vm-virtio: vsock: Expect an identifier upon device creation

This identifier is chosen from the DeviceManager so that it will manage
all identifiers across the VM, which will ensure uniqueness.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vm-virtio/src/vsock/device.rs

@@ -376,6 +376,7 @@ where
 
 /// Virtio device exposing virtual socket to the guest.
 pub struct Vsock<B: VsockBackend> {
+    id: String,
     cid: u64,
     backend: Arc<RwLock<B>>,
     kill_evt: Option<EventFd>,
@@ -394,7 +395,7 @@ where
 {
     /// Create a new virtio-vsock device with the given VM CID and vsock
     /// backend.
-    pub fn new(cid: u64, backend: B, iommu: bool) -> io::Result<Vsock<B>> {
+    pub fn new(id: String, cid: u64, backend: B, iommu: bool) -> io::Result<Vsock<B>> {
         let mut avail_features = 1u64 << VIRTIO_F_VERSION_1 | 1u64 << VIRTIO_F_IN_ORDER;
 
         if iommu {
@@ -402,6 +403,7 @@ where
         }
 
         Ok(Vsock {
+            id,
             cid,
             backend: Arc::new(RwLock::new(backend)),
             kill_evt: None,
@@ -574,7 +576,14 @@ where
 
 virtio_pausable!(Vsock, T: 'static + VsockBackend + Sync);
 
-impl<B> Snapshottable for Vsock<B> where B: VsockBackend + Sync + 'static {}
+impl<B> Snapshottable for Vsock<B>
+where
+    B: VsockBackend + Sync + 'static,
+{
+    fn id(&self) -> String {
+        self.id.clone()
+    }
+}
 impl<B> Transportable for Vsock<B> where B: VsockBackend + Sync + 'static {}
 impl<B> Migratable for Vsock<B> where B: VsockBackend + Sync + 'static {}
 

vm-virtio/src/vsock/mod.rs

@@ -265,7 +265,7 @@ mod tests {
                 cid: CID,
                 mem: GuestMemoryMmap::from_ranges(&[(GuestAddress(0), MEM_SIZE)]).unwrap(),
                 mem_size: MEM_SIZE,
-                device: Vsock::new(CID, TestBackend::new(), false).unwrap(),
+                device: Vsock::new(String::from("vsock"), CID, TestBackend::new(), false).unwrap(),
             }
         }
 

vmm/src/device_manager.rs

@@ -1690,9 +1690,13 @@ impl DeviceManager {
         &mut self,
         vsock_cfg: &mut VsockConfig,
     ) -> DeviceManagerResult<(VirtioDeviceArc, bool, Option<String>)> {
-        if vsock_cfg.id.is_none() {
+        let id = if let Some(id) = &vsock_cfg.id {
-            vsock_cfg.id = Some(self.next_device_name(VSOCK_DEVICE_NAME_PREFIX)?);
+            id.clone()
-        }
+        } else {
+            let id = self.next_device_name(VSOCK_DEVICE_NAME_PREFIX)?;
+            vsock_cfg.id = Some(id.clone());
+            id
+        };
 
         let socket_path = vsock_cfg
             .sock
@@ -1703,18 +1707,16 @@ impl DeviceManager {
                 .map_err(DeviceManagerError::CreateVsockBackend)?;
 
         let vsock_device = Arc::new(Mutex::new(
-            vm_virtio::Vsock::new(vsock_cfg.cid, backend, vsock_cfg.iommu)
+            vm_virtio::Vsock::new(id.clone(), vsock_cfg.cid, backend, vsock_cfg.iommu)
                 .map_err(DeviceManagerError::CreateVirtioVsock)?,
         ));
 
-        let migratable = Arc::clone(&vsock_device) as Arc<Mutex<dyn Migratable>>;
+        self.add_migratable_device(Arc::clone(&vsock_device) as Arc<Mutex<dyn Migratable>>);
-        let id = migratable.lock().unwrap().id();
-        self.migratable_devices.push((id, migratable));
 
         Ok((
             Arc::clone(&vsock_device) as VirtioDeviceArc,
             vsock_cfg.iommu,
-            vsock_cfg.id.clone(),
+            Some(id),
         ))
     }