Re: [Qemu-devel] [PATCH] vhost_net: do not expose MTU feature bit to kernel backend

["Michael S. Tsirkin" <mst@redhat.com>]

On Sat, May 20, 2017 at 10:06:58AM +0200, Maxime Coquelin wrote:
> This patch removes MTU from the list of features supported by
> the kernel backend, so that vhost kernel backend does not have
> to advertise it to be negotiated.
> 
> Cc: Aaron Conole <aconole@redhat.com>
> Suggested-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>

This will break cross-version migration when the kernel
does not advertise it though. I'm afraid we'll need
a compat flag.

> ---
>  hw/net/vhost_net.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index 22874a9..bdd8633 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -51,7 +51,6 @@ static const int kernel_feature_bits[] = {
>      VIRTIO_RING_F_EVENT_IDX,
>      VIRTIO_NET_F_MRG_RXBUF,
>      VIRTIO_F_VERSION_1,
> -    VIRTIO_NET_F_MTU,
>      VIRTIO_F_IOMMU_PLATFORM,
>      VHOST_INVALID_FEATURE_BIT
>  };
> -- 
> 2.9.3