sound: use thread trait

crates/sound/src/vhu_sound.rs

@@ -89,18 +89,30 @@ struct VirtioSoundHeader {
 // reading its content from byte array.
 unsafe impl ByteValued for VirtioSoundHeader {}
 
-struct VhostUserSoundThread {
+trait VhostUserSoundThread {
+    fn queue_mask(&self) -> u64;
+    fn set_event_idx(&mut self, enabled: bool);
+    fn update_memory(&mut self, mem: GuestMemoryAtomic<GuestMemoryMmap>) -> IoResult<()>;
+    fn handle_event(&self, device_event: u16, vrings: &[VringRwLock]) -> IoResult<bool>;
+}
+struct VhostUserSoundSingleThread {
     mem: Option<GuestMemoryAtomic<GuestMemoryMmap>>,
     event_idx: bool,
 }
 
-impl VhostUserSoundThread {
+impl VhostUserSoundSingleThread {
     pub fn new() -> Result<Self> {
-        Ok(VhostUserSoundThread {
+        Ok(VhostUserSoundSingleThread {
             event_idx: false,
             mem: None,
         })
     }
+}
+
+impl VhostUserSoundThread for VhostUserSoundSingleThread {
+    fn queue_mask(&self) -> u64 {
+        0xffff_ffff
+    }
 
     fn set_event_idx(&mut self, enabled: bool) {
         self.event_idx = enabled;
@@ -127,7 +139,7 @@ impl VhostUserSoundThread {
 }
 
 pub(crate) struct VhostUserSoundBackend {
-    thread: RwLock<VhostUserSoundThread>,
+    thread: RwLock<Box<dyn VhostUserSoundThread + Sync + Send>>,
     config: VirtioSoundConfig,
     queues_per_thread: Vec<u64>,
     pub(crate) exit_event: EventFd,
@@ -136,10 +148,10 @@ pub(crate) struct VhostUserSoundBackend {
 impl VhostUserSoundBackend {
     pub fn new(_config: SoundConfig) -> Result<Self> {
         let queues_per_thread = vec![0b1111];
-        let thread = RwLock::new(VhostUserSoundThread::new()?);
+        let thread = Box::new(VhostUserSoundSingleThread::new()?);
 
         Ok(Self {
-            thread,
+            thread: RwLock::new(thread),
             config: VirtioSoundConfig {
                 jacks: 0.into(),
                 streams: 1.into(),