Without this patch, packets are being silently dropped by the tap backend.

Signed-off-by: Greg Kurz <[email protected]>
---
 drivers/vhost/net.c |   32 ++++++++++++++++++++++++++------
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index afa06d2..2923eee 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -288,6 +288,16 @@ static void vhost_zerocopy_callback(struct ubuf_info 
*ubuf, bool success)
        rcu_read_unlock_bh();
 }
 
+static void fix_virtio_net_hdr(struct vhost_virtqueue *vq)
+{
+       struct virtio_net_hdr *hdr = vq->iov[0].iov_base;
+
+       hdr->hdr_len = vhost16_to_cpu(vq, hdr->hdr_len);
+       hdr->gso_size = vhost16_to_cpu(vq, hdr->gso_size);
+       hdr->csum_start  = vhost16_to_cpu(vq, hdr->csum_start);
+       hdr->csum_offset = vhost16_to_cpu(vq, hdr->csum_offset);
+}
+
 /* Expects to be always run from workqueue - which acts as
  * read-size critical section for our kind of RCU. */
 static void handle_tx(struct vhost_net *net)
@@ -352,6 +362,10 @@ static void handle_tx(struct vhost_net *net)
                               "out %d, int %d\n", out, in);
                        break;
                }
+
+               if (!hdr_size)
+                       fix_virtio_net_hdr(vq);
+
                /* Skip header. TODO: support TSO. */
                len = iov_length(vq->iov, out);
                iov_iter_init(&msg.msg_iter, WRITE, vq->iov, out, len);
@@ -609,12 +623,18 @@ static void handle_rx(struct vhost_net *net)
                        continue;
                }
                /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
-               if (unlikely(vhost_hlen) &&
-                   copy_to_iter(&hdr, sizeof(hdr), &fixup) != sizeof(hdr)) {
-                       vq_err(vq, "Unable to write vnet_hdr at addr %p\n",
-                              vq->iov->iov_base);
-                       break;
-               }
+               if (unlikely(vhost_hlen)) {
+                       size_t len = copy_to_iter(&hdr, sizeof(hdr), &fixup);
+
+                       if (len != sizeof(hdr)) {
+                               vq_err(vq,
+                                      "Unable to write vnet_hdr at addr %p\n",
+                                      vq->iov->iov_base);
+                               break;
+                       }
+               } else
+                       fix_virtio_net_hdr(vq);
+
                /* TODO: Should check and handle checksum. */
 
                num_buffers = cpu_to_vhost16(vq, headcount);

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to