vhost: check message header size read

[dpdk.git] / lib / librte_vhost / virtio_net.c

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 73bf98b..37c47c7 100644 (file)
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -2133,6 +2133,20 @@ virtio_dev_tx_packed_zmbuf(struct virtio_net *dev,
        return pkt_idx;
 }
 
+static __rte_always_inline bool
+next_desc_is_avail(const struct vhost_virtqueue *vq)
+{
+       bool wrap_counter = vq->avail_wrap_counter;
+       uint16_t next_used_idx = vq->last_used_idx + 1;
+
+       if (next_used_idx >= vq->size) {
+               next_used_idx -= vq->size;
+               wrap_counter ^= 1;
+       }
+
+       return desc_is_avail(&vq->desc_packed[next_used_idx], wrap_counter);
+}
+
 static __rte_noinline uint16_t
 virtio_dev_tx_packed(struct virtio_net *dev,
                     struct vhost_virtqueue *vq,
@@ -2165,9 +2179,20 @@ virtio_dev_tx_packed(struct virtio_net *dev,
 
        } while (remained);
 
-       if (vq->shadow_used_idx)
+       if (vq->shadow_used_idx) {
                do_data_copy_dequeue(vq);
 
+               if (remained && !next_desc_is_avail(vq)) {
+                       /*
+                        * The guest may be waiting to TX some buffers to
+                        * enqueue more to avoid bufferfloat, so we try to
+                        * reduce latency here.
+                        */
+                       vhost_flush_dequeue_shadow_packed(dev, vq);
+                       vhost_vring_call_packed(dev, vq);
+               }
+       }
+
        return pkt_idx;
 }