refactor(virtio): add id method to the VirtioDevice trait

Add a trait method to VirtioDevice to get a unique device id.
This can be used in default imps of some other methods to
print current device id in case of an error/warning etc.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

Author: ShadowCurse

src/vmm/src/builder.rs

@@ -31,6 +31,7 @@ use crate::device_manager::{
 };
 use crate::devices::virtio::balloon::Balloon;
 use crate::devices::virtio::block::device::Block;
+use crate::devices::virtio::device::VirtioDevice;
 use crate::devices::virtio::mem::{VIRTIO_MEM_DEFAULT_SLOT_SIZE_MIB, VirtioMem};
 use crate::devices::virtio::net::Net;
 use crate::devices::virtio::pmem::device::Pmem;
@@ -682,7 +683,7 @@ 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 = net_device.lock().expect("Poisoned lock").id().to_string();
         event_manager.add_subscriber(net_device.clone());
         // The device mutex mustn't be locked here otherwise it will deadlock.
         device_manager.attach_virtio_device(vm, id, net_device.clone(), cmdline, false)?;

src/vmm/src/device_manager/mmio.rs

@@ -493,6 +493,10 @@ pub(crate) mod tests {
     impl VirtioDevice for DummyDevice {
         impl_device_type!(VirtioDeviceType::Net);
 
+        fn id(&self) -> &str {
+            "dummy"
+        }
+
         fn avail_features(&self) -> u64 {
             0
         }

src/vmm/src/devices/virtio/balloon/device.rs

@@ -672,11 +672,6 @@ impl Balloon {
         Ok(())
     }
 
-    /// Provides the ID of this balloon device.
-    pub fn id(&self) -> &str {
-        BALLOON_DEV_ID
-    }
-
     fn trigger_stats_update(&mut self) -> Result<(), BalloonError> {
         // The communication is driven by the device by using the buffer
         // and sending a used buffer notification
@@ -868,6 +863,10 @@ impl Balloon {
 impl VirtioDevice for Balloon {
     impl_device_type!(VirtioDeviceType::Balloon);
 
+    fn id(&self) -> &str {
+        BALLOON_DEV_ID
+    }
+
     fn avail_features(&self) -> u64 {
         self.avail_features
     }

src/vmm/src/devices/virtio/block/device.rs

@@ -95,13 +95,6 @@ impl Block {
         }
     }
 
-    pub fn id(&self) -> &str {
-        match self {
-            Self::Virtio(b) => &b.id,
-            Self::VhostUser(b) => &b.id,
-        }
-    }
-
     pub fn root_device(&self) -> bool {
         match self {
             Self::Virtio(b) => b.root_device,
@@ -134,6 +127,13 @@ impl Block {
 impl VirtioDevice for Block {
     impl_device_type!(VirtioDeviceType::Block);
 
+    fn id(&self) -> &str {
+        match self {
+            Self::Virtio(b) => b.id(),
+            Self::VhostUser(b) => b.id(),
+        }
+    }
+
     fn avail_features(&self) -> u64 {
         match self {
             Self::Virtio(b) => b.avail_features,

src/vmm/src/devices/virtio/block/vhost_user/device.rs

@@ -290,6 +290,10 @@ impl<T: VhostUserHandleBackend> VhostUserBlockImpl<T> {
 impl<T: VhostUserHandleBackend + Send + 'static> VirtioDevice for VhostUserBlockImpl<T> {
     impl_device_type!(VirtioDeviceType::Block);
 
+    fn id(&self) -> &str {
+        &self.id
+    }
+
     fn avail_features(&self) -> u64 {
         self.avail_features
     }

src/vmm/src/devices/virtio/block/virtio/device.rs

@@ -585,6 +585,10 @@ impl VirtioBlock {
 impl VirtioDevice for VirtioBlock {
     impl_device_type!(VirtioDeviceType::Block);
 
+    fn id(&self) -> &str {
+        &self.id
+    }
+
     fn avail_features(&self) -> u64 {
         self.avail_features
     }

src/vmm/src/devices/virtio/device.rs

@@ -119,6 +119,9 @@ pub trait VirtioDevice: AsAny + Send {
     /// It should be the same as returned by Self::const_device_type().
     fn device_type(&self) -> VirtioDeviceType;
 
+    /// Returns unique device id
+    fn id(&self) -> &str;
+
     /// Returns the device queues.
     fn queues(&self) -> &[Queue];
 
@@ -239,6 +242,10 @@ pub(crate) mod tests {
     impl VirtioDevice for MockVirtioDevice {
         impl_device_type!(VirtioDeviceType::Net);
 
+        fn id(&self) -> &str {
+            "mock"
+        }
+
         fn avail_features(&self) -> u64 {
             self.avail_features
         }

src/vmm/src/devices/virtio/mem/device.rs

@@ -169,10 +169,6 @@ impl VirtioMem {
         })
     }
 
-    pub fn id(&self) -> &str {
-        VIRTIO_MEM_DEV_ID
-    }
-
     pub fn guest_address(&self) -> GuestAddress {
         GuestAddress(self.config.addr)
     }
@@ -603,6 +599,10 @@ impl VirtioMem {
 impl VirtioDevice for VirtioMem {
     impl_device_type!(VirtioDeviceType::Mem);
 
+    fn id(&self) -> &str {
+        VIRTIO_MEM_DEV_ID
+    }
+
     fn queues(&self) -> &[Queue] {
         &self.queues
     }

src/vmm/src/devices/virtio/net/device.rs

@@ -343,11 +343,6 @@ impl Net {
         Self::new_with_tap(id, tap, guest_mac, rx_rate_limiter, tx_rate_limiter)
     }
 
-    /// Provides the ID of this net device.
-    pub fn id(&self) -> &String {
-        &self.id
-    }
-
     /// Provides the MAC of this net device.
     pub fn guest_mac(&self) -> Option<&MacAddr> {
         self.guest_mac.as_ref()
@@ -962,6 +957,10 @@ impl Net {
 impl VirtioDevice for Net {
     impl_device_type!(VirtioDeviceType::Net);
 
+    fn id(&self) -> &str {
+        &self.id
+    }
+
     fn avail_features(&self) -> u64 {
         self.avail_features
     }

src/vmm/src/devices/virtio/net/persist.rs

@@ -74,7 +74,7 @@ impl Persist<'_> for Net {
 
     fn save(&self) -> Self::State {
         NetState {
-            id: self.id().clone(),
+            id: self.id.clone(),
             tap_if_name: self.iface_name(),
             rx_rate_limiter_state: self.rx_rate_limiter.save(),
             tx_rate_limiter_state: self.tx_rate_limiter.save(),