On Tue, Jun 11, 2019 at 02:51:37PM +0800, Tiwei Bie wrote:
> The VIRTIO_NET_F_CTRL_VLAN feature requires the support of
> vhost-user backend. But it will be advertised to guest driver
> as long as it's enabled by users in QEMU, while it's not
> supported by vhost-user backend. This patch fixes this issue.
Fixes by making guest refuse to send vlan tags?
I agree it seems cleaner, but which guests does this actually help?
> Fixes: 72018d1e1917 ("vhost-user: ignore qemu-only features")
> Cc: qemu-sta...@nongnu.org
>
> Signed-off-by: Tiwei Bie <tiwei....@intel.com>
A change like that will break migration compatibility, will it not?
Maybe we need to tie it to a machine version somehow...
> ---
> It's not clear in the spec that, whether vlan filtering is
> also best-effort:
> https://github.com/oasis-tcs/virtio-spec/blob/37057052e7/content.tex#L3372
So what breaks if we declare it best effort for now?
And does it really help if we report that vlan filtering
is not supported to guests?
> hw/net/vhost_net.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index a6b719035c..1444fc9230 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -75,6 +75,8 @@ static const int user_feature_bits[] = {
> VIRTIO_NET_F_MTU,
> VIRTIO_F_IOMMU_PLATFORM,
>
> + VIRTIO_NET_F_CTRL_VLAN,
> +
> /* This bit implies RARP isn't sent by QEMU out of band */
> VIRTIO_NET_F_GUEST_ANNOUNCE,
>
> --
> 2.17.1
