fix: insert missing activate_fails metrics increases

Make sure that whenever the activation of a virtio device fails, we set
the `activate_fails` metric.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

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

@@ -336,13 +336,13 @@ impl<T: VhostUserHandleBackend + Send + 'static> VirtioDevice for VhostUserBlock
         // with guest driver as well.
         self.vu_handle
             .set_features(self.acked_features)
-            .map_err(ActivateError::VhostUser)?;
-        self.vu_handle
-            .setup_backend(
-                &mem,
-                &[(0, &self.queues[0], &self.queue_evts[0])],
-                &self.irq_trigger,
-            )
+            .and_then(|()| {
+                self.vu_handle.setup_backend(
+                    &mem,
+                    &[(0, &self.queues[0], &self.queue_evts[0])],
+                    &self.irq_trigger,
+                )
+            })
             .map_err(|err| {
                 self.metrics.activate_fails.inc();
                 ActivateError::VhostUser(err)

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

@@ -652,6 +652,7 @@ impl VirtioDevice for VirtioBlock {
         }
 
         if self.activate_evt.write(1).is_err() {
+            self.metrics.activate_fails.inc();
             return Err(ActivateError::EventFd);
         }
         self.device_state = DeviceState::Activated(mem);

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

@@ -862,6 +862,7 @@ impl VirtioDevice for Net {
         }
 
         if self.activate_evt.write(1).is_err() {
+            self.metrics.activate_fails.inc();
             return Err(ActivateError::EventFd);
         }
         self.device_state = DeviceState::Activated(mem);