virtio-serial: pop all the received data

Pop all the received data from port queue and virtio queue and try to fill the caller's buffer as much as possible after receiving from virtio serial device. Signed-off-by: Jiaqi Gao <[email protected]>
intel · Oct 23, 2024 · f568ea1 · f568ea1
1 parent 7bf7394
commit f568ea1
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Showing 2 changed files with 32 additions and 9 deletions.
diff --git a/src/devices/virtio_serial/src/lib.rs b/src/devices/virtio_serial/src/lib.rs
@@ -854,6 +854,18 @@ impl VirtioSerial {
     fn port_queue_pop(port_id: u32) -> Option<Vec<u8>> {
         RECEIVE_QUEUES.lock().get_mut(&port_id)?.pop_front()
     }
+
+    fn can_recv(&self, port_id: u32) -> bool {
+        RECEIVE_QUEUES
+            .lock()
+            .get(&port_id)
+            .is_some_and(|q| !q.is_empty())
+            || self
+                .queues
+                .index(Self::port_queue_index(port_id) as usize)
+                .borrow_mut()
+                .can_pop()
+    }
 }
 
 /// Align `size` up to a page.

diff --git a/src/devices/virtio_serial/src/port.rs b/src/devices/virtio_serial/src/port.rs
@@ -64,26 +64,37 @@ impl VirtioSerialPort {
 
     pub fn recv(&mut self, data: &mut [u8]) -> Result<usize> {
         if self.cache.is_empty() {
-            let recv_bytes = SERIAL_DEVICE
-                .lock()
-                .get_mut()
-                .ok_or(VirtioSerialError::InvalidParameter)?
-                .dequeue(self.port_id, DEFAULT_TIMEOUT)?;
-            self.cache.push_back(recv_bytes);
+            loop {
+                let recv_bytes = SERIAL_DEVICE
+                    .lock()
+                    .get_mut()
+                    .ok_or(VirtioSerialError::InvalidParameter)?
+                    .dequeue(self.port_id, DEFAULT_TIMEOUT)?;
+                self.cache.push_back(recv_bytes);
+
+                if !SERIAL_DEVICE
+                    .lock()
+                    .get_mut()
+                    .ok_or(VirtioSerialError::InvalidParameter)?
+                    .can_recv(self.port_id)
+                {
+                    break;
+                }
+            }
         }
 
         let mut recvd = 0;
-        if !self.cache.is_empty() {
+        while !self.cache.is_empty() {
             let front = self.cache.front_mut().unwrap();
             let expect = data.len() - recvd;
             if front.len() <= expect {
-                data[..front.len()].copy_from_slice(front);
+                data[recvd..recvd + front.len()].copy_from_slice(front);
                 recvd += front.len();
                 self.cache.pop_front();
             } else {
                 data[recvd..].copy_from_slice(&front[..expect]);
                 front.drain(..expect);
-                recvd = expect;
+                recvd += expect;
             }
         }