vmm: Implement basic reset capability for net device

Signed-off-by: Adam Jensen <adam@acj.sh>

Author: acj

src/vmm/src/devices/virtio/mmio.rs

@@ -201,7 +201,10 @@ impl MmioTransport {
                     let mut device_status = self.device_status;
                     let reset_result = self.locked_device().reset();
                     match reset_result {
-                        Some((_interrupt_evt, mut _queue_evts)) => {}
+                        Some((_interrupt_evt, mut _queue_evts)) => {
+                            // The device MUST initialize device status to 0 upon reset.
+                            device_status = INIT;
+                        }
                         None => {
                             device_status |= FAILED;
                         }

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

@@ -870,6 +870,26 @@ impl VirtioDevice for Net {
     fn is_activated(&self) -> bool {
         self.device_state.is_activated()
     }
+
+    fn reset(&mut self) -> Option<(EventFd, Vec<EventFd>)> {
+        self.device_state = DeviceState::Inactive;
+        self.rx_bytes_read = 0;
+        self.rx_deferred_frame = false;
+        self.rx_frame_buf = [0u8; MAX_BUFFER_SIZE];
+        self.metrics = NetMetricsPerDevice::alloc(self.id.clone());
+
+        let queue_evts: Vec<_> = self
+            .queue_evts
+            .iter()
+            .filter_map(|q| q.try_clone().ok())
+            .collect();
+
+        if let Ok(irq_evt) = self.irq_trigger.irq_evt.try_clone() {
+            Some((irq_evt, queue_evts))
+        } else {
+            None
+        }
+    }
 }
 
 #[cfg(test)]
@@ -2015,17 +2035,29 @@ pub mod tests {
         th.activate_net();
         let net = th.net.lock().unwrap();
 
-        // Test queues count (TX and RX).
-        let queues = net.queues();
-        assert_eq!(queues.len(), NET_QUEUE_SIZES.len());
-        assert_eq!(queues[RX_INDEX].size, th.rxq.size());
-        assert_eq!(queues[TX_INDEX].size, th.txq.size());
+        let validate = |net: &Net| {
+            // Test queues count (TX and RX).
+            let queues = net.queues();
+            assert_eq!(queues.len(), NET_QUEUE_SIZES.len());
+            assert_eq!(queues[RX_INDEX].size, th.rxq.size());
+            assert_eq!(queues[TX_INDEX].size, th.txq.size());
+
+            // Test corresponding queues events.
+            assert_eq!(net.queue_events().len(), NET_QUEUE_SIZES.len());
+
+            // Test interrupts.
+            assert!(!&net.irq_trigger.has_pending_irq(IrqType::Vring));
+        };
+
+        validate(&net);
 
-        // Test corresponding queues events.
-        assert_eq!(net.queue_events().len(), NET_QUEUE_SIZES.len());
+        // Test reset.
+        let mut net = net;
+        assert!(net.device_state.is_activated());
+        let (_interrupt_evt, _queue_evts) = net.reset().unwrap();
+        assert!(!net.device_state.is_activated());
 
-        // Test interrupts.
-        assert!(!&net.irq_trigger.has_pending_irq(IrqType::Vring));
+        validate(&net);
     }
 
     #[test]