Add canonical types adapters for NNAPI AIDL interface

Also:
* Add missing AIDL<->CT conversions
* Add AIDL-specific info to neuralnetworks/utils/README.md
* Add mock classes and tests AIDL adapters

Bug: 179015258
Test: neuralnetworks_utils_hal_test
Change-Id: Ifa98fadd46dca5dbf9b3ceb4da811aa8da45b6e4
Merged-In: Ifa98fadd46dca5dbf9b3ceb4da811aa8da45b6e4
(cherry picked from commit 3b93b0b56a4f5128eaa942d804dd490317c0abcb)
diff --git a/neuralnetworks/aidl/utils/src/Buffer.cpp b/neuralnetworks/aidl/utils/src/Buffer.cpp
new file mode 100644
index 0000000..c729a68
--- /dev/null
+++ b/neuralnetworks/aidl/utils/src/Buffer.cpp
@@ -0,0 +1,78 @@
+/*
+ * 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 "Buffer.h"
+
+#include <nnapi/IPreparedModel.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+
+#include "Conversions.h"
+#include "Utils.h"
+#include "nnapi/hal/aidl/Conversions.h"
+
+#include <memory>
+#include <utility>
+
+// See hardware/interfaces/neuralnetworks/utils/README.md for more information on AIDL interface
+// lifetimes across processes.
+
+namespace aidl::android::hardware::neuralnetworks::utils {
+
+nn::GeneralResult<std::shared_ptr<const Buffer>> Buffer::create(
+        std::shared_ptr<aidl_hal::IBuffer> buffer, nn::Request::MemoryDomainToken token) {
+    if (buffer == nullptr) {
+        return NN_ERROR() << "aidl_hal::utils::Buffer::create must have non-null buffer";
+    }
+    if (token == static_cast<nn::Request::MemoryDomainToken>(0)) {
+        return NN_ERROR() << "aidl_hal::utils::Buffer::create must have non-zero token";
+    }
+
+    return std::make_shared<const Buffer>(PrivateConstructorTag{}, std::move(buffer), token);
+}
+
+Buffer::Buffer(PrivateConstructorTag /*tag*/, std::shared_ptr<aidl_hal::IBuffer> buffer,
+               nn::Request::MemoryDomainToken token)
+    : kBuffer(std::move(buffer)), kToken(token) {
+    CHECK(kBuffer != nullptr);
+    CHECK(kToken != static_cast<nn::Request::MemoryDomainToken>(0));
+}
+
+nn::Request::MemoryDomainToken Buffer::getToken() const {
+    return kToken;
+}
+
+nn::GeneralResult<void> Buffer::copyTo(const nn::SharedMemory& dst) const {
+    const auto aidlDst = NN_TRY(convert(dst));
+
+    const auto ret = kBuffer->copyTo(aidlDst);
+    HANDLE_ASTATUS(ret) << "IBuffer::copyTo failed";
+
+    return {};
+}
+
+nn::GeneralResult<void> Buffer::copyFrom(const nn::SharedMemory& src,
+                                         const nn::Dimensions& dimensions) const {
+    const auto aidlSrc = NN_TRY(convert(src));
+    const auto aidlDimensions = NN_TRY(toSigned(dimensions));
+
+    const auto ret = kBuffer->copyFrom(aidlSrc, aidlDimensions);
+    HANDLE_ASTATUS(ret) << "IBuffer::copyFrom failed";
+
+    return {};
+}
+
+}  // namespace aidl::android::hardware::neuralnetworks::utils
diff --git a/neuralnetworks/aidl/utils/src/Callbacks.cpp b/neuralnetworks/aidl/utils/src/Callbacks.cpp
new file mode 100644
index 0000000..8055665
--- /dev/null
+++ b/neuralnetworks/aidl/utils/src/Callbacks.cpp
@@ -0,0 +1,61 @@
+/*
+ * 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 "Callbacks.h"
+
+#include "Conversions.h"
+#include "PreparedModel.h"
+#include "ProtectCallback.h"
+#include "Utils.h"
+
+#include <nnapi/IPreparedModel.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+
+#include <utility>
+
+// See hardware/interfaces/neuralnetworks/utils/README.md for more information on AIDL interface
+// lifetimes across processes and for protecting asynchronous calls across AIDL.
+
+namespace aidl::android::hardware::neuralnetworks::utils {
+namespace {
+
+// Converts the results of IDevice::prepareModel* to the NN canonical format. On success, this
+// function returns with a non-null nn::SharedPreparedModel with a feature level of
+// nn::Version::ANDROID_S. On failure, this function returns with the appropriate nn::GeneralError.
+nn::GeneralResult<nn::SharedPreparedModel> prepareModelCallback(
+        ErrorStatus status, const std::shared_ptr<IPreparedModel>& preparedModel) {
+    HANDLE_HAL_STATUS(status) << "model preparation failed with " << toString(status);
+    return NN_TRY(PreparedModel::create(preparedModel));
+}
+
+}  // namespace
+
+ndk::ScopedAStatus PreparedModelCallback::notify(
+        ErrorStatus status, const std::shared_ptr<IPreparedModel>& preparedModel) {
+    mData.put(prepareModelCallback(status, preparedModel));
+    return ndk::ScopedAStatus::ok();
+}
+
+void PreparedModelCallback::notifyAsDeadObject() {
+    mData.put(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
+}
+
+PreparedModelCallback::Data PreparedModelCallback::get() {
+    return mData.take();
+}
+
+}  // namespace aidl::android::hardware::neuralnetworks::utils
diff --git a/neuralnetworks/aidl/utils/src/Conversions.cpp b/neuralnetworks/aidl/utils/src/Conversions.cpp
index db3504b..5d9c55b 100644
--- a/neuralnetworks/aidl/utils/src/Conversions.cpp
+++ b/neuralnetworks/aidl/utils/src/Conversions.cpp
@@ -18,6 +18,8 @@
 
 #include <aidl/android/hardware/common/NativeHandle.h>
 #include <android-base/logging.h>
+#include <android-base/unique_fd.h>
+#include <android/binder_auto_utils.h>
 #include <android/hardware_buffer.h>
 #include <cutils/native_handle.h>
 #include <nnapi/OperandTypes.h>
@@ -42,14 +44,17 @@
 #define VERIFY_NON_NEGATIVE(value) \
     while (UNLIKELY(value < 0)) return NN_ERROR()
 
-namespace {
+#define VERIFY_LE_INT32_MAX(value) \
+    while (UNLIKELY(value > std::numeric_limits<int32_t>::max())) return NN_ERROR()
 
+namespace {
 template <typename Type>
 constexpr std::underlying_type_t<Type> underlyingType(Type value) {
     return static_cast<std::underlying_type_t<Type>>(value);
 }
 
 constexpr auto kVersion = android::nn::Version::ANDROID_S;
+constexpr int64_t kNoTiming = -1;
 
 }  // namespace
 
@@ -134,13 +139,8 @@
     std::vector<base::unique_fd> fds;
     fds.reserve(aidlNativeHandle.fds.size());
     for (const auto& fd : aidlNativeHandle.fds) {
-        const int dupFd = dup(fd.get());
-        if (dupFd == -1) {
-            // TODO(b/120417090): is ANEURALNETWORKS_UNEXPECTED_NULL the correct error to return
-            // here?
-            return NN_ERROR() << "Failed to dup the fd";
-        }
-        fds.emplace_back(dupFd);
+        auto duplicatedFd = NN_TRY(dupFd(fd.get()));
+        fds.emplace_back(duplicatedFd.release());
     }
 
     return Handle{.fds = std::move(fds), .ints = aidlNativeHandle.ints};
@@ -157,16 +157,12 @@
 
 using UniqueNativeHandle = std::unique_ptr<native_handle_t, NativeHandleDeleter>;
 
-static nn::GeneralResult<UniqueNativeHandle> nativeHandleFromAidlHandle(
-        const NativeHandle& handle) {
+static GeneralResult<UniqueNativeHandle> nativeHandleFromAidlHandle(const NativeHandle& handle) {
     std::vector<base::unique_fd> fds;
     fds.reserve(handle.fds.size());
     for (const auto& fd : handle.fds) {
-        const int dupFd = dup(fd.get());
-        if (dupFd == -1) {
-            return NN_ERROR() << "Failed to dup the fd";
-        }
-        fds.emplace_back(dupFd);
+        auto duplicatedFd = NN_TRY(dupFd(fd.get()));
+        fds.emplace_back(duplicatedFd.release());
     }
 
     constexpr size_t kIntMax = std::numeric_limits<int>::max();
@@ -382,14 +378,14 @@
 
 GeneralResult<SharedMemory> unvalidatedConvert(const aidl_hal::Memory& memory) {
     VERIFY_NON_NEGATIVE(memory.size) << "Memory size must not be negative";
-    if (memory.size > std::numeric_limits<uint32_t>::max()) {
+    if (memory.size > std::numeric_limits<size_t>::max()) {
         return NN_ERROR() << "Memory: size must be <= std::numeric_limits<size_t>::max()";
     }
 
     if (memory.name != "hardware_buffer_blob") {
         return std::make_shared<const Memory>(Memory{
                 .handle = NN_TRY(unvalidatedConvertHelper(memory.handle)),
-                .size = static_cast<uint32_t>(memory.size),
+                .size = static_cast<size_t>(memory.size),
                 .name = memory.name,
         });
     }
@@ -434,11 +430,28 @@
 
     return std::make_shared<const Memory>(Memory{
             .handle = HardwareBufferHandle(hardwareBuffer, /*takeOwnership=*/true),
-            .size = static_cast<uint32_t>(memory.size),
+            .size = static_cast<size_t>(memory.size),
             .name = memory.name,
     });
 }
 
+GeneralResult<Timing> unvalidatedConvert(const aidl_hal::Timing& timing) {
+    if (timing.timeInDriver < -1) {
+        return NN_ERROR() << "Timing: timeInDriver must not be less than -1";
+    }
+    if (timing.timeOnDevice < -1) {
+        return NN_ERROR() << "Timing: timeOnDevice must not be less than -1";
+    }
+    constexpr auto convertTiming = [](int64_t halTiming) -> OptionalDuration {
+        if (halTiming == kNoTiming) {
+            return {};
+        }
+        return nn::Duration(static_cast<uint64_t>(halTiming));
+    };
+    return Timing{.timeOnDevice = convertTiming(timing.timeOnDevice),
+                  .timeInDriver = convertTiming(timing.timeInDriver)};
+}
+
 GeneralResult<Model::OperandValues> unvalidatedConvert(const std::vector<uint8_t>& operandValues) {
     return Model::OperandValues(operandValues.data(), operandValues.size());
 }
@@ -515,6 +528,23 @@
     return std::make_shared<const Handle>(NN_TRY(unvalidatedConvertHelper(aidlNativeHandle)));
 }
 
+GeneralResult<SyncFence> unvalidatedConvert(const ndk::ScopedFileDescriptor& syncFence) {
+    auto duplicatedFd = NN_TRY(dupFd(syncFence.get()));
+    return SyncFence::create(std::move(duplicatedFd));
+}
+
+GeneralResult<Capabilities> convert(const aidl_hal::Capabilities& capabilities) {
+    return validatedConvert(capabilities);
+}
+
+GeneralResult<DeviceType> convert(const aidl_hal::DeviceType& deviceType) {
+    return validatedConvert(deviceType);
+}
+
+GeneralResult<ErrorStatus> convert(const aidl_hal::ErrorStatus& errorStatus) {
+    return validatedConvert(errorStatus);
+}
+
 GeneralResult<ExecutionPreference> convert(
         const aidl_hal::ExecutionPreference& executionPreference) {
     return validatedConvert(executionPreference);
@@ -548,6 +578,18 @@
     return validatedConvert(request);
 }
 
+GeneralResult<Timing> convert(const aidl_hal::Timing& timing) {
+    return validatedConvert(timing);
+}
+
+GeneralResult<SyncFence> convert(const ndk::ScopedFileDescriptor& syncFence) {
+    return unvalidatedConvert(syncFence);
+}
+
+GeneralResult<std::vector<Extension>> convert(const std::vector<aidl_hal::Extension>& extension) {
+    return validatedConvert(extension);
+}
+
 GeneralResult<std::vector<Operation>> convert(const std::vector<aidl_hal::Operation>& operations) {
     return unvalidatedConvert(operations);
 }
@@ -556,6 +598,11 @@
     return validatedConvert(memories);
 }
 
+GeneralResult<std::vector<OutputShape>> convert(
+        const std::vector<aidl_hal::OutputShape>& outputShapes) {
+    return validatedConvert(outputShapes);
+}
+
 GeneralResult<std::vector<uint32_t>> toUnsigned(const std::vector<int32_t>& vec) {
     if (!std::all_of(vec.begin(), vec.end(), [](int32_t v) { return v >= 0; })) {
         return NN_ERROR() << "Negative value passed to conversion from signed to unsigned";
@@ -575,14 +622,21 @@
 template <typename Type>
 nn::GeneralResult<std::vector<UnvalidatedConvertOutput<Type>>> unvalidatedConvertVec(
         const std::vector<Type>& arguments) {
-    std::vector<UnvalidatedConvertOutput<Type>> halObject(arguments.size());
-    for (size_t i = 0; i < arguments.size(); ++i) {
-        halObject[i] = NN_TRY(unvalidatedConvert(arguments[i]));
+    std::vector<UnvalidatedConvertOutput<Type>> halObject;
+    halObject.reserve(arguments.size());
+    for (const auto& argument : arguments) {
+        halObject.push_back(NN_TRY(unvalidatedConvert(argument)));
     }
     return halObject;
 }
 
 template <typename Type>
+nn::GeneralResult<std::vector<UnvalidatedConvertOutput<Type>>> unvalidatedConvert(
+        const std::vector<Type>& arguments) {
+    return unvalidatedConvertVec(arguments);
+}
+
+template <typename Type>
 nn::GeneralResult<UnvalidatedConvertOutput<Type>> validatedConvert(const Type& canonical) {
     const auto maybeVersion = nn::validate(canonical);
     if (!maybeVersion.has_value()) {
@@ -609,29 +663,29 @@
     common::NativeHandle aidlNativeHandle;
     aidlNativeHandle.fds.reserve(handle.fds.size());
     for (const auto& fd : handle.fds) {
-        const int dupFd = dup(fd.get());
-        if (dupFd == -1) {
-            // TODO(b/120417090): is ANEURALNETWORKS_UNEXPECTED_NULL the correct error to return
-            // here?
-            return NN_ERROR() << "Failed to dup the fd";
-        }
-        aidlNativeHandle.fds.emplace_back(dupFd);
+        auto duplicatedFd = NN_TRY(nn::dupFd(fd.get()));
+        aidlNativeHandle.fds.emplace_back(duplicatedFd.release());
     }
     aidlNativeHandle.ints = handle.ints;
     return aidlNativeHandle;
 }
 
+// Helper template for std::visit
+template <class... Ts>
+struct overloaded : Ts... {
+    using Ts::operator()...;
+};
+template <class... Ts>
+overloaded(Ts...)->overloaded<Ts...>;
+
 static nn::GeneralResult<common::NativeHandle> aidlHandleFromNativeHandle(
         const native_handle_t& handle) {
     common::NativeHandle aidlNativeHandle;
 
     aidlNativeHandle.fds.reserve(handle.numFds);
     for (int i = 0; i < handle.numFds; ++i) {
-        const int dupFd = dup(handle.data[i]);
-        if (dupFd == -1) {
-            return NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "Failed to dup the fd";
-        }
-        aidlNativeHandle.fds.emplace_back(dupFd);
+        auto duplicatedFd = NN_TRY(nn::dupFd(handle.data[i]));
+        aidlNativeHandle.fds.emplace_back(duplicatedFd.release());
     }
 
     aidlNativeHandle.ints = std::vector<int>(&handle.data[handle.numFds],
@@ -642,6 +696,30 @@
 
 }  // namespace
 
+nn::GeneralResult<std::vector<uint8_t>> unvalidatedConvert(const nn::CacheToken& cacheToken) {
+    return std::vector<uint8_t>(cacheToken.begin(), cacheToken.end());
+}
+
+nn::GeneralResult<BufferDesc> unvalidatedConvert(const nn::BufferDesc& bufferDesc) {
+    return BufferDesc{.dimensions = NN_TRY(toSigned(bufferDesc.dimensions))};
+}
+
+nn::GeneralResult<BufferRole> unvalidatedConvert(const nn::BufferRole& bufferRole) {
+    VERIFY_LE_INT32_MAX(bufferRole.modelIndex)
+            << "BufferRole: modelIndex must be <= std::numeric_limits<int32_t>::max()";
+    VERIFY_LE_INT32_MAX(bufferRole.ioIndex)
+            << "BufferRole: ioIndex must be <= std::numeric_limits<int32_t>::max()";
+    return BufferRole{
+            .modelIndex = static_cast<int32_t>(bufferRole.modelIndex),
+            .ioIndex = static_cast<int32_t>(bufferRole.ioIndex),
+            .frequency = bufferRole.frequency,
+    };
+}
+
+nn::GeneralResult<bool> unvalidatedConvert(const nn::MeasureTiming& measureTiming) {
+    return measureTiming == nn::MeasureTiming::YES;
+}
+
 nn::GeneralResult<common::NativeHandle> unvalidatedConvert(const nn::SharedHandle& sharedHandle) {
     CHECK(sharedHandle != nullptr);
     return unvalidatedConvert(*sharedHandle);
@@ -707,6 +785,230 @@
                        .isSufficient = outputShape.isSufficient};
 }
 
+nn::GeneralResult<ExecutionPreference> unvalidatedConvert(
+        const nn::ExecutionPreference& executionPreference) {
+    return static_cast<ExecutionPreference>(executionPreference);
+}
+
+nn::GeneralResult<OperandType> unvalidatedConvert(const nn::OperandType& operandType) {
+    return static_cast<OperandType>(operandType);
+}
+
+nn::GeneralResult<OperandLifeTime> unvalidatedConvert(
+        const nn::Operand::LifeTime& operandLifeTime) {
+    return static_cast<OperandLifeTime>(operandLifeTime);
+}
+
+nn::GeneralResult<DataLocation> unvalidatedConvert(const nn::DataLocation& location) {
+    VERIFY_LE_INT32_MAX(location.poolIndex)
+            << "DataLocation: pool index must be <= std::numeric_limits<int32_t>::max()";
+    return DataLocation{
+            .poolIndex = static_cast<int32_t>(location.poolIndex),
+            .offset = static_cast<int64_t>(location.offset),
+            .length = static_cast<int64_t>(location.length),
+    };
+}
+
+nn::GeneralResult<std::optional<OperandExtraParams>> unvalidatedConvert(
+        const nn::Operand::ExtraParams& extraParams) {
+    return std::visit(
+            overloaded{
+                    [](const nn::Operand::NoParams&)
+                            -> nn::GeneralResult<std::optional<OperandExtraParams>> {
+                        return std::nullopt;
+                    },
+                    [](const nn::Operand::SymmPerChannelQuantParams& symmPerChannelQuantParams)
+                            -> nn::GeneralResult<std::optional<OperandExtraParams>> {
+                        if (symmPerChannelQuantParams.channelDim >
+                            std::numeric_limits<int32_t>::max()) {
+                            // Using explicit type conversion because std::optional in successful
+                            // result confuses the compiler.
+                            return (NN_ERROR() << "symmPerChannelQuantParams.channelDim must be <= "
+                                                  "std::numeric_limits<int32_t>::max(), received: "
+                                               << symmPerChannelQuantParams.channelDim)
+                                    .
+                                    operator nn::GeneralResult<std::optional<OperandExtraParams>>();
+                        }
+                        return OperandExtraParams::make<OperandExtraParams::Tag::channelQuant>(
+                                SymmPerChannelQuantParams{
+                                        .scales = symmPerChannelQuantParams.scales,
+                                        .channelDim = static_cast<int32_t>(
+                                                symmPerChannelQuantParams.channelDim),
+                                });
+                    },
+                    [](const nn::Operand::ExtensionParams& extensionParams)
+                            -> nn::GeneralResult<std::optional<OperandExtraParams>> {
+                        return OperandExtraParams::make<OperandExtraParams::Tag::extension>(
+                                extensionParams);
+                    },
+            },
+            extraParams);
+}
+
+nn::GeneralResult<Operand> unvalidatedConvert(const nn::Operand& operand) {
+    return Operand{
+            .type = NN_TRY(unvalidatedConvert(operand.type)),
+            .dimensions = NN_TRY(toSigned(operand.dimensions)),
+            .scale = operand.scale,
+            .zeroPoint = operand.zeroPoint,
+            .lifetime = NN_TRY(unvalidatedConvert(operand.lifetime)),
+            .location = NN_TRY(unvalidatedConvert(operand.location)),
+            .extraParams = NN_TRY(unvalidatedConvert(operand.extraParams)),
+    };
+}
+
+nn::GeneralResult<OperationType> unvalidatedConvert(const nn::OperationType& operationType) {
+    return static_cast<OperationType>(operationType);
+}
+
+nn::GeneralResult<Operation> unvalidatedConvert(const nn::Operation& operation) {
+    return Operation{
+            .type = NN_TRY(unvalidatedConvert(operation.type)),
+            .inputs = NN_TRY(toSigned(operation.inputs)),
+            .outputs = NN_TRY(toSigned(operation.outputs)),
+    };
+}
+
+nn::GeneralResult<Subgraph> unvalidatedConvert(const nn::Model::Subgraph& subgraph) {
+    return Subgraph{
+            .operands = NN_TRY(unvalidatedConvert(subgraph.operands)),
+            .operations = NN_TRY(unvalidatedConvert(subgraph.operations)),
+            .inputIndexes = NN_TRY(toSigned(subgraph.inputIndexes)),
+            .outputIndexes = NN_TRY(toSigned(subgraph.outputIndexes)),
+    };
+}
+
+nn::GeneralResult<std::vector<uint8_t>> unvalidatedConvert(
+        const nn::Model::OperandValues& operandValues) {
+    return std::vector<uint8_t>(operandValues.data(), operandValues.data() + operandValues.size());
+}
+
+nn::GeneralResult<ExtensionNameAndPrefix> unvalidatedConvert(
+        const nn::Model::ExtensionNameAndPrefix& extensionNameToPrefix) {
+    return ExtensionNameAndPrefix{
+            .name = extensionNameToPrefix.name,
+            .prefix = extensionNameToPrefix.prefix,
+    };
+}
+
+nn::GeneralResult<Model> unvalidatedConvert(const nn::Model& model) {
+    return Model{
+            .main = NN_TRY(unvalidatedConvert(model.main)),
+            .referenced = NN_TRY(unvalidatedConvert(model.referenced)),
+            .operandValues = NN_TRY(unvalidatedConvert(model.operandValues)),
+            .pools = NN_TRY(unvalidatedConvert(model.pools)),
+            .relaxComputationFloat32toFloat16 = model.relaxComputationFloat32toFloat16,
+            .extensionNameToPrefix = NN_TRY(unvalidatedConvert(model.extensionNameToPrefix)),
+    };
+}
+
+nn::GeneralResult<Priority> unvalidatedConvert(const nn::Priority& priority) {
+    return static_cast<Priority>(priority);
+}
+
+nn::GeneralResult<Request> unvalidatedConvert(const nn::Request& request) {
+    return Request{
+            .inputs = NN_TRY(unvalidatedConvert(request.inputs)),
+            .outputs = NN_TRY(unvalidatedConvert(request.outputs)),
+            .pools = NN_TRY(unvalidatedConvert(request.pools)),
+    };
+}
+
+nn::GeneralResult<RequestArgument> unvalidatedConvert(
+        const nn::Request::Argument& requestArgument) {
+    if (requestArgument.lifetime == nn::Request::Argument::LifeTime::POINTER) {
+        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
+               << "Request cannot be unvalidatedConverted because it contains pointer-based memory";
+    }
+    const bool hasNoValue = requestArgument.lifetime == nn::Request::Argument::LifeTime::NO_VALUE;
+    return RequestArgument{
+            .hasNoValue = hasNoValue,
+            .location = NN_TRY(unvalidatedConvert(requestArgument.location)),
+            .dimensions = NN_TRY(toSigned(requestArgument.dimensions)),
+    };
+}
+
+nn::GeneralResult<RequestMemoryPool> unvalidatedConvert(const nn::Request::MemoryPool& memoryPool) {
+    return std::visit(
+            overloaded{
+                    [](const nn::SharedMemory& memory) -> nn::GeneralResult<RequestMemoryPool> {
+                        return RequestMemoryPool::make<RequestMemoryPool::Tag::pool>(
+                                NN_TRY(unvalidatedConvert(memory)));
+                    },
+                    [](const nn::Request::MemoryDomainToken& token)
+                            -> nn::GeneralResult<RequestMemoryPool> {
+                        return RequestMemoryPool::make<RequestMemoryPool::Tag::token>(
+                                underlyingType(token));
+                    },
+                    [](const nn::SharedBuffer& /*buffer*/) {
+                        return (NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
+                                << "Unable to make memory pool from IBuffer")
+                                .
+                                operator nn::GeneralResult<RequestMemoryPool>();
+                    },
+            },
+            memoryPool);
+}
+
+nn::GeneralResult<Timing> unvalidatedConvert(const nn::Timing& timing) {
+    return Timing{
+            .timeOnDevice = NN_TRY(unvalidatedConvert(timing.timeOnDevice)),
+            .timeInDriver = NN_TRY(unvalidatedConvert(timing.timeInDriver)),
+    };
+}
+
+nn::GeneralResult<int64_t> unvalidatedConvert(const nn::Duration& duration) {
+    const uint64_t nanoseconds = duration.count();
+    if (nanoseconds > std::numeric_limits<int64_t>::max()) {
+        return std::numeric_limits<int64_t>::max();
+    }
+    return static_cast<int64_t>(nanoseconds);
+}
+
+nn::GeneralResult<int64_t> unvalidatedConvert(const nn::OptionalDuration& optionalDuration) {
+    if (!optionalDuration.has_value()) {
+        return kNoTiming;
+    }
+    return unvalidatedConvert(optionalDuration.value());
+}
+
+nn::GeneralResult<int64_t> unvalidatedConvert(const nn::OptionalTimePoint& optionalTimePoint) {
+    if (!optionalTimePoint.has_value()) {
+        return kNoTiming;
+    }
+    return unvalidatedConvert(optionalTimePoint->time_since_epoch());
+}
+
+nn::GeneralResult<ndk::ScopedFileDescriptor> unvalidatedConvert(const nn::SyncFence& syncFence) {
+    auto duplicatedFd = NN_TRY(nn::dupFd(syncFence.getFd()));
+    return ndk::ScopedFileDescriptor(duplicatedFd.release());
+}
+
+nn::GeneralResult<ndk::ScopedFileDescriptor> unvalidatedConvertCache(
+        const nn::SharedHandle& handle) {
+    if (handle->ints.size() != 0) {
+        NN_ERROR() << "Cache handle must not contain ints";
+    }
+    if (handle->fds.size() != 1) {
+        NN_ERROR() << "Cache handle must contain exactly one fd but contains "
+                   << handle->fds.size();
+    }
+    auto duplicatedFd = NN_TRY(nn::dupFd(handle->fds.front().get()));
+    return ndk::ScopedFileDescriptor(duplicatedFd.release());
+}
+
+nn::GeneralResult<std::vector<uint8_t>> convert(const nn::CacheToken& cacheToken) {
+    return unvalidatedConvert(cacheToken);
+}
+
+nn::GeneralResult<BufferDesc> convert(const nn::BufferDesc& bufferDesc) {
+    return validatedConvert(bufferDesc);
+}
+
+nn::GeneralResult<bool> convert(const nn::MeasureTiming& measureTiming) {
+    return validatedConvert(measureTiming);
+}
+
 nn::GeneralResult<Memory> convert(const nn::SharedMemory& memory) {
     return validatedConvert(memory);
 }
@@ -715,11 +1017,62 @@
     return validatedConvert(errorStatus);
 }
 
+nn::GeneralResult<ExecutionPreference> convert(const nn::ExecutionPreference& executionPreference) {
+    return validatedConvert(executionPreference);
+}
+
+nn::GeneralResult<Model> convert(const nn::Model& model) {
+    return validatedConvert(model);
+}
+
+nn::GeneralResult<Priority> convert(const nn::Priority& priority) {
+    return validatedConvert(priority);
+}
+
+nn::GeneralResult<Request> convert(const nn::Request& request) {
+    return validatedConvert(request);
+}
+
+nn::GeneralResult<Timing> convert(const nn::Timing& timing) {
+    return validatedConvert(timing);
+}
+
+nn::GeneralResult<int64_t> convert(const nn::OptionalDuration& optionalDuration) {
+    return validatedConvert(optionalDuration);
+}
+
+nn::GeneralResult<int64_t> convert(const nn::OptionalTimePoint& outputShapes) {
+    return validatedConvert(outputShapes);
+}
+
+nn::GeneralResult<std::vector<BufferRole>> convert(const std::vector<nn::BufferRole>& bufferRoles) {
+    return validatedConvert(bufferRoles);
+}
+
 nn::GeneralResult<std::vector<OutputShape>> convert(
         const std::vector<nn::OutputShape>& outputShapes) {
     return validatedConvert(outputShapes);
 }
 
+nn::GeneralResult<std::vector<ndk::ScopedFileDescriptor>> convert(
+        const std::vector<nn::SharedHandle>& cacheHandles) {
+    const auto version = NN_TRY(hal::utils::makeGeneralFailure(nn::validate(cacheHandles)));
+    if (version > kVersion) {
+        return NN_ERROR() << "Insufficient version: " << version << " vs required " << kVersion;
+    }
+    std::vector<ndk::ScopedFileDescriptor> cacheFds;
+    cacheFds.reserve(cacheHandles.size());
+    for (const auto& cacheHandle : cacheHandles) {
+        cacheFds.push_back(NN_TRY(unvalidatedConvertCache(cacheHandle)));
+    }
+    return cacheFds;
+}
+
+nn::GeneralResult<std::vector<ndk::ScopedFileDescriptor>> convert(
+        const std::vector<nn::SyncFence>& syncFences) {
+    return unvalidatedConvert(syncFences);
+}
+
 nn::GeneralResult<std::vector<int32_t>> toSigned(const std::vector<uint32_t>& vec) {
     if (!std::all_of(vec.begin(), vec.end(),
                      [](uint32_t v) { return v <= std::numeric_limits<int32_t>::max(); })) {
diff --git a/neuralnetworks/aidl/utils/src/Device.cpp b/neuralnetworks/aidl/utils/src/Device.cpp
new file mode 100644
index 0000000..02ca861
--- /dev/null
+++ b/neuralnetworks/aidl/utils/src/Device.cpp
@@ -0,0 +1,294 @@
+/*
+ * 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 "Device.h"
+
+#include "Buffer.h"
+#include "Callbacks.h"
+#include "Conversions.h"
+#include "PreparedModel.h"
+#include "ProtectCallback.h"
+#include "Utils.h"
+
+#include <aidl/android/hardware/neuralnetworks/IDevice.h>
+#include <android/binder_auto_utils.h>
+#include <android/binder_interface_utils.h>
+#include <nnapi/IBuffer.h>
+#include <nnapi/IDevice.h>
+#include <nnapi/IPreparedModel.h>
+#include <nnapi/OperandTypes.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/CommonUtils.h>
+
+#include <any>
+#include <functional>
+#include <memory>
+#include <optional>
+#include <string>
+#include <vector>
+
+// See hardware/interfaces/neuralnetworks/utils/README.md for more information on AIDL interface
+// lifetimes across processes and for protecting asynchronous calls across AIDL.
+
+namespace aidl::android::hardware::neuralnetworks::utils {
+
+namespace {
+
+nn::GeneralResult<std::vector<std::shared_ptr<IPreparedModel>>> convert(
+        const std::vector<nn::SharedPreparedModel>& preparedModels) {
+    std::vector<std::shared_ptr<IPreparedModel>> aidlPreparedModels(preparedModels.size());
+    for (size_t i = 0; i < preparedModels.size(); ++i) {
+        std::any underlyingResource = preparedModels[i]->getUnderlyingResource();
+        if (const auto* aidlPreparedModel =
+                    std::any_cast<std::shared_ptr<aidl_hal::IPreparedModel>>(&underlyingResource)) {
+            aidlPreparedModels[i] = *aidlPreparedModel;
+        } else {
+            return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
+                   << "Unable to convert from nn::IPreparedModel to aidl_hal::IPreparedModel";
+        }
+    }
+    return aidlPreparedModels;
+}
+
+nn::GeneralResult<nn::Capabilities> getCapabilitiesFrom(IDevice* device) {
+    CHECK(device != nullptr);
+    Capabilities capabilities;
+    const auto ret = device->getCapabilities(&capabilities);
+    HANDLE_ASTATUS(ret) << "getCapabilities failed";
+    return nn::convert(capabilities);
+}
+
+nn::GeneralResult<std::string> getVersionStringFrom(aidl_hal::IDevice* device) {
+    CHECK(device != nullptr);
+    std::string version;
+    const auto ret = device->getVersionString(&version);
+    HANDLE_ASTATUS(ret) << "getVersionString failed";
+    return version;
+}
+
+nn::GeneralResult<nn::DeviceType> getDeviceTypeFrom(aidl_hal::IDevice* device) {
+    CHECK(device != nullptr);
+    DeviceType deviceType;
+    const auto ret = device->getType(&deviceType);
+    HANDLE_ASTATUS(ret) << "getDeviceType failed";
+    return nn::convert(deviceType);
+}
+
+nn::GeneralResult<std::vector<nn::Extension>> getSupportedExtensionsFrom(
+        aidl_hal::IDevice* device) {
+    CHECK(device != nullptr);
+    std::vector<Extension> supportedExtensions;
+    const auto ret = device->getSupportedExtensions(&supportedExtensions);
+    HANDLE_ASTATUS(ret) << "getExtensions failed";
+    return nn::convert(supportedExtensions);
+}
+
+nn::GeneralResult<std::pair<uint32_t, uint32_t>> getNumberOfCacheFilesNeededFrom(
+        aidl_hal::IDevice* device) {
+    CHECK(device != nullptr);
+    NumberOfCacheFiles numberOfCacheFiles;
+    const auto ret = device->getNumberOfCacheFilesNeeded(&numberOfCacheFiles);
+    HANDLE_ASTATUS(ret) << "getNumberOfCacheFilesNeeded failed";
+
+    if (numberOfCacheFiles.numDataCache < 0 || numberOfCacheFiles.numModelCache < 0) {
+        return NN_ERROR() << "Driver reported negative numer of cache files needed";
+    }
+    if (static_cast<uint32_t>(numberOfCacheFiles.numModelCache) > nn::kMaxNumberOfCacheFiles) {
+        return NN_ERROR() << "getNumberOfCacheFilesNeeded returned numModelCache files greater "
+                             "than allowed max ("
+                          << numberOfCacheFiles.numModelCache << " vs "
+                          << nn::kMaxNumberOfCacheFiles << ")";
+    }
+    if (static_cast<uint32_t>(numberOfCacheFiles.numDataCache) > nn::kMaxNumberOfCacheFiles) {
+        return NN_ERROR() << "getNumberOfCacheFilesNeeded returned numDataCache files greater "
+                             "than allowed max ("
+                          << numberOfCacheFiles.numDataCache << " vs " << nn::kMaxNumberOfCacheFiles
+                          << ")";
+    }
+    return std::make_pair(numberOfCacheFiles.numDataCache, numberOfCacheFiles.numModelCache);
+}
+
+}  // namespace
+
+nn::GeneralResult<std::shared_ptr<const Device>> Device::create(
+        std::string name, std::shared_ptr<aidl_hal::IDevice> device) {
+    if (name.empty()) {
+        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
+               << "aidl_hal::utils::Device::create must have non-empty name";
+    }
+    if (device == nullptr) {
+        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
+               << "aidl_hal::utils::Device::create must have non-null device";
+    }
+
+    auto versionString = NN_TRY(getVersionStringFrom(device.get()));
+    const auto deviceType = NN_TRY(getDeviceTypeFrom(device.get()));
+    auto extensions = NN_TRY(getSupportedExtensionsFrom(device.get()));
+    auto capabilities = NN_TRY(getCapabilitiesFrom(device.get()));
+    const auto numberOfCacheFilesNeeded = NN_TRY(getNumberOfCacheFilesNeededFrom(device.get()));
+
+    auto deathHandler = NN_TRY(DeathHandler::create(device));
+    return std::make_shared<const Device>(
+            PrivateConstructorTag{}, std::move(name), std::move(versionString), deviceType,
+            std::move(extensions), std::move(capabilities), numberOfCacheFilesNeeded,
+            std::move(device), std::move(deathHandler));
+}
+
+Device::Device(PrivateConstructorTag /*tag*/, std::string name, std::string versionString,
+               nn::DeviceType deviceType, std::vector<nn::Extension> extensions,
+               nn::Capabilities capabilities,
+               std::pair<uint32_t, uint32_t> numberOfCacheFilesNeeded,
+               std::shared_ptr<aidl_hal::IDevice> device, DeathHandler deathHandler)
+    : kName(std::move(name)),
+      kVersionString(std::move(versionString)),
+      kDeviceType(deviceType),
+      kExtensions(std::move(extensions)),
+      kCapabilities(std::move(capabilities)),
+      kNumberOfCacheFilesNeeded(numberOfCacheFilesNeeded),
+      kDevice(std::move(device)),
+      kDeathHandler(std::move(deathHandler)) {}
+
+const std::string& Device::getName() const {
+    return kName;
+}
+
+const std::string& Device::getVersionString() const {
+    return kVersionString;
+}
+
+nn::Version Device::getFeatureLevel() const {
+    return nn::Version::ANDROID_S;
+}
+
+nn::DeviceType Device::getType() const {
+    return kDeviceType;
+}
+
+bool Device::isUpdatable() const {
+    return false;
+}
+
+const std::vector<nn::Extension>& Device::getSupportedExtensions() const {
+    return kExtensions;
+}
+
+const nn::Capabilities& Device::getCapabilities() const {
+    return kCapabilities;
+}
+
+std::pair<uint32_t, uint32_t> Device::getNumberOfCacheFilesNeeded() const {
+    return kNumberOfCacheFilesNeeded;
+}
+
+nn::GeneralResult<void> Device::wait() const {
+    const auto ret = ndk::ScopedAStatus::fromStatus(AIBinder_ping(kDevice->asBinder().get()));
+    HANDLE_ASTATUS(ret) << "ping failed";
+    return {};
+}
+
+nn::GeneralResult<std::vector<bool>> Device::getSupportedOperations(const nn::Model& model) const {
+    // Ensure that model is ready for IPC.
+    std::optional<nn::Model> maybeModelInShared;
+    const nn::Model& modelInShared =
+            NN_TRY(hal::utils::flushDataFromPointerToShared(&model, &maybeModelInShared));
+
+    const auto aidlModel = NN_TRY(convert(modelInShared));
+
+    std::vector<bool> supportedOperations;
+    const auto ret = kDevice->getSupportedOperations(aidlModel, &supportedOperations);
+    HANDLE_ASTATUS(ret) << "getSupportedOperations failed";
+
+    return supportedOperations;
+}
+
+nn::GeneralResult<nn::SharedPreparedModel> Device::prepareModel(
+        const nn::Model& model, nn::ExecutionPreference preference, nn::Priority priority,
+        nn::OptionalTimePoint deadline, const std::vector<nn::SharedHandle>& modelCache,
+        const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const {
+    // Ensure that model is ready for IPC.
+    std::optional<nn::Model> maybeModelInShared;
+    const nn::Model& modelInShared =
+            NN_TRY(hal::utils::flushDataFromPointerToShared(&model, &maybeModelInShared));
+
+    const auto aidlModel = NN_TRY(convert(modelInShared));
+    const auto aidlPreference = NN_TRY(convert(preference));
+    const auto aidlPriority = NN_TRY(convert(priority));
+    const auto aidlDeadline = NN_TRY(convert(deadline));
+    const auto aidlModelCache = NN_TRY(convert(modelCache));
+    const auto aidlDataCache = NN_TRY(convert(dataCache));
+    const auto aidlToken = NN_TRY(convert(token));
+
+    const auto cb = ndk::SharedRefBase::make<PreparedModelCallback>();
+    const auto scoped = kDeathHandler.protectCallback(cb.get());
+
+    const auto ret = kDevice->prepareModel(aidlModel, aidlPreference, aidlPriority, aidlDeadline,
+                                           aidlModelCache, aidlDataCache, aidlToken, cb);
+    HANDLE_ASTATUS(ret) << "prepareModel failed";
+
+    return cb->get();
+}
+
+nn::GeneralResult<nn::SharedPreparedModel> Device::prepareModelFromCache(
+        nn::OptionalTimePoint deadline, const std::vector<nn::SharedHandle>& modelCache,
+        const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const {
+    const auto aidlDeadline = NN_TRY(convert(deadline));
+    const auto aidlModelCache = NN_TRY(convert(modelCache));
+    const auto aidlDataCache = NN_TRY(convert(dataCache));
+    const auto aidlToken = NN_TRY(convert(token));
+
+    const auto cb = ndk::SharedRefBase::make<PreparedModelCallback>();
+    const auto scoped = kDeathHandler.protectCallback(cb.get());
+
+    const auto ret = kDevice->prepareModelFromCache(aidlDeadline, aidlModelCache, aidlDataCache,
+                                                    aidlToken, cb);
+    HANDLE_ASTATUS(ret) << "prepareModelFromCache failed";
+
+    return cb->get();
+}
+
+nn::GeneralResult<nn::SharedBuffer> Device::allocate(
+        const nn::BufferDesc& desc, const std::vector<nn::SharedPreparedModel>& preparedModels,
+        const std::vector<nn::BufferRole>& inputRoles,
+        const std::vector<nn::BufferRole>& outputRoles) const {
+    const auto aidlDesc = NN_TRY(convert(desc));
+    const auto aidlPreparedModels = NN_TRY(convert(preparedModels));
+    const auto aidlInputRoles = NN_TRY(convert(inputRoles));
+    const auto aidlOutputRoles = NN_TRY(convert(outputRoles));
+
+    std::vector<IPreparedModelParcel> aidlPreparedModelParcels;
+    aidlPreparedModelParcels.reserve(aidlPreparedModels.size());
+    for (const auto& preparedModel : aidlPreparedModels) {
+        aidlPreparedModelParcels.push_back({.preparedModel = preparedModel});
+    }
+
+    DeviceBuffer buffer;
+    const auto ret = kDevice->allocate(aidlDesc, aidlPreparedModelParcels, aidlInputRoles,
+                                       aidlOutputRoles, &buffer);
+    HANDLE_ASTATUS(ret) << "IDevice::allocate failed";
+
+    if (buffer.token < 0) {
+        return NN_ERROR() << "IDevice::allocate returned negative token";
+    }
+
+    return Buffer::create(buffer.buffer, static_cast<nn::Request::MemoryDomainToken>(buffer.token));
+}
+
+DeathMonitor* Device::getDeathMonitor() const {
+    return kDeathHandler.getDeathMonitor().get();
+}
+
+}  // namespace aidl::android::hardware::neuralnetworks::utils
diff --git a/neuralnetworks/aidl/utils/src/PreparedModel.cpp b/neuralnetworks/aidl/utils/src/PreparedModel.cpp
new file mode 100644
index 0000000..aee4d90
--- /dev/null
+++ b/neuralnetworks/aidl/utils/src/PreparedModel.cpp
@@ -0,0 +1,172 @@
+/*
+ * 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 "PreparedModel.h"
+
+#include "Callbacks.h"
+#include "Conversions.h"
+#include "ProtectCallback.h"
+#include "Utils.h"
+
+#include <android/binder_auto_utils.h>
+#include <nnapi/IPreparedModel.h>
+#include <nnapi/Result.h>
+#include <nnapi/TypeUtils.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/1.0/Burst.h>
+#include <nnapi/hal/CommonUtils.h>
+#include <nnapi/hal/HandleError.h>
+
+#include <memory>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+// See hardware/interfaces/neuralnetworks/utils/README.md for more information on AIDL interface
+// lifetimes across processes and for protecting asynchronous calls across AIDL.
+
+namespace aidl::android::hardware::neuralnetworks::utils {
+namespace {
+
+nn::GeneralResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> convertExecutionResults(
+        const std::vector<OutputShape>& outputShapes, const Timing& timing) {
+    return std::make_pair(NN_TRY(nn::convert(outputShapes)), NN_TRY(nn::convert(timing)));
+}
+
+nn::GeneralResult<std::pair<nn::Timing, nn::Timing>> convertFencedExecutionResults(
+        ErrorStatus status, const aidl_hal::Timing& timingLaunched,
+        const aidl_hal::Timing& timingFenced) {
+    HANDLE_HAL_STATUS(status) << "fenced execution callback info failed with " << toString(status);
+    return std::make_pair(NN_TRY(nn::convert(timingLaunched)), NN_TRY(nn::convert(timingFenced)));
+}
+
+}  // namespace
+
+nn::GeneralResult<std::shared_ptr<const PreparedModel>> PreparedModel::create(
+        std::shared_ptr<aidl_hal::IPreparedModel> preparedModel) {
+    if (preparedModel == nullptr) {
+        return NN_ERROR()
+               << "aidl_hal::utils::PreparedModel::create must have non-null preparedModel";
+    }
+
+    return std::make_shared<const PreparedModel>(PrivateConstructorTag{}, std::move(preparedModel));
+}
+
+PreparedModel::PreparedModel(PrivateConstructorTag /*tag*/,
+                             std::shared_ptr<aidl_hal::IPreparedModel> preparedModel)
+    : kPreparedModel(std::move(preparedModel)) {}
+
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> PreparedModel::execute(
+        const nn::Request& request, nn::MeasureTiming measure,
+        const nn::OptionalTimePoint& deadline,
+        const nn::OptionalDuration& loopTimeoutDuration) const {
+    // Ensure that request is ready for IPC.
+    std::optional<nn::Request> maybeRequestInShared;
+    const nn::Request& requestInShared = NN_TRY(hal::utils::makeExecutionFailure(
+            hal::utils::flushDataFromPointerToShared(&request, &maybeRequestInShared)));
+
+    const auto aidlRequest = NN_TRY(hal::utils::makeExecutionFailure(convert(requestInShared)));
+    const auto aidlMeasure = NN_TRY(hal::utils::makeExecutionFailure(convert(measure)));
+    const auto aidlDeadline = NN_TRY(hal::utils::makeExecutionFailure(convert(deadline)));
+    const auto aidlLoopTimeoutDuration =
+            NN_TRY(hal::utils::makeExecutionFailure(convert(loopTimeoutDuration)));
+
+    ExecutionResult executionResult;
+    const auto ret = kPreparedModel->executeSynchronously(
+            aidlRequest, aidlMeasure, aidlDeadline, aidlLoopTimeoutDuration, &executionResult);
+    HANDLE_ASTATUS(ret) << "executeSynchronously failed";
+    if (!executionResult.outputSufficientSize) {
+        auto canonicalOutputShapes =
+                nn::convert(executionResult.outputShapes).value_or(std::vector<nn::OutputShape>{});
+        return NN_ERROR(nn::ErrorStatus::OUTPUT_INSUFFICIENT_SIZE, std::move(canonicalOutputShapes))
+               << "execution failed with " << nn::ErrorStatus::OUTPUT_INSUFFICIENT_SIZE;
+    }
+    auto [outputShapes, timing] = NN_TRY(hal::utils::makeExecutionFailure(
+            convertExecutionResults(executionResult.outputShapes, executionResult.timing)));
+
+    NN_TRY(hal::utils::makeExecutionFailure(
+            hal::utils::unflushDataFromSharedToPointer(request, maybeRequestInShared)));
+
+    return std::make_pair(std::move(outputShapes), timing);
+}
+
+nn::GeneralResult<std::pair<nn::SyncFence, nn::ExecuteFencedInfoCallback>>
+PreparedModel::executeFenced(const nn::Request& request, const std::vector<nn::SyncFence>& waitFor,
+                             nn::MeasureTiming measure, const nn::OptionalTimePoint& deadline,
+                             const nn::OptionalDuration& loopTimeoutDuration,
+                             const nn::OptionalDuration& timeoutDurationAfterFence) const {
+    // Ensure that request is ready for IPC.
+    std::optional<nn::Request> maybeRequestInShared;
+    const nn::Request& requestInShared =
+            NN_TRY(hal::utils::flushDataFromPointerToShared(&request, &maybeRequestInShared));
+
+    const auto aidlRequest = NN_TRY(convert(requestInShared));
+    const auto aidlWaitFor = NN_TRY(convert(waitFor));
+    const auto aidlMeasure = NN_TRY(convert(measure));
+    const auto aidlDeadline = NN_TRY(convert(deadline));
+    const auto aidlLoopTimeoutDuration = NN_TRY(convert(loopTimeoutDuration));
+    const auto aidlTimeoutDurationAfterFence = NN_TRY(convert(timeoutDurationAfterFence));
+
+    FencedExecutionResult result;
+    const auto ret = kPreparedModel->executeFenced(aidlRequest, aidlWaitFor, aidlMeasure,
+                                                   aidlDeadline, aidlLoopTimeoutDuration,
+                                                   aidlTimeoutDurationAfterFence, &result);
+    HANDLE_ASTATUS(ret) << "executeFenced failed";
+
+    auto resultSyncFence = nn::SyncFence::createAsSignaled();
+    if (result.syncFence.get() != -1) {
+        resultSyncFence = NN_TRY(nn::convert(result.syncFence));
+    }
+
+    auto callback = result.callback;
+    if (callback == nullptr) {
+        return NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "callback is null";
+    }
+
+    // If executeFenced required the request memory to be moved into shared memory, block here until
+    // the fenced execution has completed and flush the memory back.
+    if (maybeRequestInShared.has_value()) {
+        const auto state = resultSyncFence.syncWait({});
+        if (state != nn::SyncFence::FenceState::SIGNALED) {
+            return NN_ERROR() << "syncWait failed with " << state;
+        }
+        NN_TRY(hal::utils::unflushDataFromSharedToPointer(request, maybeRequestInShared));
+    }
+
+    // Create callback which can be used to retrieve the execution error status and timings.
+    nn::ExecuteFencedInfoCallback resultCallback =
+            [callback]() -> nn::GeneralResult<std::pair<nn::Timing, nn::Timing>> {
+        ErrorStatus errorStatus;
+        Timing timingLaunched;
+        Timing timingFenced;
+        const auto ret = callback->getExecutionInfo(&timingLaunched, &timingFenced, &errorStatus);
+        HANDLE_ASTATUS(ret) << "fenced execution callback getExecutionInfo failed";
+        return convertFencedExecutionResults(errorStatus, timingLaunched, timingFenced);
+    };
+
+    return std::make_pair(std::move(resultSyncFence), std::move(resultCallback));
+}
+
+nn::GeneralResult<nn::SharedBurst> PreparedModel::configureExecutionBurst() const {
+    return hal::V1_0::utils::Burst::create(shared_from_this());
+}
+
+std::any PreparedModel::getUnderlyingResource() const {
+    std::shared_ptr<aidl_hal::IPreparedModel> resource = kPreparedModel;
+    return resource;
+}
+
+}  // namespace aidl::android::hardware::neuralnetworks::utils
diff --git a/neuralnetworks/aidl/utils/src/ProtectCallback.cpp b/neuralnetworks/aidl/utils/src/ProtectCallback.cpp
new file mode 100644
index 0000000..124641c
--- /dev/null
+++ b/neuralnetworks/aidl/utils/src/ProtectCallback.cpp
@@ -0,0 +1,112 @@
+/*
+ * 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 "ProtectCallback.h"
+
+#include <android-base/logging.h>
+#include <android-base/scopeguard.h>
+#include <android-base/thread_annotations.h>
+#include <android/binder_auto_utils.h>
+#include <android/binder_interface_utils.h>
+#include <nnapi/Result.h>
+#include <nnapi/hal/ProtectCallback.h>
+
+#include <algorithm>
+#include <functional>
+#include <memory>
+#include <mutex>
+#include <vector>
+
+#include "Utils.h"
+
+namespace aidl::android::hardware::neuralnetworks::utils {
+
+void DeathMonitor::serviceDied() {
+    std::lock_guard guard(mMutex);
+    std::for_each(mObjects.begin(), mObjects.end(),
+                  [](hal::utils::IProtectedCallback* killable) { killable->notifyAsDeadObject(); });
+}
+
+void DeathMonitor::serviceDied(void* cookie) {
+    auto deathMonitor = static_cast<DeathMonitor*>(cookie);
+    deathMonitor->serviceDied();
+}
+
+void DeathMonitor::add(hal::utils::IProtectedCallback* killable) const {
+    CHECK(killable != nullptr);
+    std::lock_guard guard(mMutex);
+    mObjects.push_back(killable);
+}
+
+void DeathMonitor::remove(hal::utils::IProtectedCallback* killable) const {
+    CHECK(killable != nullptr);
+    std::lock_guard guard(mMutex);
+    const auto removedIter = std::remove(mObjects.begin(), mObjects.end(), killable);
+    mObjects.erase(removedIter);
+}
+
+nn::GeneralResult<DeathHandler> DeathHandler::create(std::shared_ptr<ndk::ICInterface> object) {
+    if (object == nullptr) {
+        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
+               << "utils::DeathHandler::create must have non-null object";
+    }
+    auto deathMonitor = std::make_shared<DeathMonitor>();
+    auto deathRecipient = ndk::ScopedAIBinder_DeathRecipient(
+            AIBinder_DeathRecipient_new(DeathMonitor::serviceDied));
+
+    // If passed a local binder, AIBinder_linkToDeath will do nothing and return
+    // STATUS_INVALID_OPERATION. We ignore this case because we only use local binders in tests
+    // where this is not an error.
+    if (object->isRemote()) {
+        const auto ret = ndk::ScopedAStatus::fromStatus(AIBinder_linkToDeath(
+                object->asBinder().get(), deathRecipient.get(), deathMonitor.get()));
+        HANDLE_ASTATUS(ret) << "AIBinder_linkToDeath failed";
+    }
+
+    return DeathHandler(std::move(object), std::move(deathRecipient), std::move(deathMonitor));
+}
+
+DeathHandler::DeathHandler(std::shared_ptr<ndk::ICInterface> object,
+                           ndk::ScopedAIBinder_DeathRecipient deathRecipient,
+                           std::shared_ptr<DeathMonitor> deathMonitor)
+    : kObject(std::move(object)),
+      kDeathRecipient(std::move(deathRecipient)),
+      kDeathMonitor(std::move(deathMonitor)) {
+    CHECK(kObject != nullptr);
+    CHECK(kDeathRecipient.get() != nullptr);
+    CHECK(kDeathMonitor != nullptr);
+}
+
+DeathHandler::~DeathHandler() {
+    if (kObject != nullptr && kDeathRecipient.get() != nullptr && kDeathMonitor != nullptr) {
+        const auto ret = ndk::ScopedAStatus::fromStatus(AIBinder_unlinkToDeath(
+                kObject->asBinder().get(), kDeathRecipient.get(), kDeathMonitor.get()));
+        const auto maybeSuccess = handleTransportError(ret);
+        if (!maybeSuccess.ok()) {
+            LOG(ERROR) << maybeSuccess.error().message;
+        }
+    }
+}
+
+[[nodiscard]] ::android::base::ScopeGuard<DeathHandler::Cleanup> DeathHandler::protectCallback(
+        hal::utils::IProtectedCallback* killable) const {
+    CHECK(killable != nullptr);
+    kDeathMonitor->add(killable);
+    return ::android::base::make_scope_guard(
+            [deathMonitor = kDeathMonitor, killable] { deathMonitor->remove(killable); });
+}
+
+}  // namespace aidl::android::hardware::neuralnetworks::utils
diff --git a/neuralnetworks/aidl/utils/src/Service.cpp b/neuralnetworks/aidl/utils/src/Service.cpp
new file mode 100644
index 0000000..5ec6ded
--- /dev/null
+++ b/neuralnetworks/aidl/utils/src/Service.cpp
@@ -0,0 +1,50 @@
+/*
+ * 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 "Service.h"
+
+#include <android/binder_auto_utils.h>
+#include <android/binder_manager.h>
+
+#include <nnapi/IDevice.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/ResilientDevice.h>
+#include <string>
+
+#include "Device.h"
+
+namespace aidl::android::hardware::neuralnetworks::utils {
+
+nn::GeneralResult<nn::SharedDevice> getDevice(const std::string& name) {
+    hal::utils::ResilientDevice::Factory makeDevice =
+            [name](bool blocking) -> nn::GeneralResult<nn::SharedDevice> {
+        auto service = blocking ? IDevice::fromBinder(
+                                          ndk::SpAIBinder(AServiceManager_getService(name.c_str())))
+                                : IDevice::fromBinder(ndk::SpAIBinder(
+                                          AServiceManager_checkService(name.c_str())));
+        if (service == nullptr) {
+            return NN_ERROR() << (blocking ? "AServiceManager_getService"
+                                           : "AServiceManager_checkService")
+                              << " returned nullptr";
+        }
+        return Device::create(name, std::move(service));
+    };
+
+    return hal::utils::ResilientDevice::create(std::move(makeDevice));
+}
+
+}  // namespace aidl::android::hardware::neuralnetworks::utils
diff --git a/neuralnetworks/aidl/utils/src/Utils.cpp b/neuralnetworks/aidl/utils/src/Utils.cpp
index 8d00e59..95516c8 100644
--- a/neuralnetworks/aidl/utils/src/Utils.cpp
+++ b/neuralnetworks/aidl/utils/src/Utils.cpp
@@ -16,13 +16,12 @@
 
 #include "Utils.h"
 
+#include <android/binder_status.h>
 #include <nnapi/Result.h>
 
 namespace aidl::android::hardware::neuralnetworks::utils {
 namespace {
 
-using ::android::nn::GeneralResult;
-
 template <typename Type>
 nn::GeneralResult<std::vector<Type>> cloneVec(const std::vector<Type>& arguments) {
     std::vector<Type> clonedObjects;
@@ -34,13 +33,13 @@
 }
 
 template <typename Type>
-GeneralResult<std::vector<Type>> clone(const std::vector<Type>& arguments) {
+nn::GeneralResult<std::vector<Type>> clone(const std::vector<Type>& arguments) {
     return cloneVec(arguments);
 }
 
 }  // namespace
 
-GeneralResult<Memory> clone(const Memory& memory) {
+nn::GeneralResult<Memory> clone(const Memory& memory) {
     common::NativeHandle nativeHandle;
     nativeHandle.ints = memory.handle.ints;
     nativeHandle.fds.reserve(memory.handle.fds.size());
@@ -58,7 +57,7 @@
     };
 }
 
-GeneralResult<RequestMemoryPool> clone(const RequestMemoryPool& requestPool) {
+nn::GeneralResult<RequestMemoryPool> clone(const RequestMemoryPool& requestPool) {
     using Tag = RequestMemoryPool::Tag;
     switch (requestPool.getTag()) {
         case Tag::pool:
@@ -70,10 +69,10 @@
     // compiler.
     return (NN_ERROR() << "Unrecognized request pool tag: " << requestPool.getTag())
             .
-            operator GeneralResult<RequestMemoryPool>();
+            operator nn::GeneralResult<RequestMemoryPool>();
 }
 
-GeneralResult<Request> clone(const Request& request) {
+nn::GeneralResult<Request> clone(const Request& request) {
     return Request{
             .inputs = request.inputs,
             .outputs = request.outputs,
@@ -81,7 +80,7 @@
     };
 }
 
-GeneralResult<Model> clone(const Model& model) {
+nn::GeneralResult<Model> clone(const Model& model) {
     return Model{
             .main = model.main,
             .referenced = model.referenced,
@@ -92,4 +91,20 @@
     };
 }
 
+nn::GeneralResult<void> handleTransportError(const ndk::ScopedAStatus& ret) {
+    if (ret.getStatus() == STATUS_DEAD_OBJECT) {
+        return nn::error(nn::ErrorStatus::DEAD_OBJECT)
+               << "Binder transaction returned STATUS_DEAD_OBJECT: " << ret.getDescription();
+    }
+    if (ret.isOk()) {
+        return {};
+    }
+    if (ret.getExceptionCode() != EX_SERVICE_SPECIFIC) {
+        return nn::error(nn::ErrorStatus::GENERAL_FAILURE)
+               << "Binder transaction returned exception: " << ret.getDescription();
+    }
+    return nn::error(static_cast<nn::ErrorStatus>(ret.getServiceSpecificError()))
+           << ret.getMessage();
+}
+
 }  // namespace aidl::android::hardware::neuralnetworks::utils