virtio-devices: balloon: Port to VirtioCommon

Use VirtioCommon to handle activate() preparation, reset() and Pausable.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

virtio-devices/src/balloon.rs

@@ -311,14 +311,7 @@ pub struct Balloon {
     common: VirtioCommon,
     id: String,
     resize: VirtioBalloonResize,
-    kill_evt: Option<EventFd>,
-    pause_evt: Option<EventFd>,
     config: Arc<Mutex<VirtioBalloonConfig>>,
-    queue_evts: Option<Vec<EventFd>>,
-    interrupt_cb: Option<Arc<dyn VirtioInterrupt>>,
-    epoll_threads: Option<Vec<thread::JoinHandle<()>>>,
-    paused: Arc<AtomicBool>,
-    paused_sync: Arc<Barrier>,
     seccomp_action: SeccompAction,
 }
 
@@ -332,19 +325,15 @@ impl Balloon {
 
         Ok(Balloon {
             common: VirtioCommon {
+                device_type: VirtioDeviceType::TYPE_BALLOON as u32,
                 avail_features,
+                paused_sync: Some(Arc::new(Barrier::new(2))),
+                queue_sizes: QUEUE_SIZES.to_vec(),
                 ..Default::default()
             },
             id,
             resize: VirtioBalloonResize::new()?,
-            kill_evt: None,
-            pause_evt: None,
             config: Arc::new(Mutex::new(config)),
-            queue_evts: None,
-            interrupt_cb: None,
-            epoll_threads: None,
-            paused: Arc::new(AtomicBool::new(false)),
-            paused_sync: Arc::new(Barrier::new(2)),
             seccomp_action,
         })
     }
@@ -356,7 +345,7 @@ impl Balloon {
 
 impl Drop for Balloon {
     fn drop(&mut self) {
-        if let Some(kill_evt) = self.kill_evt.take() {
+        if let Some(kill_evt) = self.common.kill_evt.take() {
             // Ignore the result because there is nothing we can do about it.
             let _ = kill_evt.write(1);
         }
@@ -365,11 +354,11 @@ impl Drop for Balloon {
 
 impl VirtioDevice for Balloon {
     fn device_type(&self) -> u32 {
-        VirtioDeviceType::TYPE_BALLOON as u32
+        self.common.device_type
     }
 
     fn queue_max_sizes(&self) -> &[u16] {
-        QUEUE_SIZES
+        &self.common.queue_sizes
     }
 
     fn features(&self) -> u64 {
@@ -391,43 +380,27 @@ impl VirtioDevice for Balloon {
         queues: Vec<Queue>,
         mut queue_evts: Vec<EventFd>,
     ) -> ActivateResult {
-        if queues.len() != NUM_QUEUES || queue_evts.len() != NUM_QUEUES {
+        self.common.activate(&queues, &queue_evts, &interrupt_cb)?;
-            error!(
+        let kill_evt = self
-                "Cannot perform activate. Expected {} queue(s), got {}",
+            .common
-                NUM_QUEUES,
+            .kill_evt
-                queues.len()
+            .as_ref()
-            );
+            .unwrap()
-            return Err(ActivateError::BadActivate);
+            .try_clone()
-        }
-
-        let (self_kill_evt, kill_evt) = EventFd::new(EFD_NONBLOCK)
-            .and_then(|e| Ok((e.try_clone()?, e)))
             .map_err(|e| {
-                error!("failed creating kill EventFd pair: {}", e);
+                error!("failed to clone kill_evt eventfd: {}", e);
                 ActivateError::BadActivate
             })?;
-        self.kill_evt = Some(self_kill_evt);
+        let pause_evt = self
-
+            .common
-        let (self_pause_evt, pause_evt) = EventFd::new(EFD_NONBLOCK)
+            .pause_evt
-            .and_then(|e| Ok((e.try_clone()?, e)))
+            .as_ref()
+            .unwrap()
+            .try_clone()
             .map_err(|e| {
-                error!("failed creating pause EventFd pair: {}", e);
+                error!("failed to clone pause_evt eventfd: {}", e);
                 ActivateError::BadActivate
             })?;
-        self.pause_evt = Some(self_pause_evt);
-
-        self.interrupt_cb = Some(interrupt_cb.clone());
-
-        let mut tmp_queue_evts: Vec<EventFd> = Vec::new();
-        for queue_evt in queue_evts.iter() {
-            // Save the queue EventFD as we need to return it on reset
-            // but clone it to pass into the thread.
-            tmp_queue_evts.push(queue_evt.try_clone().map_err(|e| {
-                error!("failed to clone queue EventFd: {}", e);
-                ActivateError::BadActivate
-            })?);
-        }
-        self.queue_evts = Some(tmp_queue_evts);
 
         let mut handler = BalloonEpollHandler {
             config: self.config.clone(),
@@ -444,8 +417,8 @@ impl VirtioDevice for Balloon {
             pause_evt,
         };
 
-        let paused = self.paused.clone();
+        let paused = self.common.paused.clone();
-        let paused_sync = self.paused_sync.clone();
+        let paused_sync = self.common.paused_sync.clone();
         let mut epoll_threads = Vec::new();
         let virtio_balloon_seccomp_filter =
             get_seccomp_filter(&self.seccomp_action, Thread::VirtioBalloon)
@@ -455,7 +428,7 @@ impl VirtioDevice for Balloon {
             .spawn(move || {
                 if let Err(e) = SeccompFilter::apply(virtio_balloon_seccomp_filter) {
                     error!("Error applying seccomp filter: {:?}", e);
-                } else if let Err(e) = handler.run(paused, paused_sync) {
+                } else if let Err(e) = handler.run(paused, paused_sync.unwrap()) {
                     error!("Error running worker: {:?}", e);
                 }
             })
@@ -464,31 +437,26 @@ impl VirtioDevice for Balloon {
                 error!("failed to clone virtio-balloon epoll thread: {}", e);
                 ActivateError::BadActivate
             })?;
-        self.epoll_threads = Some(epoll_threads);
+        self.common.epoll_threads = Some(epoll_threads);
 
         Ok(())
     }
 
     fn reset(&mut self) -> Option<(Arc<dyn VirtioInterrupt>, Vec<EventFd>)> {
-        // We first must resume the virtio thread if it was paused.
+        self.common.reset()
-        if self.pause_evt.take().is_some() {
+    }
-            self.resume().ok()?;
+}
-        }
+
-
+impl Pausable for Balloon {
-        if let Some(kill_evt) = self.kill_evt.take() {
+    fn pause(&mut self) -> result::Result<(), MigratableError> {
-            // Ignore the result because there is nothing we can do about it.
+        self.common.pause()
-            let _ = kill_evt.write(1);
+    }
-        }
+
-
+    fn resume(&mut self) -> result::Result<(), MigratableError> {
-        // Return the interrupt and queue EventFDs
+        self.common.resume()
-        Some((
-            self.interrupt_cb.take().unwrap(),
-            self.queue_evts.take().unwrap(),
-        ))
     }
 }
 
-virtio_pausable!(Balloon);
 impl Snapshottable for Balloon {
     fn id(&self) -> String {
         self.id.clone()