Without this patch, packets are being silently dropped by the tap backend.
Signed-off-by: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>
---
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);
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