Support streaming dma mappings

services/comps/virtio/src/device/block/device.rs

@@ -24,6 +24,7 @@ pub struct BlockDevice {
 
 impl BlockDevice {
     /// read data from block device, this function is blocking
+    /// FIEME: replace slice with a more secure data structure to use dma mapping.
     pub fn read(&self, block_id: usize, buf: &mut [u8]) {
         assert_eq!(buf.len(), BLK_SIZE);
         let req = BlkReq {
@@ -47,6 +48,7 @@ impl BlockDevice {
         };
     }
     /// write data to block device, this function is blocking
+    /// FIEME: replace slice with a more secure data structure to use dma mapping.
     pub fn write(&self, block_id: usize, buf: &[u8]) {
         assert_eq!(buf.len(), BLK_SIZE);
         let req = BlkReq {

services/comps/virtio/src/device/input/device.rs

@@ -79,6 +79,7 @@ impl InputDevice {
             .expect("create status virtqueue failed");
 
         for (i, event) in event_buf.as_mut().iter_mut().enumerate() {
+            // FIEME: replace slice with a more secure data structure to use dma mapping.
             let token = event_queue.add(&[], &[event.as_bytes_mut()]);
             match token {
                 Ok(value) => {
@@ -144,6 +145,7 @@ impl InputDevice {
             }
             let event = &mut self.event_buf.lock()[token as usize];
             // requeue
+            // FIEME: replace slice with a more secure data structure to use dma mapping.
             if let Ok(new_token) = lock.add(&[], &[event.as_bytes_mut()]) {
                 // This only works because nothing happen between `pop_used` and `add` that affects
                 // the list of free descriptors in the queue, so `add` reuses the descriptor which

services/comps/virtio/src/device/network/device.rs

@@ -60,6 +60,7 @@ impl NetworkDevice {
         let mut rx_buffers = SlotVec::new();
         for i in 0..QUEUE_SIZE {
             let mut rx_buffer = RxBuffer::new(RX_BUFFER_LEN, size_of::<VirtioNetHdr>());
+            // FIEME: Replace rx_buffer with VM segment-based data structure to use dma mapping.
             let token = recv_queue.add(&[], &[rx_buffer.buf_mut()])?;
             assert_eq!(i, token);
             assert_eq!(rx_buffers.put(rx_buffer) as u16, i);
@@ -106,6 +107,7 @@ impl NetworkDevice {
     }
 
     /// Add a rx buffer to recv queue
+    /// FIEME: Replace rx_buffer with VM segment-based data structure to use dma mapping.
     fn add_rx_buffer(&mut self, mut rx_buffer: RxBuffer) -> Result<(), VirtioNetError> {
         let token = self
             .recv_queue
@@ -136,6 +138,7 @@ impl NetworkDevice {
     }
 
     /// Send a packet to network. Return until the request completes.
+    /// FIEME: Replace tx_buffer with VM segment-based data structure to use dma mapping.
     fn send(&mut self, tx_buffer: TxBuffer) -> Result<(), VirtioNetError> {
         let header = VirtioNetHdr::default();
         let token = self