vhost-net: create vhost based Net backend

src/vmm/Cargo.toml

@@ -18,18 +18,18 @@ kvm-ioctls = "0.16.0"
 lazy_static = "1.4.0"
 libc = "0.2.117"
 memfd = "0.6.3"
-linux-loader = "0.10.0"
+linux-loader = "0.11.0"
 serde = { version = "1.0.136", features = ["derive", "rc"] }
 semver = { version = "1.0.17", features = ["serde"] }
 serde_json = "1.0.78"
 timerfd = "1.5.0"
 thiserror = "1.0.32"
 displaydoc = "0.2.4"
 userfaultfd = "0.7.0"
-vhost = { version = "0.10.0", features = ["vhost-user-frontend"] }
+vhost = { version = "0.10", features = ["vhost-user-frontend", "vhost-net", "vhost-user"] }
 vm-allocator = "0.1.0"
 vm-superio = "0.7.0"
-vm-memory = { version = "0.13.1", features = ["backend-mmap", "backend-bitmap"] }
+vm-memory = { version = "0.14.0", features = ["backend-mmap", "backend-bitmap"] }
 log = { version = "0.4.17", features = ["std", "serde"] }
 aes-gcm =  { version = "0.10.1", default-features = false, features = ["aes"] }
 base64 = "0.21.0"

src/vmm/src/builder.rs

@@ -883,9 +883,19 @@ fn attach_net_devices<'a, I: Iterator<Item = &'a Arc<Mutex<Net>>> + Debug>(
     event_manager: &mut EventManager,
 ) -> Result<(), StartMicrovmError> {
     for net_device in net_devices {
-        let id = net_device.lock().expect("Poisoned lock").id().clone();
+        let (id, is_vhost) = {
+            let locked = net_device.lock().expect("Poisoned lock");
+            (locked.id().clone(), locked.is_vhost())
+        };
         // The device mutex mustn't be locked here otherwise it will deadlock.
-        attach_virtio_device(event_manager, vmm, id, net_device.clone(), cmdline, false)?;
+        attach_virtio_device(
+            event_manager,
+            vmm,
+            id,
+            net_device.clone(),
+            cmdline,
+            is_vhost,
+        )?;
     }
     Ok(())
 }

src/vmm/src/device_manager/persist.rs

@@ -290,19 +290,34 @@ impl<'a> Persist<'a> for MMIODeviceManager {
                 }
                 TYPE_NET => {
                     let net = locked_device.as_any().downcast_ref::<Net>().unwrap();
-                    if let (Some(mmds_ns), None) =
-                        (net.mmds_ns.as_ref(), states.mmds_version.as_ref())
-                    {
-                        states.mmds_version =
-                            Some(mmds_ns.mmds.lock().expect("Poisoned lock").version().into());
+                    if net.is_vhost() {
+                        warn!("skipping vhost-net device. It doesn't support snapshotting yet");
+                    } else {
+                        match net {
+                            Net::Virtio(virtionet) => {
+                                if let (Some(mmds_ns), None) =
+                                    (virtionet.mmds_ns.as_ref(), states.mmds_version.as_ref())
+                                {
+                                    states.mmds_version = Some(
+                                        mmds_ns
+                                            .mmds
+                                            .lock()
+                                            .expect("Poisoned lock")
+                                            .version()
+                                            .into(),
+                                    );
+                                }
+
+                                states.net_devices.push(ConnectedNetState {
+                                    device_id: devid.clone(),
+                                    device_state: net.save(),
+                                    transport_state,
+                                    device_info: device_info.clone(),
+                                })
+                            }
+                            Net::Vhost(_) => panic!(),
+                        }
                     }
-
-                    states.net_devices.push(ConnectedNetState {
-                        device_id: devid.clone(),
-                        device_state: net.save(),
-                        transport_state,
-                        device_info: device_info.clone(),
-                    });
                 }
                 TYPE_VSOCK => {
                     let vsock = locked_device
@@ -506,7 +521,7 @@ impl<'a> Persist<'a> for MMIODeviceManager {
         } else if state
             .net_devices
             .iter()
-            .any(|dev| dev.device_state.mmds_ns.is_some())
+            .any(|dev| dev.device_state.mmds_ns().is_some())
         {
             // If there's at least one network device having an mmds_ns, it means
             // that we are restoring from a version that did not persist the `MmdsVersionState`.

src/vmm/src/devices/virtio/mod.rs

@@ -10,6 +10,8 @@
 use std::any::Any;
 use std::io::Error as IOError;
 
+pub use ::vhost::Error as VhostError;
+
 pub mod balloon;
 pub mod block;
 pub mod device;
@@ -66,6 +68,9 @@ pub enum ActivateError {
     BadActivate,
     /// Vhost user: {0}
     VhostUser(vhost_user::VhostUserError),
+
+    /// Vhost errored on one of the ioctls
+    Vhost(VhostError),
 }
 
 /// Trait that helps in upcasting an object to Any