vhost/net: fix up num_buffers endian-ness

In virtio 1.0 mode, when mergeable buffers are enabled on a big-endian
host, num_buffers wasn't byte-swapped correctly, so large incoming
packets got corrupted.

To fix, fill it in within hdr - this also makes sure it gets
the correct type.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index d415d69dc237..9484d5652ca5 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -650,8 +650,10 @@ static void handle_rx(struct vhost_net *net)
                         break;
                 }
                 /* TODO: Should check and handle checksum. */
+
+                hdr.num_buffers = cpu_to_vhost16(vq, headcount);
                 if (likely(mergeable) &&
-                    memcpy_toiovecend(nvq->hdr, (unsigned char *)&headcount,
+                    memcpy_toiovecend(nvq->hdr, (void *)&hdr.num_buffers,
                                       offsetof(typeof(hdr), num_buffers),
                                       sizeof hdr.num_buffers)) {
                         vq_err(vq, "Failed num_buffers write");