block: add aio disk backend

Signed-off-by: Thomas Barrett <tbarrett@crusoeenergy.com>

block/src/lib.rs

@@ -24,6 +24,7 @@ pub mod qcow_sync;
 ///
 /// Enabled with the `"io_uring"` feature
 pub mod raw_async;
+pub mod raw_async_aio;
 pub mod raw_sync;
 pub mod vhd;
 pub mod vhdx;
@@ -61,6 +62,7 @@ use vm_memory::{
     GuestMemoryError, GuestMemoryLoadGuard,
 };
 use vm_virtio::{AccessPlatform, Translatable};
+use vmm_sys_util::aio;
 use vmm_sys_util::eventfd::EventFd;
 use vmm_sys_util::{ioctl_io_nr, ioctl_ioc_nr};
 
@@ -565,6 +567,11 @@ unsafe impl ByteValued for VirtioBlockConfig {}
 // SAFETY: data structure only contain a series of integers
 unsafe impl ByteValued for VirtioBlockGeometry {}
 
+/// Check if aio can be used on the current system.
+pub fn block_aio_is_supported() -> bool {
+    aio::IoContext::new(1).is_ok()
+}
+
 /// Check if io_uring for block device can be used on the current system, as
 /// it correctly supports the expected io_uring features.
 pub fn block_io_uring_is_supported() -> bool {

block/src/raw_async_aio.rs

@@ -0,0 +1,138 @@
+use crate::async_io::{
+    AsyncIo, AsyncIoError, AsyncIoResult, DiskFile, DiskFileError, DiskFileResult,
+};
+use crate::DiskTopology;
+use std::fs::File;
+use std::io::{Seek, SeekFrom};
+use std::os::unix::io::{AsRawFd, RawFd};
+use vmm_sys_util::aio;
+use vmm_sys_util::eventfd::EventFd;
+
+pub struct RawFileDiskAio {
+    file: File,
+}
+
+impl RawFileDiskAio {
+    pub fn new(file: File) -> Self {
+        RawFileDiskAio { file }
+    }
+}
+
+impl DiskFile for RawFileDiskAio {
+    fn size(&mut self) -> DiskFileResult<u64> {
+        self.file
+            .seek(SeekFrom::End(0))
+            .map_err(DiskFileError::Size)
+    }
+
+    fn new_async_io(&self, ring_depth: u32) -> DiskFileResult<Box<dyn AsyncIo>> {
+        Ok(Box::new(
+            RawFileAsyncAio::new(self.file.as_raw_fd(), ring_depth)
+                .map_err(DiskFileError::NewAsyncIo)?,
+        ) as Box<dyn AsyncIo>)
+    }
+
+    fn topology(&mut self) -> DiskTopology {
+        if let Ok(topology) = DiskTopology::probe(&self.file) {
+            topology
+        } else {
+            warn!("Unable to get device topology. Using default topology");
+            DiskTopology::default()
+        }
+    }
+}
+
+pub struct RawFileAsyncAio {
+    fd: RawFd,
+    ctx: aio::IoContext,
+    eventfd: EventFd,
+}
+
+impl RawFileAsyncAio {
+    pub fn new(fd: RawFd, queue_depth: u32) -> std::io::Result<Self> {
+        let eventfd = EventFd::new(libc::EFD_NONBLOCK)?;
+        let ctx = aio::IoContext::new(queue_depth)?;
+
+        Ok(RawFileAsyncAio { fd, ctx, eventfd })
+    }
+}
+
+impl AsyncIo for RawFileAsyncAio {
+    fn notifier(&self) -> &EventFd {
+        &self.eventfd
+    }
+
+    fn read_vectored(
+        &mut self,
+        offset: libc::off_t,
+        iovecs: &[libc::iovec],
+        user_data: u64,
+    ) -> AsyncIoResult<()> {
+        let iocbs = [&mut aio::IoControlBlock {
+            aio_fildes: self.fd.as_raw_fd() as u32,
+            aio_lio_opcode: aio::IOCB_CMD_PREADV as u16,
+            aio_buf: iovecs.as_ptr() as u64,
+            aio_nbytes: iovecs.len() as u64,
+            aio_offset: offset,
+            aio_data: user_data,
+            aio_flags: aio::IOCB_FLAG_RESFD,
+            aio_resfd: self.eventfd.as_raw_fd() as u32,
+            ..Default::default()
+        }];
+        let _ = self
+            .ctx
+            .submit(&iocbs[..])
+            .map_err(AsyncIoError::ReadVectored)?;
+
+        Ok(())
+    }
+
+    fn write_vectored(
+        &mut self,
+        offset: libc::off_t,
+        iovecs: &[libc::iovec],
+        user_data: u64,
+    ) -> AsyncIoResult<()> {
+        let iocbs = [&mut aio::IoControlBlock {
+            aio_fildes: self.fd.as_raw_fd() as u32,
+            aio_lio_opcode: aio::IOCB_CMD_PWRITEV as u16,
+            aio_buf: iovecs.as_ptr() as u64,
+            aio_nbytes: iovecs.len() as u64,
+            aio_offset: offset,
+            aio_data: user_data,
+            aio_flags: aio::IOCB_FLAG_RESFD,
+            aio_resfd: self.eventfd.as_raw_fd() as u32,
+            ..Default::default()
+        }];
+        let _ = self
+            .ctx
+            .submit(&iocbs[..])
+            .map_err(AsyncIoError::WriteVectored)?;
+
+        Ok(())
+    }
+
+    fn fsync(&mut self, user_data: Option<u64>) -> AsyncIoResult<()> {
+        let iocbs = [&mut aio::IoControlBlock {
+            aio_fildes: self.fd.as_raw_fd() as u32,
+            aio_lio_opcode: aio::IOCB_CMD_FSYNC as u16,
+            aio_data: user_data.unwrap_or(0),
+            aio_flags: aio::IOCB_FLAG_RESFD,
+            aio_resfd: self.eventfd.as_raw_fd() as u32,
+            ..Default::default()
+        }];
+        let _ = self.ctx.submit(&iocbs[..]).map_err(AsyncIoError::Fsync)?;
+
+        Ok(())
+    }
+
+    fn next_completed_request(&mut self) -> Option<(u64, i32)> {
+        let mut events: [aio::IoEvent; 1] = [aio::IoEvent::default()];
+        let rc = self.ctx.get_events(0, &mut events, None).unwrap();
+        if rc == 0 {
+            None
+        } else {
+            Some((events[0].data, events[0].res as i32))
+        }
+    }
+}

tests/integration.rs

@@ -3055,7 +3055,7 @@ mod common_parallel {
         handle_child_output(r, &output);
     }
 
-    fn _test_virtio_block(image_name: &str, disable_io_uring: bool) {
+    fn _test_virtio_block(image_name: &str, disable_io_uring: bool, disable_aio: bool) {
         let focal = UbuntuDiskConfig::new(image_name.to_string());
         let guest = Guest::new(Box::new(focal));
 
@@ -3085,9 +3085,10 @@ mod common_parallel {
                 )
                 .as_str(),
                 format!(
-                    "path={},readonly=on,direct=on,num_queues=4,_disable_io_uring={}",
+                    "path={},readonly=on,direct=on,num_queues=4,_disable_io_uring={},_disable_aio={}",
                     blk_file_path.to_str().unwrap(),
-                    disable_io_uring
+                    disable_io_uring,
+                    disable_aio,
                 )
                 .as_str(),
             ])
@@ -3140,23 +3141,28 @@ mod common_parallel {
     }
 
     #[test]
-    fn test_virtio_block() {
-        _test_virtio_block(FOCAL_IMAGE_NAME, false)
+    fn test_virtio_block_io_uring() {
+        _test_virtio_block(FOCAL_IMAGE_NAME, false, true)
     }
 
     #[test]
-    fn test_virtio_block_disable_io_uring() {
-        _test_virtio_block(FOCAL_IMAGE_NAME, true)
+    fn test_virtio_block_aio() {
+        _test_virtio_block(FOCAL_IMAGE_NAME, true, false)
+    }
+
+    #[test]
+    fn test_virtio_block_sync() {
+        _test_virtio_block(FOCAL_IMAGE_NAME, true, true)
     }
 
     #[test]
     fn test_virtio_block_qcow2() {
-        _test_virtio_block(FOCAL_IMAGE_NAME_QCOW2, false)
+        _test_virtio_block(FOCAL_IMAGE_NAME_QCOW2, false, false)
     }
 
     #[test]
     fn test_virtio_block_qcow2_backing_file() {
-        _test_virtio_block(FOCAL_IMAGE_NAME_QCOW2_BACKING_FILE, false)
+        _test_virtio_block(FOCAL_IMAGE_NAME_QCOW2_BACKING_FILE, false, false)
     }
 
     #[test]
@@ -3181,7 +3187,7 @@ mod common_parallel {
             .output()
             .expect("Expect generating VHD image from RAW image");
 
-        _test_virtio_block(FOCAL_IMAGE_NAME_VHD, false)
+        _test_virtio_block(FOCAL_IMAGE_NAME_VHD, false, false)
     }
 
     #[test]
@@ -3205,7 +3211,7 @@ mod common_parallel {
             .output()
             .expect("Expect generating dynamic VHDx image from RAW image");
 
-        _test_virtio_block(FOCAL_IMAGE_NAME_VHDX, false)
+        _test_virtio_block(FOCAL_IMAGE_NAME_VHDX, false, false)
     }
 
     #[test]

virtio-devices/src/seccomp_filters.rs

@@ -86,6 +86,9 @@ fn virtio_block_thread_rules() -> Vec<(i64, Vec<SeccompRule>)> {
         (libc::SYS_fsync, vec![]),
         (libc::SYS_ftruncate, vec![]),
         (libc::SYS_getrandom, vec![]),
+        (libc::SYS_io_destroy, vec![]),
+        (libc::SYS_io_getevents, vec![]),
+        (libc::SYS_io_submit, vec![]),
         (libc::SYS_io_uring_enter, vec![]),
         (libc::SYS_lseek, vec![]),
         (libc::SYS_prctl, vec![]),

vmm/src/config.rs

@@ -888,6 +888,7 @@ impl DiskConfig {
             .add("ops_refill_time")
             .add("id")
             .add("_disable_io_uring")
+            .add("_disable_aio")
             .add("pci_segment")
             .add("serial");
         parser.parse(disk).map_err(Error::ParseDisk)?;
@@ -928,6 +929,11 @@ impl DiskConfig {
             .map_err(Error::ParseDisk)?
             .unwrap_or(Toggle(false))
             .0;
+        let disable_aio = parser
+            .convert::<Toggle>("_disable_aio")
+            .map_err(Error::ParseDisk)?
+            .unwrap_or(Toggle(false))
+            .0;
         let pci_segment = parser
             .convert("pci_segment")
             .map_err(Error::ParseDisk)?
@@ -996,6 +1002,7 @@ impl DiskConfig {
             rate_limiter_config,
             id,
             disable_io_uring,
+            disable_aio,
             pci_segment,
             serial,
         })

vmm/src/device_manager.rs

@@ -35,9 +35,9 @@ use arch::NumaNodes;
 #[cfg(target_arch = "aarch64")]
 use arch::{DeviceType, MmioDeviceInfo};
 use block::{
-    async_io::DiskFile, block_io_uring_is_supported, detect_image_type,
-    fixed_vhd_sync::FixedVhdDiskSync, qcow, qcow_sync::QcowDiskSync, raw_sync::RawFileDiskSync,
-    vhdx, vhdx_sync::VhdxDiskSync, ImageType,
+    async_io::DiskFile, block_aio_is_supported, block_io_uring_is_supported, detect_image_type,
+    fixed_vhd_sync::FixedVhdDiskSync, qcow, qcow_sync::QcowDiskSync, raw_async_aio::RawFileDiskAio,
+    raw_sync::RawFileDiskSync, vhdx, vhdx_sync::VhdxDiskSync, ImageType,
 };
 #[cfg(feature = "io_uring")]
 use block::{fixed_vhd_async::FixedVhdDiskAsync, raw_async::RawFileDisk};
@@ -949,6 +949,9 @@ pub struct DeviceManager {
     // io_uring availability if detected
     io_uring_supported: Option<bool>,
 
+    // aio availability if detected
+    aio_supported: Option<bool>,
+
     // List of unique identifiers provided at boot through the configuration.
     boot_id_list: BTreeSet<String>,
 
@@ -1138,6 +1141,7 @@ impl DeviceManager {
             pvpanic_device: None,
             force_iommu,
             io_uring_supported: None,
+            aio_supported: None,
             boot_id_list,
             timestamp,
             pending_activations: Arc::new(Mutex::new(Vec::default())),
@@ -2171,6 +2175,17 @@ impl DeviceManager {
         Ok(devices)
     }
 
+    // Cache whether aio is supported to avoid checking for very block device
+    fn aio_is_supported(&mut self) -> bool {
+        if let Some(supported) = self.aio_supported {
+            return supported;
+        }
+
+        let supported = block_aio_is_supported();
+        self.aio_supported = Some(supported);
+        supported
+    }
+
     // Cache whether io_uring is supported to avoid probing for very block device
     fn io_uring_is_supported(&mut self) -> bool {
         if let Some(supported) = self.io_uring_supported {
@@ -2292,6 +2307,9 @@ impl DeviceManager {
                         {
                             Box::new(RawFileDisk::new(file)) as Box<dyn DiskFile>
                         }
+                    } else if !disk_cfg.disable_aio && self.aio_is_supported() {
+                        info!("Using asynchronous RAW disk file (aio)");
+                        Box::new(RawFileDiskAio::new(file)) as Box<dyn DiskFile>
                     } else {
                         info!("Using synchronous RAW disk file");
                         Box::new(RawFileDiskSync::new(file)) as Box<dyn DiskFile>

vmm/src/seccomp_filters.rs

@@ -553,6 +553,11 @@ fn vmm_thread_rules(
             libc::SYS_ioctl,
             create_vmm_ioctl_seccomp_rule(hypervisor_type)?,
         ),
+        (libc::SYS_io_cancel, vec![]),
+        (libc::SYS_io_destroy, vec![]),
+        (libc::SYS_io_getevents, vec![]),
+        (libc::SYS_io_setup, vec![]),
+        (libc::SYS_io_submit, vec![]),
         (libc::SYS_io_uring_enter, vec![]),
         (libc::SYS_io_uring_setup, vec![]),
         (libc::SYS_io_uring_register, vec![]),

vmm/src/vm_config.rs

@@ -218,6 +218,9 @@ pub struct DiskConfig {
     // For testing use only. Not exposed in API.
     #[serde(default)]
     pub disable_io_uring: bool,
+    // For testing use only. Not exposed in API.
+    #[serde(default)]
+    pub disable_aio: bool,
     #[serde(default)]
     pub pci_segment: u16,
     #[serde(default)]
@@ -249,6 +252,7 @@ impl Default for DiskConfig {
             vhost_socket: None,
             id: None,
             disable_io_uring: false,
+            disable_aio: false,
             rate_limiter_config: None,
             pci_segment: 0,
             serial: None,