyStore(mValuePool)),
+      mFakeObd2Frame(new obd2frame::FakeObd2Frame(mServerSidePropStore)),
+      mFakeUserHal(new FakeUserHal(mValuePool)) {
+    init();
 }
 
 FakeVehicleHardware::FakeVehicleHardware(std::unique_ptr<VehiclePropValuePool> valuePool)
-    : mValuePool(std::move(valuePool)) {
-    init(mValuePool);
+    : mValuePool(std::move(valuePool)),
+      mServerSidePropStore(new VehiclePropertyStore(mValuePool)),
+      mFakeObd2Frame(new obd2frame::FakeObd2Frame(mServerSidePropStore)),
+      mFakeUserHal(new FakeUserHal(mValuePool)) {
+    init();
 }
 
-void FakeVehicleHardware::init(std::shared_ptr<VehiclePropValuePool> valuePool) {
-    mServerSidePropStore.reset(new VehiclePropertyStore(valuePool));
+void FakeVehicleHardware::init() {
     for (auto& it : defaultconfig::getDefaultConfigs()) {
         VehiclePropConfig cfg = it.config;
-        mServerSidePropStore->registerProperty(cfg);
+        VehiclePropertyStore::TokenFunction tokenFunction = nullptr;
+
+        if (cfg.prop == OBD2_FREEZE_FRAME) {
+            tokenFunction = [](const VehiclePropValue& propValue) { return propValue.timestamp; };
+        }
+
+        mServerSidePropStore->registerProperty(cfg, tokenFunction);
+        if (obd2frame::FakeObd2Frame::isDiagnosticProperty(cfg)) {
+            // Ignore storing default value for diagnostic property. They have special get/set
+            // logic.
+            continue;
+        }
         storePropInitialValue(it);
     }
 
     maybeOverrideProperties(VENDOR_OVERRIDE_DIR);
 
+    // OBD2_LIVE_FRAME and OBD2_FREEZE_FRAME must be configured in default configs.
+    mFakeObd2Frame->initObd2LiveFrame(*mServerSidePropStore->getConfig(OBD2_LIVE_FRAME).value());
+    mFakeObd2Frame->initObd2FreezeFrame(
+            *mServerSidePropStore->getConfig(OBD2_FREEZE_FRAME).value());
+
     mServerSidePropStore->setOnValueChangeCallback(
             [this](const VehiclePropValue& value) { return onValueChangeCallback(value); });
 }
@@ -140,15 +188,14 @@
     return req;
 }
 
-StatusCode FakeVehicleHardware::setApPowerStateReport(const VehiclePropValue& value) {
+Result<void> FakeVehicleHardware::setApPowerStateReport(const VehiclePropValue& value) {
     auto updatedValue = mValuePool->obtain(value);
     updatedValue->timestamp = elapsedRealtimeNano();
 
     if (auto writeResult = mServerSidePropStore->writeValue(std::move(updatedValue));
         !writeResult.ok()) {
-        ALOGE("failed to write value into property store, error: %s",
-              writeResult.error().message().c_str());
-        return StatusCode::INVALID_ARG;
+        return Error(getIntErrorCode(writeResult))
+               << "failed to write value into property store, error: " << getErrorMsg(writeResult);
     }
 
     VehiclePropValuePool::RecyclableType prop;
@@ -168,9 +215,9 @@
             if (auto writeResult =
                         mServerSidePropStore->writeValue(std::move(prop), /*updateStatus=*/true);
                 !writeResult.ok()) {
-                ALOGE("failed to write AP_POWER_STATE_REQ into property store, error: %s",
-                      writeResult.error().message().c_str());
-                return StatusCode::INTERNAL_ERROR;
+                return Error(getIntErrorCode(writeResult))
+                       << "failed to write AP_POWER_STATE_REQ into property store, error: "
+                       << getErrorMsg(writeResult);
             }
             break;
         case toInt(VehicleApPowerStateReport::DEEP_SLEEP_ENTRY):
@@ -185,27 +232,137 @@
             if (auto writeResult =
                         mServerSidePropStore->writeValue(std::move(prop), /*updateStatus=*/true);
                 !writeResult.ok()) {
-                ALOGE("failed to write AP_POWER_STATE_REQ into property store, error: %s",
-                      writeResult.error().message().c_str());
-                return StatusCode::INTERNAL_ERROR;
+                return Error(getIntErrorCode(writeResult))
+                       << "failed to write AP_POWER_STATE_REQ into property store, error: "
+                       << getErrorMsg(writeResult);
             }
             break;
         default:
             ALOGE("Unknown VehicleApPowerStateReport: %d", state);
             break;
     }
-    return StatusCode::OK;
+    return {};
 }
 
-StatusCode FakeVehicleHardware::maybeSetSpecialValue(const VehiclePropValue& value,
-                                                     bool* isSpecialValue) {
+bool FakeVehicleHardware::isHvacPropAndHvacNotAvailable(int32_t propId) {
+    std::unordered_set<int32_t> powerProps(std::begin(HVAC_POWER_PROPERTIES),
+                                           std::end(HVAC_POWER_PROPERTIES));
+    if (powerProps.count(propId)) {
+        auto hvacPowerOnResult =
+                mServerSidePropStore->readValue(toInt(VehicleProperty::HVAC_POWER_ON), HVAC_ALL);
+
+        if (hvacPowerOnResult.ok() && hvacPowerOnResult.value()->value.int32Values.size() == 1 &&
+            hvacPowerOnResult.value()->value.int32Values[0] == 0) {
+            return true;
+        }
+    }
+    return false;
+}
+
+Result<void> FakeVehicleHardware::setUserHalProp(const VehiclePropValue& value) {
+    auto result = mFakeUserHal->onSetProperty(value);
+    if (!result.ok()) {
+        return Error(getIntErrorCode(result))
+               << "onSetProperty(): HAL returned error: " << getErrorMsg(result);
+    }
+    auto& updatedValue = result.value();
+    if (updatedValue != nullptr) {
+        ALOGI("onSetProperty(): updating property returned by HAL: %s",
+              updatedValue->toString().c_str());
+        if (auto writeResult = mServerSidePropStore->writeValue(std::move(result.value()));
+            !writeResult.ok()) {
+            return Error(getIntErrorCode(writeResult))
+                   << "failed to write value into property store, error: "
+                   << getErrorMsg(writeResult);
+        }
+    }
+    return {};
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeVehicleHardware::getUserHalProp(
+        const VehiclePropValue& value) const {
+    auto propId = value.prop;
+    ALOGI("get(): getting value for prop %d from User HAL", propId);
+
+    auto result = mFakeUserHal->onGetProperty(value);
+    if (!result.ok()) {
+        return Error(getIntErrorCode(result))
+               << "get(): User HAL returned error: " << getErrorMsg(result);
+    } else {
+        auto& gotValue = result.value();
+        if (gotValue != nullptr) {
+            ALOGI("get(): User HAL returned value: %s", gotValue->toString().c_str());
+            gotValue->timestamp = elapsedRealtimeNano();
+            return result;
+        } else {
+            return Error(toInt(StatusCode::INTERNAL_ERROR))
+                   << "get(): User HAL returned null value";
+        }
+    }
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeVehicleHardware::maybeGetSpecialValue(
+        const VehiclePropValue& value, bool* isSpecialValue) const {
+    *isSpecialValue = false;
+    int32_t propId = value.prop;
+    Result<VehiclePropValuePool::RecyclableType> result;
+
+    if (mFakeUserHal->isSupported(propId)) {
+        *isSpecialValue = true;
+        return getUserHalProp(value);
+    }
+
+    switch (propId) {
+        case OBD2_FREEZE_FRAME:
+            *isSpecialValue = true;
+            result = mFakeObd2Frame->getObd2FreezeFrame(value);
+            if (result.ok()) {
+                result.value()->timestamp = elapsedRealtimeNano();
+            }
+            return result;
+        case OBD2_FREEZE_FRAME_INFO:
+            *isSpecialValue = true;
+            result = mFakeObd2Frame->getObd2DtcInfo();
+            if (result.ok()) {
+                result.value()->timestamp = elapsedRealtimeNano();
+            }
+            return result;
+        default:
+            // Do nothing.
+            break;
+    }
+
+    return nullptr;
+}
+
+Result<void> FakeVehicleHardware::maybeSetSpecialValue(const VehiclePropValue& value,
+                                                       bool* isSpecialValue) {
     *isSpecialValue = false;
     VehiclePropValuePool::RecyclableType updatedValue;
+    int32_t propId = value.prop;
 
-    switch (value.prop) {
+    if (mFakeUserHal->isSupported(propId)) {
+        *isSpecialValue = true;
+        return setUserHalProp(value);
+    }
+
+    if (isHvacPropAndHvacNotAvailable(propId)) {
+        *isSpecialValue = true;
+        return Error(toInt(StatusCode::NOT_AVAILABLE)) << "hvac not available";
+    }
+
+    switch (propId) {
         case toInt(VehicleProperty::AP_POWER_STATE_REPORT):
             *isSpecialValue = true;
             return setApPowerStateReport(value);
+        case toInt(VehicleProperty::VEHICLE_MAP_SERVICE):
+            // Placeholder for future implementation of VMS property in the default hal. For
+            // now, just returns OK; otherwise, hal clients crash with property not supported.
+            *isSpecialValue = true;
+            return {};
+        case OBD2_FREEZE_FRAME_CLEAR:
+            *isSpecialValue = true;
+            return mFakeObd2Frame->clearObd2FreezeFrames(value);
 
 #ifdef ENABLE_VENDOR_CLUSTER_PROPERTY_FOR_TESTING
         case toInt(VehicleProperty::CLUSTER_REPORT_STATE):
@@ -230,17 +387,17 @@
             updatedValue->areaId = value.areaId;
             if (auto writeResult = mServerSidePropStore->writeValue(std::move(updatedValue));
                 !writeResult.ok()) {
-                ALOGE("failed to write value into property store, error: %s",
-                      writeResult.error().message().c_str());
-                return StatusCode::INVALID_ARG;
+                return Error(getIntErrorCode(writeResult))
+                       << "failed to write value into property store, error: "
+                       << getErrorMsg(writeResult);
             }
-            return StatusCode::OK;
+            return {};
 #endif  // ENABLE_VENDOR_CLUSTER_PROPERTY_FOR_TESTING
 
         default:
             break;
     }
-    return StatusCode::OK;
+    return {};
 }
 
 StatusCode FakeVehicleHardware::setValues(FakeVehicleHardware::SetValuesCallback&& callback,
@@ -258,13 +415,14 @@
         setValueResult.status = StatusCode::OK;
 
         bool isSpecialValue = false;
-        StatusCode status = maybeSetSpecialValue(value, &isSpecialValue);
+        auto setSpecialValueResult = maybeSetSpecialValue(value, &isSpecialValue);
 
         if (isSpecialValue) {
-            if (status != StatusCode::OK) {
-                ALOGE("failed to set special value for property ID: %d, status: %d", propId,
-                      status);
-                setValueResult.status = status;
+            if (!setSpecialValueResult.ok()) {
+                ALOGE("failed to set special value for property ID: %d, error: %s, status: %d",
+                      propId, getErrorMsg(setSpecialValueResult).c_str(),
+                      getIntErrorCode(setSpecialValueResult));
+                setValueResult.status = getErrorCode(setSpecialValueResult);
             }
 
             // Special values are already handled.
@@ -279,8 +437,8 @@
         auto writeResult = mServerSidePropStore->writeValue(std::move(updatedValue));
         if (!writeResult.ok()) {
             ALOGE("failed to write value into property store, error: %s, code: %d",
-                  writeResult.error().message().c_str(), writeResult.error().code());
-            setValueResult.status = StatusCode::INVALID_ARG;
+                  getErrorMsg(writeResult).c_str(), getIntErrorCode(writeResult));
+            setValueResult.status = getErrorCode(writeResult);
         }
         results.push_back(std::move(setValueResult));
     }
@@ -296,22 +454,37 @@
                                           const std::vector<GetValueRequest>& requests) const {
     std::vector<GetValueResult> results;
     for (auto& request : requests) {
-        const VehiclePropValue* value = &request.prop;
-        ALOGD("getValues(%d)", value->prop);
+        const VehiclePropValue& value = request.prop;
+        ALOGD("getValues(%d)", value.prop);
 
-        auto readResult = mServerSidePropStore->readValue(*value);
         GetValueResult getValueResult;
         getValueResult.requestId = request.requestId;
-        if (!readResult.ok()) {
-            auto error = readResult.error();
-            if (error.code() == toInt(StatusCode::NOT_AVAILABLE)) {
-                ALOGW("%s", "value has not been set yet");
-                getValueResult.status = StatusCode::NOT_AVAILABLE;
+        bool isSpecialValue = false;
+
+        auto result = maybeGetSpecialValue(value, &isSpecialValue);
+        if (isSpecialValue) {
+            if (!result.ok()) {
+                ALOGE("failed to get special value: %d, error: %s, code: %d", value.prop,
+                      getErrorMsg(result).c_str(), getIntErrorCode(result));
+                getValueResult.status = getErrorCode(result);
             } else {
-                ALOGE("failed to get value, error: %s, code: %d", error.message().c_str(),
-                      error.code());
-                getValueResult.status = StatusCode::INVALID_ARG;
+                getValueResult.status = StatusCode::OK;
+                getValueResult.prop = *result.value();
             }
+            results.push_back(std::move(getValueResult));
+            continue;
+        }
+
+        auto readResult = mServerSidePropStore->readValue(value);
+        if (!readResult.ok()) {
+            StatusCode errorCode = getErrorCode(readResult);
+            if (errorCode == StatusCode::NOT_AVAILABLE) {
+                ALOGW("%s", "value has not been set yet");
+            } else {
+                ALOGE("failed to get value, error: %s, code: %d", getErrorMsg(readResult).c_str(),
+                      toInt(errorCode));
+            }
+            getValueResult.status = errorCode;
         } else {
             getValueResult.status = StatusCode::OK;
             getValueResult.prop = *readResult.value();
@@ -378,8 +551,8 @@
                 if (auto result = mServerSidePropStore->writeValue(std::move(propToStore),
                                                                    /*updateStatus=*/true);
                     !result.ok()) {
-                    ALOGW("failed to write vendor override properties: %d, error: %s", prop.prop,
-                          result.error().message().c_str());
+                    ALOGW("failed to write vendor override properties: %d, error: %s, code: %d",
+                          prop.prop, getErrorMsg(result).c_str(), getIntErrorCode(result));
                 }
             }
         }
diff --git a/automotive/vehicle/aidl/impl/fake_impl/hardware/test/Android.bp b/automotive/vehicle/aidl/impl/fake_impl/hardware/test/Android.bp
index 3399317..90d1516 100644
--- a/automotive/vehicle/aidl/impl/fake_impl/hardware/test/Android.bp
+++ b/automotive/vehicle/aidl/impl/fake_impl/hardware/test/Android.bp
@@ -32,6 +32,8 @@
         "VehicleHalUtils",
         "FakeVehicleHardware",
         "FakeVehicleHalValueGenerators",
+        "FakeObd2Frame",
+        "FakeUserHal",
         "libgtest",
         "libgmock",
     ],
diff --git a/automotive/vehicle/aidl/impl/fake_impl/hardware/test/FakeVehicleHardwareTest.cpp b/automotive/vehicle/aidl/impl/fake_impl/hardware/test/FakeVehicleHardwareTest.cpp
index 523214c..88834f3 100644
--- a/automotive/vehicle/aidl/impl/fake_impl/hardware/test/FakeVehicleHardwareTest.cpp
+++ b/automotive/vehicle/aidl/impl/fake_impl/hardware/test/FakeVehicleHardwareTest.cpp
@@ -17,6 +17,9 @@
 #include <FakeVehicleHardware.h>
 
 #include <DefaultConfig.h>
+#include <FakeObd2Frame.h>
+#include <FakeUserHal.h>
+#include <PropertyUtils.h>
 #include <TestPropertyUtils.h>
 
 #include <android-base/expected.h>
@@ -72,7 +75,12 @@
 
 class FakeVehicleHardwareTest : public ::testing::Test {
   protected:
-    void SetUp() override {}
+    void SetUp() override {
+        getHardware()->registerOnPropertyChangeEvent(
+                [this](const std::vector<VehiclePropValue>& values) {
+                    return onPropertyChangeEvent(values);
+                });
+    }
 
     FakeVehicleHardware* getHardware() { return &mHardware; }
 
@@ -169,6 +177,8 @@
 
     const std::vector<VehiclePropValue>& getChangedProperties() { return mChangedProperties; }
 
+    void clearChangedProperties() { mChangedProperties.clear(); }
+
     static void addSetValueRequest(std::vector<SetValueRequest>& requests,
                                    std::vector<SetValueResult>& expectedResults, int64_t requestId,
                                    const VehiclePropValue& value, StatusCode expectedStatus) {
@@ -249,6 +259,17 @@
     int64_t requestId = 1;
 
     for (auto& config : defaultconfig::getDefaultConfigs()) {
+        if (obd2frame::FakeObd2Frame::isDiagnosticProperty(config.config)) {
+            // Ignore storing default value for diagnostic property. They have special get/set
+            // logic.
+            continue;
+        }
+
+        if (FakeUserHal::isSupported(config.config.prop)) {
+            // Ignore fake user HAL properties, they have special logic for getting values.
+            continue;
+        }
+
         int propId = config.config.prop;
         if (isGlobalProp(propId)) {
             if (config.initialValue == RawPropValues{}) {
@@ -345,6 +366,7 @@
 }
 
 TEST_F(FakeVehicleHardwareTest, testRegisterOnPropertyChangeEvent) {
+    // We have already registered this callback in Setup, here we are registering again.
     getHardware()->registerOnPropertyChangeEvent(std::bind(
             &FakeVehicleHardwareTest_testRegisterOnPropertyChangeEvent_Test::onPropertyChangeEvent,
             this, std::placeholders::_1));
@@ -862,11 +884,6 @@
       public testing::WithParamInterface<SetSpecialValueTestCase> {};
 
 TEST_P(FakeVehicleHardwareSpecialValuesTest, testSetSpecialProperties) {
-    getHardware()->registerOnPropertyChangeEvent(
-            [this](const std::vector<VehiclePropValue>& values) {
-                return onPropertyChangeEvent(values);
-            });
-
     const SetSpecialValueTestCase& tc = GetParam();
 
     for (const auto& value : tc.valuesToSet) {
@@ -901,6 +918,288 @@
             return info.param.name;
         });
 
+TEST_F(FakeVehicleHardwareTest, testGetObd2FreezeFrame) {
+    int64_t timestamp = elapsedRealtimeNano();
+
+    auto result = getValue(VehiclePropValue{.prop = OBD2_FREEZE_FRAME_INFO});
+
+    ASSERT_TRUE(result.ok());
+
+    auto propValue = result.value();
+    ASSERT_GE(propValue.timestamp, timestamp);
+    ASSERT_EQ(propValue.value.int64Values.size(), static_cast<size_t>(3))
+            << "expect 3 obd2 freeze frames stored";
+
+    for (int64_t timestamp : propValue.value.int64Values) {
+        auto freezeFrameResult = getValue(VehiclePropValue{
+                .prop = OBD2_FREEZE_FRAME,
+                .value.int64Values = {timestamp},
+        });
+
+        EXPECT_TRUE(result.ok()) << "expect to get freeze frame for timestamp " << timestamp
+                                 << " ok";
+        EXPECT_GE(freezeFrameResult.value().timestamp, timestamp);
+    }
+}
+
+TEST_F(FakeVehicleHardwareTest, testClearObd2FreezeFrame) {
+    int64_t timestamp = elapsedRealtimeNano();
+
+    auto getValueResult = getValue(VehiclePropValue{.prop = OBD2_FREEZE_FRAME_INFO});
+
+    ASSERT_TRUE(getValueResult.ok());
+
+    auto propValue = getValueResult.value();
+    ASSERT_GE(propValue.timestamp, timestamp);
+    ASSERT_EQ(propValue.value.int64Values.size(), static_cast<size_t>(3))
+            << "expect 3 obd2 freeze frames stored";
+
+    // No int64Values should clear all freeze frames.
+    StatusCode status = setValue(VehiclePropValue{.prop = OBD2_FREEZE_FRAME_CLEAR});
+
+    ASSERT_EQ(status, StatusCode::OK);
+
+    getValueResult = getValue(VehiclePropValue{.prop = OBD2_FREEZE_FRAME_INFO});
+
+    ASSERT_TRUE(getValueResult.ok());
+    ASSERT_EQ(getValueResult.value().value.int64Values.size(), static_cast<size_t>(0))
+            << "expect 0 obd2 freeze frames after cleared";
+}
+
+TEST_F(FakeVehicleHardwareTest, testSetVehicleMapService) {
+    StatusCode status =
+            setValue(VehiclePropValue{.prop = toInt(VehicleProperty::VEHICLE_MAP_SERVICE)});
+
+    EXPECT_EQ(status, StatusCode::OK);
+
+    auto getValueResult =
+            getValue(VehiclePropValue{.prop = toInt(VehicleProperty::VEHICLE_MAP_SERVICE)});
+
+    EXPECT_FALSE(getValueResult.ok());
+    EXPECT_EQ(getValueResult.error(), StatusCode::NOT_AVAILABLE);
+}
+
+TEST_F(FakeVehicleHardwareTest, testGetUserPropertySetOnly) {
+    for (VehicleProperty prop : std::vector<VehicleProperty>({
+                 VehicleProperty::INITIAL_USER_INFO,
+                 VehicleProperty::SWITCH_USER,
+                 VehicleProperty::CREATE_USER,
+                 VehicleProperty::REMOVE_USER,
+         })) {
+        auto result = getValue(VehiclePropValue{.prop = toInt(prop)});
+
+        EXPECT_FALSE(result.ok());
+        if (!result.ok()) {
+            EXPECT_EQ(result.error(), StatusCode::INVALID_ARG);
+        }
+    }
+}
+
+TEST_F(FakeVehicleHardwareTest, testGetUserIdAssoc) {
+    int32_t userIdAssocProp = toInt(VehicleProperty::USER_IDENTIFICATION_ASSOCIATION);
+
+    auto result = getValue(VehiclePropValue{.prop = userIdAssocProp});
+
+    // Default returns NOT_AVAILABLE.
+    ASSERT_FALSE(result.ok());
+    ASSERT_EQ(result.error(), StatusCode::NOT_AVAILABLE);
+
+    // This is the same example as used in User HAL Emulation doc.
+    VehiclePropValue valueToSet = {
+            .prop = toInt(VehicleProperty::USER_IDENTIFICATION_ASSOCIATION),
+            .areaId = 1,
+            .value.int32Values = {666, 1, 1, 2},
+    };
+
+    StatusCode status = setValue(valueToSet);
+
+    ASSERT_EQ(status, StatusCode::OK);
+
+    result = getValue(VehiclePropValue{
+            .prop = userIdAssocProp,
+            // Request ID
+            .value.int32Values = {1},
+    });
+
+    ASSERT_TRUE(result.ok());
+
+    auto& gotValue = result.value();
+    gotValue.timestamp = 0;
+
+    // Expect to get the same request ID.
+    valueToSet.value.int32Values[0] = 1;
+
+    ASSERT_EQ(gotValue, valueToSet);
+}
+
+TEST_F(FakeVehicleHardwareTest, testSwitchUser) {
+    // This is the same example as used in User HAL Emulation doc.
+    VehiclePropValue valueToSet = {
+            .prop = toInt(VehicleProperty::SWITCH_USER),
+            .areaId = 1,
+            .value.int32Values = {666, 3, 2},
+    };
+
+    StatusCode status = setValue(valueToSet);
+
+    ASSERT_EQ(status, StatusCode::OK);
+
+    // Simulate a request from Android side.
+    VehiclePropValue switchUserRequest = {
+            .prop = toInt(VehicleProperty::SWITCH_USER),
+            .areaId = 0,
+            .value.int32Values = {666, 3},
+    };
+    // Clear existing events.
+    clearChangedProperties();
+
+    status = setValue(switchUserRequest);
+
+    ASSERT_EQ(status, StatusCode::OK);
+
+    // Should generate an event for user hal response.
+    auto events = getChangedProperties();
+    ASSERT_EQ(events.size(), static_cast<size_t>(1));
+
+    events[0].timestamp = 0;
+    ASSERT_EQ(events[0], valueToSet);
+
+    // Try to get switch_user again, should return default value.
+    clearChangedProperties();
+    status = setValue(switchUserRequest);
+    ASSERT_EQ(status, StatusCode::OK);
+
+    events = getChangedProperties();
+    ASSERT_EQ(events.size(), static_cast<size_t>(1));
+    events[0].timestamp = 0;
+    ASSERT_EQ(events[0], (VehiclePropValue{
+                                 .areaId = 0,
+                                 .prop = toInt(VehicleProperty::SWITCH_USER),
+                                 .value.int32Values =
+                                         {
+                                                 // Request ID
+                                                 666,
+                                                 // VEHICLE_RESPONSE
+                                                 3,
+                                                 // SUCCESS
+                                                 1,
+                                         },
+                         }));
+}
+
+TEST_F(FakeVehicleHardwareTest, testCreateUser) {
+    // This is the same example as used in User HAL Emulation doc.
+    VehiclePropValue valueToSet = {
+            .prop = toInt(VehicleProperty::CREATE_USER),
+            .areaId = 1,
+            .value.int32Values = {666, 2},
+    };
+
+    StatusCode status = setValue(valueToSet);
+
+    ASSERT_EQ(status, StatusCode::OK);
+
+    // Simulate a request from Android side.
+    VehiclePropValue createUserRequest = {
+            .prop = toInt(VehicleProperty::CREATE_USER),
+            .areaId = 0,
+            .value.int32Values = {666},
+    };
+    // Clear existing events.
+    clearChangedProperties();
+
+    status = setValue(createUserRequest);
+
+    ASSERT_EQ(status, StatusCode::OK);
+
+    // Should generate an event for user hal response.
+    auto events = getChangedProperties();
+    ASSERT_EQ(events.size(), static_cast<size_t>(1));
+    events[0].timestamp = 0;
+    EXPECT_EQ(events[0], valueToSet);
+
+    // Try to get create_user again, should return default value.
+    clearChangedProperties();
+    status = setValue(createUserRequest);
+    ASSERT_EQ(status, StatusCode::OK);
+
+    events = getChangedProperties();
+    ASSERT_EQ(events.size(), static_cast<size_t>(1));
+    events[0].timestamp = 0;
+    ASSERT_EQ(events[0], (VehiclePropValue{
+                                 .areaId = 0,
+                                 .prop = toInt(VehicleProperty::CREATE_USER),
+                                 .value.int32Values =
+                                         {
+                                                 // Request ID
+                                                 666,
+                                                 // SUCCESS
+                                                 1,
+                                         },
+                         }));
+}
+
+TEST_F(FakeVehicleHardwareTest, testInitialUserInfo) {
+    // This is the same example as used in User HAL Emulation doc.
+    VehiclePropValue valueToSet = {
+            .prop = toInt(VehicleProperty::INITIAL_USER_INFO),
+            .areaId = 1,
+            .value.int32Values = {666, 1, 11},
+    };
+
+    StatusCode status = setValue(valueToSet);
+
+    ASSERT_EQ(status, StatusCode::OK);
+
+    // Simulate a request from Android side.
+    VehiclePropValue initialUserInfoRequest = {
+            .prop = toInt(VehicleProperty::INITIAL_USER_INFO),
+            .areaId = 0,
+            .value.int32Values = {3},
+    };
+    // Clear existing events.
+    clearChangedProperties();
+
+    status = setValue(initialUserInfoRequest);
+
+    ASSERT_EQ(status, StatusCode::OK);
+
+    // Should generate an event for user hal response.
+    auto events = getChangedProperties();
+    ASSERT_EQ(events.size(), static_cast<size_t>(1));
+    events[0].timestamp = 0;
+    EXPECT_EQ(events[0], (VehiclePropValue{
+                                 .areaId = 1,
+                                 .prop = toInt(VehicleProperty::INITIAL_USER_INFO),
+                                 .value.int32Values = {3, 1, 11},
+                         }));
+
+    // Try to get create_user again, should return default value.
+    clearChangedProperties();
+    status = setValue(initialUserInfoRequest);
+    ASSERT_EQ(status, StatusCode::OK);
+
+    events = getChangedProperties();
+    ASSERT_EQ(events.size(), static_cast<size_t>(1));
+    events[0].timestamp = 0;
+    EXPECT_EQ(events[0], (VehiclePropValue{
+                                 .areaId = 0,
+                                 .prop = toInt(VehicleProperty::INITIAL_USER_INFO),
+                                 .value.int32Values =
+                                         {
+                                                 // Request ID
+                                                 3,
+                                                 // ACTION: DEFAULT
+                                                 0,
+                                                 // User id: 0
+                                                 0,
+                                                 // Flags: 0
+                                                 0,
+                                         },
+                                 .value.stringValue = "||",
+                         }));
+}
+
 }  // namespace fake
 }  // namespace vehicle
 }  // namespace automotive
diff --git a/automotive/vehicle/aidl/impl/fake_impl/obd2frame/include/FakeObd2Frame.h b/automotive/vehicle/aidl/impl/fake_impl/obd2frame/include/FakeObd2Frame.h
index aee6866..118bb34 100644
--- a/automotive/vehicle/aidl/impl/fake_impl/obd2frame/include/FakeObd2Frame.h
+++ b/automotive/vehicle/aidl/impl/fake_impl/obd2frame/include/FakeObd2Frame.h
@@ -42,7 +42,7 @@
             const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue&
                     requestedPropValue) const;
     ::android::base::Result<VehiclePropValuePool::RecyclableType> getObd2DtcInfo() const;
-    ::aidl::android::hardware::automotive::vehicle::StatusCode clearObd2FreezeFrames(
+    ::android::base::Result<void> clearObd2FreezeFrames(
             const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& propValue);
     static bool isDiagnosticProperty(
             const ::aidl::android::hardware::automotive::vehicle::VehiclePropConfig& propConfig);
diff --git a/automotive/vehicle/aidl/impl/fake_impl/obd2frame/src/FakeObd2Frame.cpp b/automotive/vehicle/aidl/impl/fake_impl/obd2frame/src/FakeObd2Frame.cpp
index a9e865d..5585fb4 100644
--- a/automotive/vehicle/aidl/impl/fake_impl/obd2frame/src/FakeObd2Frame.cpp
+++ b/automotive/vehicle/aidl/impl/fake_impl/obd2frame/src/FakeObd2Frame.cpp
@@ -169,20 +169,21 @@
     return outValue;
 }
 
-StatusCode FakeObd2Frame::clearObd2FreezeFrames(const VehiclePropValue& propValue) {
+Result<void> FakeObd2Frame::clearObd2FreezeFrames(const VehiclePropValue& propValue) {
     if (propValue.value.int64Values.size() == 0) {
         mPropStore->removeValuesForProperty(OBD2_FREEZE_FRAME);
-        return StatusCode::OK;
+        return {};
     }
     for (int64_t timestamp : propValue.value.int64Values) {
-        auto result = mPropStore->readValue(OBD2_FREEZE_FRAME, /*area=*/0, timestamp);
+        auto result = mPropStore->readValue(OBD2_FREEZE_FRAME, 0, timestamp);
         if (!result.ok()) {
-            ALOGE("asked for OBD2_FREEZE_FRAME at invalid timestamp");
-            return StatusCode::INVALID_ARG;
+            return Error(toInt(StatusCode::INVALID_ARG))
+                   << "asked for OBD2_FREEZE_FRAME at invalid timestamp, error: %s"
+                   << result.error().message();
         }
         mPropStore->removeValue(*result.value());
     }
-    return StatusCode::OK;
+    return {};
 }
 
 bool FakeObd2Frame::isDiagnosticProperty(const VehiclePropConfig& propConfig) {
diff --git a/automotive/vehicle/aidl/impl/fake_impl/obd2frame/test/FakeObd2FrameTest.cpp b/automotive/vehicle/aidl/impl/fake_impl/obd2frame/test/FakeObd2FrameTest.cpp
index 987115a..54ec1b2 100644
--- a/automotive/vehicle/aidl/impl/fake_impl/obd2frame/test/FakeObd2FrameTest.cpp
+++ b/automotive/vehicle/aidl/impl/fake_impl/obd2frame/test/FakeObd2FrameTest.cpp
@@ -167,7 +167,7 @@
     ASSERT_EQ(result.value()->prop, OBD2_FREEZE_FRAME_INFO);
     ASSERT_EQ(result.value()->value.int64Values.size(), static_cast<size_t>(3));
 
-    getFakeObd2Frame()->clearObd2FreezeFrames(VehiclePropValue{});
+    ASSERT_TRUE(getFakeObd2Frame()->clearObd2FreezeFrames(VehiclePropValue{}).ok());
 
     result = getFakeObd2Frame()->getObd2DtcInfo();
 
@@ -185,9 +185,11 @@
     ASSERT_EQ(result.value()->prop, OBD2_FREEZE_FRAME_INFO);
     ASSERT_EQ(result.value()->value.int64Values.size(), static_cast<size_t>(3));
 
-    getFakeObd2Frame()->clearObd2FreezeFrames(
-            VehiclePropValue{.value.int64Values = {result.value()->value.int64Values[0],
-                                                   result.value()->value.int64Values[1]}});
+    ASSERT_TRUE(getFakeObd2Frame()
+                        ->clearObd2FreezeFrames(VehiclePropValue{
+                                .value.int64Values = {result.value()->value.int64Values[0],
+                                                      result.value()->value.int64Values[1]}})
+                        .ok());
 
     result = getFakeObd2Frame()->getObd2DtcInfo();
 
diff --git a/automotive/vehicle/aidl/impl/fake_impl/userhal/Android.bp b/automotive/vehicle/aidl/impl/fake_impl/userhal/Android.bp
new file mode 100644
index 0000000..2e95531
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/fake_impl/userhal/Android.bp
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+cc_library {
+    name: "FakeUserHal",
+    vendor: true,
+    srcs: ["src/*.cpp"],
+    local_include_dirs: ["include"],
+    export_include_dirs: ["include"],
+    defaults: ["VehicleHalDefaults"],
+    static_libs: [
+        "VehicleHalUtils",
+    ],
+    export_static_lib_headers: ["VehicleHalUtils"],
+}
diff --git a/automotive/vehicle/aidl/impl/fake_impl/userhal/include/FakeUserHal.h b/automotive/vehicle/aidl/impl/fake_impl/userhal/include/FakeUserHal.h
new file mode 100644
index 0000000..1424c81
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/fake_impl/userhal/include/FakeUserHal.h
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef android_hardware_automotive_vehicle_aidl_impl_fake_impl_userhal_include_FakeUserHal_H_
+#define android_hardware_automotive_vehicle_aidl_impl_fake_impl_userhal_include_FakeUserHal_H_
+
+#include <android-base/format.h>
+#include <android-base/result.h>
+#include <android-base/thread_annotations.h>
+
+#include <VehicleHalTypes.h>
+#include <VehicleObjectPool.h>
+
+#include <memory>
+#include <mutex>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+namespace fake {
+
+constexpr char kUserHalDumpOption[] = "--user-hal";
+
+// Class used to emulate a real User HAL behavior through lshal debug requests.
+class FakeUserHal final {
+  public:
+    explicit FakeUserHal(std::shared_ptr<VehiclePropValuePool> valuePool) : mValuePool(valuePool) {}
+
+    ~FakeUserHal() = default;
+
+    // Checks if the emulator can handle the property.
+    static bool isSupported(int32_t prop);
+
+    // Lets the emulator set the property.
+    //
+    // @return updated property and StatusCode
+    android::base::Result<VehiclePropValuePool::RecyclableType> onSetProperty(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value);
+
+    // Gets the property value from the emulator.
+    //
+    // @return property value and StatusCode
+    android::base::Result<VehiclePropValuePool::RecyclableType> onGetProperty(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value) const;
+
+    // Shows the User HAL emulation help.
+    std::string showDumpHelp() const;
+
+    // Dump its contents.
+    std::string dump(std::string indent) const;
+
+  private:
+    const std::shared_ptr<VehiclePropValuePool> mValuePool;
+    mutable std::mutex mLock;
+    VehiclePropValuePool::RecyclableType mInitialUserResponseFromCmd GUARDED_BY(mLock);
+    VehiclePropValuePool::RecyclableType mSwitchUserResponseFromCmd GUARDED_BY(mLock);
+    VehiclePropValuePool::RecyclableType mCreateUserResponseFromCmd GUARDED_BY(mLock);
+    VehiclePropValuePool::RecyclableType mSetUserIdentificationAssociationResponseFromCmd
+            GUARDED_BY(mLock);
+
+    // INITIAL_USER_INFO is called by Android when it starts, and it's expecting a property change
+    // indicating what the initial user should be.
+    //
+    // During normal circumstances, the emulator will reply right away, passing a response if
+    // InitialUserInfoResponseAction::DEFAULT (so Android could use its own logic to decide which
+    // user to boot).
+    //
+    // But during development / testing, the behavior can be changed using lshal dump, which must
+    // use the areaId to indicate what should happen next.
+    //
+    // So, the behavior of set(INITIAL_USER_INFO) is:
+    //
+    // - if it has an areaId, store the property into mInitialUserResponseFromCmd (as it was called
+    // by lshal).
+    // - else if mInitialUserResponseFromCmd is not set, return a response with the same request id
+    // and InitialUserInfoResponseAction::DEFAULT
+    // - else the behavior is defined by the areaId on mInitialUserResponseFromCmd:
+    // - if it's 1, reply with mInitialUserResponseFromCmd and the right request id
+    // - if it's 2, reply with mInitialUserResponseFromCmd but a wrong request id (so Android can
+    // test this error scenario)
+    // - if it's 3, then don't send a property change (so Android can emulate a timeout)
+    android::base::Result<VehiclePropValuePool::RecyclableType> onSetInitialUserInfoResponse(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value);
+
+    // Used to emulate SWITCH_USER - see onSetInitialUserInfoResponse() for usage.
+    android::base::Result<VehiclePropValuePool::RecyclableType> onSetSwitchUserResponse(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value);
+
+    // Used to emulate CREATE_USER - see onSetInitialUserInfoResponse() for usage.
+    android::base::Result<VehiclePropValuePool::RecyclableType> onSetCreateUserResponse(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value);
+
+    // Used to emulate set USER_IDENTIFICATION_ASSOCIATION - see onSetInitialUserInfoResponse() for
+    // usage.
+    android::base::Result<VehiclePropValuePool::RecyclableType> onSetUserIdentificationAssociation(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value);
+
+    // Used to emulate get USER_IDENTIFICATION_ASSOCIATION - see onSetInitialUserInfoResponse() for
+    // usage.
+    android::base::Result<VehiclePropValuePool::RecyclableType> onGetUserIdentificationAssociation(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value) const;
+
+    // Creates a default USER_IDENTIFICATION_ASSOCIATION when it was not set by lshal.
+    static android::base::Result<VehiclePropValuePool::RecyclableType>
+    defaultUserIdentificationAssociation(
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& request);
+
+    android::base::Result<VehiclePropValuePool::RecyclableType> sendUserHalResponse(
+            VehiclePropValuePool::RecyclableType response, int32_t requestId);
+};
+
+}  // namespace fake
+}  // namespace vehicle
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android
+
+#endif  // android_hardware_automotive_vehicle_aidl_impl_fake_impl_userhal_include_FakeUserHal_H_
diff --git a/automotive/vehicle/aidl/impl/fake_impl/userhal/include/UserHalHelper.h b/automotive/vehicle/aidl/impl/fake_impl/userhal/include/UserHalHelper.h
new file mode 100644
index 0000000..5be13be
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/fake_impl/userhal/include/UserHalHelper.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef android_hardware_automotive_vehicle_aidl_impl_fake_impl_userhal_include_UserHalHelper_H_
+#define android_hardware_automotive_vehicle_aidl_impl_fake_impl_userhal_include_UserHalHelper_H_
+
+#include <UserHalTypes.h>
+#include <VehicleHalTypes.h>
+#include <VehicleObjectPool.h>
+#include <android-base/result.h>
+
+#include <functional>
+#include <memory>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+namespace fake {
+namespace user_hal_helper {
+
+// Verify whether the |value| can be casted to the type |T| and return the casted value on success.
+// Otherwise, return the error.
+template <typename T>
+::android::base::Result<T> verifyAndCast(int32_t value);
+
+// Below functions parse VehiclePropValues to the respective User HAL request structs. On success,
+// these functions return the User HAL struct. Otherwise, they return the error.
+::android::base::Result<::aidl::android::hardware::automotive::vehicle::InitialUserInfoRequest>
+toInitialUserInfoRequest(
+        const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& propValue);
+::android::base::Result<::aidl::android::hardware::automotive::vehicle::SwitchUserRequest>
+toSwitchUserRequest(
+        const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& propValue);
+::android::base::Result<::aidl::android::hardware::automotive::vehicle::CreateUserRequest>
+toCreateUserRequest(
+        const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& propValue);
+::android::base::Result<::aidl::android::hardware::automotive::vehicle::RemoveUserRequest>
+toRemoveUserRequest(
+        const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& propValue);
+::android::base::Result<
+        ::aidl::android::hardware::automotive::vehicle::UserIdentificationGetRequest>
+toUserIdentificationGetRequest(
+        const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& propValue);
+::android::base::Result<
+        ::aidl::android::hardware::automotive::vehicle::UserIdentificationSetRequest>
+toUserIdentificationSetRequest(
+        const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& propValue);
+
+// Below functions convert the User HAL structs to VehiclePropValues. On success, these functions
+// return the pointer to VehiclePropValue. Otherwise, they return the error.
+::android::base::Result<VehiclePropValuePool::RecyclableType> toVehiclePropValue(
+        VehiclePropValuePool& pool,
+        const ::aidl::android::hardware::automotive::vehicle::SwitchUserRequest& request);
+VehiclePropValuePool::RecyclableType toVehiclePropValue(
+        VehiclePropValuePool& pool,
+        const ::aidl::android::hardware::automotive::vehicle::InitialUserInfoResponse& response);
+VehiclePropValuePool::RecyclableType toVehiclePropValue(
+        VehiclePropValuePool& pool,
+        const ::aidl::android::hardware::automotive::vehicle::SwitchUserResponse& response);
+VehiclePropValuePool::RecyclableType toVehiclePropValue(
+        VehiclePropValuePool& pool,
+        const ::aidl::android::hardware::automotive::vehicle::CreateUserResponse& response);
+VehiclePropValuePool::RecyclableType toVehiclePropValue(
+        VehiclePropValuePool& pool,
+        const ::aidl::android::hardware::automotive::vehicle::UserIdentificationResponse& response);
+
+}  // namespace user_hal_helper
+}  // namespace fake
+}  // namespace vehicle
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android
+
+#endif  // android_hardware_automotive_vehicle_aidl_impl_fake_impl_userhal_include_UserHalHelper_H_
diff --git a/automotive/vehicle/aidl/impl/fake_impl/userhal/include/UserHalTypes.h b/automotive/vehicle/aidl/impl/fake_impl/userhal/include/UserHalTypes.h
new file mode 100644
index 0000000..b5e17b3
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/fake_impl/userhal/include/UserHalTypes.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef android_hardware_automotive_vehicle_aidl_impl_fake_impl_userhal_include_UserHalTypes_H_
+#define android_hardware_automotive_vehicle_aidl_impl_fake_impl_userhal_include_UserHalTypes_H_
+
+#include <aidl/android/hardware/automotive/vehicle/CreateUserRequest.h>
+#include <aidl/android/hardware/automotive/vehicle/CreateUserResponse.h>
+#include <aidl/android/hardware/automotive/vehicle/CreateUserStatus.h>
+#include <aidl/android/hardware/automotive/vehicle/InitialUserInfoRequest.h>
+#include <aidl/android/hardware/automotive/vehicle/InitialUserInfoRequestType.h>
+#include <aidl/android/hardware/automotive/vehicle/InitialUserInfoResponse.h>
+#include <aidl/android/hardware/automotive/vehicle/RemoveUserRequest.h>
+#include <aidl/android/hardware/automotive/vehicle/SwitchUserMessageType.h>
+#include <aidl/android/hardware/automotive/vehicle/SwitchUserRequest.h>
+#include <aidl/android/hardware/automotive/vehicle/SwitchUserResponse.h>
+#include <aidl/android/hardware/automotive/vehicle/SwitchUserStatus.h>
+#include <aidl/android/hardware/automotive/vehicle/UserIdentificationGetRequest.h>
+#include <aidl/android/hardware/automotive/vehicle/UserIdentificationResponse.h>
+#include <aidl/android/hardware/automotive/vehicle/UserIdentificationSetRequest.h>
+#include <aidl/android/hardware/automotive/vehicle/UserInfo.h>
+#include <aidl/android/hardware/automotive/vehicle/UsersInfo.h>
+
+#endif  // android_hardware_automotive_vehicle_aidl_impl_fake_impl_userhal_include_UserHalTypes_H_
diff --git a/automotive/vehicle/aidl/impl/fake_impl/userhal/src/FakeUserHal.cpp b/automotive/vehicle/aidl/impl/fake_impl/userhal/src/FakeUserHal.cpp
new file mode 100644
index 0000000..9b60053
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/fake_impl/userhal/src/FakeUserHal.cpp
@@ -0,0 +1,374 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#define LOG_TAG "FakeUserHal"
+
+#include "FakeUserHal.h"
+
+#include "UserHalHelper.h"
+
+#include <VehicleUtils.h>
+#include <utils/Log.h>
+#include <utils/SystemClock.h>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+namespace fake {
+
+namespace {
+
+using ::aidl::android::hardware::automotive::vehicle::CreateUserResponse;
+using ::aidl::android::hardware::automotive::vehicle::CreateUserStatus;
+using ::aidl::android::hardware::automotive::vehicle::InitialUserInfoResponse;
+using ::aidl::android::hardware::automotive::vehicle::InitialUserInfoResponseAction;
+using ::aidl::android::hardware::automotive::vehicle::StatusCode;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserMessageType;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserResponse;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserStatus;
+using ::aidl::android::hardware::automotive::vehicle::VehicleProperty;
+using ::aidl::android::hardware::automotive::vehicle::VehiclePropValue;
+using ::android::base::Error;
+using ::android::base::Result;
+
+constexpr int32_t INITIAL_USER_INFO = toInt(VehicleProperty::INITIAL_USER_INFO);
+constexpr int32_t SWITCH_USER = toInt(VehicleProperty::SWITCH_USER);
+constexpr int32_t CREATE_USER = toInt(VehicleProperty::CREATE_USER);
+constexpr int32_t REMOVE_USER = toInt(VehicleProperty::REMOVE_USER);
+constexpr int32_t USER_IDENTIFICATION_ASSOCIATION =
+        toInt(VehicleProperty::USER_IDENTIFICATION_ASSOCIATION);
+
+Result<int32_t> getRequestId(const VehiclePropValue& value) {
+    if (value.value.int32Values.size() < 1) {
+        return Error(toInt(StatusCode::INVALID_ARG))
+               << "no int32Values on property: " << value.toString();
+    }
+    return value.value.int32Values[0];
+}
+
+Result<SwitchUserMessageType> getSwitchUserMessageType(const VehiclePropValue& value) {
+    if (value.value.int32Values.size() < 2) {
+        return Error(toInt(StatusCode::INVALID_ARG))
+               << "missing switch user message type on property: " << value.toString();
+    }
+    return user_hal_helper::verifyAndCast<SwitchUserMessageType>(value.value.int32Values[1]);
+}
+
+}  // namespace
+
+bool FakeUserHal::isSupported(int32_t prop) {
+    switch (prop) {
+        case INITIAL_USER_INFO:
+        case SWITCH_USER:
+        case CREATE_USER:
+        case REMOVE_USER:
+        case USER_IDENTIFICATION_ASSOCIATION:
+            return true;
+        default:
+            return false;
+    }
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeUserHal::onSetProperty(
+        const VehiclePropValue& value) {
+    ALOGV("onSetProperty(): %s", value.toString().c_str());
+
+    switch (value.prop) {
+        case INITIAL_USER_INFO:
+            return onSetInitialUserInfoResponse(value);
+        case SWITCH_USER:
+            return onSetSwitchUserResponse(value);
+        case CREATE_USER:
+            return onSetCreateUserResponse(value);
+        case REMOVE_USER:
+            ALOGI("REMOVE_USER is FYI only, nothing to do...");
+            return nullptr;
+        case USER_IDENTIFICATION_ASSOCIATION:
+            return onSetUserIdentificationAssociation(value);
+        default:
+            return Error(toInt(StatusCode::INVALID_ARG))
+                   << "Unsupported property: " << value.toString();
+    }
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeUserHal::onGetProperty(
+        const VehiclePropValue& value) const {
+    ALOGV("onGetProperty(%s)", value.toString().c_str());
+    switch (value.prop) {
+        case INITIAL_USER_INFO:
+        case SWITCH_USER:
+        case CREATE_USER:
+        case REMOVE_USER:
+            ALOGE("onGetProperty(): %d is only supported on SET", value.prop);
+            return Error(toInt(StatusCode::INVALID_ARG)) << "only supported on SET";
+        case USER_IDENTIFICATION_ASSOCIATION:
+            return onGetUserIdentificationAssociation(value);
+        default:
+            ALOGE("onGetProperty(): %d is not supported", value.prop);
+            return Error(toInt(StatusCode::INVALID_ARG)) << "not supported by User HAL";
+    }
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeUserHal::onGetUserIdentificationAssociation(
+        const VehiclePropValue& value) const {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    if (mSetUserIdentificationAssociationResponseFromCmd == nullptr) {
+        return defaultUserIdentificationAssociation(value);
+    }
+    ALOGI("get(USER_IDENTIFICATION_ASSOCIATION): returning %s",
+          mSetUserIdentificationAssociationResponseFromCmd->toString().c_str());
+    auto newValue = mValuePool->obtain(*mSetUserIdentificationAssociationResponseFromCmd);
+    auto requestId = getRequestId(value);
+    if (requestId.ok()) {
+        // Must use the same requestId
+        newValue->value.int32Values[0] = *requestId;
+    } else {
+        ALOGE("get(USER_IDENTIFICATION_ASSOCIATION): no requestId on %s", value.toString().c_str());
+        return requestId.error();
+    }
+    return newValue;
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeUserHal::onSetInitialUserInfoResponse(
+        const VehiclePropValue& value) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    auto requestId = getRequestId(value);
+    if (!requestId.ok()) {
+        ALOGE("Failed to get requestId on set(INITIAL_USER_INFO): %s",
+              requestId.error().message().c_str());
+        return requestId.error();
+    }
+
+    if (value.areaId != 0) {
+        ALOGD("set(INITIAL_USER_INFO) called from lshal; storing it: %s", value.toString().c_str());
+        mInitialUserResponseFromCmd = mValuePool->obtain(value);
+        return nullptr;
+    }
+
+    ALOGD("set(INITIAL_USER_INFO) called from Android: %s", value.toString().c_str());
+    if (mInitialUserResponseFromCmd != nullptr) {
+        ALOGI("replying INITIAL_USER_INFO with lshal value: %s",
+              mInitialUserResponseFromCmd->toString().c_str());
+        return sendUserHalResponse(std::move(mInitialUserResponseFromCmd), *requestId);
+    }
+
+    // Returns default response
+    auto updatedValue = user_hal_helper::toVehiclePropValue(
+            *mValuePool, InitialUserInfoResponse{
+                                 .requestId = *requestId,
+                                 .action = InitialUserInfoResponseAction::DEFAULT,
+                         });
+    ALOGI("no lshal response; replying with InitialUserInfoResponseAction::DEFAULT: %s",
+          updatedValue->toString().c_str());
+    return updatedValue;
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeUserHal::onSetSwitchUserResponse(
+        const VehiclePropValue& value) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    auto requestId = getRequestId(value);
+    if (!requestId.ok()) {
+        ALOGE("Failed to get requestId on set(SWITCH_USER): %s",
+              requestId.error().message().c_str());
+        return requestId.error();
+    }
+
+    auto messageType = getSwitchUserMessageType(value);
+    if (!messageType.ok()) {
+        ALOGE("Failed to get messageType on set(SWITCH_USER): %s",
+              messageType.error().message().c_str());
+        return messageType.error();
+    }
+
+    if (value.areaId != 0) {
+        if (*messageType == SwitchUserMessageType::VEHICLE_REQUEST) {
+            // User HAL can also request a user switch, so we need to check it first
+            ALOGD("set(SWITCH_USER) called from lshal to emulate a vehicle request: %s",
+                  value.toString().c_str());
+            return mValuePool->obtain(value);
+        }
+        // Otherwise, we store it
+        ALOGD("set(SWITCH_USER) called from lshal; storing it: %s", value.toString().c_str());
+        mSwitchUserResponseFromCmd = mValuePool->obtain(value);
+        return nullptr;
+    }
+    ALOGD("set(SWITCH_USER) called from Android: %s", value.toString().c_str());
+
+    if (mSwitchUserResponseFromCmd != nullptr) {
+        ALOGI("replying SWITCH_USER with lshal value:  %s",
+              mSwitchUserResponseFromCmd->toString().c_str());
+        return sendUserHalResponse(std::move(mSwitchUserResponseFromCmd), *requestId);
+    }
+
+    if (*messageType == SwitchUserMessageType::LEGACY_ANDROID_SWITCH ||
+        *messageType == SwitchUserMessageType::ANDROID_POST_SWITCH) {
+        ALOGI("request is %s; ignoring it", toString(*messageType).c_str());
+        return nullptr;
+    }
+
+    // Returns default response
+    auto updatedValue = user_hal_helper::toVehiclePropValue(
+            *mValuePool, SwitchUserResponse{
+                                 .requestId = *requestId,
+                                 .messageType = SwitchUserMessageType::VEHICLE_RESPONSE,
+                                 .status = SwitchUserStatus::SUCCESS,
+                         });
+    ALOGI("no lshal response; replying with VEHICLE_RESPONSE / SUCCESS: %s",
+          updatedValue->toString().c_str());
+    return updatedValue;
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeUserHal::onSetCreateUserResponse(
+        const VehiclePropValue& value) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    auto requestId = getRequestId(value);
+    if (!requestId.ok()) {
+        ALOGE("Failed to get requestId on set(CREATE_USER): %s",
+              requestId.error().message().c_str());
+        return requestId.error();
+    }
+
+    if (value.areaId != 0) {
+        ALOGD("set(CREATE_USER) called from lshal; storing it: %s", value.toString().c_str());
+        mCreateUserResponseFromCmd = mValuePool->obtain(value);
+        return nullptr;
+    }
+    ALOGD("set(CREATE_USER) called from Android: %s", value.toString().c_str());
+
+    if (mCreateUserResponseFromCmd != nullptr) {
+        ALOGI("replying CREATE_USER with lshal value:  %s",
+              mCreateUserResponseFromCmd->toString().c_str());
+        return sendUserHalResponse(std::move(mCreateUserResponseFromCmd), *requestId);
+    }
+
+    // Returns default response
+    auto updatedValue = user_hal_helper::toVehiclePropValue(
+            *mValuePool, CreateUserResponse{
+                                 .requestId = *requestId,
+                                 .status = CreateUserStatus::SUCCESS,
+                         });
+    ALOGI("no lshal response; replying with SUCCESS: %s", updatedValue->toString().c_str());
+    return updatedValue;
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeUserHal::onSetUserIdentificationAssociation(
+        const VehiclePropValue& value) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    auto requestId = getRequestId(value);
+    if (!requestId.ok()) {
+        ALOGE("Failed to get requestId on set(USER_IDENTIFICATION_ASSOCIATION): %s",
+              requestId.error().message().c_str());
+        return requestId.error();
+    }
+
+    if (value.areaId != 0) {
+        ALOGD("set(USER_IDENTIFICATION_ASSOCIATION) called from lshal; storing it: %s",
+              value.toString().c_str());
+        mSetUserIdentificationAssociationResponseFromCmd = mValuePool->obtain(value);
+        return nullptr;
+    }
+    ALOGD("set(USER_IDENTIFICATION_ASSOCIATION) called from Android: %s", value.toString().c_str());
+
+    if (mSetUserIdentificationAssociationResponseFromCmd != nullptr) {
+        ALOGI("replying USER_IDENTIFICATION_ASSOCIATION with lshal value:  %s",
+              mSetUserIdentificationAssociationResponseFromCmd->toString().c_str());
+        // Not moving response so it can be used on GET requests
+        auto copy = mValuePool->obtain(*mSetUserIdentificationAssociationResponseFromCmd);
+        return sendUserHalResponse(std::move(copy), *requestId);
+    }
+    // Returns default response
+    return defaultUserIdentificationAssociation(value);
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeUserHal::defaultUserIdentificationAssociation(
+        const VehiclePropValue& request) {
+    // TODO(b/159498909): return a response with NOT_ASSOCIATED_ANY_USER for all requested types
+    ALOGE("no lshal response for %s; replying with NOT_AVAILABLE", request.toString().c_str());
+    return Error(toInt(StatusCode::NOT_AVAILABLE)) << "not set by lshal";
+}
+
+Result<VehiclePropValuePool::RecyclableType> FakeUserHal::sendUserHalResponse(
+        VehiclePropValuePool::RecyclableType response, int32_t requestId) {
+    switch (response->areaId) {
+        case 1:
+            ALOGD("returning response with right request id");
+            response->value.int32Values[0] = requestId;
+            break;
+        case 2:
+            ALOGD("returning response with wrong request id");
+            response->value.int32Values[0] = -requestId;
+            break;
+        case 3:
+            ALOGD("not generating a property change event because of lshal prop: %s",
+                  response->toString().c_str());
+            return Error(toInt(StatusCode::NOT_AVAILABLE))
+                   << "not generating a property change event because of lshal prop: "
+                   << response->toString();
+        default:
+            ALOGE("invalid action on lshal response: %s", response->toString().c_str());
+            return Error(toInt(StatusCode::INTERNAL_ERROR))
+                   << "invalid action on lshal response: " << response->toString();
+    }
+
+    ALOGD("updating property to: %s", response->toString().c_str());
+    return response;
+}
+
+std::string FakeUserHal::showDumpHelp() const {
+    return fmt::format("{}: dumps state used for user management\n", kUserHalDumpOption);
+}
+
+std::string FakeUserHal::dump(std::string indent) const {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    std::string info;
+    if (mInitialUserResponseFromCmd != nullptr) {
+        info += fmt::format("{}InitialUserInfo response: {}\n", indent,
+                            mInitialUserResponseFromCmd->toString());
+    } else {
+        info += fmt::format("{}No InitialUserInfo response\n", indent);
+    }
+    if (mSwitchUserResponseFromCmd != nullptr) {
+        info += fmt::format("{}SwitchUser response: {}\n", indent,
+                            mSwitchUserResponseFromCmd->toString());
+    } else {
+        info += fmt::format("{}No SwitchUser response\n", indent);
+    }
+    if (mCreateUserResponseFromCmd != nullptr) {
+        info += fmt::format("{}CreateUser response: {}\n", indent,
+                            mCreateUserResponseFromCmd->toString());
+    } else {
+        info += fmt::format("{}No CreateUser response\n", indent);
+    }
+    if (mSetUserIdentificationAssociationResponseFromCmd != nullptr) {
+        info += fmt::format("{}SetUserIdentificationAssociation response: {}\n", indent,
+                            mSetUserIdentificationAssociationResponseFromCmd->toString());
+    } else {
+        info += fmt::format("{}No SetUserIdentificationAssociation response\n", indent);
+    }
+    return info;
+}
+
+}  // namespace fake
+}  // namespace vehicle
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android
diff --git a/automotive/vehicle/aidl/impl/fake_impl/userhal/src/UserHalHelper.cpp b/automotive/vehicle/aidl/impl/fake_impl/userhal/src/UserHalHelper.cpp
new file mode 100644
index 0000000..4fd93ae
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/fake_impl/userhal/src/UserHalHelper.cpp
@@ -0,0 +1,403 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "UserHalHelper"
+
+#include "UserHalHelper.h"
+
+#include <VehicleUtils.h>
+#include <log/log.h>
+#include <utils/SystemClock.h>
+
+#include <vector>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+namespace fake {
+namespace user_hal_helper {
+
+namespace {
+
+using ::aidl::android::hardware::automotive::vehicle::CreateUserRequest;
+using ::aidl::android::hardware::automotive::vehicle::CreateUserResponse;
+using ::aidl::android::hardware::automotive::vehicle::CreateUserStatus;
+using ::aidl::android::hardware::automotive::vehicle::InitialUserInfoRequest;
+using ::aidl::android::hardware::automotive::vehicle::InitialUserInfoRequestType;
+using ::aidl::android::hardware::automotive::vehicle::InitialUserInfoResponse;
+using ::aidl::android::hardware::automotive::vehicle::RemoveUserRequest;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserMessageType;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserRequest;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserResponse;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserStatus;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationAssociationSetValue;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationAssociationType;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationGetRequest;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationResponse;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationSetAssociation;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationSetRequest;
+using ::aidl::android::hardware::automotive::vehicle::UserInfo;
+using ::aidl::android::hardware::automotive::vehicle::UsersInfo;
+using ::aidl::android::hardware::automotive::vehicle::VehicleProperty;
+using ::aidl::android::hardware::automotive::vehicle::VehiclePropValue;
+using ::android::base::Error;
+using ::android::base::Result;
+
+constexpr const char kSeparator[] = "||";
+constexpr size_t kNumFieldsPerUserInfo = 2;
+constexpr size_t kNumFieldsPerSetAssociation = 2;
+
+Result<void> verifyPropValue(const VehiclePropValue& propValue, VehicleProperty vehicleProperty,
+                             size_t minInt32Values) {
+    auto prop = verifyAndCast<VehicleProperty>(propValue.prop);
+    if (!prop.ok()) {
+        return Error() << "Invalid vehicle property: " << prop.error();
+    }
+    if (*prop != vehicleProperty) {
+        return Error() << "Mismatching " << toString(vehicleProperty) << " request, received "
+                       << toString(*prop) << " property";
+    }
+    if (propValue.value.int32Values.size() < minInt32Values) {
+        return Error() << "Int32Values must have at least " << minInt32Values
+                       << " values, received " << propValue.value.int32Values.size();
+    }
+    return {};
+}
+
+Result<void> parseUserInfo(const std::vector<int32_t>& int32Values, size_t startPos,
+                           UserInfo* userInfo) {
+    if (int32Values.size() < startPos + kNumFieldsPerUserInfo) {
+        return Error() << "Int32Values must have at least " << startPos + 2 << " values, received "
+                       << int32Values.size();
+    }
+    userInfo->userId = int32Values[startPos];
+    int32_t intUserFlags = int32Values[startPos + 1];
+    const int32_t combinedFlags = UserInfo::USER_FLAG_SYSTEM | UserInfo::USER_FLAG_GUEST |
+                                  UserInfo::USER_FLAG_EPHEMERAL | UserInfo::USER_FLAG_ADMIN |
+                                  UserInfo::USER_FLAG_DISABLED | UserInfo::USER_FLAG_PROFILE;
+
+    if ((intUserFlags & ~combinedFlags) != 0) {
+        return Error() << "Invalid user flags: " << intUserFlags << ", must be '|' of UserFlags";
+    }
+    userInfo->flags = intUserFlags;
+    return {};
+}
+
+Result<void> parseUsersInfo(const std::vector<int32_t>& int32Values, size_t startPos,
+                            UsersInfo* usersInfo) {
+    if (int32Values.size() < startPos + 3) {
+        return Error() << "Int32Values must have at least " << startPos + 3 << " values, received "
+                       << int32Values.size();
+    }
+    auto ret = parseUserInfo(int32Values, startPos, &usersInfo->currentUser);
+    if (!ret.ok()) {
+        return ret;
+    }
+    usersInfo->numberUsers = int32Values[startPos + 2];
+    usersInfo->existingUsers.resize(usersInfo->numberUsers);
+    for (size_t i = 0; i < static_cast<size_t>(usersInfo->numberUsers); ++i) {
+        ret = parseUserInfo(int32Values, startPos + 3 + (kNumFieldsPerUserInfo * i),
+                            &usersInfo->existingUsers[i]);
+        if (!ret.ok()) {
+            return Error() << "Failed to parse existing user '" << i << "' info: " << ret.error();
+        }
+    }
+    return {};
+}
+
+Result<void> parseUserAssociationTypes(
+        const std::vector<int32_t>& int32Values, size_t startPos, size_t numberAssociationTypes,
+        std::vector<UserIdentificationAssociationType>* associationTypes) {
+    size_t minInt32Values = startPos + numberAssociationTypes;
+    if (int32Values.size() < minInt32Values) {
+        return Error() << "Int32Values must have at least " << minInt32Values
+                       << " values, received " << int32Values.size();
+    }
+    associationTypes->resize(numberAssociationTypes);
+    for (size_t i = 0; i < static_cast<size_t>(numberAssociationTypes); ++i) {
+        size_t pos = startPos + i;
+        auto type = verifyAndCast<UserIdentificationAssociationType>(int32Values[pos]);
+        if (!type.ok()) {
+            return Error() << "Invalid association type in query '" << i << "': " << type.error();
+        }
+        (*associationTypes)[i] = *type;
+    }
+    return {};
+}
+
+Result<void> parseUserAssociations(const std::vector<int32_t>& int32Values, size_t startPos,
+                                   size_t numberAssociations,
+                                   std::vector<UserIdentificationSetAssociation>* associations) {
+    size_t minInt32Values = startPos + (numberAssociations * kNumFieldsPerSetAssociation);
+    if (int32Values.size() < minInt32Values) {
+        return Error() << "Int32Values must have at least " << minInt32Values
+                       << " values, received " << int32Values.size();
+    }
+    associations->resize(numberAssociations);
+    for (size_t i = 0; i < static_cast<size_t>(numberAssociations); ++i) {
+        size_t pos = startPos + (kNumFieldsPerSetAssociation * i);
+        auto type = verifyAndCast<UserIdentificationAssociationType>(int32Values[pos]);
+        if (!type.ok()) {
+            return Error() << "Invalid association type in request '" << i << "': " << type.error();
+        }
+        (*associations)[i].type = *type;
+        auto value = verifyAndCast<UserIdentificationAssociationSetValue>(int32Values[pos + 1]);
+        if (!value.ok()) {
+            return Error() << "Invalid association set value in request '" << i
+                           << "': " << value.error();
+        }
+        (*associations)[i].value = *value;
+    }
+    return {};
+}
+
+}  // namespace
+
+template <typename T>
+Result<T> verifyAndCast(int32_t value) {
+    T castValue = static_cast<T>(value);
+    for (const auto& v : ::ndk::enum_range<T>()) {
+        if (castValue == v) {
+            return castValue;
+        }
+    }
+
+    return Error() << "Value " << value << " not in enum values";
+}
+
+Result<InitialUserInfoRequest> toInitialUserInfoRequest(const VehiclePropValue& propValue) {
+    auto ret = verifyPropValue(propValue, VehicleProperty::INITIAL_USER_INFO, /*minInt32Values=*/2);
+    if (!ret.ok()) {
+        return ret.error();
+    }
+    InitialUserInfoRequest request;
+    request.requestId = propValue.value.int32Values[0];
+    auto requestType = verifyAndCast<InitialUserInfoRequestType>(propValue.value.int32Values[1]);
+    if (!requestType.ok()) {
+        return Error() << "Invalid InitialUserInfoRequestType: " << requestType.error();
+    }
+    request.requestType = *requestType;
+    ret = parseUsersInfo(propValue.value.int32Values, 2, &request.usersInfo);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse users info: " << ret.error();
+    }
+    return request;
+}
+
+Result<SwitchUserRequest> toSwitchUserRequest(const VehiclePropValue& propValue) {
+    auto ret = verifyPropValue(propValue, VehicleProperty::SWITCH_USER, /*minInt32Values=*/2);
+    if (!ret.ok()) {
+        return ret.error();
+    }
+    SwitchUserRequest request;
+    auto messageType = verifyAndCast<SwitchUserMessageType>(propValue.value.int32Values[1]);
+    if (!messageType.ok()) {
+        return Error() << "Invalid SwitchUserMessageType: " << messageType.error();
+    }
+    if (*messageType != SwitchUserMessageType::LEGACY_ANDROID_SWITCH &&
+        *messageType != SwitchUserMessageType::ANDROID_SWITCH &&
+        *messageType != SwitchUserMessageType::ANDROID_POST_SWITCH) {
+        return Error() << "Invalid " << toString(*messageType)
+                       << " message type from Android System";
+    }
+    request.requestId = propValue.value.int32Values[0];
+    request.messageType = *messageType;
+    ret = parseUserInfo(propValue.value.int32Values, /*startPos=*/2, &request.targetUser);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse target user info: " << ret.error();
+    }
+    ret = parseUsersInfo(propValue.value.int32Values, /*startPos=*/4, &request.usersInfo);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse users info: " << ret.error();
+    }
+    return request;
+}
+
+Result<CreateUserRequest> toCreateUserRequest(const VehiclePropValue& propValue) {
+    auto ret = verifyPropValue(propValue, VehicleProperty::CREATE_USER, /*minInt32Values=*/1);
+    if (!ret.ok()) {
+        return ret.error();
+    }
+    CreateUserRequest request;
+    request.requestId = propValue.value.int32Values[0];
+    ret = parseUserInfo(propValue.value.int32Values, /*startPos=*/1, &request.newUserInfo);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse new user info: " << ret.error();
+    }
+    request.newUserName = propValue.value.stringValue;
+    ret = parseUsersInfo(propValue.value.int32Values, /*startPos=*/3, &request.usersInfo);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse users info: " << ret.error();
+    }
+    return request;
+}
+
+Result<RemoveUserRequest> toRemoveUserRequest(const VehiclePropValue& propValue) {
+    auto ret = verifyPropValue(propValue, VehicleProperty::REMOVE_USER, /*minInt32Values=*/1);
+    if (!ret.ok()) {
+        return ret.error();
+    }
+    RemoveUserRequest request;
+    request.requestId = propValue.value.int32Values[0];
+    ret = parseUserInfo(propValue.value.int32Values, /*startPos=*/1, &request.removedUserInfo);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse removed user info: " << ret.error();
+    }
+    ret = parseUsersInfo(propValue.value.int32Values, /*startPos=*/3, &request.usersInfo);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse users info: " << ret.error();
+    }
+    return request;
+}
+
+Result<UserIdentificationGetRequest> toUserIdentificationGetRequest(
+        const VehiclePropValue& propValue) {
+    auto ret = verifyPropValue(propValue, VehicleProperty::USER_IDENTIFICATION_ASSOCIATION,
+                               /*minInt32Values=*/4);
+    if (!ret.ok()) {
+        return ret.error();
+    }
+    UserIdentificationGetRequest request;
+    request.requestId = propValue.value.int32Values[0];
+    ret = parseUserInfo(propValue.value.int32Values, /*startPos=*/1, &request.userInfo);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse user info: " << ret.error();
+    }
+    request.numberAssociationTypes = propValue.value.int32Values[3];
+    ret = parseUserAssociationTypes(propValue.value.int32Values, 4, request.numberAssociationTypes,
+                                    &request.associationTypes);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse UserIdentificationAssociationType: " << ret.error();
+    }
+    return request;
+}
+
+Result<UserIdentificationSetRequest> toUserIdentificationSetRequest(
+        const VehiclePropValue& propValue) {
+    auto ret = verifyPropValue(propValue, VehicleProperty::USER_IDENTIFICATION_ASSOCIATION,
+                               /*minInt32Values=*/4);
+    if (!ret.ok()) {
+        return ret.error();
+    }
+    UserIdentificationSetRequest request;
+    request.requestId = propValue.value.int32Values[0];
+    ret = parseUserInfo(propValue.value.int32Values, /*startPos=*/1, &request.userInfo);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse user info: " << ret.error();
+    }
+    request.numberAssociations = propValue.value.int32Values[3];
+    ret = parseUserAssociations(propValue.value.int32Values, 4, request.numberAssociations,
+                                &request.associations);
+    if (!ret.ok()) {
+        return Error() << "Failed to parse UserIdentificationSetAssociation: " << ret.error();
+    }
+    return request;
+}
+
+Result<VehiclePropValuePool::RecyclableType> toVehiclePropValue(VehiclePropValuePool& pool,
+                                                                const SwitchUserRequest& request) {
+    if (request.messageType != SwitchUserMessageType::VEHICLE_REQUEST) {
+        return Errorf("Invalid %s message type %s from HAL",
+                      toString(VehicleProperty::SWITCH_USER).c_str(),
+                      toString(request.messageType).c_str());
+    }
+    int32_t switchUserProp = toInt(VehicleProperty::SWITCH_USER);
+    auto propValue = pool.obtain(getPropType(switchUserProp));
+    propValue->prop = switchUserProp;
+    propValue->timestamp = elapsedRealtimeNano();
+    propValue->value.int32Values.resize(3);
+    propValue->value.int32Values[0] = static_cast<int32_t>(request.requestId);
+    propValue->value.int32Values[1] = static_cast<int32_t>(request.messageType);
+    propValue->value.int32Values[2] = static_cast<int32_t>(request.targetUser.userId);
+    return propValue;
+}
+
+VehiclePropValuePool::RecyclableType toVehiclePropValue(VehiclePropValuePool& pool,
+                                                        const InitialUserInfoResponse& response) {
+    int32_t initialUserInfoProp = toInt(VehicleProperty::INITIAL_USER_INFO);
+    auto propValue = pool.obtain(getPropType(initialUserInfoProp));
+    propValue->prop = initialUserInfoProp;
+    propValue->timestamp = elapsedRealtimeNano();
+    propValue->value.int32Values.resize(4);
+    propValue->value.int32Values[0] = static_cast<int32_t>(response.requestId);
+    propValue->value.int32Values[1] = static_cast<int32_t>(response.action);
+    propValue->value.int32Values[2] = static_cast<int32_t>(response.userToSwitchOrCreate.userId);
+    propValue->value.int32Values[3] = response.userToSwitchOrCreate.flags;
+    propValue->value.stringValue = std::string(response.userLocales) + std::string(kSeparator) +
+                                   std::string(response.userNameToCreate);
+    return propValue;
+}
+
+VehiclePropValuePool::RecyclableType toVehiclePropValue(VehiclePropValuePool& pool,
+                                                        const SwitchUserResponse& response) {
+    int32_t switchUserProp = toInt(VehicleProperty::SWITCH_USER);
+    auto propValue = pool.obtain(getPropType(switchUserProp));
+    propValue->prop = switchUserProp;
+    propValue->timestamp = elapsedRealtimeNano();
+    propValue->value.int32Values.resize(3);
+    propValue->value.int32Values[0] = static_cast<int32_t>(response.requestId);
+    propValue->value.int32Values[1] = static_cast<int32_t>(response.messageType);
+    propValue->value.int32Values[2] = static_cast<int32_t>(response.status);
+    if (response.status == SwitchUserStatus::FAILURE) {
+        propValue->value.stringValue = response.errorMessage;
+    }
+    return propValue;
+}
+
+VehiclePropValuePool::RecyclableType toVehiclePropValue(VehiclePropValuePool& pool,
+                                                        const CreateUserResponse& response) {
+    int32_t createUserProp = toInt(VehicleProperty::CREATE_USER);
+    auto propValue = pool.obtain(getPropType(createUserProp));
+    propValue->prop = createUserProp;
+    propValue->timestamp = elapsedRealtimeNano();
+    propValue->value.int32Values.resize(2);
+    propValue->value.int32Values[0] = static_cast<int32_t>(response.requestId);
+    propValue->value.int32Values[1] = static_cast<int32_t>(response.status);
+    if (response.status == CreateUserStatus::FAILURE) {
+        propValue->value.stringValue = response.errorMessage;
+    }
+    return propValue;
+}
+
+VehiclePropValuePool::RecyclableType toVehiclePropValue(
+        VehiclePropValuePool& pool, const UserIdentificationResponse& response) {
+    int32_t userIdAssocProp = toInt(VehicleProperty::USER_IDENTIFICATION_ASSOCIATION);
+    auto propValue = pool.obtain(getPropType(userIdAssocProp));
+    propValue->prop = userIdAssocProp;
+    propValue->timestamp = elapsedRealtimeNano();
+    propValue->value.int32Values.resize(2 + (response.numberAssociation * 2));
+    propValue->value.int32Values[0] = static_cast<int32_t>(response.requestId);
+    propValue->value.int32Values[1] = static_cast<int32_t>(response.numberAssociation);
+    for (size_t i = 0; i < static_cast<size_t>(response.numberAssociation); ++i) {
+        size_t int32ValuesPos = 2 + (2 * i);
+        propValue->value.int32Values[int32ValuesPos] =
+                static_cast<int32_t>(response.associations[i].type);
+        propValue->value.int32Values[int32ValuesPos + 1] =
+                static_cast<int32_t>(response.associations[i].value);
+    }
+    if (!response.errorMessage.empty()) {
+        propValue->value.stringValue = response.errorMessage;
+    }
+    return propValue;
+}
+
+}  // namespace user_hal_helper
+}  // namespace fake
+}  // namespace vehicle
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android
diff --git a/automotive/vehicle/aidl/impl/fake_impl/userhal/test/Android.bp b/automotive/vehicle/aidl/impl/fake_impl/userhal/test/Android.bp
new file mode 100644
index 0000000..7d0a534
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/fake_impl/userhal/test/Android.bp
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+cc_test {
+    name: "FakeUserHalTest",
+    vendor: true,
+    srcs: ["*.cpp"],
+    defaults: ["VehicleHalDefaults"],
+    static_libs: [
+        "FakeUserHal",
+        "VehicleHalUtils",
+        "libgtest",
+        "libgmock",
+    ],
+    test_suites: ["device-tests"],
+}
diff --git a/automotive/vehicle/aidl/impl/fake_impl/userhal/test/UserHalHelper_test.cpp b/automotive/vehicle/aidl/impl/fake_impl/userhal/test/UserHalHelper_test.cpp
new file mode 100644
index 0000000..2afb2e3
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/fake_impl/userhal/test/UserHalHelper_test.cpp
@@ -0,0 +1,715 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "UserHalHelper.h"
+
+#include <VehicleUtils.h>
+#include <aidl/android/hardware/automotive/vehicle/InitialUserInfoResponseAction.h>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include <cstdint>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+namespace fake {
+namespace user_hal_helper {
+
+namespace {
+
+using ::testing::Eq;
+using ::testing::Gt;
+using ::testing::IsNull;
+using ::testing::NotNull;
+using ::testing::Pointee;
+
+using ::aidl::android::hardware::automotive::vehicle::CreateUserRequest;
+using ::aidl::android::hardware::automotive::vehicle::CreateUserResponse;
+using ::aidl::android::hardware::automotive::vehicle::CreateUserStatus;
+using ::aidl::android::hardware::automotive::vehicle::InitialUserInfoRequest;
+using ::aidl::android::hardware::automotive::vehicle::InitialUserInfoRequestType;
+using ::aidl::android::hardware::automotive::vehicle::InitialUserInfoResponse;
+using ::aidl::android::hardware::automotive::vehicle::InitialUserInfoResponseAction;
+using ::aidl::android::hardware::automotive::vehicle::RemoveUserRequest;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserMessageType;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserRequest;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserResponse;
+using ::aidl::android::hardware::automotive::vehicle::SwitchUserStatus;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationAssociationSetValue;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationAssociationType;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationAssociationValue;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationGetRequest;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationResponse;
+using ::aidl::android::hardware::automotive::vehicle::UserIdentificationSetRequest;
+using ::aidl::android::hardware::automotive::vehicle::UserInfo;
+using ::aidl::android::hardware::automotive::vehicle::VehicleProperty;
+using ::aidl::android::hardware::automotive::vehicle::VehiclePropValue;
+
+constexpr int32_t INITIAL_USER_INFO = toInt(VehicleProperty::INITIAL_USER_INFO);
+constexpr int32_t SWITCH_USER = toInt(VehicleProperty::SWITCH_USER);
+constexpr int32_t CREATE_USER = toInt(VehicleProperty::CREATE_USER);
+constexpr int32_t REMOVE_USER = toInt(VehicleProperty::REMOVE_USER);
+constexpr int32_t USER_IDENTIFICATION_ASSOCIATION =
+        toInt(VehicleProperty::USER_IDENTIFICATION_ASSOCIATION);
+
+constexpr int32_t FIRST_BOOT_AFTER_OTA = toInt(InitialUserInfoRequestType::FIRST_BOOT_AFTER_OTA);
+constexpr int32_t LEGACY_ANDROID_SWITCH = toInt(SwitchUserMessageType::LEGACY_ANDROID_SWITCH);
+constexpr int32_t VEHICLE_REQUEST = toInt(SwitchUserMessageType::VEHICLE_REQUEST);
+
+constexpr int32_t NONE_USER = 0;
+constexpr int32_t GUEST_USER = toInt(UserInfo::USER_FLAG_GUEST);
+constexpr int32_t SYSTEM_USER = toInt(UserInfo::USER_FLAG_SYSTEM);
+constexpr int32_t SYSTEM_ADMIN_USER = SYSTEM_USER | toInt(UserInfo::USER_FLAG_ADMIN);
+// 0x1111 is not a valid UserFlags combination.
+constexpr int32_t INVALID_USER_FLAG = 0x1111;
+
+constexpr int32_t USER_ID_ASSOC_KEY_FOB = toInt(UserIdentificationAssociationType::KEY_FOB);
+constexpr int32_t USER_ID_ASSOC_CUSTOM_1 = toInt(UserIdentificationAssociationType::CUSTOM_1);
+
+constexpr int32_t USER_ID_ASSOC_SET_CURRENT_USER =
+        toInt(UserIdentificationAssociationSetValue::ASSOCIATE_CURRENT_USER);
+constexpr int32_t USER_ID_ASSOC_UNSET_CURRENT_USER =
+        toInt(UserIdentificationAssociationSetValue::DISASSOCIATE_CURRENT_USER);
+
+constexpr int32_t USER_ID_ASSOC_CURRENT_USER =
+        toInt(UserIdentificationAssociationValue::ASSOCIATED_CURRENT_USER);
+constexpr int32_t USER_ID_ASSOC_NO_USER =
+        toInt(UserIdentificationAssociationValue::NOT_ASSOCIATED_ANY_USER);
+
+}  // namespace
+
+TEST(UserHalHelperTest, TestToInitialUserInfoRequest) {
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, FIRST_BOOT_AFTER_OTA, 10, NONE_USER, 2, 0, SYSTEM_USER,
+                                      10, NONE_USER}},
+    };
+    InitialUserInfoRequest expected{
+            .requestId = 23,
+            .requestType = InitialUserInfoRequestType::FIRST_BOOT_AFTER_OTA,
+            .usersInfo = {{10, 0}, 2, {{0, SYSTEM_USER}, {10, 0}}},
+    };
+
+    auto actual = toInitialUserInfoRequest(propValue);
+
+    ASSERT_TRUE(actual.ok()) << actual.error().message();
+    EXPECT_THAT(actual.value(), Eq(expected));
+}
+
+TEST(UserHalHelperTest, TestToInitialUserInfoRequestUserFlagsBitCombination) {
+    // SYSTEM_ADMIN_USER is two UserFlags combined.
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, FIRST_BOOT_AFTER_OTA, 10, NONE_USER, 2, 0,
+                                      SYSTEM_ADMIN_USER, 10, NONE_USER}},
+    };
+    InitialUserInfoRequest expected{
+            .requestId = 23,
+            .requestType = InitialUserInfoRequestType::FIRST_BOOT_AFTER_OTA,
+            .usersInfo = {{10, 0}, 2, {{0, SYSTEM_ADMIN_USER}, {10, 0}}},
+    };
+
+    auto actual = toInitialUserInfoRequest(propValue);
+
+    ASSERT_TRUE(actual.ok()) << actual.error().message();
+    EXPECT_THAT(actual.value(), Eq(expected));
+}
+
+TEST(UserHalHelperTest, TestToInitialUserInfoRequestUserInvalidUserFlag) {
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, FIRST_BOOT_AFTER_OTA, 10, NONE_USER, 2, 0,
+                                      INVALID_USER_FLAG, 10, NONE_USER}},
+    };
+
+    auto actual = toInitialUserInfoRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on invalid user flags";
+}
+
+TEST(UserHalHelperTest, TestFailsToInitialUserInfoRequestWithMismatchingPropType) {
+    VehiclePropValue propValue{
+            .prop = INT32_MAX,
+            .value = {.int32Values = {23, FIRST_BOOT_AFTER_OTA, 10, NONE_USER, 2, 0, SYSTEM_USER,
+                                      10, NONE_USER}},
+    };
+
+    auto actual = toInitialUserInfoRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on mismatching property type";
+}
+
+TEST(UserHalHelperTest, TestFailsToInitialUserInfoRequestWithInvalidRequestType) {
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, INT32_MAX, 10, NONE_USER, 2, 0, SYSTEM_USER, 10,
+                                      NONE_USER}},
+    };
+
+    auto actual = toInitialUserInfoRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on invalid request type";
+}
+
+TEST(UserHalHelperTest, TestFailsToInitialUserInfoRequestWithInvalidUserFlag) {
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, FIRST_BOOT_AFTER_OTA, 10, NONE_USER, 2, 0, SYSTEM_USER,
+                                      10, INT32_MAX}},
+    };
+
+    auto actual = toInitialUserInfoRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on invalid user flags";
+}
+
+TEST(UserHalHelperTest, TestFailsToInitialUserInfoRequestWithIncompleteUsersInfo) {
+    VehiclePropValue propValueMissingSecondUserInfo{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, FIRST_BOOT_AFTER_OTA, 10, NONE_USER, 2, 0,
+                                      SYSTEM_USER /*Missing 2nd UserInfo*/}},
+    };
+
+    auto actual = toInitialUserInfoRequest(propValueMissingSecondUserInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing second user info";
+
+    VehiclePropValue propValueMissingUsersInfo{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, FIRST_BOOT_AFTER_OTA, /*Missing UsersInfo*/}},
+    };
+
+    actual = toInitialUserInfoRequest(propValueMissingUsersInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing users info";
+}
+
+TEST(UserHalHelperTest, TestToSwitchUserRequest) {
+    VehiclePropValue propValue{
+            .prop = SWITCH_USER,
+            .value = {.int32Values = {23, LEGACY_ANDROID_SWITCH, 0, SYSTEM_USER, 10, NONE_USER, 2,
+                                      0, SYSTEM_USER, 10, NONE_USER}},
+    };
+    SwitchUserRequest expected{
+            .requestId = 23,
+            .messageType = SwitchUserMessageType::LEGACY_ANDROID_SWITCH,
+            .targetUser = {0, SYSTEM_USER},
+            .usersInfo = {{10, 0}, 2, {{0, SYSTEM_USER}, {10, 0}}},
+    };
+
+    auto actual = toSwitchUserRequest(propValue);
+
+    ASSERT_TRUE(actual.ok()) << actual.error().message();
+    EXPECT_THAT(actual.value(), Eq(expected));
+}
+
+TEST(UserHalHelperTest, TestFailsToSwitchUserRequestWithMismatchingPropType) {
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, LEGACY_ANDROID_SWITCH, 0, SYSTEM_USER, 10, NONE_USER, 2,
+                                      0, SYSTEM_USER, 10, NONE_USER}},
+    };
+
+    auto actual = toSwitchUserRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on mismatching property type";
+}
+
+TEST(UserHalHelperTest, TestFailsToSwitchUserRequestWithInvalidMessageType) {
+    VehiclePropValue propValueIncompatibleMessageType{
+            .prop = SWITCH_USER,
+            .value = {.int32Values = {23, VEHICLE_REQUEST, 0, SYSTEM_USER, 10, NONE_USER, 2, 0,
+                                      SYSTEM_USER, 10, NONE_USER}},
+    };
+
+    auto actual = toSwitchUserRequest(propValueIncompatibleMessageType);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on incompatible message type";
+
+    VehiclePropValue propValueInvalidMessageType{
+            .prop = SWITCH_USER,
+            .value = {.int32Values = {23, INT32_MAX, 0, SYSTEM_USER, 10, NONE_USER, 2, 0,
+                                      SYSTEM_USER, 10, NONE_USER}},
+    };
+
+    actual = toSwitchUserRequest(propValueInvalidMessageType);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on invalid message type";
+}
+
+TEST(UserHalHelperTest, TestFailsToSwitchUserRequestWithIncompleteUsersInfo) {
+    VehiclePropValue propValueMissingSecondUserInfo{
+            .prop = SWITCH_USER,
+            .value = {.int32Values = {23, LEGACY_ANDROID_SWITCH, 0, SYSTEM_USER, 10, NONE_USER, 2,
+                                      0, SYSTEM_USER,
+                                      /*Missing 2nd UserInfo*/}},
+    };
+
+    auto actual = toSwitchUserRequest(propValueMissingSecondUserInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing second user info";
+
+    VehiclePropValue propValueMissingUsersInfo{
+            .prop = SWITCH_USER,
+            .value = {.int32Values = {23, LEGACY_ANDROID_SWITCH, 0, SYSTEM_USER,
+                                      /*Missing UsersInfo*/}},
+    };
+
+    actual = toSwitchUserRequest(propValueMissingUsersInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing users info";
+
+    VehiclePropValue propValueMissingTargetUser{
+            .prop = SWITCH_USER,
+            .value = {.int32Values = {23, LEGACY_ANDROID_SWITCH, /*Missing target UserInfo*/}},
+    };
+
+    actual = toSwitchUserRequest(propValueMissingTargetUser);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing target user info";
+}
+
+TEST(UserHalHelperTest, TestToCreateUserRequest) {
+    VehiclePropValue propValue{
+            .prop = CREATE_USER,
+            .value = {.int32Values = {23, 11, GUEST_USER, 10, NONE_USER, 2, 0, SYSTEM_USER, 10,
+                                      NONE_USER},
+                      .stringValue = "Guest11"},
+    };
+    CreateUserRequest expected{
+            .requestId = 23,
+            .newUserInfo = {11, GUEST_USER},
+            .newUserName = "Guest11",
+            .usersInfo = {{10, 0}, 2, {{0, SYSTEM_USER}, {10, 0}}},
+    };
+
+    auto actual = toCreateUserRequest(propValue);
+
+    ASSERT_TRUE(actual.ok()) << actual.error().message();
+    EXPECT_THAT(actual.value(), Eq(expected));
+}
+
+TEST(UserHalHelperTest, TestFailsToCreateUserRequestWithMismatchingPropType) {
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, 11, GUEST_USER, 10, NONE_USER, 2, 0, SYSTEM_USER, 10,
+                                      NONE_USER},
+                      .stringValue = "Guest11"},
+    };
+
+    auto actual = toCreateUserRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on mismatching property type";
+}
+
+TEST(UserHalHelperTest, TestFailsToCreateUserRequestWithIncompleteUsersInfo) {
+    VehiclePropValue propValueMissingSecondUserInfo{
+            .prop = CREATE_USER,
+            .value = {.int32Values = {23, 11, GUEST_USER, 10, NONE_USER, 2, 0,
+                                      SYSTEM_USER /*Missing 2nd UserInfo*/},
+                      .stringValue = "Guest11"},
+    };
+
+    auto actual = toCreateUserRequest(propValueMissingSecondUserInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing second user info";
+
+    VehiclePropValue propValueMissingUsersInfo{
+            .prop = CREATE_USER,
+            .value = {.int32Values = {23, 11, GUEST_USER, /*Missing UsersInfo*/},
+                      .stringValue = "Guest11"},
+    };
+
+    actual = toCreateUserRequest(propValueMissingUsersInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing users info";
+
+    VehiclePropValue propValueMissingCreateUserInfo{
+            .prop = CREATE_USER,
+            .value = {.int32Values = {23, /*Missing create UserInfo*/}, .stringValue = "Guest11"},
+    };
+
+    actual = toCreateUserRequest(propValueMissingCreateUserInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing create user info";
+}
+
+TEST(UserHalHelperTest, TestToRemoveUserRequest) {
+    VehiclePropValue propValue{
+            .prop = REMOVE_USER,
+            .value = {.int32Values = {23, 10, NONE_USER, 10, NONE_USER, 2, 0, SYSTEM_USER, 10,
+                                      NONE_USER}},
+    };
+    RemoveUserRequest expected{
+            .requestId = 23,
+            .removedUserInfo = {10, 0},
+            .usersInfo = {{10, 0}, 2, {{0, SYSTEM_USER}, {10, 0}}},
+    };
+
+    auto actual = toRemoveUserRequest(propValue);
+
+    ASSERT_TRUE(actual.ok()) << actual.error().message();
+    EXPECT_THAT(actual.value(), Eq(expected));
+}
+
+TEST(UserHalHelperTest, TestFailsToRemoveUserRequestWithMismatchingPropType) {
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, 10, NONE_USER, 10, NONE_USER, 2, 0, SYSTEM_USER, 10,
+                                      NONE_USER}},
+    };
+
+    auto actual = toRemoveUserRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on mismatching property type";
+}
+
+TEST(UserHalHelperTest, TestFailsToRemoveUserRequestWithIncompleteUsersInfo) {
+    VehiclePropValue propValueMissingSecondUserInfo{
+            .prop = REMOVE_USER,
+            .value = {.int32Values = {23, 10, NONE_USER, 10, NONE_USER, 2, 0,
+                                      SYSTEM_USER /*Missing 2nd UserInfo*/}},
+    };
+
+    auto actual = toRemoveUserRequest(propValueMissingSecondUserInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing second user info";
+
+    VehiclePropValue propValueMissingUsersInfo{
+            .prop = REMOVE_USER,
+            .value = {.int32Values = {23, 10, NONE_USER, /*Missing UsersInfo*/}},
+    };
+
+    actual = toRemoveUserRequest(propValueMissingUsersInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing users info";
+
+    VehiclePropValue propValueMissingRemoveUserInfo{
+            .prop = REMOVE_USER,
+            .value = {.int32Values = {23, /*Missing remove UserInfo*/}},
+    };
+
+    actual = toRemoveUserRequest(propValueMissingRemoveUserInfo);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing remove user info";
+}
+
+TEST(UserHalHelperTest, TestFailsToUserIdentificationGetRequest) {
+    VehiclePropValue propValue{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 10, NONE_USER, 2, USER_ID_ASSOC_KEY_FOB,
+                                      USER_ID_ASSOC_CUSTOM_1}},
+    };
+    UserIdentificationGetRequest expected{
+            .requestId = 23,
+            .userInfo = {10, 0},
+            .numberAssociationTypes = 2,
+            .associationTypes = {UserIdentificationAssociationType::KEY_FOB,
+                                 UserIdentificationAssociationType::CUSTOM_1},
+    };
+
+    auto actual = toUserIdentificationGetRequest(propValue);
+
+    ASSERT_TRUE(actual.ok()) << actual.error().message();
+    EXPECT_THAT(actual.value(), Eq(expected));
+}
+
+TEST(UserHalHelperTest, TestFailsToUserIdentificationGetRequestWithMismatchingPropType) {
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, 10, NONE_USER, 2, USER_ID_ASSOC_KEY_FOB,
+                                      USER_ID_ASSOC_CUSTOM_1}},
+    };
+
+    auto actual = toUserIdentificationGetRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on mismatching property type";
+}
+
+TEST(UserHalHelperTest, TestFailsToUserIdentificationGetRequestWithInvalidAssociationTypes) {
+    VehiclePropValue propValue{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 10, NONE_USER, 1, INT32_MAX}},
+    };
+
+    auto actual = toUserIdentificationGetRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on invalid association type";
+}
+
+TEST(UserHalHelperTest, TestFailsToUserIdentificationGetRequestWithIncompleteAssociationTypes) {
+    VehiclePropValue propValueMissingSecondAssociationType{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 10, NONE_USER, 2,
+                                      USER_ID_ASSOC_KEY_FOB /*Missing 2nd association type*/}},
+    };
+
+    auto actual = toUserIdentificationGetRequest(propValueMissingSecondAssociationType);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing second association type";
+
+    VehiclePropValue propValueMissingNumberAssociationTypes{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 10, NONE_USER, /*Missing number association types*/}},
+    };
+
+    actual = toUserIdentificationGetRequest(propValueMissingNumberAssociationTypes);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing number association types";
+}
+
+TEST(UserHalHelperTest, TestFailsToUserIdentificationGetRequestWithMissingUserInfo) {
+    VehiclePropValue propValue{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, /*Missing user info*/}},
+    };
+
+    auto actual = toUserIdentificationGetRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing UserInfo";
+}
+
+TEST(UserHalHelperTest, TestToUserIdentificationSetRequest) {
+    VehiclePropValue propValue{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 10, NONE_USER, 2, USER_ID_ASSOC_KEY_FOB,
+                                      USER_ID_ASSOC_SET_CURRENT_USER, USER_ID_ASSOC_CUSTOM_1,
+                                      USER_ID_ASSOC_UNSET_CURRENT_USER}},
+    };
+    UserIdentificationSetRequest expected{
+            .requestId = 23,
+            .userInfo = {10, 0},
+            .numberAssociations = 2,
+            .associations = {{UserIdentificationAssociationType::KEY_FOB,
+                              UserIdentificationAssociationSetValue::ASSOCIATE_CURRENT_USER},
+                             {UserIdentificationAssociationType::CUSTOM_1,
+                              UserIdentificationAssociationSetValue::DISASSOCIATE_CURRENT_USER}},
+    };
+
+    auto actual = toUserIdentificationSetRequest(propValue);
+
+    ASSERT_TRUE(actual.ok()) << actual.error().message();
+    EXPECT_THAT(actual.value(), Eq(expected));
+}
+
+TEST(UserHalHelperTest, TestFailsToUserIdentificationSetRequestWithMismatchingPropType) {
+    VehiclePropValue propValue{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23, 10, NONE_USER, 2, USER_ID_ASSOC_KEY_FOB,
+                                      USER_ID_ASSOC_SET_CURRENT_USER, USER_ID_ASSOC_CUSTOM_1,
+                                      USER_ID_ASSOC_UNSET_CURRENT_USER}},
+    };
+
+    auto actual = toUserIdentificationSetRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on mismatching property type";
+}
+
+TEST(UserHalHelperTest, TestFailsToUserIdentificationSetRequestWithInvalidAssociations) {
+    VehiclePropValue propValueInvalidAssociationType{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 10, NONE_USER, 1, INT32_MAX,
+                                      USER_ID_ASSOC_SET_CURRENT_USER}},
+    };
+
+    auto actual = toUserIdentificationSetRequest(propValueInvalidAssociationType);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on invalid association type";
+
+    VehiclePropValue propValueInvalidAssociationValue{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 10, NONE_USER, USER_ID_ASSOC_KEY_FOB, INT32_MAX}},
+    };
+
+    actual = toUserIdentificationSetRequest(propValueInvalidAssociationValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing number association types";
+}
+
+TEST(UserHalHelperTest, TestFailsToUserIdentificationSetRequestWithIncompleteAssociations) {
+    VehiclePropValue propValueMissingSecondAssociationType{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 10, NONE_USER, 2, USER_ID_ASSOC_KEY_FOB,
+                                      USER_ID_ASSOC_SET_CURRENT_USER,
+                                      /*Missing 2nd association*/}},
+    };
+
+    auto actual = toUserIdentificationSetRequest(propValueMissingSecondAssociationType);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing second association type";
+
+    VehiclePropValue propValueMissingNumberAssociationTypes{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 10, NONE_USER, /*Missing number associations*/}},
+    };
+
+    actual = toUserIdentificationSetRequest(propValueMissingNumberAssociationTypes);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing number association types";
+}
+
+TEST(UserHalHelperTest, TestFailsToUserIdentificationSetRequestWithMissingUserInfo) {
+    VehiclePropValue propValue{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, /*Missing user info*/}},
+    };
+
+    auto actual = toUserIdentificationSetRequest(propValue);
+
+    EXPECT_FALSE(actual.ok()) << "No error returned on missing UserInfo";
+}
+
+TEST(UserHalHelperTest, TestSwitchUserRequestToVehiclePropValue) {
+    SwitchUserRequest request{
+            .requestId = 23,
+            .messageType = SwitchUserMessageType::VEHICLE_REQUEST,
+            .targetUser = {11, GUEST_USER},
+    };
+    VehiclePropValue expected{
+            .prop = SWITCH_USER,
+            .value = {.int32Values = {23,
+                                      static_cast<int32_t>(SwitchUserMessageType::VEHICLE_REQUEST),
+                                      11}},
+    };
+
+    VehiclePropValuePool pool;
+    auto result = toVehiclePropValue(pool, request);
+
+    ASSERT_TRUE(result.ok());
+    EXPECT_THAT(result.value()->timestamp, Gt(0));
+    // Don't rely on real timestamp in tests as the expected and actual objects won't have the same
+    // timestamps. Thus remove the timestamps before comparing them.
+    result.value()->timestamp = 0;
+    EXPECT_THAT(result.value(), Pointee(Eq(expected)));
+}
+
+TEST(UserHalHelperTest, TestFailsSwitchUserRequestToVehiclePropValueWithIncompatibleMessageType) {
+    SwitchUserRequest request{
+            .requestId = 23,
+            .messageType = SwitchUserMessageType::VEHICLE_RESPONSE,
+            .targetUser = {11, GUEST_USER},
+    };
+
+    VehiclePropValuePool pool;
+    auto result = toVehiclePropValue(pool, request);
+
+    EXPECT_FALSE(result.ok());
+}
+
+TEST(UserHalHelperTest, TestInitialUserInfoResponseToVehiclePropValue) {
+    InitialUserInfoResponse response{
+            .requestId = 23,
+            .action = InitialUserInfoResponseAction::CREATE,
+            .userToSwitchOrCreate = {11, GUEST_USER},
+            .userLocales = "en-US,pt-BR",
+            .userNameToCreate = "Owner",
+    };
+    VehiclePropValue expected{
+            .prop = INITIAL_USER_INFO,
+            .value = {.int32Values = {23,
+                                      static_cast<int32_t>(InitialUserInfoResponseAction::CREATE),
+                                      11, GUEST_USER},
+                      .stringValue = "en-US,pt-BR||Owner"},
+    };
+
+    VehiclePropValuePool pool;
+    auto actual = toVehiclePropValue(pool, response);
+
+    ASSERT_THAT(actual, NotNull());
+    EXPECT_THAT(actual->timestamp, Gt(0));
+    actual->timestamp = 0;
+    EXPECT_THAT(actual, Pointee(Eq(expected)));
+}
+
+TEST(UserHalHelperTest, TestSwitchUserResponseToVehiclePropValue) {
+    SwitchUserResponse response{
+            .requestId = 23,
+            .messageType = SwitchUserMessageType::VEHICLE_RESPONSE,
+            .status = SwitchUserStatus::FAILURE,
+            .errorMessage = "random error",
+    };
+    VehiclePropValue expected{
+            .prop = SWITCH_USER,
+            .value = {.int32Values = {23,
+                                      static_cast<int32_t>(SwitchUserMessageType::VEHICLE_RESPONSE),
+                                      static_cast<int32_t>(SwitchUserStatus::FAILURE)},
+                      .stringValue = "random error"},
+    };
+
+    VehiclePropValuePool pool;
+    auto actual = toVehiclePropValue(pool, response);
+
+    ASSERT_THAT(actual, NotNull());
+    EXPECT_THAT(actual->timestamp, Gt(0));
+    actual->timestamp = 0;
+    EXPECT_THAT(actual, Pointee(Eq(expected)));
+}
+
+TEST(UserHalHelperTest, TestCreateUserResponseToVehiclePropValue) {
+    CreateUserResponse response{
+            .requestId = 23,
+            .status = CreateUserStatus::FAILURE,
+            .errorMessage = "random error",
+    };
+    VehiclePropValue expected{
+            .prop = CREATE_USER,
+            .value = {.int32Values = {23, static_cast<int32_t>(CreateUserStatus::FAILURE)},
+                      .stringValue = "random error"},
+    };
+
+    VehiclePropValuePool pool;
+    auto actual = toVehiclePropValue(pool, response);
+
+    ASSERT_THAT(actual, NotNull());
+    EXPECT_THAT(actual->timestamp, Gt(0));
+    actual->timestamp = 0;
+    EXPECT_THAT(actual, Pointee(Eq(expected)));
+}
+
+TEST(UserHalHelperTest, TestUserIdentificationResponseToVehiclePropValue) {
+    UserIdentificationResponse response{
+            .requestId = 23,
+            .numberAssociation = 2,
+            .associations = {{UserIdentificationAssociationType::KEY_FOB,
+                              UserIdentificationAssociationValue::ASSOCIATED_CURRENT_USER},
+                             {UserIdentificationAssociationType::CUSTOM_1,
+                              UserIdentificationAssociationValue::NOT_ASSOCIATED_ANY_USER}},
+            .errorMessage = "random error",
+    };
+    VehiclePropValue expected{
+            .prop = USER_IDENTIFICATION_ASSOCIATION,
+            .value = {.int32Values = {23, 2, USER_ID_ASSOC_KEY_FOB, USER_ID_ASSOC_CURRENT_USER,
+                                      USER_ID_ASSOC_CUSTOM_1, USER_ID_ASSOC_NO_USER},
+                      .stringValue = "random error"},
+    };
+
+    VehiclePropValuePool pool;
+    auto actual = toVehiclePropValue(pool, response);
+
+    ASSERT_THAT(actual, NotNull());
+    EXPECT_THAT(actual->timestamp, Gt(0));
+    actual->timestamp = 0;
+    EXPECT_THAT(actual, Pointee(Eq(expected)));
+}
+
+}  // namespace user_hal_helper
+}  // namespace fake
+}  // namespace vehicle
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android
diff --git a/automotive/vehicle/aidl/impl/utils/common/include/PropertyUtils.h b/automotive/vehicle/aidl/impl/utils/common/include/PropertyUtils.h
index 441c54b..2743578 100644
--- a/automotive/vehicle/aidl/impl/utils/common/include/PropertyUtils.h
+++ b/automotive/vehicle/aidl/impl/utils/common/include/PropertyUtils.h
@@ -107,7 +107,7 @@
 constexpr int HVAC_RIGHT = SEAT_1_RIGHT | SEAT_2_RIGHT;
 constexpr int HVAC_ALL = HVAC_LEFT | HVAC_RIGHT;
 
-const int32_t kHvacPowerProperties[] = {
+const int32_t HVAC_POWER_PROPERTIES[] = {
         toInt(propertyutils_impl::VehicleProperty::HVAC_FAN_SPEED),
         toInt(propertyutils_impl::VehicleProperty::HVAC_FAN_DIRECTION),
 };
diff --git a/cas/1.0/vts/functional/OWNERS b/cas/1.0/vts/functional/OWNERS
index aec93b0..7d8c2ee 100644
--- a/cas/1.0/vts/functional/OWNERS
+++ b/cas/1.0/vts/functional/OWNERS
@@ -1,2 +1,2 @@
 # Bug component: 1344
-quxiangfang@google.com
+include ../../../1.2/vts/functional/OWNERS
diff --git a/cas/1.1/vts/functional/OWNERS b/cas/1.1/vts/functional/OWNERS
index 29246ed..7d8c2ee 100644
--- a/cas/1.1/vts/functional/OWNERS
+++ b/cas/1.1/vts/functional/OWNERS
@@ -1,3 +1,2 @@
-nchalko@google.com
-chz@google.com
-quxiangfang@google.com
+# Bug component: 1344
+include ../../../1.2/vts/functional/OWNERS
diff --git a/cas/1.2/vts/functional/OWNERS b/cas/1.2/vts/functional/OWNERS
index 29246ed..4c55752 100644
--- a/cas/1.2/vts/functional/OWNERS
+++ b/cas/1.2/vts/functional/OWNERS
@@ -1,3 +1,3 @@
-nchalko@google.com
-chz@google.com
+# Bug component: 1344
 quxiangfang@google.com
+hgchen@google.com
diff --git a/graphics/composer/aidl/android/hardware/graphics/composer3/vts/functional/VtsHalGraphicsComposer3_TargetTest.cpp b/graphics/composer/aidl/android/hardware/graphics/composer3/vts/functional/VtsHalGraphicsComposer3_TargetTest.cpp
index 2dc80fc..3fbb105 100644
--- a/graphics/composer/aidl/android/hardware/graphics/composer3/vts/functional/VtsHalGraphicsComposer3_TargetTest.cpp
+++ b/graphics/composer/aidl/android/hardware/graphics/composer3/vts/functional/VtsHalGraphicsComposer3_TargetTest.cpp
@@ -8,15 +8,18 @@
 #include <binder/ProcessState.h>
 #include <composer-vts/include/GraphicsComposerCallback.h>
 #include <gtest/gtest.h>
+#include <algorithm>
+#include <regex>
 #include <string>
 #include <thread>
+#include <unordered_map>
+#include <unordered_set>
+#include <utility>
 
 #pragma push_macro("LOG_TAG")
 #undef LOG_TAG
 #define LOG_TAG "VtsHalGraphicsComposer3_TargetTest"
 
-typedef int32_t Config;
-
 namespace aidl::android::hardware::graphics::composer3::vts {
 namespace {
 
@@ -61,8 +64,8 @@
     // returns an invalid display id (one that has not been registered to a
     // display.  Currently assuming that a device will never have close to
     // std::numeric_limit<uint64_t>::max() displays registered while running tests
-    uint64_t GetInvalidDisplayId() {
-        uint64_t id = std::numeric_limits<uint64_t>::max();
+    int64_t GetInvalidDisplayId() {
+        int64_t id = std::numeric_limits<int64_t>::max();
         while (id > 0) {
             if (std::none_of(mDisplays.begin(), mDisplays.end(),
                              [&](const VtsDisplay& display) { return id == display.get(); })) {
@@ -87,7 +90,7 @@
             std::vector<VtsDisplay> vtsDisplays;
             vtsDisplays.reserve(displays.size());
             for (int64_t display : displays) {
-                Config activeConfig;
+                int32_t activeConfig;
                 EXPECT_TRUE(mComposerClient->getActiveConfig(display, &activeConfig).isOk());
                 int32_t displayWidth;
                 EXPECT_TRUE(mComposerClient
@@ -106,6 +109,61 @@
         }
     }
 
+    // returns an invalid config id which is std::numeric_limit<int32_t>::max()
+    int32_t GetInvalidConfigId() { return IComposerClient::INVALID_CONFIGURATION; }
+
+    ndk::ScopedAStatus setActiveConfigWithConstraints(
+            VtsDisplay& display, int32_t config, const VsyncPeriodChangeConstraints& constraints,
+            VsyncPeriodChangeTimeline* timeline) {
+        auto error = mComposerClient->setActiveConfigWithConstraints(display.get(), config,
+                                                                     constraints, timeline);
+        if (error.isOk()) {
+            int32_t displayWidth;
+            EXPECT_TRUE(mComposerClient
+                                ->getDisplayAttribute(display.get(), config,
+                                                      DisplayAttribute::WIDTH, &displayWidth)
+                                .isOk());
+            int32_t displayHeight;
+            EXPECT_TRUE(mComposerClient
+                                ->getDisplayAttribute(display.get(), config,
+                                                      DisplayAttribute::HEIGHT, &displayHeight)
+                                .isOk());
+            display.setDimensions(displayWidth, displayHeight);
+        }
+        return error;
+    }
+
+    void Test_setContentTypeForDisplay(const int64_t& display,
+                                       const std::vector<ContentType>& capabilities,
+                                       const ContentType& contentType, const char* contentTypeStr) {
+        const bool contentTypeSupport = std::find(capabilities.begin(), capabilities.end(),
+                                                  contentType) != capabilities.end();
+
+        if (!contentTypeSupport) {
+            EXPECT_EQ(IComposerClient::EX_UNSUPPORTED,
+                      mComposerClient->setContentType(display, contentType)
+                              .getServiceSpecificError());
+            GTEST_SUCCEED() << contentTypeStr << " content type is not supported on display "
+                            << std::to_string(display) << ", skipping test";
+            return;
+        }
+
+        EXPECT_TRUE(mComposerClient->setContentType(display, contentType).isOk());
+        EXPECT_TRUE(mComposerClient->setContentType(display, ContentType::NONE).isOk());
+    }
+
+    void Test_setContentType(const ContentType& contentType, const char* contentTypeStr) {
+        for (const auto& display : mDisplays) {
+            std::vector<ContentType> supportedContentTypes;
+            const auto error = mComposerClient->getSupportedContentTypes(display.get(),
+                                                                         &supportedContentTypes);
+            EXPECT_TRUE(error.isOk());
+
+            Test_setContentTypeForDisplay(display.get(), supportedContentTypes, contentType,
+                                          contentTypeStr);
+        }
+    }
+
     std::shared_ptr<IComposer> mComposer;
     std::shared_ptr<IComposerClient> mComposerClient;
     int64_t mInvalidDisplayId;
@@ -129,6 +187,270 @@
     }
 }
 
+TEST_P(GraphicsComposerAidlTest, getDisplayConnectionType) {
+    DisplayConnectionType type;
+    EXPECT_FALSE(mComposerClient->getDisplayConnectionType(mInvalidDisplayId, &type).isOk());
+    for (const auto& display : mDisplays) {
+        EXPECT_TRUE(mComposerClient->getDisplayConnectionType(display.get(), &type).isOk());
+    }
+}
+
+TEST_P(GraphicsComposerAidlTest, getDisplayAttribute) {
+    for (const auto& display : mDisplays) {
+        std::vector<int32_t> configs;
+        mComposerClient->getDisplayConfigs(display.get(), &configs);
+        for (const auto& config : configs) {
+            const std::array<DisplayAttribute, 4> requiredAttributes = {{
+                    DisplayAttribute::WIDTH,
+                    DisplayAttribute::HEIGHT,
+                    DisplayAttribute::VSYNC_PERIOD,
+                    DisplayAttribute::CONFIG_GROUP,
+            }};
+            int32_t value;
+            for (const auto& attribute : requiredAttributes) {
+                EXPECT_TRUE(mComposerClient
+                                    ->getDisplayAttribute(display.get(), config, attribute, &value)
+                                    .isOk());
+                EXPECT_NE(-1, value);
+            }
+
+            const std::array<DisplayAttribute, 2> optionalAttributes = {{
+                    DisplayAttribute::DPI_X,
+                    DisplayAttribute::DPI_Y,
+            }};
+            for (const auto& attribute : optionalAttributes) {
+                const auto error = mComposerClient->getDisplayAttribute(display.get(), config,
+                                                                        attribute, &value);
+                if (error.isOk()) {
+                    EXPECT_EQ(EX_NONE, error.getServiceSpecificError());
+                } else {
+                    EXPECT_EQ(IComposerClient::EX_UNSUPPORTED, error.getServiceSpecificError());
+                }
+            }
+        }
+    }
+}
+
+TEST_P(GraphicsComposerAidlTest, checkConfigsAreValid) {
+    for (const auto& display : mDisplays) {
+        std::vector<int32_t> configs;
+        mComposerClient->getDisplayConfigs(display.get(), &configs);
+
+        EXPECT_FALSE(std::any_of(configs.begin(), configs.end(), [](auto config) {
+            return config == IComposerClient::INVALID_CONFIGURATION;
+        }));
+    }
+}
+
+TEST_P(GraphicsComposerAidlTest, getDisplayAttributeConfigsInAGroupDifferOnlyByVsyncPeriod) {
+    struct Resolution {
+        int32_t width;
+        int32_t height;
+    };
+    struct Dpi {
+        int32_t x;
+        int32_t y;
+    };
+    for (const auto& display : mDisplays) {
+        std::vector<int32_t> configs;
+        EXPECT_TRUE(mComposerClient->getDisplayConfigs(display.get(), &configs).isOk());
+        std::unordered_map<int32_t, Resolution> configGroupToResolutionMap;
+        std::unordered_map<int32_t, Dpi> configGroupToDpiMap;
+        for (const auto& config : configs) {
+            int32_t configGroup = -1;
+            EXPECT_TRUE(mComposerClient
+                                ->getDisplayAttribute(display.get(), config,
+                                                      DisplayAttribute::CONFIG_GROUP, &configGroup)
+                                .isOk());
+            int32_t width = -1;
+            EXPECT_TRUE(mComposerClient
+                                ->getDisplayAttribute(display.get(), config,
+                                                      DisplayAttribute::WIDTH, &width)
+                                .isOk());
+            int32_t height = -1;
+            EXPECT_TRUE(mComposerClient
+                                ->getDisplayAttribute(display.get(), config,
+                                                      DisplayAttribute::HEIGHT, &height)
+                                .isOk());
+            if (configGroupToResolutionMap.find(configGroup) == configGroupToResolutionMap.end()) {
+                configGroupToResolutionMap[configGroup] = {width, height};
+            }
+            EXPECT_EQ(configGroupToResolutionMap[configGroup].width, width);
+            EXPECT_EQ(configGroupToResolutionMap[configGroup].height, height);
+
+            int32_t dpiX = -1;
+            mComposerClient->getDisplayAttribute(display.get(), config, DisplayAttribute::DPI_X,
+                                                 &dpiX);
+
+            int32_t dpiY = -1;
+            mComposerClient->getDisplayAttribute(display.get(), config, DisplayAttribute::DPI_Y,
+                                                 &dpiY);
+            if (dpiX == -1 && dpiY == -1) {
+                continue;
+            }
+
+            if (configGroupToDpiMap.find(configGroup) == configGroupToDpiMap.end()) {
+                configGroupToDpiMap[configGroup] = {dpiX, dpiY};
+            }
+            EXPECT_EQ(configGroupToDpiMap[configGroup].x, dpiX);
+            EXPECT_EQ(configGroupToDpiMap[configGroup].y, dpiY);
+        }
+    }
+}
+
+TEST_P(GraphicsComposerAidlTest, getDisplayVsyncPeriod_BadDisplay) {
+    int32_t vsyncPeriodNanos;
+    const auto error = mComposerClient->getDisplayVsyncPeriod(mInvalidDisplayId, &vsyncPeriodNanos);
+    EXPECT_FALSE(error.isOk());
+    EXPECT_EQ(IComposerClient::EX_BAD_DISPLAY, error.getServiceSpecificError());
+}
+
+TEST_P(GraphicsComposerAidlTest, setActiveConfigWithConstraints_BadDisplay) {
+    VsyncPeriodChangeTimeline timeline;
+    VsyncPeriodChangeConstraints constraints;
+
+    constraints.seamlessRequired = false;
+    constraints.desiredTimeNanos = systemTime();
+    int32_t config = 0;
+    auto const error = mComposerClient->setActiveConfigWithConstraints(mInvalidDisplayId, config,
+                                                                       constraints, &timeline);
+
+    EXPECT_FALSE(error.isOk());
+    EXPECT_EQ(IComposerClient::EX_BAD_DISPLAY, error.getServiceSpecificError());
+}
+
+TEST_P(GraphicsComposerAidlTest, setActiveConfigWithConstraints_BadConfig) {
+    VsyncPeriodChangeTimeline timeline;
+    VsyncPeriodChangeConstraints constraints;
+
+    constraints.seamlessRequired = false;
+    constraints.desiredTimeNanos = systemTime();
+
+    for (VtsDisplay& display : mDisplays) {
+        int32_t invalidConfigId = GetInvalidConfigId();
+        const auto error =
+                setActiveConfigWithConstraints(display, invalidConfigId, constraints, &timeline);
+        EXPECT_FALSE(error.isOk());
+        EXPECT_EQ(IComposerClient::EX_BAD_CONFIG, error.getServiceSpecificError());
+    }
+}
+
+TEST_P(GraphicsComposerAidlTest, setAutoLowLatencyModeBadDisplay) {
+    EXPECT_EQ(IComposerClient::EX_BAD_DISPLAY,
+              mComposerClient->setAutoLowLatencyMode(mInvalidDisplayId, true)
+                      .getServiceSpecificError());
+    EXPECT_EQ(IComposerClient::EX_BAD_DISPLAY,
+              mComposerClient->setAutoLowLatencyMode(mInvalidDisplayId, false)
+                      .getServiceSpecificError());
+}
+
+TEST_P(GraphicsComposerAidlTest, setAutoLowLatencyMode) {
+    for (const auto& display : mDisplays) {
+        std::vector<DisplayCapability> capabilities;
+        const auto error = mComposerClient->getDisplayCapabilities(display.get(), &capabilities);
+        EXPECT_TRUE(error.isOk());
+
+        const bool allmSupport =
+                std::find(capabilities.begin(), capabilities.end(),
+                          DisplayCapability::AUTO_LOW_LATENCY_MODE) != capabilities.end();
+
+        if (!allmSupport) {
+            const auto errorIsOn = mComposerClient->setAutoLowLatencyMode(display.get(), true);
+            EXPECT_FALSE(errorIsOn.isOk());
+            EXPECT_EQ(IComposerClient::EX_UNSUPPORTED, errorIsOn.getServiceSpecificError());
+            const auto errorIsOff = mComposerClient->setAutoLowLatencyMode(display.get(), false);
+            EXPECT_FALSE(errorIsOff.isOk());
+            EXPECT_EQ(IComposerClient::EX_UNSUPPORTED, errorIsOff.getServiceSpecificError());
+            GTEST_SUCCEED() << "Auto Low Latency Mode is not supported on display "
+                            << std::to_string(display.get()) << ", skipping test";
+            return;
+        }
+
+        EXPECT_TRUE(mComposerClient->setAutoLowLatencyMode(display.get(), true).isOk());
+        EXPECT_TRUE(mComposerClient->setAutoLowLatencyMode(display.get(), false).isOk());
+    }
+}
+
+TEST_P(GraphicsComposerAidlTest, getSupportedContentTypesBadDisplay) {
+    std::vector<ContentType> supportedContentTypes;
+    const auto error =
+            mComposerClient->getSupportedContentTypes(mInvalidDisplayId, &supportedContentTypes);
+    EXPECT_FALSE(error.isOk());
+    EXPECT_EQ(IComposerClient::EX_BAD_DISPLAY, error.getServiceSpecificError());
+}
+
+TEST_P(GraphicsComposerAidlTest, getSupportedContentTypes) {
+    std::vector<ContentType> supportedContentTypes;
+    for (const auto& display : mDisplays) {
+        supportedContentTypes.clear();
+        const auto error =
+                mComposerClient->getSupportedContentTypes(display.get(), &supportedContentTypes);
+
+        ASSERT_TRUE(error.isOk());
+
+        const bool noneSupported =
+                std::find(supportedContentTypes.begin(), supportedContentTypes.end(),
+                          ContentType::NONE) != supportedContentTypes.end();
+        EXPECT_FALSE(noneSupported);
+    }
+}
+
+TEST_P(GraphicsComposerAidlTest, setContentTypeNoneAlwaysAccepted) {
+    for (const auto& display : mDisplays) {
+        const auto error = mComposerClient->setContentType(display.get(), ContentType::NONE);
+        EXPECT_TRUE(error.isOk());
+    }
+}
+
+TEST_P(GraphicsComposerAidlTest, setContentTypeBadDisplay) {
+    constexpr ContentType types[] = {ContentType::NONE, ContentType::GRAPHICS, ContentType::PHOTO,
+                                     ContentType::CINEMA, ContentType::GAME};
+    for (const auto& type : types) {
+        auto const error = mComposerClient->setContentType(mInvalidDisplayId, type);
+
+        EXPECT_FALSE(error.isOk());
+        EXPECT_EQ(IComposerClient::EX_BAD_DISPLAY, error.getServiceSpecificError());
+    }
+}
+
+TEST_P(GraphicsComposerAidlTest, setGraphicsContentType) {
+    Test_setContentType(ContentType::GRAPHICS, "GRAPHICS");
+}
+
+TEST_P(GraphicsComposerAidlTest, setPhotoContentType) {
+    Test_setContentType(ContentType::PHOTO, "PHOTO");
+}
+
+TEST_P(GraphicsComposerAidlTest, setCinemaContentType) {
+    Test_setContentType(ContentType::CINEMA, "CINEMA");
+}
+
+TEST_P(GraphicsComposerAidlTest, setGameContentType) {
+    Test_setContentType(ContentType::GAME, "GAME");
+}
+
+TEST_P(GraphicsComposerAidlTest, getLayerGenericMetadataKeys) {
+    std::vector<LayerGenericMetadataKey> keys;
+    EXPECT_TRUE(mComposerClient->getLayerGenericMetadataKeys(&keys).isOk());
+
+    std::regex reverseDomainName("^[a-zA-Z-]{2,}(\\.[a-zA-Z0-9-]+)+$");
+    std::unordered_set<std::string> uniqueNames;
+    for (const auto& key : keys) {
+        std::string name(key.name.c_str());
+
+        // Keys must not start with 'android' or 'com.android'
+        EXPECT_FALSE(name.find("android") == 0);
+        EXPECT_FALSE(name.find("com.android") == 0);
+
+        // Keys must be in reverse domain name format
+        EXPECT_TRUE(std::regex_match(name, reverseDomainName));
+
+        // Keys must be unique within this list
+        const auto& [iter, inserted] = uniqueNames.insert(name);
+        EXPECT_TRUE(inserted);
+    }
+}
+
 GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(GraphicsComposerAidlTest);
 INSTANTIATE_TEST_SUITE_P(
         PerInstance, GraphicsComposerAidlTest,
diff --git a/neuralnetworks/1.0/utils/Android.bp b/neuralnetworks/1.0/utils/Android.bp
index 4e35a26..31cdded 100644
--- a/neuralnetworks/1.0/utils/Android.bp
+++ b/neuralnetworks/1.0/utils/Android.bp
@@ -55,7 +55,7 @@
     static_libs: [
         "android.hardware.neuralnetworks@1.0",
         "libgmock",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
         "neuralnetworks_types",
         "neuralnetworks_utils_hal_common",
         "neuralnetworks_utils_hal_1_0",
diff --git a/neuralnetworks/1.0/vts/functional/Android.bp b/neuralnetworks/1.0/vts/functional/Android.bp
index ae9ff0a..29b31d2 100644
--- a/neuralnetworks/1.0/vts/functional/Android.bp
+++ b/neuralnetworks/1.0/vts/functional/Android.bp
@@ -50,7 +50,7 @@
         "libgmock",
         "libhidlmemory",
         "libneuralnetworks_generated_test_harness",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
     ],
     header_libs: [
         "libneuralnetworks_headers",
@@ -81,7 +81,7 @@
         "libgmock",
         "libhidlmemory",
         "libneuralnetworks_generated_test_harness",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
     ],
     whole_static_libs: [
         "neuralnetworks_generated_V1_0_example",
diff --git a/neuralnetworks/1.1/utils/Android.bp b/neuralnetworks/1.1/utils/Android.bp
index 478a742..737ff58 100644
--- a/neuralnetworks/1.1/utils/Android.bp
+++ b/neuralnetworks/1.1/utils/Android.bp
@@ -52,7 +52,7 @@
         "android.hardware.neuralnetworks@1.0",
         "android.hardware.neuralnetworks@1.1",
         "libgmock",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
         "neuralnetworks_types",
         "neuralnetworks_utils_hal_common",
         "neuralnetworks_utils_hal_1_0",
diff --git a/neuralnetworks/1.1/vts/functional/Android.bp b/neuralnetworks/1.1/vts/functional/Android.bp
index 4c57788..e9d4b76 100644
--- a/neuralnetworks/1.1/vts/functional/Android.bp
+++ b/neuralnetworks/1.1/vts/functional/Android.bp
@@ -48,7 +48,7 @@
         "libgmock",
         "libhidlmemory",
         "libneuralnetworks_generated_test_harness",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
     ],
     whole_static_libs: [
         "neuralnetworks_generated_V1_0_example",
diff --git a/neuralnetworks/1.2/utils/Android.bp b/neuralnetworks/1.2/utils/Android.bp
index 2a86a00..4eefb0f 100644
--- a/neuralnetworks/1.2/utils/Android.bp
+++ b/neuralnetworks/1.2/utils/Android.bp
@@ -71,7 +71,7 @@
         "android.hardware.neuralnetworks@1.1",
         "android.hardware.neuralnetworks@1.2",
         "libgmock",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
         "neuralnetworks_types",
         "neuralnetworks_utils_hal_common",
         "neuralnetworks_utils_hal_1_0",
diff --git a/neuralnetworks/1.2/vts/functional/Android.bp b/neuralnetworks/1.2/vts/functional/Android.bp
index 15a5d2f..52d51e2 100644
--- a/neuralnetworks/1.2/vts/functional/Android.bp
+++ b/neuralnetworks/1.2/vts/functional/Android.bp
@@ -71,7 +71,7 @@
         "libgmock",
         "libhidlmemory",
         "libneuralnetworks_generated_test_harness",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
     ],
     whole_static_libs: [
         "neuralnetworks_generated_V1_0_example",
diff --git a/neuralnetworks/1.3/utils/Android.bp b/neuralnetworks/1.3/utils/Android.bp
index 8ae509f..7acb4fc 100644
--- a/neuralnetworks/1.3/utils/Android.bp
+++ b/neuralnetworks/1.3/utils/Android.bp
@@ -69,7 +69,7 @@
         "android.hardware.neuralnetworks@1.2",
         "android.hardware.neuralnetworks@1.3",
         "libgmock",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
         "neuralnetworks_types",
         "neuralnetworks_utils_hal_common",
         "neuralnetworks_utils_hal_1_0",
diff --git a/neuralnetworks/1.3/vts/functional/Android.bp b/neuralnetworks/1.3/vts/functional/Android.bp
index ca59cc2..8951760 100644
--- a/neuralnetworks/1.3/vts/functional/Android.bp
+++ b/neuralnetworks/1.3/vts/functional/Android.bp
@@ -75,7 +75,7 @@
         "libgmock",
         "libhidlmemory",
         "libneuralnetworks_generated_test_harness",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
         "libsync",
     ],
     whole_static_libs: [
diff --git a/neuralnetworks/aidl/utils/include/AidlBufferTracker.h b/neuralnetworks/aidl/utils/include/AidlBufferTracker.h
new file mode 100644
index 0000000..4421876
--- /dev/null
+++ b/neuralnetworks/aidl/utils/include/AidlBufferTracker.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "nnapi/hal/aidl/BufferTracker.h"
diff --git a/neuralnetworks/aidl/utils/include/AidlHalInterfaces.h b/neuralnetworks/aidl/utils/include/AidlHalInterfaces.h
new file mode 100644
index 0000000..3777969
--- /dev/null
+++ b/neuralnetworks/aidl/utils/include/AidlHalInterfaces.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "nnapi/hal/aidl/HalInterfaces.h"
diff --git a/neuralnetworks/aidl/utils/include/AidlHalUtils.h b/neuralnetworks/aidl/utils/include/AidlHalUtils.h
new file mode 100644
index 0000000..98bfbad
--- /dev/null
+++ b/neuralnetworks/aidl/utils/include/AidlHalUtils.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "nnapi/hal/aidl/HalUtils.h"
diff --git a/neuralnetworks/aidl/utils/include/AidlValidateHal.h b/neuralnetworks/aidl/utils/include/AidlValidateHal.h
new file mode 100644
index 0000000..5aaa74d
--- /dev/null
+++ b/neuralnetworks/aidl/utils/include/AidlValidateHal.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "nnapi/hal/aidl/ValidateHal.h"
diff --git a/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/BufferTracker.h b/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/BufferTracker.h
new file mode 100644
index 0000000..18d01e2
--- /dev/null
+++ b/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/BufferTracker.h
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_BUFFER_TRACKER_H
+#define ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_BUFFER_TRACKER_H
+
+#include <android-base/macros.h>
+#include <android-base/thread_annotations.h>
+
+#include <map>
+#include <memory>
+#include <mutex>
+#include <set>
+#include <stack>
+#include <utility>
+#include <vector>
+
+#include "nnapi/hal/aidl/HalInterfaces.h"
+#include "nnapi/hal/aidl/ValidateHal.h"
+
+namespace android::nn {
+
+// This class manages a CPU buffer allocated on heap and provides validation methods.
+class AidlManagedBuffer {
+  public:
+    static std::shared_ptr<AidlManagedBuffer> create(uint32_t size,
+                                                     std::set<AidlHalPreparedModelRole> roles,
+                                                     const Operand& operand);
+
+    // Prefer AidlManagedBuffer::create.
+    AidlManagedBuffer(std::unique_ptr<uint8_t[]> buffer, uint32_t size,
+                      std::set<AidlHalPreparedModelRole> roles, const Operand& operand);
+
+    uint8_t* getPointer() const { return kBuffer.get(); }
+    uint32_t getSize() const { return kSize; }
+
+    // "poolIndex" is the index of this buffer in the request.pools.
+    ErrorStatus validateRequest(uint32_t poolIndex, const Request& request,
+                                const aidl_hal::IPreparedModel* preparedModel) const;
+
+    // "size" is the byte size of the Memory provided to the copyFrom or copyTo method.
+    ErrorStatus validateCopyFrom(const std::vector<uint32_t>& dimensions, uint32_t size) const;
+    ErrorStatus validateCopyTo(uint32_t size) const;
+
+    bool updateDimensions(const std::vector<uint32_t>& dimensions);
+    void setInitialized(bool initialized);
+
+  private:
+    mutable std::mutex mMutex;
+    const std::unique_ptr<uint8_t[]> kBuffer;
+    const uint32_t kSize;
+    const std::set<AidlHalPreparedModelRole> kRoles;
+    const OperandType kOperandType;
+    const std::vector<uint32_t> kInitialDimensions;
+    std::vector<uint32_t> mUpdatedDimensions GUARDED_BY(mMutex);
+    bool mInitialized GUARDED_BY(mMutex) = false;
+};
+
+// Keep track of all AidlManagedBuffers and assign each with a unique token.
+class AidlBufferTracker : public std::enable_shared_from_this<AidlBufferTracker> {
+    DISALLOW_COPY_AND_ASSIGN(AidlBufferTracker);
+
+  public:
+    // A RAII class to help manage the lifetime of the token.
+    // It is only supposed to be constructed in AidlBufferTracker::add.
+    class Token {
+        DISALLOW_COPY_AND_ASSIGN(Token);
+
+      public:
+        Token(uint32_t token, std::shared_ptr<AidlBufferTracker> tracker)
+            : kToken(token), kBufferTracker(std::move(tracker)) {}
+        ~Token() { kBufferTracker->free(kToken); }
+        uint32_t get() const { return kToken; }
+
+      private:
+        const uint32_t kToken;
+        const std::shared_ptr<AidlBufferTracker> kBufferTracker;
+    };
+
+    // The factory of AidlBufferTracker. This ensures that the AidlBufferTracker is always managed
+    // by a shared_ptr.
+    static std::shared_ptr<AidlBufferTracker> create() {
+        return std::make_shared<AidlBufferTracker>();
+    }
+
+    // Prefer AidlBufferTracker::create.
+    AidlBufferTracker() : mTokenToBuffers(1) {}
+
+    std::unique_ptr<Token> add(std::shared_ptr<AidlManagedBuffer> buffer);
+    std::shared_ptr<AidlManagedBuffer> get(uint32_t token) const;
+
+  private:
+    void free(uint32_t token);
+
+    mutable std::mutex mMutex;
+    std::stack<uint32_t, std::vector<uint32_t>> mFreeTokens GUARDED_BY(mMutex);
+
+    // Since the tokens are allocated in a non-sparse way, we use a vector to represent the mapping.
+    // The index of the vector is the token. When the token gets freed, the corresponding entry is
+    // set to nullptr. mTokenToBuffers[0] is always set to nullptr because 0 is an invalid token.
+    std::vector<std::shared_ptr<AidlManagedBuffer>> mTokenToBuffers GUARDED_BY(mMutex);
+};
+
+}  // namespace android::nn
+
+#endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_BUFFER_TRACKER_H
diff --git a/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/HalInterfaces.h b/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/HalInterfaces.h
new file mode 100644
index 0000000..3fb443c
--- /dev/null
+++ b/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/HalInterfaces.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_HAL_INTERFACES_H
+#define ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_HAL_INTERFACES_H
+
+#include <aidl/android/hardware/neuralnetworks/BnBuffer.h>
+#include <aidl/android/hardware/neuralnetworks/BnBurst.h>
+#include <aidl/android/hardware/neuralnetworks/BnDevice.h>
+#include <aidl/android/hardware/neuralnetworks/BnFencedExecutionCallback.h>
+#include <aidl/android/hardware/neuralnetworks/BnPreparedModel.h>
+#include <aidl/android/hardware/neuralnetworks/BnPreparedModelCallback.h>
+#include <aidl/android/hardware/neuralnetworks/BufferDesc.h>
+#include <aidl/android/hardware/neuralnetworks/BufferRole.h>
+#include <aidl/android/hardware/neuralnetworks/Capabilities.h>
+#include <aidl/android/hardware/neuralnetworks/DataLocation.h>
+#include <aidl/android/hardware/neuralnetworks/DeviceBuffer.h>
+#include <aidl/android/hardware/neuralnetworks/DeviceType.h>
+#include <aidl/android/hardware/neuralnetworks/ErrorStatus.h>
+#include <aidl/android/hardware/neuralnetworks/ExecutionPreference.h>
+#include <aidl/android/hardware/neuralnetworks/Extension.h>
+#include <aidl/android/hardware/neuralnetworks/ExtensionNameAndPrefix.h>
+#include <aidl/android/hardware/neuralnetworks/ExtensionOperandTypeInformation.h>
+#include <aidl/android/hardware/neuralnetworks/FusedActivationFunc.h>
+#include <aidl/android/hardware/neuralnetworks/IBuffer.h>
+#include <aidl/android/hardware/neuralnetworks/IDevice.h>
+#include <aidl/android/hardware/neuralnetworks/IFencedExecutionCallback.h>
+#include <aidl/android/hardware/neuralnetworks/IPreparedModel.h>
+#include <aidl/android/hardware/neuralnetworks/IPreparedModelCallback.h>
+#include <aidl/android/hardware/neuralnetworks/IPreparedModelParcel.h>
+#include <aidl/android/hardware/neuralnetworks/Memory.h>
+#include <aidl/android/hardware/neuralnetworks/Model.h>
+#include <aidl/android/hardware/neuralnetworks/NumberOfCacheFiles.h>
+#include <aidl/android/hardware/neuralnetworks/Operand.h>
+#include <aidl/android/hardware/neuralnetworks/OperandExtraParams.h>
+#include <aidl/android/hardware/neuralnetworks/OperandLifeTime.h>
+#include <aidl/android/hardware/neuralnetworks/OperandPerformance.h>
+#include <aidl/android/hardware/neuralnetworks/OperandType.h>
+#include <aidl/android/hardware/neuralnetworks/Operation.h>
+#include <aidl/android/hardware/neuralnetworks/OperationType.h>
+#include <aidl/android/hardware/neuralnetworks/OutputShape.h>
+#include <aidl/android/hardware/neuralnetworks/PerformanceInfo.h>
+#include <aidl/android/hardware/neuralnetworks/Priority.h>
+#include <aidl/android/hardware/neuralnetworks/Request.h>
+#include <aidl/android/hardware/neuralnetworks/RequestArgument.h>
+#include <aidl/android/hardware/neuralnetworks/RequestMemoryPool.h>
+#include <aidl/android/hardware/neuralnetworks/Subgraph.h>
+#include <aidl/android/hardware/neuralnetworks/SymmPerChannelQuantParams.h>
+#include <aidl/android/hardware/neuralnetworks/Timing.h>
+
+namespace android::nn {
+
+namespace aidl_hal = ::aidl::android::hardware::neuralnetworks;
+
+inline constexpr aidl_hal::Priority kDefaultPriorityAidl = aidl_hal::Priority::MEDIUM;
+
+}  // namespace android::nn
+
+#endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_HAL_INTERFACES_H
diff --git a/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/HalUtils.h b/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/HalUtils.h
new file mode 100644
index 0000000..89552bc
--- /dev/null
+++ b/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/HalUtils.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_HAL_UTILS_H
+#define ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_HAL_UTILS_H
+
+#include <vector>
+
+#include "nnapi/hal/aidl/HalInterfaces.h"
+
+namespace android {
+namespace nn {
+
+// Return a vector with one entry for each non-extension OperandType except
+// SUBGRAPH, set to the specified PerformanceInfo value.  The vector will be
+// sorted by OperandType.
+//
+// Control flow (OperandType::SUBGRAPH) operation performance is specified
+// separately using Capabilities::ifPerformance and
+// Capabilities::whilePerformance.
+std::vector<aidl_hal::OperandPerformance> nonExtensionOperandPerformance(
+        aidl_hal::PerformanceInfo perf);
+
+// Update the vector entry corresponding to the specified OperandType with the
+// specified PerformanceInfo value.  The vector must already have an entry for
+// that OperandType, and must be sorted by OperandType.
+void update(std::vector<aidl_hal::OperandPerformance>* operandPerformance,
+            aidl_hal::OperandType type, aidl_hal::PerformanceInfo perf);
+
+// Returns true if an operand type is an extension type.
+bool isExtensionOperandType(aidl_hal::OperandType type);
+
+// Returns true if an operand type is a scalar type.
+bool isNonExtensionScalar(aidl_hal::OperandType type);
+
+}  // namespace nn
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_HAL_UTILS_H
diff --git a/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/ValidateHal.h b/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/ValidateHal.h
new file mode 100644
index 0000000..62aba31
--- /dev/null
+++ b/neuralnetworks/aidl/utils/include/nnapi/hal/aidl/ValidateHal.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_VALIDATE_HAL_H
+#define ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_VALIDATE_HAL_H
+
+#include "nnapi/hal/aidl/HalInterfaces.h"
+
+#include <memory>
+#include <set>
+#include <tuple>
+#include <vector>
+
+#include <nnapi/TypeUtils.h>
+#include <nnapi/Validation.h>
+
+namespace android {
+namespace nn {
+
+using AidlHalPreparedModelRole = std::tuple<const aidl_hal::IPreparedModel*, IOType, uint32_t>;
+
+bool validateMemoryDesc(
+        const aidl_hal::BufferDesc& desc,
+        const std::vector<std::shared_ptr<aidl_hal::IPreparedModel>>& preparedModels,
+        const std::vector<aidl_hal::BufferRole>& inputRoles,
+        const std::vector<aidl_hal::BufferRole>& outputRoles,
+        std::function<const aidl_hal::Model*(const std::shared_ptr<aidl_hal::IPreparedModel>&)>
+                getModel,
+        std::set<AidlHalPreparedModelRole>* preparedModelRoles, aidl_hal::Operand* combinedOperand);
+
+}  // namespace nn
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_AIDL_UTILS_VALIDATE_HAL_H
diff --git a/neuralnetworks/aidl/utils/src/AidlBufferTracker.cpp b/neuralnetworks/aidl/utils/src/AidlBufferTracker.cpp
new file mode 100644
index 0000000..15d0810
--- /dev/null
+++ b/neuralnetworks/aidl/utils/src/AidlBufferTracker.cpp
@@ -0,0 +1,227 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "AidlBufferTracker.h"
+
+#include <android-base/macros.h>
+
+#include <memory>
+#include <mutex>
+#include <set>
+#include <stack>
+#include <utility>
+#include <vector>
+
+#include "AidlHalInterfaces.h"
+#include "nnapi/TypeUtils.h"
+
+namespace android::nn {
+
+std::shared_ptr<AidlManagedBuffer> AidlManagedBuffer::create(
+        uint32_t size, std::set<AidlHalPreparedModelRole> roles, const Operand& operand) {
+    std::unique_ptr<uint8_t[]> buffer(new (std::nothrow) uint8_t[size]);
+    if (buffer == nullptr) {
+        return nullptr;
+    }
+    if (isExtension(operand.type)) {
+        LOG(ERROR) << "AidlManagedBuffer cannot handle extension operands.";
+        return nullptr;
+    }
+    return std::make_shared<AidlManagedBuffer>(std::move(buffer), size, std::move(roles), operand);
+}
+
+AidlManagedBuffer::AidlManagedBuffer(std::unique_ptr<uint8_t[]> buffer, uint32_t size,
+                                     std::set<AidlHalPreparedModelRole> roles,
+                                     const Operand& operand)
+    : kBuffer(std::move(buffer)),
+      kSize(size),
+      kRoles(std::move(roles)),
+      kOperandType(operand.type),
+      kInitialDimensions(operand.dimensions),
+      mUpdatedDimensions(operand.dimensions) {
+    CHECK(!isExtension(kOperandType));
+}
+
+ErrorStatus AidlManagedBuffer::validateRequest(
+        uint32_t poolIndex, const Request& request,
+        const aidl_hal::IPreparedModel* preparedModel) const {
+    CHECK_LT(poolIndex, request.pools.size());
+    CHECK(std::holds_alternative<Request::MemoryDomainToken>(request.pools[poolIndex]));
+    std::lock_guard<std::mutex> guard(mMutex);
+
+    bool usedAsInput = false, usedAsOutput = false;
+    for (uint32_t i = 0; i < request.inputs.size(); i++) {
+        if (request.inputs[i].lifetime != Request::Argument::LifeTime::POOL) continue;
+        if (request.inputs[i].location.poolIndex != poolIndex) continue;
+        // Validate if the input role is specified during allocation.
+        if (kRoles.count({preparedModel, IOType::INPUT, i}) == 0) {
+            LOG(ERROR) << "AidlManagedBuffer::validateRequest -- invalid buffer role.";
+            return ErrorStatus::INVALID_ARGUMENT;
+        }
+        if (!mInitialized) {
+            LOG(ERROR)
+                    << "AidlManagedBuffer::validateRequest -- using uninitialized buffer as input "
+                       "request.";
+            return ErrorStatus::GENERAL_FAILURE;
+        }
+        auto combined = combineDimensions(mUpdatedDimensions, request.inputs[i].dimensions);
+        if (!combined.has_value()) {
+            LOG(ERROR) << "AidlManagedBuffer::validateRequest -- incompatible dimensions ("
+                       << toString(mUpdatedDimensions) << " vs "
+                       << toString(request.inputs[i].dimensions) << ")";
+            return ErrorStatus::INVALID_ARGUMENT;
+        }
+        usedAsInput = true;
+    }
+    for (uint32_t i = 0; i < request.outputs.size(); i++) {
+        if (request.outputs[i].lifetime != Request::Argument::LifeTime::POOL) continue;
+        if (request.outputs[i].location.poolIndex != poolIndex) continue;
+        if (usedAsInput || usedAsOutput) {
+            LOG(ERROR) << "AidlManagedBuffer::validateRequest -- using the same device memory for "
+                          "input/output or multiple outputs";
+            return ErrorStatus::INVALID_ARGUMENT;
+        }
+        // Validate if the output role is specified during allocation.
+        if (kRoles.count({preparedModel, IOType::OUTPUT, i}) == 0) {
+            LOG(ERROR) << "AidlManagedBuffer::validateRequest -- invalid buffer role.";
+            return ErrorStatus::INVALID_ARGUMENT;
+        }
+        auto combined = combineDimensions(kInitialDimensions, request.outputs[i].dimensions);
+        if (!combined.has_value()) {
+            LOG(ERROR) << "AidlManagedBuffer::validateRequest -- incompatible dimensions ("
+                       << toString(kInitialDimensions) << " vs "
+                       << toString(request.outputs[i].dimensions) << ")";
+            return ErrorStatus::INVALID_ARGUMENT;
+        }
+        usedAsOutput = true;
+    }
+    return ErrorStatus::NONE;
+}
+
+ErrorStatus AidlManagedBuffer::validateCopyFrom(const std::vector<uint32_t>& dimensions,
+                                                uint32_t size) const {
+    if (size != kSize) {
+        LOG(ERROR) << "AidlManagedBuffer::validateCopyFrom -- invalid memory size: " << kSize
+                   << " vs " << size;
+        return ErrorStatus::INVALID_ARGUMENT;
+    }
+
+    if (isNonExtensionScalar(kOperandType)) {
+        if (!dimensions.empty()) {
+            LOG(ERROR) << "AidlManagedBuffer::validateCopyFrom -- invalid dimensions for scalar "
+                          "operand: "
+                       << toString(dimensions);
+            return ErrorStatus::INVALID_ARGUMENT;
+        }
+        return ErrorStatus::NONE;
+    }
+
+    if (dimensions.empty()) {
+        if (tensorHasUnspecifiedDimensions(kOperandType, kInitialDimensions)) {
+            LOG(ERROR) << "AidlManagedBuffer::validateCopyFrom -- the initial dimensions are not "
+                          "fully "
+                          "specified and no dimension update is provided: "
+                       << toString(kInitialDimensions);
+            return ErrorStatus::INVALID_ARGUMENT;
+        }
+    } else {
+        if (tensorHasUnspecifiedDimensions(kOperandType, dimensions)) {
+            LOG(ERROR) << "AidlManagedBuffer::validateCopyFrom -- the updated dimensions are not "
+                          "fully "
+                          "specified: "
+                       << toString(dimensions);
+            return ErrorStatus::INVALID_ARGUMENT;
+        }
+    }
+
+    const auto combined = combineDimensions(kInitialDimensions, dimensions);
+    if (!combined.has_value()) {
+        LOG(ERROR) << "AidlManagedBuffer::validateCopyFrom -- incompatible dimensions ("
+                   << toString(kInitialDimensions) << " vs " << toString(dimensions) << ")";
+        return ErrorStatus::INVALID_ARGUMENT;
+    }
+    return ErrorStatus::NONE;
+}
+
+ErrorStatus AidlManagedBuffer::validateCopyTo(uint32_t size) const {
+    if (size != kSize) {
+        LOG(ERROR) << "AidlManagedBuffer::validateCopyTo -- invalid memory size: " << kSize
+                   << " vs " << size;
+        return ErrorStatus::INVALID_ARGUMENT;
+    }
+    std::lock_guard<std::mutex> guard(mMutex);
+    if (!mInitialized) {
+        LOG(ERROR) << "AidlManagedBuffer::validateCopyTo -- using uninitialized buffer as source.";
+        return ErrorStatus::GENERAL_FAILURE;
+    }
+    return ErrorStatus::NONE;
+}
+
+bool AidlManagedBuffer::updateDimensions(const std::vector<uint32_t>& dimensions) {
+    auto combined = combineDimensions(kInitialDimensions, dimensions);
+    if (!combined.has_value()) {
+        LOG(ERROR) << "AidlManagedBuffer::updateDimensions -- incompatible dimensions ("
+                   << toString(kInitialDimensions) << " vs " << toString(dimensions) << ")";
+        return false;
+    }
+    std::lock_guard<std::mutex> guard(mMutex);
+    mUpdatedDimensions = std::move(combined).value();
+    return true;
+}
+
+void AidlManagedBuffer::setInitialized(bool initialized) {
+    std::lock_guard<std::mutex> guard(mMutex);
+    mInitialized = initialized;
+}
+
+std::unique_ptr<AidlBufferTracker::Token> AidlBufferTracker::add(
+        std::shared_ptr<AidlManagedBuffer> buffer) {
+    if (buffer == nullptr) {
+        return nullptr;
+    }
+    std::lock_guard<std::mutex> guard(mMutex);
+    uint32_t token = 0;
+    if (mFreeTokens.empty()) {
+        token = mTokenToBuffers.size();
+        mTokenToBuffers.push_back(std::move(buffer));
+    } else {
+        token = mFreeTokens.top();
+        mFreeTokens.pop();
+        mTokenToBuffers[token] = std::move(buffer);
+    }
+    VLOG(MEMORY) << "AidlBufferTracker::add -- new token = " << token;
+    return std::make_unique<Token>(token, shared_from_this());
+}
+
+std::shared_ptr<AidlManagedBuffer> AidlBufferTracker::get(uint32_t token) const {
+    std::lock_guard<std::mutex> guard(mMutex);
+    if (mTokenToBuffers.size() <= token || mTokenToBuffers[token] == nullptr) {
+        LOG(ERROR) << "AidlBufferTracker::get -- unknown token " << token;
+        return nullptr;
+    }
+    return mTokenToBuffers[token];
+}
+
+void AidlBufferTracker::free(uint32_t token) {
+    std::lock_guard<std::mutex> guard(mMutex);
+    CHECK_LT(token, mTokenToBuffers.size());
+    CHECK(mTokenToBuffers[token] != nullptr);
+    VLOG(MEMORY) << "AidlBufferTracker::free -- release token = " << token;
+    mTokenToBuffers[token] = nullptr;
+    mFreeTokens.push(token);
+}
+
+}  // namespace android::nn
diff --git a/neuralnetworks/aidl/utils/src/AidlHalUtils.cpp b/neuralnetworks/aidl/utils/src/AidlHalUtils.cpp
new file mode 100644
index 0000000..6fc46ab
--- /dev/null
+++ b/neuralnetworks/aidl/utils/src/AidlHalUtils.cpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// This file contains pre-canonical-types utility code and includes HAL
+// utilities. LegacyUtils.h is the subset of these utilities that do not touch
+// HAL.
+
+#include "AidlHalUtils.h"
+
+#include <android-base/logging.h>
+#include <nnapi/hal/aidl/Conversions.h>
+
+#include <algorithm>
+#include <iterator>
+#include <type_traits>
+#include <vector>
+
+#include "AidlHalInterfaces.h"
+#include "nnapi/TypeUtils.h"
+
+namespace android::nn {
+
+std::vector<aidl_hal::OperandPerformance> nonExtensionOperandPerformance(
+        aidl_hal::PerformanceInfo perf) {
+    static constexpr ndk::enum_range<aidl_hal::OperandType> kOperandTypeRange;
+    std::vector<aidl_hal::OperandPerformance> ret;
+    ret.reserve(std::distance(kOperandTypeRange.begin(), kOperandTypeRange.end()));
+    for (aidl_hal::OperandType type : kOperandTypeRange) {
+        if (type != aidl_hal::OperandType::SUBGRAPH) {
+            ret.push_back(aidl_hal::OperandPerformance{type, perf});
+        }
+    }
+    std::sort(ret.begin(), ret.end(),
+              [](const aidl_hal::OperandPerformance& a, const aidl_hal::OperandPerformance& b) {
+                  return a.type < b.type;
+              });
+
+    return ret;
+}
+
+void update(std::vector<aidl_hal::OperandPerformance>* operandPerformance,
+            aidl_hal::OperandType type, aidl_hal::PerformanceInfo perf) {
+    CHECK(operandPerformance != nullptr);
+    const auto it = std::lower_bound(operandPerformance->begin(), operandPerformance->end(), type,
+                                     [](const aidl_hal::OperandPerformance& perf,
+                                        aidl_hal::OperandType type) { return perf.type < type; });
+    CHECK(it != operandPerformance->end())
+            << toString(type) << " not in operand performance vector";
+    it->info = perf;
+}
+
+bool isExtensionOperandType(aidl_hal::OperandType type) {
+    return isExtension(convert(type).value());
+}
+
+bool isNonExtensionScalar(aidl_hal::OperandType type) {
+    return isNonExtensionScalar(convert(type).value());
+}
+
+}  // namespace android::nn
diff --git a/neuralnetworks/aidl/utils/src/AidlValidateHal.cpp b/neuralnetworks/aidl/utils/src/AidlValidateHal.cpp
new file mode 100644
index 0000000..a1c496a
--- /dev/null
+++ b/neuralnetworks/aidl/utils/src/AidlValidateHal.cpp
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "ValidateHal"
+
+#include "AidlValidateHal.h"
+
+#include <android-base/logging.h>
+#include <nnapi/hal/aidl/Conversions.h>
+
+#include <algorithm>
+#include <memory>
+#include <set>
+#include <utility>
+#include <vector>
+
+#include "AidlHalUtils.h"
+#include "nnapi/TypeUtils.h"
+
+namespace android {
+namespace nn {
+
+bool validateMemoryDesc(
+        const aidl_hal::BufferDesc& desc,
+        const std::vector<std::shared_ptr<aidl_hal::IPreparedModel>>& preparedModels,
+        const std::vector<aidl_hal::BufferRole>& inputRoles,
+        const std::vector<aidl_hal::BufferRole>& outputRoles,
+        std::function<const aidl_hal::Model*(const std::shared_ptr<aidl_hal::IPreparedModel>&)>
+                getModel,
+        std::set<AidlHalPreparedModelRole>* preparedModelRoles,
+        aidl_hal::Operand* combinedOperand) {
+    NN_RET_CHECK(!preparedModels.empty());
+    NN_RET_CHECK(!inputRoles.empty() || !outputRoles.empty());
+
+    std::set<AidlHalPreparedModelRole> roles;
+    std::vector<aidl_hal::Operand> operands;
+    operands.reserve(inputRoles.size() + outputRoles.size());
+    for (const auto& role : inputRoles) {
+        NN_RET_CHECK_GE(role.modelIndex, 0);
+        NN_RET_CHECK_LT(static_cast<size_t>(role.modelIndex), preparedModels.size());
+        const auto& preparedModel = preparedModels[role.modelIndex];
+        NN_RET_CHECK(preparedModel != nullptr);
+        const auto* model = getModel(preparedModel);
+        NN_RET_CHECK(model != nullptr);
+        const auto& inputIndexes = model->main.inputIndexes;
+        NN_RET_CHECK_GE(role.ioIndex, 0);
+        NN_RET_CHECK_LT(static_cast<size_t>(role.ioIndex), inputIndexes.size());
+        NN_RET_CHECK_GT(role.probability, 0.0f);
+        NN_RET_CHECK_LE(role.probability, 1.0f);
+        const auto [it, success] = roles.emplace(preparedModel.get(), IOType::INPUT, role.ioIndex);
+        NN_RET_CHECK(success);
+        operands.push_back(model->main.operands[inputIndexes[role.ioIndex]]);
+    }
+    for (const auto& role : outputRoles) {
+        NN_RET_CHECK_GE(role.modelIndex, 0);
+        NN_RET_CHECK_LT(static_cast<size_t>(role.modelIndex), preparedModels.size());
+        const auto& preparedModel = preparedModels[role.modelIndex];
+        NN_RET_CHECK(preparedModel != nullptr);
+        const auto* model = getModel(preparedModel);
+        NN_RET_CHECK(model != nullptr);
+        const auto& outputIndexes = model->main.outputIndexes;
+        NN_RET_CHECK_GE(role.ioIndex, 0);
+        NN_RET_CHECK_LT(static_cast<size_t>(role.ioIndex), outputIndexes.size());
+        NN_RET_CHECK_GT(role.probability, 0.0f);
+        NN_RET_CHECK_LE(role.probability, 1.0f);
+        const auto [it, success] = roles.emplace(preparedModel.get(), IOType::OUTPUT, role.ioIndex);
+        NN_RET_CHECK(success);
+        operands.push_back(model->main.operands[outputIndexes[role.ioIndex]]);
+    }
+
+    CHECK(!operands.empty());
+    const auto opType = operands[0].type;
+    const auto canonicalOperandType = convert(opType);
+    NN_RET_CHECK(canonicalOperandType.has_value()) << canonicalOperandType.error().message;
+    const bool isExtensionOperand = isExtension(canonicalOperandType.value());
+
+    auto maybeDimensions = toUnsigned(desc.dimensions);
+    NN_RET_CHECK(maybeDimensions.has_value()) << maybeDimensions.error().message;
+    std::vector<uint32_t> dimensions = std::move(maybeDimensions).value();
+
+    for (const auto& operand : operands) {
+        NN_RET_CHECK(operand.type == operands[0].type)
+                << toString(operand.type) << " vs " << toString(operands[0].type);
+        NN_RET_CHECK_EQ(operand.scale, operands[0].scale);
+        NN_RET_CHECK_EQ(operand.zeroPoint, operands[0].zeroPoint);
+        // NOTE: validateMemoryDesc cannot validate extra parameters for extension operand type.
+        if (!isExtensionOperand) {
+            const auto& lhsExtraParams = operand.extraParams;
+            const auto& rhsExtraParams = operands[0].extraParams;
+            NN_RET_CHECK(lhsExtraParams == rhsExtraParams)
+                    << (lhsExtraParams.has_value() ? lhsExtraParams.value().toString()
+                                                   : "std::nullopt")
+                    << " vs "
+                    << (rhsExtraParams.has_value() ? rhsExtraParams.value().toString()
+                                                   : "std::nullopt");
+        }
+        const auto maybeRhsDimensions = toUnsigned(operand.dimensions);
+        NN_RET_CHECK(maybeRhsDimensions.has_value()) << maybeRhsDimensions.error().message;
+        const auto combined = combineDimensions(dimensions, maybeRhsDimensions.value());
+        NN_RET_CHECK(combined.has_value());
+        dimensions = combined.value();
+    }
+
+    // NOTE: validateMemoryDesc cannot validate scalar dimensions with extension operand type.
+    if (!isExtensionOperand) {
+        NN_RET_CHECK(!isNonExtensionScalar(opType) || dimensions.empty())
+                << "invalid dimensions with scalar operand type.";
+    }
+
+    if (preparedModelRoles != nullptr) {
+        *preparedModelRoles = std::move(roles);
+    }
+    if (combinedOperand != nullptr) {
+        *combinedOperand = operands[0];
+        // No need to check that values fit int32_t here, since the original values are obtained
+        // from int32_t.
+        combinedOperand->dimensions = aidl_hal::utils::toSigned(dimensions).value();
+    }
+    return true;
+}
+
+}  // namespace nn
+}  // namespace android
diff --git a/neuralnetworks/utils/common/Android.bp b/neuralnetworks/utils/common/Android.bp
index c01460e..39927a3 100644
--- a/neuralnetworks/utils/common/Android.bp
+++ b/neuralnetworks/utils/common/Android.bp
@@ -39,7 +39,7 @@
     srcs: ["test/*.cpp"],
     static_libs: [
         "libgmock",
-        "libneuralnetworks_common_hidl",
+        "libneuralnetworks_common",
         "neuralnetworks_types",
         "neuralnetworks_utils_hal_common",
     ],
diff --git a/security/keymint/aidl/OWNERS b/security/OWNERS
similarity index 100%
rename from security/keymint/aidl/OWNERS
rename to security/OWNERS
diff --git a/security/keymint/support/OWNERS b/security/keymint/support/OWNERS
deleted file mode 100644
index a93b171..0000000
--- a/security/keymint/support/OWNERS
+++ /dev/null
@@ -1,4 +0,0 @@
-jbires@google.com
-jdanis@google.com
-seleneh@google.com
-swillden@google.com
diff --git a/security/secureclock/aidl/OWNERS b/security/secureclock/aidl/OWNERS
deleted file mode 100644
index a93b171..0000000
--- a/security/secureclock/aidl/OWNERS
+++ /dev/null
@@ -1,4 +0,0 @@
-jbires@google.com
-jdanis@google.com
-seleneh@google.com
-swillden@google.com
diff --git a/security/sharedsecret/aidl/OWNERS b/security/sharedsecret/aidl/OWNERS
deleted file mode 100644
index a93b171..0000000
--- a/security/sharedsecret/aidl/OWNERS
+++ /dev/null
@@ -1,4 +0,0 @@
-jbires@google.com
-jdanis@google.com
-seleneh@google.com
-swillden@google.com
diff --git a/tv/tuner/aidl/default/Filter.cpp b/tv/tuner/aidl/default/Filter.cpp
index c377772..345a984 100644
--- a/tv/tuner/aidl/default/Filter.cpp
+++ b/tv/tuner/aidl/default/Filter.cpp
@@ -34,16 +34,132 @@
 
 #define WAIT_TIMEOUT 3000000000
 
-Filter::Filter() {}
+FilterCallbackScheduler::FilterCallbackScheduler(const std::shared_ptr<IFilterCallback>& cb)
+    : mCallback(cb), mDataLength(0), mTimeDelayInMs(0), mDataSizeDelayInBytes(0) {
+    start();
+}
+
+FilterCallbackScheduler::~FilterCallbackScheduler() {
+    stop();
+}
+
+void FilterCallbackScheduler::onFilterEvent(DemuxFilterEvent&& event) {
+    std::lock_guard<std::mutex> lock(mLock);
+    mCallbackBuffer.push_back(std::move(event));
+    mDataLength += getDemuxFilterEventDataLength(event);
+
+    if (mDataLength >= mDataSizeDelayInBytes) {
+        // size limit has been reached, send out events
+        mCv.notify_all();
+    }
+}
+
+void FilterCallbackScheduler::onFilterStatus(const DemuxFilterStatus& status) {
+    if (mCallback) {
+        mCallback->onFilterStatus(status);
+    }
+}
+
+void FilterCallbackScheduler::setTimeDelayHint(int timeDelay) {
+    // updating the setTimeDelay does not go into effect until the condition
+    // variable times out or is notified.
+    // One possibility is to notify the condition variable right away when the
+    // time delay changes, but I don't see the benefit over waiting for the next
+    // timeout / push, since -- in any case -- this will not change very often.
+    mTimeDelayInMs = timeDelay;
+}
+
+void FilterCallbackScheduler::setDataSizeDelayHint(int dataSizeDelay) {
+    // similar to updating the time delay hint, when mDataSizeDelayInBytes
+    // changes, this will not go into immediate effect, but will wait until the
+    // next filterEvent.
+    // We could technically check the current data length and notify the
+    // condition variable if we wanted to, but again, this may be overkill.
+    mDataSizeDelayInBytes = dataSizeDelay;
+}
+
+bool FilterCallbackScheduler::hasCallbackRegistered() const {
+    return mCallback != nullptr;
+}
+
+void FilterCallbackScheduler::start() {
+    mIsRunning = true;
+    mCallbackThread = std::thread(&FilterCallbackScheduler::threadLoop, this);
+}
+
+void FilterCallbackScheduler::stop() {
+    mIsRunning = false;
+    if (mCallbackThread.joinable()) {
+        mCallbackThread.join();
+    }
+}
+
+void FilterCallbackScheduler::threadLoop() {
+    while (mIsRunning) {
+        threadLoopOnce();
+    }
+}
+
+void FilterCallbackScheduler::threadLoopOnce() {
+    std::unique_lock<std::mutex> lock(mLock);
+    // mTimeDelayInMs is an atomic value, so it should be copied into a local
+    // variable before use (to make sure both the if statement and wait_for use
+    // the same value).
+    int timeDelayInMs = mTimeDelayInMs;
+    if (timeDelayInMs > 0) {
+        mCv.wait_for(lock, std::chrono::milliseconds(timeDelayInMs));
+    } else {
+        // no reason to timeout, just wait until main thread determines it's
+        // okay to send data.
+        mCv.wait(lock);
+    }
+
+    // condition_variable wait locks mutex on timeout / notify
+    if (!mCallbackBuffer.empty()) {
+        if (mCallback) {
+            mCallback->onFilterEvent(mCallbackBuffer);
+        }
+        mCallbackBuffer.clear();
+        mDataLength = 0;
+    }
+    lock.unlock();
+}
+
+int FilterCallbackScheduler::getDemuxFilterEventDataLength(const DemuxFilterEvent& event) {
+    // there is a risk that dataLength could be a negative value, but it
+    // *should* be safe to assume that it is always positive.
+    switch (event.getTag()) {
+        case DemuxFilterEvent::Tag::section:
+            return event.get<DemuxFilterEvent::Tag::section>().dataLength;
+        case DemuxFilterEvent::Tag::media:
+            return event.get<DemuxFilterEvent::Tag::media>().dataLength;
+        case DemuxFilterEvent::Tag::pes:
+            return event.get<DemuxFilterEvent::Tag::pes>().dataLength;
+        case DemuxFilterEvent::Tag::download:
+            return event.get<DemuxFilterEvent::Tag::download>().dataLength;
+        case DemuxFilterEvent::Tag::ipPayload:
+            return event.get<DemuxFilterEvent::Tag::ipPayload>().dataLength;
+
+        case DemuxFilterEvent::Tag::tsRecord:
+        case DemuxFilterEvent::Tag::mmtpRecord:
+        case DemuxFilterEvent::Tag::temi:
+        case DemuxFilterEvent::Tag::monitorEvent:
+        case DemuxFilterEvent::Tag::startId:
+            // these events do not include a payload and should therefore return
+            // 0.
+            // do not add a default option, so this will not compile when new types
+            // are added.
+            return 0;
+    }
+}
 
 Filter::Filter(DemuxFilterType type, int64_t filterId, uint32_t bufferSize,
-               const std::shared_ptr<IFilterCallback>& cb, std::shared_ptr<Demux> demux) {
-    mType = type;
-    mFilterId = filterId;
-    mBufferSize = bufferSize;
-    mDemux = demux;
-    mCallback = cb;
-
+               const std::shared_ptr<IFilterCallback>& cb, std::shared_ptr<Demux> demux)
+    : mDemux(demux),
+      mCallbackScheduler(cb),
+      mFilterId(filterId),
+      mBufferSize(bufferSize),
+      mType(type) {
     switch (mType.mainType) {
         case DemuxFilterMainType::TS:
             if (mType.subType.get<DemuxFilterSubType::Tag::tsFilterType>() ==
@@ -112,9 +228,29 @@
 }
 
 ::ndk::ScopedAStatus Filter::setDelayHint(const FilterDelayHint& in_hint) {
+    if (mIsMediaFilter) {
+        // delay hint is not supported for media filters
+        return ::ndk::ScopedAStatus::fromServiceSpecificError(
+                static_cast<int32_t>(Result::UNAVAILABLE));
+    }
+
     ALOGV("%s", __FUNCTION__);
-    (void)in_hint;
-    // TODO: implement
+    if (in_hint.hintValue < 0) {
+        return ::ndk::ScopedAStatus::fromServiceSpecificError(
+                static_cast<int32_t>(Result::INVALID_ARGUMENT));
+    }
+
+    switch (in_hint.hintType) {
+        case FilterDelayHintType::TIME_DELAY_IN_MS:
+            mCallbackScheduler.setTimeDelayHint(in_hint.hintValue);
+            break;
+        case FilterDelayHintType::DATA_SIZE_DELAY_IN_BYTES:
+            mCallbackScheduler.setDataSizeDelayHint(in_hint.hintValue);
+            break;
+        default:
+            return ::ndk::ScopedAStatus::fromServiceSpecificError(
+                    static_cast<int32_t>(Result::INVALID_ARGUMENT));
+    }
 
     return ::ndk::ScopedAStatus::ok();
 }
@@ -155,40 +291,36 @@
 ::ndk::ScopedAStatus Filter::start() {
     ALOGV("%s", __FUNCTION__);
     mFilterThreadRunning = true;
-    vector<DemuxFilterEvent> events;
+    std::vector<DemuxFilterEvent> events;
     // All the filter event callbacks in start are for testing purpose.
     switch (mType.mainType) {
         case DemuxFilterMainType::TS:
             createMediaEvent(events);
-            mCallback->onFilterEvent(events);
             createTsRecordEvent(events);
-            mCallback->onFilterEvent(events);
             createTemiEvent(events);
-            mCallback->onFilterEvent(events);
             break;
         case DemuxFilterMainType::MMTP:
             createDownloadEvent(events);
-            mCallback->onFilterEvent(events);
             createMmtpRecordEvent(events);
-            mCallback->onFilterEvent(events);
             break;
         case DemuxFilterMainType::IP:
             createSectionEvent(events);
-            mCallback->onFilterEvent(events);
             createIpPayloadEvent(events);
-            mCallback->onFilterEvent(events);
             break;
         case DemuxFilterMainType::TLV:
             createMonitorEvent(events);
-            mCallback->onFilterEvent(events);
             break;
         case DemuxFilterMainType::ALP:
             createMonitorEvent(events);
-            mCallback->onFilterEvent(events);
             break;
         default:
             break;
     }
+
+    for (auto&& event : events) {
+        mCallbackScheduler.onFilterEvent(std::move(event));
+    }
+
     return startFilterLoop();
 }
 
@@ -327,15 +459,14 @@
     if (newScramblingStatus ^ mScramblingStatusMonitored) {
         mScramblingStatusMonitored = newScramblingStatus;
         if (mScramblingStatusMonitored) {
-            if (mCallback != nullptr) {
+            if (mCallbackScheduler.hasCallbackRegistered()) {
                 // Assuming current status is always NOT_SCRAMBLED
-                vector<DemuxFilterEvent> events;
-                DemuxFilterMonitorEvent monitorEvent;
-                events.resize(1);
-                monitorEvent.set<DemuxFilterMonitorEvent::Tag::scramblingStatus>(
+                auto monitorEvent = DemuxFilterMonitorEvent::make<
+                        DemuxFilterMonitorEvent::Tag::scramblingStatus>(
                         ScramblingStatus::NOT_SCRAMBLED);
-                events[0].set<DemuxFilterEvent::monitorEvent>(monitorEvent);
-                mCallback->onFilterEvent(events);
+                auto event =
+                        DemuxFilterEvent::make<DemuxFilterEvent::Tag::monitorEvent>(monitorEvent);
+                mCallbackScheduler.onFilterEvent(std::move(event));
             } else {
                 return ::ndk::ScopedAStatus::fromServiceSpecificError(
                         static_cast<int32_t>(Result::INVALID_STATE));
@@ -347,14 +478,13 @@
     if (newIpCid ^ mIpCidMonitored) {
         mIpCidMonitored = newIpCid;
         if (mIpCidMonitored) {
-            if (mCallback != nullptr) {
+            if (mCallbackScheduler.hasCallbackRegistered()) {
                 // Return random cid
-                vector<DemuxFilterEvent> events;
-                DemuxFilterMonitorEvent monitorEvent;
-                events.resize(1);
-                monitorEvent.set<DemuxFilterMonitorEvent::Tag::cid>(1);
-                events[0].set<DemuxFilterEvent::monitorEvent>(monitorEvent);
-                mCallback->onFilterEvent(events);
+                auto monitorEvent =
+                        DemuxFilterMonitorEvent::make<DemuxFilterMonitorEvent::Tag::cid>(1);
+                auto event =
+                        DemuxFilterEvent::make<DemuxFilterEvent::Tag::monitorEvent>(monitorEvent);
+                mCallbackScheduler.onFilterEvent(std::move(event));
             } else {
                 return ::ndk::ScopedAStatus::fromServiceSpecificError(
                         static_cast<int32_t>(Result::INVALID_STATE));
@@ -410,26 +540,26 @@
         }
 
         // After successfully write, send a callback and wait for the read to be done
-        if (mCallback != nullptr) {
+        if (mCallbackScheduler.hasCallbackRegistered()) {
             if (mConfigured) {
-                vector<DemuxFilterEvent> startEvent;
-                startEvent.resize(1);
-                startEvent[0].set<DemuxFilterEvent::Tag::startId>(mStartId++);
-                mCallback->onFilterEvent(startEvent);
+                auto startEvent =
+                        DemuxFilterEvent::make<DemuxFilterEvent::Tag::startId>(mStartId++);
+                mCallbackScheduler.onFilterEvent(std::move(startEvent));
                 mConfigured = false;
             }
-            mCallback->onFilterEvent(mFilterEvents);
+
+            for (auto&& event : mFilterEvents) {
+                mCallbackScheduler.onFilterEvent(std::move(event));
+            }
         } else {
             ALOGD("[Filter] filter callback is not configured yet.");
             mFilterThreadRunning = false;
             return;
         }
 
-        mFilterEvents.resize(0);
+        mFilterEvents.clear();
         mFilterStatus = DemuxFilterStatus::DATA_READY;
-        if (mCallback != nullptr) {
-            mCallback->onFilterStatus(mFilterStatus);
-        }
+        mCallbackScheduler.onFilterStatus(mFilterStatus);
         break;
     }
 
@@ -460,10 +590,10 @@
                     continue;
                 }
                 // After successfully write, send a callback and wait for the read to be done
-                if (mCallback != nullptr) {
-                    mCallback->onFilterEvent(mFilterEvents);
+                for (auto&& event : mFilterEvents) {
+                    mCallbackScheduler.onFilterEvent(std::move(event));
                 }
-                mFilterEvents.resize(0);
+                mFilterEvents.clear();
                 break;
             }
             // We do not wait for the last read to be done
@@ -499,9 +629,7 @@
     DemuxFilterStatus newStatus = checkFilterStatusChange(
             availableToWrite, availableToRead, ceil(fmqSize * 0.75), ceil(fmqSize * 0.25));
     if (mFilterStatus != newStatus) {
-        if (mCallback != nullptr) {
-            mCallback->onFilterStatus(newStatus);
-        }
+        mCallbackScheduler.onFilterStatus(newStatus);
         mFilterStatus = newStatus;
     }
 }
@@ -657,9 +785,7 @@
             ALOGD("[Filter] assembled pes data length %d", pesEvent.dataLength);
         }
 
-        int size = mFilterEvents.size();
-        mFilterEvents.resize(size + 1);
-        mFilterEvents[size].set<DemuxFilterEvent::Tag::pes>(pesEvent);
+        mFilterEvents.push_back(DemuxFilterEvent::make<DemuxFilterEvent::Tag::pes>(pesEvent));
         mPesOutput.clear();
     }
 
@@ -763,11 +889,7 @@
             .firstMbInSlice = 0,  // random address
     };
 
-    int size;
-    size = mFilterEvents.size();
-    mFilterEvents.resize(size + 1);
-    mFilterEvents[size].set<DemuxFilterEvent::Tag::tsRecord>(recordEvent);
-
+    mFilterEvents.push_back(DemuxFilterEvent::make<DemuxFilterEvent::Tag::tsRecord>(recordEvent));
     mRecordFilterOutput.clear();
     return ::ndk::ScopedAStatus::ok();
 }
@@ -789,8 +911,6 @@
     if (!writeDataToFilterMQ(data)) {
         return false;
     }
-    int size = mFilterEvents.size();
-    mFilterEvents.resize(size + 1);
     DemuxFilterSectionEvent secEvent;
     secEvent = {
             // temp dump meta data
@@ -799,7 +919,7 @@
             .sectionNum = 1,
             .dataLength = static_cast<int32_t>(data.size()),
     };
-    mFilterEvents[size].set<DemuxFilterEvent::Tag::section>(secEvent);
+    mFilterEvents.push_back(DemuxFilterEvent::make<DemuxFilterEvent::Tag::section>(secEvent));
     return true;
 }
 
@@ -888,19 +1008,16 @@
     mDataId2Avfd[dataId] = dup(av_fd);
 
     // Create mediaEvent and send callback
-    int size = mFilterEvents.size();
-    mFilterEvents.resize(size + 1);
-
-    mFilterEvents[size] = DemuxFilterEvent::make<DemuxFilterEvent::Tag::media>();
-    mFilterEvents[size].get<DemuxFilterEvent::Tag::media>().avMemory =
-            ::android::dupToAidl(nativeHandle);
-    mFilterEvents[size].get<DemuxFilterEvent::Tag::media>().dataLength =
-            static_cast<int64_t>(output.size());
-    mFilterEvents[size].get<DemuxFilterEvent::Tag::media>().avDataId = static_cast<int64_t>(dataId);
+    auto event = DemuxFilterEvent::make<DemuxFilterEvent::Tag::media>();
+    auto& mediaEvent = event.get<DemuxFilterEvent::Tag::media>();
+    mediaEvent.avMemory = ::android::dupToAidl(nativeHandle);
+    mediaEvent.dataLength = static_cast<int64_t>(output.size());
+    mediaEvent.avDataId = static_cast<int64_t>(dataId);
     if (mPts) {
-        mFilterEvents[size].get<DemuxFilterEvent::Tag::media>().pts = mPts;
+        mediaEvent.pts = mPts;
         mPts = 0;
     }
+    mFilterEvents.push_back(std::move(event));
 
     // Clear and log
     native_handle_close(nativeHandle);
@@ -931,18 +1048,17 @@
     }
 
     // Create mediaEvent and send callback
-    int size = mFilterEvents.size();
-    mFilterEvents.resize(size + 1);
-    mFilterEvents[size] = DemuxFilterEvent::make<DemuxFilterEvent::Tag::media>();
-    mFilterEvents[size].get<DemuxFilterEvent::Tag::media>().avMemory =
-            ::android::dupToAidl(nativeHandle);
-    mFilterEvents[size].get<DemuxFilterEvent::Tag::media>().offset = mSharedAvMemOffset;
-    mFilterEvents[size].get<DemuxFilterEvent::Tag::media>().dataLength =
-            static_cast<int64_t>(output.size());
+    auto event = DemuxFilterEvent::make<DemuxFilterEvent::Tag::media>();
+    auto& mediaEvent = event.get<DemuxFilterEvent::Tag::media>();
+    mediaEvent.avMemory = ::android::dupToAidl(nativeHandle);
+    mediaEvent.offset = mSharedAvMemOffset;
+    mediaEvent.dataLength = static_cast<int64_t>(output.size());
     if (mPts) {
-        mFilterEvents[size].get<DemuxFilterEvent::Tag::media>().pts = mPts;
+        mediaEvent.pts = mPts;
         mPts = 0;
     }
+    mFilterEvents.push_back(std::move(event));
+
     mSharedAvMemOffset += output.size();
 
     // Clear and log
diff --git a/tv/tuner/aidl/default/Filter.h b/tv/tuner/aidl/default/Filter.h
index 11bbc11..a5adf4c 100644
--- a/tv/tuner/aidl/default/Filter.h
+++ b/tv/tuner/aidl/default/Filter.h
@@ -18,6 +18,8 @@
 
 #include <aidl/android/hardware/tv/tuner/BnFilter.h>
 #include <aidl/android/hardware/tv/tuner/Constant.h>
+#include <aidl/android/hardware/tv/tuner/DemuxFilterEvent.h>
+#include <aidl/android/hardware/tv/tuner/DemuxFilterStatus.h>
 
 #include <fmq/AidlMessageQueue.h>
 #include <inttypes.h>
@@ -25,6 +27,7 @@
 #include <math.h>
 #include <sys/stat.h>
 #include <atomic>
+#include <condition_variable>
 #include <set>
 #include <thread>
 
@@ -52,10 +55,49 @@
 class Demux;
 class Dvr;
 
-class Filter : public BnFilter {
+class FilterCallbackScheduler final {
   public:
-    Filter();
+    FilterCallbackScheduler(const std::shared_ptr<IFilterCallback>& cb);
+    ~FilterCallbackScheduler();
 
+    void onFilterEvent(DemuxFilterEvent&& event);
+    void onFilterStatus(const DemuxFilterStatus& status);
+
+    void setTimeDelayHint(int timeDelay);
+    void setDataSizeDelayHint(int dataSizeDelay);
+
+    bool hasCallbackRegistered() const;
+
+  private:
+    void start();
+    void stop();
+
+    void threadLoop();
+    void threadLoopOnce();
+
+    static int getDemuxFilterEventDataLength(const DemuxFilterEvent& event);
+
+  private:
+    std::shared_ptr<IFilterCallback> mCallback;
+    std::thread mCallbackThread;
+    std::atomic<bool> mIsRunning;
+
+    // mLock protects mCallbackBuffer, mCv, and mDataLength
+    std::mutex mLock;
+    std::vector<DemuxFilterEvent> mCallbackBuffer;
+    std::condition_variable mCv;
+    int mDataLength;
+
+    // both of these need to be atomic (not just mTimeDelayInMs) as this class
+    // needs to be threadsafe.
+    std::atomic<int> mTimeDelayInMs;
+    std::atomic<int> mDataSizeDelayInBytes;
+};
+
+class Filter : public BnFilter {
+    friend class FilterCallbackScheduler;
+
+  public:
     Filter(DemuxFilterType type, int64_t filterId, uint32_t bufferSize,
            const std::shared_ptr<IFilterCallback>& cb, std::shared_ptr<Demux> demux);
 
@@ -104,10 +146,8 @@
     std::shared_ptr<Demux> mDemux;
     // Dvr reference once the filter is attached to any
     std::shared_ptr<Dvr> mDvr = nullptr;
-    /**
-     * Filter callbacks used on filter events or FMQ status
-     */
-    std::shared_ptr<IFilterCallback> mCallback = nullptr;
+
+    FilterCallbackScheduler mCallbackScheduler;
 
     int64_t mFilterId;
     int32_t mCid = static_cast<int32_t>(Constant::INVALID_IP_FILTER_CONTEXT_ID);
diff --git a/tv/tuner/aidl/vts/functional/FilterTests.h b/tv/tuner/aidl/vts/functional/FilterTests.h
index 91a0a4a..c965d95 100644
--- a/tv/tuner/aidl/vts/functional/FilterTests.h
+++ b/tv/tuner/aidl/vts/functional/FilterTests.h
@@ -74,7 +74,6 @@
 
     void setFilterId(int32_t filterId) { mFilterId = filterId; }
     void setFilterInterface(std::shared_ptr<IFilter> filter) { mFilter = filter; }
-    void setFilterEventType(FilterEventType type) { mFilterEventType = type; }
     void setSharedHandle(native_handle_t* sharedHandle) { mAvSharedHandle = sharedHandle; }
     void setMemSize(uint64_t size) { mAvSharedMemSize = size; }
 
@@ -89,7 +88,6 @@
   private:
     int32_t mFilterId;
     std::shared_ptr<IFilter> mFilter;
-    FilterEventType mFilterEventType;
 
     native_handle_t* mAvSharedHandle = nullptr;
     uint64_t mAvSharedMemSize = -1;