Re: [PATCH 4/5] virtio-net: Update virtio-net curr_queue_pairs in vdpa backends

[Jason Wang <jasowang@redhat.com>]

在 2022/8/20 01:13, Eugenio Pérez 写道:
> It was returned as error before. Instead of it, simply update the
> corresponding field so qemu can send it in the migration data.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---


Looks correct.

Adding Si Wei for double check.

Thanks


>   hw/net/virtio-net.c | 17 ++++++-----------
>   1 file changed, 6 insertions(+), 11 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index dd0d056fde..63a8332cd0 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1412,19 +1412,14 @@ static int virtio_net_handle_mq(VirtIONet *n, uint8_t cmd,
>           return VIRTIO_NET_ERR;
>       }
>   
> -    /* Avoid changing the number of queue_pairs for vdpa device in
> -     * userspace handler. A future fix is needed to handle the mq
> -     * change in userspace handler with vhost-vdpa. Let's disable
> -     * the mq handling from userspace for now and only allow get
> -     * done through the kernel. Ripples may be seen when falling
> -     * back to userspace, but without doing it qemu process would
> -     * crash on a recursive entry to virtio_net_set_status().
> -     */
> +    n->curr_queue_pairs = queue_pairs;
>       if (nc->peer && nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) {
> -        return VIRTIO_NET_ERR;
> +        /*
> +         * Avoid updating the backend for a vdpa device: We're only interested
> +         * in updating the device model queues.
> +         */
> +        return VIRTIO_NET_OK;
>       }
> -
> -    n->curr_queue_pairs = queue_pairs;
>       /* stop the backend before changing the number of queue_pairs to avoid handling a
>        * disabled queue */
>       virtio_net_set_status(vdev, vdev->status);