Add persistent backing for encrypted storage in VM

Virtualization service will allow clients to pass the file that will
back the (encrypted) storage inside VM.

This patch:
1. Exposes (optional) encryptedStorageImage in VirtualMachineAppConfig.
2. Expose it as a block device to VM (by including it as partition in a
   writable disk).

Test: bin/vm run-app --storage -> inspect the block device in vm
Bug: 241543632
Change-Id: I9adbe832bda2c5f5a749d8614f056f51244ae52c
diff --git a/compos/common/compos_client.rs b/compos/common/compos_client.rs
index 7327df7..68e1948 100644
--- a/compos/common/compos_client.rs
+++ b/compos/common/compos_client.rs
@@ -122,6 +122,7 @@
             apk: Some(apk_fd),
             idsig: Some(idsig_fd),
             instanceImage: Some(instance_fd),
+            encryptedStorageImage: None,
             payload: Payload::ConfigPath(config_path),
             debugLevel: debug_level,
             extraIdsigs: extra_idsigs,
diff --git a/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineAppConfig.aidl b/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineAppConfig.aidl
index 9b0a658..e99757e 100644
--- a/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineAppConfig.aidl
+++ b/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineAppConfig.aidl
@@ -34,6 +34,13 @@
     /** instance.img that has per-instance data */
     ParcelFileDescriptor instanceImage;
 
+    /**
+     * This backs the persistent, encrypted storage in vm.
+     * It also comes with some integrity guarantees.
+     * Note: Storage is an optional feature
+     */
+    @nullable ParcelFileDescriptor encryptedStorageImage;
+
     union Payload {
         /**
          * Path to a JSON file in an APK containing the configuration.
diff --git a/virtualizationservice/src/aidl.rs b/virtualizationservice/src/aidl.rs
index 563fab0..10d70ec 100644
--- a/virtualizationservice/src/aidl.rs
+++ b/virtualizationservice/src/aidl.rs
@@ -17,7 +17,7 @@
 use crate::atom::{write_vm_booted_stats, write_vm_creation_stats};
 use crate::composite::make_composite_image;
 use crate::crosvm::{CrosvmConfig, DiskFile, PayloadState, VmInstance, VmState};
-use crate::payload::add_microdroid_images;
+use crate::payload::{add_microdroid_payload_images, add_microdroid_system_images};
 use crate::{Cid, FIRST_GUEST_CID, SYSPROP_LAST_CID};
 use crate::selinux::{SeContext, getfilecon};
 use android_os_permissions_aidl::aidl::android::os::IPermissionController;
@@ -603,6 +603,12 @@
     let idsig_file = clone_file(config.idsig.as_ref().unwrap())?;
     let instance_file = clone_file(config.instanceImage.as_ref().unwrap())?;
 
+    let storage_image = if let Some(file) = config.encryptedStorageImage.as_ref() {
+        Some(clone_file(file)?)
+    } else {
+        None
+    };
+
     let vm_payload_config = match &config.payload {
         Payload::ConfigPath(config_path) => {
             load_vm_payload_config_from_file(&apk_file, config_path.as_str())
@@ -632,13 +638,15 @@
     vm_config.numCpus = config.numCpus;
     vm_config.taskProfiles = config.taskProfiles.clone();
 
-    // Microdroid requires an additional init ramdisk & payload disk image
-    add_microdroid_images(
+    // Microdroid takes additional init ramdisk & (optionally) storage image
+    add_microdroid_system_images(config, instance_file, storage_image, &mut vm_config)?;
+
+    // Include Microdroid payload disk (contains apks, idsigs) in vm config
+    add_microdroid_payload_images(
         config,
         temporary_directory,
         apk_file,
         idsig_file,
-        instance_file,
         &vm_payload_config,
         &mut vm_config,
     )?;
diff --git a/virtualizationservice/src/payload.rs b/virtualizationservice/src/payload.rs
index 82aa760..b6df500 100644
--- a/virtualizationservice/src/payload.rs
+++ b/virtualizationservice/src/payload.rs
@@ -363,13 +363,10 @@
         .collect()
 }
 
-pub fn add_microdroid_images(
+pub fn add_microdroid_system_images(
     config: &VirtualMachineAppConfig,
-    temporary_directory: &Path,
-    apk_file: File,
-    idsig_file: File,
     instance_file: File,
-    vm_payload_config: &VmPayloadConfig,
+    storage_image: Option<File>,
     vm_config: &mut VirtualMachineRawConfig,
 ) -> Result<()> {
     let debug_suffix = match config.debugLevel {
@@ -381,12 +378,37 @@
     let initrd = format!("/apex/com.android.virt/etc/microdroid_initrd_{}.img", debug_suffix);
     vm_config.initrd = Some(open_parcel_file(Path::new(&initrd), false)?);
 
-    let instance_img = Partition {
+    let mut writable_partitions = vec![Partition {
         label: "vm-instance".to_owned(),
         image: Some(ParcelFileDescriptor::new(instance_file)),
         writable: true,
-    };
-    vm_config.disks.push(DiskImage { image: None, partitions: vec![instance_img], writable: true });
+    }];
+
+    if let Some(file) = storage_image {
+        writable_partitions.push(Partition {
+            label: "encrypted-storage".to_owned(),
+            image: Some(ParcelFileDescriptor::new(file)),
+            writable: true,
+        });
+    }
+
+    vm_config.disks.push(DiskImage {
+        image: None,
+        partitions: writable_partitions,
+        writable: true,
+    });
+
+    Ok(())
+}
+
+pub fn add_microdroid_payload_images(
+    config: &VirtualMachineAppConfig,
+    temporary_directory: &Path,
+    apk_file: File,
+    idsig_file: File,
+    vm_payload_config: &VmPayloadConfig,
+    vm_config: &mut VirtualMachineRawConfig,
+) -> Result<()> {
     vm_config.disks.push(make_payload_disk(
         config,
         apk_file,
diff --git a/vm/src/main.rs b/vm/src/main.rs
index 21cc74b..3b887d3 100644
--- a/vm/src/main.rs
+++ b/vm/src/main.rs
@@ -58,6 +58,16 @@
         #[clap(short, long)]
         daemonize: bool,
 
+        /// Path to the file backing the storage.
+        /// Created if the option is used but the path does not exist in the device.
+        #[clap(long)]
+        storage: Option<PathBuf>,
+
+        /// Size of the storage. Used only if --storage is supplied but path does not exist
+        /// Default size is 10*1024*1024
+        #[clap(long)]
+        storage_size: Option<u64>,
+
         /// Path to file for VM console output.
         #[clap(long)]
         console: Option<PathBuf>,
@@ -188,6 +198,8 @@
             apk,
             idsig,
             instance,
+            storage,
+            storage_size,
             config_path,
             daemonize,
             console,
@@ -205,6 +217,8 @@
             &apk,
             &idsig,
             &instance,
+            storage.as_deref(),
+            storage_size,
             config_path.as_deref().unwrap_or(""),
             daemonize,
             console.as_deref(),
diff --git a/vm/src/run.rs b/vm/src/run.rs
index c524c59..967314b 100644
--- a/vm/src/run.rs
+++ b/vm/src/run.rs
@@ -41,6 +41,8 @@
     apk: &Path,
     idsig: &Path,
     instance: &Path,
+    storage: Option<&Path>,
+    storage_size: Option<u64>,
     config_path: &str,
     daemonize: bool,
     console_path: Option<&Path>,
@@ -88,6 +90,20 @@
         )?;
     }
 
+    let storage = if let Some(path) = storage {
+        if !path.exists() {
+            command_create_partition(
+                service,
+                path,
+                storage_size.unwrap_or(10 * 1024 * 1024),
+                PartitionType::RAW,
+            )?;
+        }
+        Some(open_parcel_file(path, true)?)
+    } else {
+        None
+    };
+
     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();
 
@@ -97,6 +113,7 @@
         idsig: idsig_fd.into(),
         extraIdsigs: extra_idsig_fds,
         instanceImage: open_parcel_file(instance, true /* writable */)?.into(),
+        encryptedStorageImage: storage,
         payload: Payload::ConfigPath(config_path.to_owned()),
         debugLevel: debug_level,
         protectedVm: protected,