On Sun, Jun 15, 2025 at 12:46 AM Konstantin Shkolnyy <k...@linux.ibm.com> wrote:
>
> After commit 0caed25cd171 vhost_vdpa_net_load_vlan() started seeing
> VIRTIO_NET_F_CTRL_VLAN flag and making 4096 calls to the kernel with
> VIRTIO_NET_CTRL_VLAN_ADD command. However, it forgot to convert the
> 16-bit VLAN IDs to LE format. On BE machine, the kernel calls failed
> when they saw "VLAN IDs" greater than 4095, and QEMU then said:
> "unable to start vhost net: 5: falling back on userspace virtio", and
> VDPA became disabled.
>
> Convert the VLAN ID to LE before putting it into virtio queue.
>
> Signed-off-by: Konstantin Shkolnyy <k...@linux.ibm.com>
Good catch! You should add the Fixes: tag though :). With that,
Acked-by: Eugenio Pérez <epere...@redhat.com>
> ---
> net/vhost-vdpa.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 58d738945d..99c9eb42b9 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -1173,9 +1173,10 @@ static int
> vhost_vdpa_net_load_single_vlan(VhostVDPAState *s,
> struct iovec *in_cursor,
> uint16_t vid)
> {
> + __le16 vid_le = cpu_to_le16(vid);
> const struct iovec data = {
> - .iov_base = &vid,
> - .iov_len = sizeof(vid),
> + .iov_base = &vid_le,
> + .iov_len = sizeof(vid_le),
> };
> ssize_t r = vhost_vdpa_net_load_cmd(s, out_cursor, in_cursor,
> VIRTIO_NET_CTRL_VLAN,
> --
> 2.34.1
>
>
