libavf: implement AVirtualMachineRawConfig_addCustomMemoryBackingFile
Bug: 381972137
Bug: 368143426
Test: m
Change-Id: Ic62ad99b1923d45406366c00541789fb1fdd9b74
diff --git a/android/virtmgr/src/aidl.rs b/android/virtmgr/src/aidl.rs
index 9ba1c04..ef76822 100644
--- a/android/virtmgr/src/aidl.rs
+++ b/android/virtmgr/src/aidl.rs
@@ -802,6 +802,25 @@
let detect_hangup = is_app_config && gdb_port.is_none();
+ let custom_memory_backing_files = config
+ .customMemoryBackingFiles
+ .iter()
+ .map(|memory_backing_file| {
+ Ok((
+ clone_file(
+ memory_backing_file
+ .file
+ .as_ref()
+ .context("missing CustomMemoryBackingFile FD")
+ .or_binder_exception(ExceptionCode::ILLEGAL_ARGUMENT)?,
+ )?
+ .into(),
+ memory_backing_file.rangeStart as u64,
+ memory_backing_file.size as u64,
+ ))
+ })
+ .collect::<binder::Result<_>>()?;
+
// Actually start the VM.
let crosvm_config = CrosvmConfig {
cid,
@@ -846,6 +865,7 @@
dump_dt_fd,
enable_hypervisor_specific_auth_method: config.enableHypervisorSpecificAuthMethod,
instance_id,
+ custom_memory_backing_files,
};
let instance = Arc::new(
VmInstance::new(
diff --git a/android/virtmgr/src/crosvm.rs b/android/virtmgr/src/crosvm.rs
index bb7712e..59f115e 100644
--- a/android/virtmgr/src/crosvm.rs
+++ b/android/virtmgr/src/crosvm.rs
@@ -140,6 +140,8 @@
pub dump_dt_fd: Option<File>,
pub enable_hypervisor_specific_auth_method: bool,
pub instance_id: [u8; 64],
+ // (memfd, guest address, size)
+ pub custom_memory_backing_files: Vec<(OwnedFd, u64, u64)>,
}
#[derive(Debug)]
@@ -1370,6 +1372,13 @@
}
}
+ for (fd, addr, size) in config.custom_memory_backing_files {
+ command.arg("--file-backed-mapping").arg(format!(
+ "{},addr={addr:#0x},size={size:#0x},rw,ram",
+ add_preserved_fd(&mut preserved_fds, fd)
+ ));
+ }
+
debug!("Preserving FDs {:?}", preserved_fds);
command.preserved_fds(preserved_fds);
diff --git a/android/virtualizationservice/aidl/android/system/virtualizationservice/CustomMemoryBackingFile.aidl b/android/virtualizationservice/aidl/android/system/virtualizationservice/CustomMemoryBackingFile.aidl
new file mode 100644
index 0000000..721ad26
--- /dev/null
+++ b/android/virtualizationservice/aidl/android/system/virtualizationservice/CustomMemoryBackingFile.aidl
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.system.virtualizationservice;
+
+/** Custom memfd for a subset of guest memory. */
+parcelable CustomMemoryBackingFile {
+ /** The memfd. */
+ ParcelFileDescriptor file;
+
+ /**
+ * Start of range in guest physical address space.
+ *
+ * The value should be interpreted as an unsigned 64 bit integer.
+ */
+ long rangeStart;
+
+ /**
+ * Size of range in bytes.
+ *
+ * The value should be interpreted as an unsigned 64 bit integer.
+ */
+ long size;
+}
diff --git a/android/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineRawConfig.aidl b/android/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineRawConfig.aidl
index a822423..c5fe982 100644
--- a/android/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineRawConfig.aidl
+++ b/android/virtualizationservice/aidl/android/system/virtualizationservice/VirtualMachineRawConfig.aidl
@@ -18,6 +18,7 @@
import android.system.virtualizationservice.AssignedDevices;
import android.system.virtualizationservice.AudioConfig;
import android.system.virtualizationservice.CpuOptions;
+import android.system.virtualizationservice.CustomMemoryBackingFile;
import android.system.virtualizationservice.DiskImage;
import android.system.virtualizationservice.DisplayConfig;
import android.system.virtualizationservice.GpuConfig;
@@ -123,4 +124,7 @@
* VMs.
*/
boolean enableHypervisorSpecificAuthMethod;
+
+ /** Custom memfds for a subset of guest memory */
+ CustomMemoryBackingFile[] customMemoryBackingFiles;
}
diff --git a/libs/libavf/include/android/virtualization.h b/libs/libavf/include/android/virtualization.h
index 8d96fac..4bfe47a 100644
--- a/libs/libavf/include/android/virtualization.h
+++ b/libs/libavf/include/android/virtualization.h
@@ -189,7 +189,7 @@
* physical memory.
*
* \param config a virtual machine config object.
- * \param fd a memfd
+ * \param fd a memfd. Ownership is transferred, even if the function is not successful.
* \param rangeStart range start of guest memory addresses
* \param rangeEnd range end of guest memory addresses
*
diff --git a/libs/libavf/src/lib.rs b/libs/libavf/src/lib.rs
index 3fa1b75..8a4970a 100644
--- a/libs/libavf/src/lib.rs
+++ b/libs/libavf/src/lib.rs
@@ -24,8 +24,9 @@
use android_system_virtualizationservice::{
aidl::android::system::virtualizationservice::{
AssignedDevices::AssignedDevices, CpuOptions::CpuOptions,
- CpuOptions::CpuTopology::CpuTopology, DiskImage::DiskImage,
- IVirtualizationService::IVirtualizationService, VirtualMachineConfig::VirtualMachineConfig,
+ CpuOptions::CpuTopology::CpuTopology, CustomMemoryBackingFile::CustomMemoryBackingFile,
+ DiskImage::DiskImage, IVirtualizationService::IVirtualizationService,
+ VirtualMachineConfig::VirtualMachineConfig,
VirtualMachineRawConfig::VirtualMachineRawConfig,
},
binder::{ParcelFileDescriptor, Strong},
@@ -254,18 +255,35 @@
0
}
-/// NOT IMPLEMENTED.
+/// Use the specified fd as the backing memfd for a range of the guest physical memory.
///
-/// # Returns
-/// It always returns `-ENOTSUP`.
+/// # Safety
+/// `config` must be a pointer returned by `AVirtualMachineRawConfig_create`.
#[no_mangle]
-pub extern "C" fn AVirtualMachineRawConfig_addCustomMemoryBackingFile(
- _config: *mut VirtualMachineRawConfig,
- _fd: c_int,
- _range_start: u64,
- _range_end: u64,
+pub unsafe extern "C" fn AVirtualMachineRawConfig_addCustomMemoryBackingFile(
+ config: *mut VirtualMachineRawConfig,
+ fd: c_int,
+ range_start: u64,
+ range_end: u64,
) -> c_int {
- -libc::ENOTSUP
+ // SAFETY: `config` is assumed to be a valid, non-null pointer returned by
+ // AVirtualMachineRawConfig_create. It's the only reference to the object.
+ let config = unsafe { &mut *config };
+
+ let Some(file) = get_file_from_fd(fd) else {
+ return -libc::EINVAL;
+ };
+ let Some(size) = range_end.checked_sub(range_start) else {
+ return -libc::EINVAL;
+ };
+ config.customMemoryBackingFiles.push(CustomMemoryBackingFile {
+ file: Some(ParcelFileDescriptor::new(file)),
+ // AIDL doesn't support unsigned ints, so we've got to reinterpret the bytes into a signed
+ // int.
+ rangeStart: range_start as i64,
+ size: size as i64,
+ });
+ 0
}
/// Add device tree overlay blob