Merge "vmbase_example: Minimize scope of unsafe blocks" into main
diff --git a/javalib/api/test-current.txt b/javalib/api/test-current.txt
index 1298000..cf95770 100644
--- a/javalib/api/test-current.txt
+++ b/javalib/api/test-current.txt
@@ -13,6 +13,7 @@
 
   public static final class VirtualMachineConfig.Builder {
     method @NonNull @RequiresPermission(android.system.virtualmachine.VirtualMachine.USE_CUSTOM_VIRTUAL_MACHINE_PERMISSION) public android.system.virtualmachine.VirtualMachineConfig.Builder setPayloadConfigPath(@NonNull String);
+    method @NonNull @RequiresPermission(android.system.virtualmachine.VirtualMachine.USE_CUSTOM_VIRTUAL_MACHINE_PERMISSION) public android.system.virtualmachine.VirtualMachineConfig.Builder setVendorDiskImage(@NonNull java.io.File);
     method @NonNull public android.system.virtualmachine.VirtualMachineConfig.Builder setVmConsoleInputSupported(boolean);
   }
 
diff --git a/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java b/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
index b400eeb..4cad2e3 100644
--- a/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
+++ b/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
@@ -76,6 +76,7 @@
     private static final String KEY_ENCRYPTED_STORAGE_BYTES = "encryptedStorageBytes";
     private static final String KEY_VM_OUTPUT_CAPTURED = "vmOutputCaptured";
     private static final String KEY_VM_CONSOLE_INPUT_SUPPORTED = "vmConsoleInputSupported";
+    private static final String KEY_VENDOR_DISK_IMAGE_PATH = "vendorDiskImagePath";
 
     /** @hide */
     @Retention(RetentionPolicy.SOURCE)
@@ -167,6 +168,8 @@
     /** Whether the app can write console input to the VM */
     private final boolean mVmConsoleInputSupported;
 
+    @Nullable private final File mVendorDiskImage;
+
     private VirtualMachineConfig(
             @Nullable String packageName,
             @Nullable String apkPath,
@@ -178,7 +181,8 @@
             @CpuTopology int cpuTopology,
             long encryptedStorageBytes,
             boolean vmOutputCaptured,
-            boolean vmConsoleInputSupported) {
+            boolean vmConsoleInputSupported,
+            @Nullable File vendorDiskImage) {
         // This is only called from Builder.build(); the builder handles parameter validation.
         mPackageName = packageName;
         mApkPath = apkPath;
@@ -191,6 +195,7 @@
         mEncryptedStorageBytes = encryptedStorageBytes;
         mVmOutputCaptured = vmOutputCaptured;
         mVmConsoleInputSupported = vmConsoleInputSupported;
+        mVendorDiskImage = vendorDiskImage;
     }
 
     /** Loads a config from a file. */
@@ -267,6 +272,11 @@
         builder.setVmOutputCaptured(b.getBoolean(KEY_VM_OUTPUT_CAPTURED));
         builder.setVmConsoleInputSupported(b.getBoolean(KEY_VM_CONSOLE_INPUT_SUPPORTED));
 
+        String vendorDiskImagePath = b.getString(KEY_VENDOR_DISK_IMAGE_PATH);
+        if (vendorDiskImagePath != null) {
+            builder.setVendorDiskImage(new File(vendorDiskImagePath));
+        }
+
         return builder.build();
     }
 
@@ -302,6 +312,9 @@
         }
         b.putBoolean(KEY_VM_OUTPUT_CAPTURED, mVmOutputCaptured);
         b.putBoolean(KEY_VM_CONSOLE_INPUT_SUPPORTED, mVmConsoleInputSupported);
+        if (mVendorDiskImage != null) {
+            b.putString(KEY_VENDOR_DISK_IMAGE_PATH, mVendorDiskImage.getAbsolutePath());
+        }
         b.writeToStream(output);
     }
 
@@ -501,6 +514,20 @@
                 vsConfig.cpuTopology = android.system.virtualizationservice.CpuTopology.ONE_CPU;
                 break;
         }
+        if (mVendorDiskImage != null) {
+            VirtualMachineAppConfig.CustomConfig customConfig =
+                    new VirtualMachineAppConfig.CustomConfig();
+            customConfig.taskProfiles = new String[0];
+            try {
+                customConfig.vendorImage =
+                        ParcelFileDescriptor.open(mVendorDiskImage, MODE_READ_ONLY);
+            } catch (FileNotFoundException e) {
+                throw new VirtualMachineException(
+                        "Failed to open vendor disk image " + mVendorDiskImage.getAbsolutePath(),
+                        e);
+            }
+            vsConfig.customConfig = customConfig;
+        }
         return vsConfig;
     }
 
@@ -572,6 +599,7 @@
         private long mEncryptedStorageBytes;
         private boolean mVmOutputCaptured = false;
         private boolean mVmConsoleInputSupported = false;
+        @Nullable private File mVendorDiskImage;
 
         /**
          * Creates a builder for the given context.
@@ -645,7 +673,8 @@
                     mCpuTopology,
                     mEncryptedStorageBytes,
                     mVmOutputCaptured,
-                    mVmConsoleInputSupported);
+                    mVmConsoleInputSupported,
+                    mVendorDiskImage);
         }
 
         /**
@@ -863,5 +892,18 @@
             mVmConsoleInputSupported = supported;
             return this;
         }
+
+        /**
+         * Sets the path to the disk image with vendor-specific modules.
+         *
+         * @hide
+         */
+        @TestApi
+        @RequiresPermission(VirtualMachine.USE_CUSTOM_VIRTUAL_MACHINE_PERMISSION)
+        @NonNull
+        public Builder setVendorDiskImage(@NonNull File vendorDiskImage) {
+            mVendorDiskImage = vendorDiskImage;
+            return this;
+        }
     }
 }
diff --git a/microdroid/Android.bp b/microdroid/Android.bp
index 5440695..2d3f084 100644
--- a/microdroid/Android.bp
+++ b/microdroid/Android.bp
@@ -23,6 +23,10 @@
     "apex",
     "linkerconfig",
     "second_stage_resources",
+
+    // Ideally we should only create the /vendor for Microdroid VMs that will mount /vendor, but
+    // for the time being we will just create it unconditionally.
+    "vendor",
 ]
 
 microdroid_symlinks = [
diff --git a/microdroid/bootconfig.x86_64 b/microdroid/bootconfig.x86_64
index 6076889..eed9212 100644
--- a/microdroid/bootconfig.x86_64
+++ b/microdroid/bootconfig.x86_64
@@ -1 +1 @@
-androidboot.boot_devices = pci0000:00/0000:00:04.0,pci0000:00/0000:00:05.0,pci0000:00/0000:00:06.0
+androidboot.boot_devices = pci0000:00/0000:00:04.0,pci0000:00/0000:00:05.0,pci0000:00/0000:00:06.0,pci0000:00/0000:00:07.0
diff --git a/microdroid/fstab.microdroid b/microdroid/fstab.microdroid
index 9478c7c..da000b9 100644
--- a/microdroid/fstab.microdroid
+++ b/microdroid/fstab.microdroid
@@ -1 +1,7 @@
 system /system ext4 noatime,ro,errors=panic wait,slotselect,avb=vbmeta,first_stage_mount,logical
+# This is a temporary solution to unblock other devs that depend on /vendor partition in Microdroid
+# The /vendor partition will only be mounted if the kernel cmdline contains
+# androidboot.microdroid.mount_vendor=1.
+# TODO(b/285855430): this should probably be defined in the DT
+# TODO(b/285855436): should be mounted on top of dm-verity device
+/dev/block/by-name/microdroid-vendor /vendor ext4 noatime,ro,errors=panic wait,first_stage_mount
diff --git a/pvmfw/src/exceptions.rs b/pvmfw/src/exceptions.rs
index 802ebbb..d9f0891 100644
--- a/pvmfw/src/exceptions.rs
+++ b/pvmfw/src/exceptions.rs
@@ -14,95 +14,14 @@
 
 //! Exception handlers.
 
-use aarch64_paging::paging::VirtualAddress;
-use core::fmt;
-use vmbase::console;
-use vmbase::logger;
-use vmbase::memory::{page_4kb_of, MemoryTrackerError, MEMORY};
-use vmbase::read_sysreg;
-use vmbase::{eprintln, power::reboot};
-
-const UART_PAGE: usize = page_4kb_of(console::BASE_ADDRESS);
-
-#[derive(Debug)]
-enum HandleExceptionError {
-    PageTableUnavailable,
-    PageTableNotInitialized,
-    InternalError(MemoryTrackerError),
-    UnknownException,
-}
-
-impl From<MemoryTrackerError> for HandleExceptionError {
-    fn from(other: MemoryTrackerError) -> Self {
-        Self::InternalError(other)
-    }
-}
-
-impl fmt::Display for HandleExceptionError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            Self::PageTableUnavailable => write!(f, "Page table is not available."),
-            Self::PageTableNotInitialized => write!(f, "Page table is not initialized."),
-            Self::InternalError(e) => write!(f, "Error while updating page table: {e}"),
-            Self::UnknownException => write!(f, "An unknown exception occurred, not handled."),
-        }
-    }
-}
-
-#[derive(Debug, PartialEq, Copy, Clone)]
-enum Esr {
-    DataAbortTranslationFault,
-    DataAbortPermissionFault,
-    DataAbortSyncExternalAbort,
-    Unknown(usize),
-}
-
-impl Esr {
-    const EXT_DABT_32BIT: usize = 0x96000010;
-    const TRANSL_FAULT_BASE_32BIT: usize = 0x96000004;
-    const TRANSL_FAULT_ISS_MASK_32BIT: usize = !0x143;
-    const PERM_FAULT_BASE_32BIT: usize = 0x9600004C;
-    const PERM_FAULT_ISS_MASK_32BIT: usize = !0x103;
-}
-
-impl From<usize> for Esr {
-    fn from(esr: usize) -> Self {
-        if esr == Self::EXT_DABT_32BIT {
-            Self::DataAbortSyncExternalAbort
-        } else if esr & Self::TRANSL_FAULT_ISS_MASK_32BIT == Self::TRANSL_FAULT_BASE_32BIT {
-            Self::DataAbortTranslationFault
-        } else if esr & Self::PERM_FAULT_ISS_MASK_32BIT == Self::PERM_FAULT_BASE_32BIT {
-            Self::DataAbortPermissionFault
-        } else {
-            Self::Unknown(esr)
-        }
-    }
-}
-
-impl fmt::Display for Esr {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            Self::DataAbortSyncExternalAbort => write!(f, "Synchronous external abort"),
-            Self::DataAbortTranslationFault => write!(f, "Translation fault"),
-            Self::DataAbortPermissionFault => write!(f, "Permission fault"),
-            Self::Unknown(v) => write!(f, "Unknown exception esr={v:#08x}"),
-        }
-    }
-}
-
-#[inline]
-fn handle_translation_fault(far: VirtualAddress) -> Result<(), HandleExceptionError> {
-    let mut guard = MEMORY.try_lock().ok_or(HandleExceptionError::PageTableUnavailable)?;
-    let memory = guard.as_mut().ok_or(HandleExceptionError::PageTableNotInitialized)?;
-    Ok(memory.handle_mmio_fault(far)?)
-}
-
-#[inline]
-fn handle_permission_fault(far: VirtualAddress) -> Result<(), HandleExceptionError> {
-    let mut guard = MEMORY.try_lock().ok_or(HandleExceptionError::PageTableUnavailable)?;
-    let memory = guard.as_mut().ok_or(HandleExceptionError::PageTableNotInitialized)?;
-    Ok(memory.handle_permission_fault(far)?)
-}
+use vmbase::{
+    eprintln,
+    exceptions::{ArmException, Esr, HandleExceptionError},
+    logger,
+    memory::{handle_permission_fault, handle_translation_fault},
+    power::reboot,
+    read_sysreg,
+};
 
 fn handle_exception(exception: &ArmException) -> Result<(), HandleExceptionError> {
     // Handle all translation faults on both read and write, and MMIO guard map
@@ -115,45 +34,6 @@
     }
 }
 
-/// A struct representing an Armv8 exception.
-struct ArmException {
-    /// The value of the exception syndrome register.
-    esr: Esr,
-    /// The faulting virtual address read from the fault address register.
-    far: VirtualAddress,
-}
-
-impl fmt::Display for ArmException {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "ArmException: esr={}, far={}", self.esr, self.far)
-    }
-}
-
-impl ArmException {
-    /// Reads the values of the EL1 exception syndrome register (`esr_el1`)
-    /// and fault address register (`far_el1`) and returns a new instance of
-    /// `ArmException` with these values.
-    fn from_el1_regs() -> Self {
-        let esr: Esr = read_sysreg!("esr_el1").into();
-        let far = read_sysreg!("far_el1");
-        Self { esr, far: VirtualAddress(far) }
-    }
-
-    /// Prints the details of an obj and the exception, excluding UART exceptions.
-    fn print<T: fmt::Display>(&self, exception_name: &str, obj: T, elr: u64) {
-        // Don't print to the UART if we are handling an exception it could raise.
-        if !self.is_uart_exception() {
-            eprintln!("{exception_name}");
-            eprintln!("{obj}");
-            eprintln!("{}, elr={:#08x}", self, elr);
-        }
-    }
-
-    fn is_uart_exception(&self) -> bool {
-        self.esr == Esr::DataAbortSyncExternalAbort && page_4kb_of(self.far.0) == UART_PAGE
-    }
-}
-
 #[no_mangle]
 extern "C" fn sync_exception_current(elr: u64, _spsr: u64) {
     // Disable logging in exception handler to prevent unsafe writes to UART.
diff --git a/tests/testapk/Android.bp b/tests/testapk/Android.bp
index fe8f5c9..8a31c21 100644
--- a/tests/testapk/Android.bp
+++ b/tests/testapk/Android.bp
@@ -43,7 +43,10 @@
     ],
     min_sdk_version: "33",
     // Defined in ../vmshareapp/Android.bp
-    data: [":MicrodroidVmShareApp"],
+    data: [
+        ":MicrodroidVmShareApp",
+        ":test_microdroid_vendor_image",
+    ],
 }
 
 // Defaults shared between MicrodroidTestNativeLib and MicrodroidPayloadInOtherAppNativeLib shared
diff --git a/tests/testapk/AndroidManifest.xml b/tests/testapk/AndroidManifest.xml
index 2ea3f6c..d6e6004 100644
--- a/tests/testapk/AndroidManifest.xml
+++ b/tests/testapk/AndroidManifest.xml
@@ -22,8 +22,7 @@
     <queries>
         <package android:name="com.android.microdroid.vmshare_app" />
     </queries>
-    <application>
-    </application>
+    <application />
     <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
         android:targetPackage="com.android.microdroid.test"
         android:label="Microdroid Test" />
diff --git a/tests/testapk/AndroidTest.xml b/tests/testapk/AndroidTest.xml
index 929dd31..e72a2e3 100644
--- a/tests/testapk/AndroidTest.xml
+++ b/tests/testapk/AndroidTest.xml
@@ -23,6 +23,14 @@
         <option name="test-file-name" value="MicrodroidTestApp.apk" />
         <option name="test-file-name" value="MicrodroidVmShareApp.apk" />
     </target_preparer>
+    <target_preparer class="com.android.tradefed.targetprep.RunCommandTargetPreparer">
+        <option name="run-command" value="mkdir -p /data/local/tmp/cts/microdroid" />
+        <option name="teardown-command" value="rm -rf /data/local/tmp/cts/microdroid" />
+    </target_preparer>
+    <target_preparer class="com.android.compatibility.common.tradefed.targetprep.FilePusher">
+        <option name="cleanup" value="true" />
+        <option name="push" value="test_microdroid_vendor_image.img->/data/local/tmp/cts/microdroid/test_microdroid_vendor_image.img" />
+    </target_preparer>
     <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
         <option name="package" value="com.android.microdroid.test" />
         <option name="runner" value="androidx.test.runner.AndroidJUnitRunner" />
diff --git a/tests/testapk/src/java/com/android/microdroid/test/MicrodroidTests.java b/tests/testapk/src/java/com/android/microdroid/test/MicrodroidTests.java
index 5ec4ca8..15cb450 100644
--- a/tests/testapk/src/java/com/android/microdroid/test/MicrodroidTests.java
+++ b/tests/testapk/src/java/com/android/microdroid/test/MicrodroidTests.java
@@ -1975,8 +1975,10 @@
                 .isEqualTo(OsConstants.S_IRUSR | OsConstants.S_IXUSR);
     }
 
-    // Taken from bionic/libs/kernel/uapi/linux/mounth.h.
+    // Taken from bionic/libc/kernel/uapi/linux/mount.h
+    private static final int MS_RDONLY = 1;
     private static final int MS_NOEXEC = 8;
+    private static final int MS_NOATIME = 1024;
 
     @Test
     @CddTest(requirements = {"9.17/C-1-5"})
@@ -2050,6 +2052,60 @@
         }
     }
 
+    @Test
+    public void configuringVendorDiskImageRequiresCustomPermission() throws Exception {
+        assumeSupportedDevice();
+
+        File vendorDiskImage =
+                new File("/data/local/tmp/cts/microdroid/test_microdroid_vendor_image.img");
+        VirtualMachineConfig config =
+                newVmConfigBuilder()
+                        .setPayloadBinaryName("MicrodroidTestNativeLib.so")
+                        .setVendorDiskImage(vendorDiskImage)
+                        .setDebugLevel(DEBUG_LEVEL_FULL)
+                        .build();
+
+        VirtualMachine vm =
+                forceCreateNewVirtualMachine("test_vendor_image_req_custom_permission", config);
+
+        SecurityException e =
+                assertThrows(
+                        SecurityException.class, () -> runVmTestService(TAG, vm, (ts, tr) -> {}));
+        assertThat(e)
+                .hasMessageThat()
+                .contains("android.permission.USE_CUSTOM_VIRTUAL_MACHINE permission");
+    }
+
+    @Test
+    public void bootsWithVendorPartition() throws Exception {
+        assumeSupportedDevice();
+
+        grantPermission(VirtualMachine.USE_CUSTOM_VIRTUAL_MACHINE_PERMISSION);
+
+        File vendorDiskImage =
+                new File("/data/local/tmp/cts/microdroid/test_microdroid_vendor_image.img");
+        VirtualMachineConfig config =
+                newVmConfigBuilder()
+                        .setPayloadBinaryName("MicrodroidTestNativeLib.so")
+                        .setVendorDiskImage(vendorDiskImage)
+                        .setDebugLevel(DEBUG_LEVEL_FULL)
+                        .build();
+
+        VirtualMachine vm = forceCreateNewVirtualMachine("test_boot_with_vendor", config);
+
+        TestResults testResults =
+                runVmTestService(
+                        TAG,
+                        vm,
+                        (ts, tr) -> {
+                            tr.mMountFlags = ts.getMountFlags("/vendor");
+                        });
+
+        assertThat(testResults.mException).isNull();
+        int expectedFlags = MS_NOATIME | MS_RDONLY;
+        assertThat(testResults.mMountFlags & expectedFlags).isEqualTo(expectedFlags);
+    }
+
     private static class VmShareServiceConnection implements ServiceConnection {
 
         private final CountDownLatch mLatch = new CountDownLatch(1);
diff --git a/tests/vendor_images/Android.bp b/tests/vendor_images/Android.bp
new file mode 100644
index 0000000..09c657c
--- /dev/null
+++ b/tests/vendor_images/Android.bp
@@ -0,0 +1,9 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+android_filesystem {
+    name: "test_microdroid_vendor_image",
+    type: "ext4",
+    file_contexts: ":microdroid_vendor_file_contexts.gen",
+}
diff --git a/virtualizationmanager/src/aidl.rs b/virtualizationmanager/src/aidl.rs
index dd74d55..d0a8e85 100644
--- a/virtualizationmanager/src/aidl.rs
+++ b/virtualizationmanager/src/aidl.rs
@@ -20,7 +20,7 @@
 use crate::composite::make_composite_image;
 use crate::crosvm::{CrosvmConfig, DiskFile, PayloadState, VmContext, VmInstance, VmState};
 use crate::debug_config::DebugConfig;
-use crate::payload::{add_microdroid_payload_images, add_microdroid_system_images};
+use crate::payload::{add_microdroid_payload_images, add_microdroid_system_images, add_microdroid_vendor_image};
 use crate::selinux::{getfilecon, SeContext};
 use android_os_permissions_aidl::aidl::android::os::IPermissionController;
 use android_system_virtualizationcommon::aidl::android::system::virtualizationcommon::{
@@ -579,6 +579,15 @@
     Ok(DiskFile { image, writable: disk.writable })
 }
 
+fn append_kernel_param(param: &str, vm_config: &mut VirtualMachineRawConfig) {
+    if let Some(ref mut params) = vm_config.params {
+        params.push(' ');
+        params.push_str(param)
+    } else {
+        vm_config.params = Some(param.to_owned())
+    }
+}
+
 fn load_app_config(
     config: &VirtualMachineAppConfig,
     debug_config: &DebugConfig,
@@ -620,6 +629,11 @@
         }
         vm_config.taskProfiles = custom_config.taskProfiles.clone();
         vm_config.gdbPort = custom_config.gdbPort;
+
+        if let Some(file) = custom_config.vendorImage.as_ref() {
+            add_microdroid_vendor_image(clone_file(file)?, &mut vm_config);
+            append_kernel_param("androidboot.microdroid.mount_vendor=1", &mut vm_config)
+        }
     }
 
     if config.memoryMib > 0 {
@@ -1349,4 +1363,19 @@
         assert!(modified_orig == modified_new, "idsig file was updated unnecessarily");
         Ok(())
     }
+
+    #[test]
+    fn test_append_kernel_param_first_param() {
+        let mut vm_config = VirtualMachineRawConfig { ..Default::default() };
+        append_kernel_param("foo=1", &mut vm_config);
+        assert_eq!(vm_config.params, Some("foo=1".to_owned()))
+    }
+
+    #[test]
+    fn test_append_kernel_param() {
+        let mut vm_config =
+            VirtualMachineRawConfig { params: Some("foo=5".to_owned()), ..Default::default() };
+        append_kernel_param("bar=42", &mut vm_config);
+        assert_eq!(vm_config.params, Some("foo=5 bar=42".to_owned()))
+    }
 }
diff --git a/virtualizationmanager/src/payload.rs b/virtualizationmanager/src/payload.rs
index 733add6..ab6f31c 100644
--- a/virtualizationmanager/src/payload.rs
+++ b/virtualizationmanager/src/payload.rs
@@ -398,6 +398,18 @@
         .collect()
 }
 
+pub fn add_microdroid_vendor_image(vendor_image: File, vm_config: &mut VirtualMachineRawConfig) {
+    vm_config.disks.push(DiskImage {
+        image: None,
+        writable: false,
+        partitions: vec![Partition {
+            label: "microdroid-vendor".to_owned(),
+            image: Some(ParcelFileDescriptor::new(vendor_image)),
+            writable: false,
+        }],
+    })
+}
+
 pub fn add_microdroid_system_images(
     config: &VirtualMachineAppConfig,
     instance_file: File,
diff --git a/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineAppConfig.aidl b/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineAppConfig.aidl
index 6a0bf7c..2b762c4 100644
--- a/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineAppConfig.aidl
+++ b/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineAppConfig.aidl
@@ -105,6 +105,9 @@
          * List of task profile names to apply for the VM
          */
         String[] taskProfiles;
+
+        /** A disk image containing vendor specific modules. */
+        @nullable ParcelFileDescriptor vendorImage;
     }
 
     /** Configuration parameters guarded by android.permission.USE_CUSTOM_VIRTUAL_MACHINE */
diff --git a/vm/src/main.rs b/vm/src/main.rs
index 0800f57..d7c2c4d 100644
--- a/vm/src/main.rs
+++ b/vm/src/main.rs
@@ -115,6 +115,10 @@
         /// Path to custom kernel image to use when booting Microdroid.
         #[clap(long)]
         kernel: Option<PathBuf>,
+
+        /// Path to disk image containing vendor-specific modules.
+        #[clap(long)]
+        vendor: Option<PathBuf>,
     },
     /// Run a virtual machine with Microdroid inside
     RunMicrodroid {
@@ -179,6 +183,10 @@
         /// Path to custom kernel image to use when booting Microdroid.
         #[clap(long)]
         kernel: Option<PathBuf>,
+
+        /// Path to disk image containing vendor-specific modules.
+        #[clap(long)]
+        vendor: Option<PathBuf>,
     },
     /// Run a virtual machine
     Run {
@@ -299,6 +307,7 @@
             extra_idsigs,
             gdb,
             kernel,
+            vendor,
         } => command_run_app(
             name,
             get_service()?.as_ref(),
@@ -320,6 +329,7 @@
             &extra_idsigs,
             gdb,
             kernel.as_deref(),
+            vendor.as_deref(),
         ),
         Opt::RunMicrodroid {
             name,
@@ -336,6 +346,7 @@
             task_profiles,
             gdb,
             kernel,
+            vendor,
         } => command_run_microdroid(
             name,
             get_service()?.as_ref(),
@@ -352,6 +363,7 @@
             task_profiles,
             gdb,
             kernel.as_deref(),
+            vendor.as_deref(),
         ),
         Opt::Run { name, config, cpu_topology, task_profiles, console, console_in, log, gdb } => {
             command_run(
diff --git a/vm/src/run.rs b/vm/src/run.rs
index 84072ca..64da2d9 100644
--- a/vm/src/run.rs
+++ b/vm/src/run.rs
@@ -65,6 +65,7 @@
     extra_idsigs: &[PathBuf],
     gdb: Option<NonZeroU16>,
     kernel: Option<&Path>,
+    vendor: Option<&Path>,
 ) -> Result<(), Error> {
     let apk_file = File::open(apk).context("Failed to open APK file")?;
 
@@ -122,6 +123,8 @@
 
     let kernel = kernel.map(|p| open_parcel_file(p, false)).transpose()?;
 
+    let vendor = vendor.map(|p| open_parcel_file(p, false)).transpose()?;
+
     let extra_idsig_files: Result<Vec<File>, _> = extra_idsigs.iter().map(File::open).collect();
     let extra_idsig_fds = extra_idsig_files?.into_iter().map(ParcelFileDescriptor::new).collect();
 
@@ -144,6 +147,7 @@
         customKernelImage: kernel,
         gdbPort: gdb.map(u16::from).unwrap_or(0) as i32, // 0 means no gdb
         taskProfiles: task_profiles,
+        vendorImage: vendor,
     };
 
     let config = VirtualMachineConfig::AppConfig(VirtualMachineAppConfig {
@@ -203,6 +207,7 @@
     task_profiles: Vec<String>,
     gdb: Option<NonZeroU16>,
     kernel: Option<&Path>,
+    vendor: Option<&Path>,
 ) -> Result<(), Error> {
     let apk = find_empty_payload_apk_path()?;
     println!("found path {}", apk.display());
@@ -236,6 +241,7 @@
         &extra_sig,
         gdb,
         kernel,
+        vendor,
     )
 }
 
diff --git a/vmbase/src/exceptions.rs b/vmbase/src/exceptions.rs
new file mode 100644
index 0000000..7833334
--- /dev/null
+++ b/vmbase/src/exceptions.rs
@@ -0,0 +1,139 @@
+// Copyright 2023, 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.
+
+//! Helper functions and structs for exception handlers.
+
+use crate::{
+    console, eprintln,
+    memory::{page_4kb_of, MemoryTrackerError},
+    read_sysreg,
+};
+use aarch64_paging::paging::VirtualAddress;
+use core::fmt;
+
+const UART_PAGE: usize = page_4kb_of(console::BASE_ADDRESS);
+
+/// Represents an error that can occur while handling an exception.
+#[derive(Debug)]
+pub enum HandleExceptionError {
+    /// The page table is unavailable.
+    PageTableUnavailable,
+    /// The page table has not been initialized.
+    PageTableNotInitialized,
+    /// An internal error occurred in the memory tracker.
+    InternalError(MemoryTrackerError),
+    /// An unknown exception occurred.
+    UnknownException,
+}
+
+impl From<MemoryTrackerError> for HandleExceptionError {
+    fn from(other: MemoryTrackerError) -> Self {
+        Self::InternalError(other)
+    }
+}
+
+impl fmt::Display for HandleExceptionError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Self::PageTableUnavailable => write!(f, "Page table is not available."),
+            Self::PageTableNotInitialized => write!(f, "Page table is not initialized."),
+            Self::InternalError(e) => write!(f, "Error while updating page table: {e}"),
+            Self::UnknownException => write!(f, "An unknown exception occurred, not handled."),
+        }
+    }
+}
+
+/// Represents the possible types of exception syndrome register (ESR) values.
+#[derive(Debug, PartialEq, Copy, Clone)]
+pub enum Esr {
+    /// Data abort due to translation fault.
+    DataAbortTranslationFault,
+    /// Data abort due to permission fault.
+    DataAbortPermissionFault,
+    /// Data abort due to a synchronous external abort.
+    DataAbortSyncExternalAbort,
+    /// An unknown ESR value.
+    Unknown(usize),
+}
+
+impl Esr {
+    const EXT_DABT_32BIT: usize = 0x96000010;
+    const TRANSL_FAULT_BASE_32BIT: usize = 0x96000004;
+    const TRANSL_FAULT_ISS_MASK_32BIT: usize = !0x143;
+    const PERM_FAULT_BASE_32BIT: usize = 0x9600004C;
+    const PERM_FAULT_ISS_MASK_32BIT: usize = !0x103;
+}
+
+impl From<usize> for Esr {
+    fn from(esr: usize) -> Self {
+        if esr == Self::EXT_DABT_32BIT {
+            Self::DataAbortSyncExternalAbort
+        } else if esr & Self::TRANSL_FAULT_ISS_MASK_32BIT == Self::TRANSL_FAULT_BASE_32BIT {
+            Self::DataAbortTranslationFault
+        } else if esr & Self::PERM_FAULT_ISS_MASK_32BIT == Self::PERM_FAULT_BASE_32BIT {
+            Self::DataAbortPermissionFault
+        } else {
+            Self::Unknown(esr)
+        }
+    }
+}
+
+impl fmt::Display for Esr {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Self::DataAbortSyncExternalAbort => write!(f, "Synchronous external abort"),
+            Self::DataAbortTranslationFault => write!(f, "Translation fault"),
+            Self::DataAbortPermissionFault => write!(f, "Permission fault"),
+            Self::Unknown(v) => write!(f, "Unknown exception esr={v:#08x}"),
+        }
+    }
+}
+/// A struct representing an Armv8 exception.
+pub struct ArmException {
+    /// The value of the exception syndrome register.
+    pub esr: Esr,
+    /// The faulting virtual address read from the fault address register.
+    pub far: VirtualAddress,
+}
+
+impl fmt::Display for ArmException {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "ArmException: esr={}, far={}", self.esr, self.far)
+    }
+}
+
+impl ArmException {
+    /// Reads the values of the EL1 exception syndrome register (`esr_el1`)
+    /// and fault address register (`far_el1`) and returns a new instance of
+    /// `ArmException` with these values.
+    pub fn from_el1_regs() -> Self {
+        let esr: Esr = read_sysreg!("esr_el1").into();
+        let far = read_sysreg!("far_el1");
+        Self { esr, far: VirtualAddress(far) }
+    }
+
+    /// Prints the details of an obj and the exception, excluding UART exceptions.
+    pub fn print<T: fmt::Display>(&self, exception_name: &str, obj: T, elr: u64) {
+        // Don't print to the UART if we are handling an exception it could raise.
+        if !self.is_uart_exception() {
+            eprintln!("{exception_name}");
+            eprintln!("{obj}");
+            eprintln!("{}, elr={:#08x}", self, elr);
+        }
+    }
+
+    fn is_uart_exception(&self) -> bool {
+        self.esr == Esr::DataAbortSyncExternalAbort && page_4kb_of(self.far.0) == UART_PAGE
+    }
+}
diff --git a/vmbase/src/hvc.rs b/vmbase/src/hvc.rs
index 4d489d5..ebd1625 100644
--- a/vmbase/src/hvc.rs
+++ b/vmbase/src/hvc.rs
@@ -30,11 +30,11 @@
 pub const ARM_SMCCC_TRNG_RND64: u32 = 0xc400_0053;
 
 /// Returns the (major, minor) version tuple, as defined by the SMCCC TRNG.
-pub fn trng_version() -> trng::Result<(u16, u16)> {
+pub fn trng_version() -> trng::Result<trng::Version> {
     let args = [0u64; 17];
 
     let version = positive_or_error_64::<Error>(hvc64(ARM_SMCCC_TRNG_VERSION, args)[0])?;
-    Ok(((version >> 16) as u16, version as u16))
+    (version as u32 as i32).try_into()
 }
 
 pub type TrngRng64Entropy = (u64, u64, u64);
diff --git a/vmbase/src/hvc/trng.rs b/vmbase/src/hvc/trng.rs
index 1a27d64..efb86f6 100644
--- a/vmbase/src/hvc/trng.rs
+++ b/vmbase/src/hvc/trng.rs
@@ -55,3 +55,40 @@
 }
 
 pub type Result<T> = result::Result<T, Error>;
+
+/// A version of the SMCCC TRNG interface.
+#[derive(Copy, Clone, Eq, Ord, PartialEq, PartialOrd)]
+pub struct Version {
+    pub major: u16,
+    pub minor: u16,
+}
+
+impl fmt::Display for Version {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}.{}", self.major, self.minor)
+    }
+}
+
+impl fmt::Debug for Version {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl TryFrom<i32> for Version {
+    type Error = Error;
+
+    fn try_from(value: i32) -> core::result::Result<Self, Error> {
+        if value < 0 {
+            Err((value as i64).into())
+        } else {
+            Ok(Self { major: (value >> 16) as u16, minor: value as u16 })
+        }
+    }
+}
+
+impl From<Version> for u32 {
+    fn from(version: Version) -> Self {
+        (u32::from(version.major) << 16) | u32::from(version.minor)
+    }
+}
diff --git a/vmbase/src/lib.rs b/vmbase/src/lib.rs
index 3d2b1c2..ca8756d 100644
--- a/vmbase/src/lib.rs
+++ b/vmbase/src/lib.rs
@@ -24,6 +24,7 @@
 pub mod bionic;
 pub mod console;
 mod entry;
+pub mod exceptions;
 pub mod fdt;
 pub mod heap;
 mod hvc;
diff --git a/vmbase/src/memory/mod.rs b/vmbase/src/memory/mod.rs
index 5e78565..898aa10 100644
--- a/vmbase/src/memory/mod.rs
+++ b/vmbase/src/memory/mod.rs
@@ -22,7 +22,10 @@
 
 pub use error::MemoryTrackerError;
 pub use page_table::PageTable;
-pub use shared::{alloc_shared, dealloc_shared, MemoryRange, MemoryTracker, MEMORY};
+pub use shared::{
+    alloc_shared, dealloc_shared, handle_permission_fault, handle_translation_fault, MemoryRange,
+    MemoryTracker, MEMORY,
+};
 pub use util::{
     flush, flushed_zeroize, min_dcache_line_size, page_4kb_of, phys_to_virt, virt_to_phys,
     PAGE_SIZE, SIZE_128KB, SIZE_2MB, SIZE_4KB, SIZE_4MB, SIZE_64KB,
diff --git a/vmbase/src/memory/shared.rs b/vmbase/src/memory/shared.rs
index 8935934..173c0ec 100644
--- a/vmbase/src/memory/shared.rs
+++ b/vmbase/src/memory/shared.rs
@@ -19,6 +19,7 @@
 use super::page_table::{is_leaf_pte, PageTable, MMIO_LAZY_MAP_FLAG};
 use super::util::{page_4kb_of, virt_to_phys};
 use crate::dsb;
+use crate::exceptions::HandleExceptionError;
 use crate::util::RangeExt as _;
 use aarch64_paging::paging::{Attributes, Descriptor, MemoryRegion as VaRange, VirtualAddress};
 use alloc::alloc::{alloc_zeroed, dealloc, handle_alloc_error};
@@ -293,7 +294,7 @@
 
     /// Handles translation fault for blocks flagged for lazy MMIO mapping by enabling the page
     /// table entry and MMIO guard mapping the block. Breaks apart a block entry if required.
-    pub fn handle_mmio_fault(&mut self, addr: VirtualAddress) -> Result<()> {
+    fn handle_mmio_fault(&mut self, addr: VirtualAddress) -> Result<()> {
         let page_start = VirtualAddress(page_4kb_of(addr.0));
         let page_range: VaRange = (page_start..page_start + MMIO_GUARD_GRANULE_SIZE).into();
         let mmio_guard = get_mmio_guard().unwrap();
@@ -325,7 +326,7 @@
     /// Handles permission fault for read-only blocks by setting writable-dirty state.
     /// In general, this should be called from the exception handler when hardware dirty
     /// state management is disabled or unavailable.
-    pub fn handle_permission_fault(&mut self, addr: VirtualAddress) -> Result<()> {
+    fn handle_permission_fault(&mut self, addr: VirtualAddress) -> Result<()> {
         self.page_table
             .modify_range(&(addr..addr + 1).into(), &mark_dirty_block)
             .map_err(|_| MemoryTrackerError::SetPteDirtyFailed)
@@ -491,3 +492,19 @@
     }
     Ok(())
 }
+
+/// Handles a translation fault with the given fault address register (FAR).
+#[inline]
+pub fn handle_translation_fault(far: VirtualAddress) -> result::Result<(), HandleExceptionError> {
+    let mut guard = MEMORY.try_lock().ok_or(HandleExceptionError::PageTableUnavailable)?;
+    let memory = guard.as_mut().ok_or(HandleExceptionError::PageTableNotInitialized)?;
+    Ok(memory.handle_mmio_fault(far)?)
+}
+
+/// Handles a permission fault with the given fault address register (FAR).
+#[inline]
+pub fn handle_permission_fault(far: VirtualAddress) -> result::Result<(), HandleExceptionError> {
+    let mut guard = MEMORY.try_lock().ok_or(HandleExceptionError::PageTableUnavailable)?;
+    let memory = guard.as_mut().ok_or(HandleExceptionError::PageTableNotInitialized)?;
+    Ok(memory.handle_permission_fault(far)?)
+}
diff --git a/vmbase/src/rand.rs b/vmbase/src/rand.rs
index a5a5f5f..6b8d7e0 100644
--- a/vmbase/src/rand.rs
+++ b/vmbase/src/rand.rs
@@ -14,7 +14,7 @@
 
 //! Functions and drivers for obtaining true entropy.
 
-use crate::hvc;
+use crate::hvc::{self, TrngRng64Entropy};
 use core::fmt;
 use core::mem::size_of;
 use smccc::{self, Hvc};
@@ -30,7 +30,7 @@
     /// Unsupported SMCCC version.
     UnsupportedSmcccVersion(smccc::arch::Version),
     /// Unsupported SMCCC TRNG version.
-    UnsupportedVersion((u16, u16)),
+    UnsupportedTrngVersion(hvc::trng::Version),
 }
 
 impl From<smccc::arch::Error> for Error {
@@ -55,9 +55,7 @@
             Self::Smccc(e) => write!(f, "Architectural SMCCC error: {e}"),
             Self::Trng(e) => write!(f, "SMCCC TRNG error: {e}"),
             Self::UnsupportedSmcccVersion(v) => write!(f, "Unsupported SMCCC version {v}"),
-            Self::UnsupportedVersion((x, y)) => {
-                write!(f, "Unsupported SMCCC TRNG version v{x}.{y}")
-            }
+            Self::UnsupportedTrngVersion(v) => write!(f, "Unsupported SMCCC TRNG version {v}"),
         }
     }
 }
@@ -78,8 +76,8 @@
 
     // TRNG_RND requires SMCCC TRNG v1.0.
     match hvc::trng_version()? {
-        (1, _) => (),
-        version => return Err(Error::UnsupportedVersion(version)),
+        hvc::trng::Version { major: 1, minor: _ } => (),
+        version => return Err(Error::UnsupportedTrngVersion(version)),
     }
 
     // TRNG_RND64 doesn't define any special capabilities so ignore the successful result.
@@ -97,7 +95,7 @@
 
 /// Fills a slice of bytes with true entropy.
 pub fn fill_with_entropy(s: &mut [u8]) -> Result<()> {
-    const MAX_BYTES_PER_CALL: usize = size_of::<hvc::TrngRng64Entropy>();
+    const MAX_BYTES_PER_CALL: usize = size_of::<TrngRng64Entropy>();
 
     let (aligned, remainder) = s.split_at_mut(s.len() - s.len() % MAX_BYTES_PER_CALL);
 
@@ -125,13 +123,14 @@
     Ok(())
 }
 
-fn repeat_trng_rnd(n_bytes: usize) -> hvc::trng::Result<hvc::TrngRng64Entropy> {
+fn repeat_trng_rnd(n_bytes: usize) -> Result<TrngRng64Entropy> {
     let bits = usize::try_from(u8::BITS).unwrap();
     let n_bits = (n_bytes * bits).try_into().unwrap();
     loop {
         match hvc::trng_rnd64(n_bits) {
-            Err(hvc::trng::Error::NoEntropy) => continue,
-            res => return res,
+            Ok(entropy) => return Ok(entropy),
+            Err(hvc::trng::Error::NoEntropy) => (),
+            Err(e) => return Err(e.into()),
         }
     }
 }