virtio-devices: vhost_user: Support inflight I/O tracking

Vhost user INFLIGHT_SHMFD protocol feature supports inflight I/O
tracking, this commit implement the vhost-user device (master) support
of the feature. Till this commit, specific vhost-user devices (blk, fs,
or net) have not enable this feature.

Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>

Cargo.lock

@@ -1111,7 +1111,7 @@ dependencies = [
 [[package]]
 name = "vhost"
 version = "0.1.0"
-source = "git+https://github.com/rust-vmm/vhost?branch=master#30ba3e7bbe9e0542cf480f44bc6845a8dbd2a6ba"
+source = "git+https://github.com/rust-vmm/vhost?branch=master#a8ff939161d41fc2f449b80e461d013c1e19f666"
 dependencies = [
  "bitflags",
  "libc",

fuzz/Cargo.lock

@@ -652,7 +652,7 @@ dependencies = [
 [[package]]
 name = "vhost"
 version = "0.1.0"
-source = "git+https://github.com/rust-vmm/vhost?branch=master#e5b930b73a47cbdd79858e2e68bcb57123d1c1f3"
+source = "git+https://github.com/rust-vmm/vhost?branch=master#a8ff939161d41fc2f449b80e461d013c1e19f666"
 dependencies = [
  "bitflags",
  "libc",

vhost_user_backend/src/lib.rs

@@ -959,6 +959,24 @@ impl<S: VhostUserBackend> VhostUserSlaveReqHandlerMut for VhostUserHandler<S> {
 
         Ok(())
     }
+
+    fn get_inflight_fd(
+        &mut self,
+        _: &vhost::vhost_user::message::VhostUserInflight,
+    ) -> std::result::Result<
+        (vhost::vhost_user::message::VhostUserInflight, i32),
+        vhost::vhost_user::Error,
+    > {
+        std::unimplemented!()
+    }
+
+    fn set_inflight_fd(
+        &mut self,
+        _: &vhost::vhost_user::message::VhostUserInflight,
+        _: std::fs::File,
+    ) -> std::result::Result<(), vhost::vhost_user::Error> {
+        std::unimplemented!()
+    }
 }
 
 impl<S: VhostUserBackend> Drop for VhostUserHandler<S> {

virtio-devices/src/vhost_user/blk.rs

@@ -231,6 +231,7 @@ impl VirtioDevice for Blk {
             &interrupt_cb,
             backend_acked_features,
             &slave_req_handler,
+            None,
         )
         .map_err(ActivateError::VhostUserBlkSetup)?;
 
@@ -251,6 +252,7 @@ impl VirtioDevice for Blk {
             socket_path: self.socket_path.clone(),
             server: false,
             slave_req_handler: None,
+            inflight: None,
         };
 
         let paused = self.common.paused.clone();

virtio-devices/src/vhost_user/fs.rs

@@ -452,6 +452,7 @@ impl VirtioDevice for Fs {
             &interrupt_cb,
             backend_acked_features,
             &slave_req_handler,
+            None,
         )
         .map_err(ActivateError::VhostUserFsSetup)?;
 
@@ -471,6 +472,7 @@ impl VirtioDevice for Fs {
             socket_path: self.socket_path.clone(),
             server: false,
             slave_req_handler,
+            inflight: None,
         };
 
         let paused = self.common.paused.clone();

virtio-devices/src/vhost_user/mod.rs

@@ -11,7 +11,7 @@ use std::io;
 use std::ops::Deref;
 use std::os::unix::io::AsRawFd;
 use std::sync::{atomic::AtomicBool, Arc, Barrier, Mutex};
-use vhost::vhost_user::message::VhostUserVirtioFeatures;
+use vhost::vhost_user::message::{VhostUserInflight, VhostUserVirtioFeatures};
 use vhost::vhost_user::{Master, MasterReqHandler, VhostUserMasterReqHandler};
 use vhost::Error as VhostError;
 use vm_memory::{Error as MmapError, GuestAddressSpace, GuestMemoryAtomic};
@@ -103,6 +103,10 @@ pub enum Error {
     VhostUserGetConfig(VhostError),
     /// Failed setting the configuration.
     VhostUserSetConfig(VhostError),
+    /// Failed getting inflight shm log.
+    VhostUserGetInflight(VhostError),
+    /// Failed setting inflight shm log.
+    VhostUserSetInflight(VhostError),
     /// Invalid used address.
     UsedAddress,
     /// Invalid features provided from vhost-user backend
@@ -128,6 +132,12 @@ pub const DEFAULT_VIRTIO_FEATURES: u64 = 1 << VIRTIO_F_RING_INDIRECT_DESC
 const HUP_CONNECTION_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 1;
 const SLAVE_REQ_EVENT: u16 = EPOLL_HELPER_EVENT_LAST + 2;
 
+#[derive(Default)]
+pub struct Inflight {
+    pub info: VhostUserInflight,
+    pub fd: Option<std::fs::File>,
+}
+
 pub struct VhostUserEpollHandler<S: VhostUserMasterReqHandler> {
     pub vu: Arc<Mutex<Master>>,
     pub mem: GuestMemoryAtomic<GuestMemoryMmap>,
@@ -141,6 +151,7 @@ pub struct VhostUserEpollHandler<S: VhostUserMasterReqHandler> {
     pub socket_path: String,
     pub server: bool,
     pub slave_req_handler: Option<MasterReqHandler<S>>,
+    pub inflight: Option<Inflight>,
 }
 
 impl<S: VhostUserMasterReqHandler> VhostUserEpollHandler<S> {
@@ -198,6 +209,7 @@ impl<S: VhostUserMasterReqHandler> VhostUserEpollHandler<S> {
             self.acked_features,
             self.acked_protocol_features,
             &self.slave_req_handler,
+            self.inflight.as_mut(),
         )
         .map_err(|e| {
             EpollHelperError::IoError(std::io::Error::new(

virtio-devices/src/vhost_user/net.rs

@@ -300,6 +300,7 @@ impl VirtioDevice for Net {
             &interrupt_cb,
             backend_acked_features,
             &slave_req_handler,
+            None,
         )
         .map_err(ActivateError::VhostUserNetSetup)?;
 
@@ -320,6 +321,7 @@ impl VirtioDevice for Net {
             socket_path: self.socket_path.clone(),
             server: self.server,
             slave_req_handler: None,
+            inflight: None,
         };
 
         let paused = self.common.paused.clone();

virtio-devices/src/vhost_user/vu_common_ctrl.rs

@@ -3,6 +3,7 @@
 
 use super::super::{Descriptor, Queue};
 use super::{Error, Result};
+use crate::vhost_user::Inflight;
 use crate::{get_host_address_range, VirtioInterrupt, VirtioInterruptType};
 use crate::{GuestMemoryMmap, GuestRegionMmap};
 use std::convert::TryInto;
@@ -12,7 +13,9 @@ use std::sync::Arc;
 use std::thread::sleep;
 use std::time::{Duration, Instant};
 use std::vec::Vec;
-use vhost::vhost_user::message::{VhostUserProtocolFeatures, VhostUserVirtioFeatures};
+use vhost::vhost_user::message::{
+    VhostUserInflight, VhostUserProtocolFeatures, VhostUserVirtioFeatures,
+};
 use vhost::vhost_user::{Master, MasterReqHandler, VhostUserMaster, VhostUserMasterReqHandler};
 use vhost::{VhostBackend, VhostUserMemoryRegionInfo, VringConfigData};
 use vm_memory::{Address, Error as MmapError, GuestMemory, GuestMemoryRegion};
@@ -100,6 +103,7 @@ pub fn negotiate_features_vhost_user(
     Ok((acked_features, acked_protocol_features))
 }
 
+#[allow(clippy::too_many_arguments)]
 pub fn setup_vhost_user<S: VhostUserMasterReqHandler>(
     vu: &mut Master,
     mem: &GuestMemoryMmap,
@@ -108,6 +112,7 @@ pub fn setup_vhost_user<S: VhostUserMasterReqHandler>(
     virtio_interrupt: &Arc<dyn VirtioInterrupt>,
     acked_features: u64,
     slave_req_handler: &Option<MasterReqHandler<S>>,
+    inflight: Option<&mut Inflight>,
 ) -> Result<()> {
     vu.set_features(acked_features)
         .map_err(Error::VhostUserSetFeatures)?;
@@ -115,6 +120,26 @@ pub fn setup_vhost_user<S: VhostUserMasterReqHandler>(
     // Let's first provide the memory table to the backend.
     update_mem_table(vu, mem)?;
 
+    // Setup for inflight I/O tracking shared memory.
+    if let Some(inflight) = inflight {
+        if inflight.fd.is_none() {
+            let inflight_req_info = VhostUserInflight {
+                mmap_size: 0,
+                mmap_offset: 0,
+                num_queues: queues.len() as u16,
+                queue_size: queues[0].actual_size(),
+            };
+            let (info, fd) = vu
+                .get_inflight_fd(&inflight_req_info)
+                .map_err(Error::VhostUserGetInflight)?;
+            inflight.info = info;
+            inflight.fd = Some(fd);
+        }
+        // Unwrapping the inflight fd is safe here since we know it can't be None.
+        vu.set_inflight_fd(&inflight.info, inflight.fd.as_ref().unwrap().as_raw_fd())
+            .map_err(Error::VhostUserSetInflight)?;
+    }
+
     for (queue_index, queue) in queues.into_iter().enumerate() {
         let actual_size: usize = queue.actual_size().try_into().unwrap();
 
@@ -194,6 +219,7 @@ pub fn reinitialize_vhost_user<S: VhostUserMasterReqHandler>(
     acked_features: u64,
     acked_protocol_features: u64,
     slave_req_handler: &Option<MasterReqHandler<S>>,
+    inflight: Option<&mut Inflight>,
 ) -> Result<()> {
     vu.set_owner().map_err(Error::VhostUserSetOwner)?;
     vu.get_features().map_err(Error::VhostUserGetFeatures)?;
@@ -215,6 +241,7 @@ pub fn reinitialize_vhost_user<S: VhostUserMasterReqHandler>(
         virtio_interrupt,
         acked_features,
         slave_req_handler,
+        inflight,
     )
 }