Re: [Qemu-devel] [PATCH] vhost: don't set vring call fd to -1 in vhost_virtqueue_start for vhost-user

[Jason Wang <jasowang@redhat.com>]

On 2017年08月21日 09:50, ZhiPeng Lu wrote:
> commit 96a3d98d2cdbd897ff5ab33427aa4cfb94077665 (vhost: don't set vring call
> if no vector) set vring call fd to -1 for drivers does not use interrupt
> at all(e.g virtio-net pmd). That patch setting vring call fd to -1 cause
> the network to not work when running dpdk in the guest. The openvswitch port
> status is down by executing the command "ovs-vsctl list interface"
> in host of running the guest. The network is ok if it doesn't set vring call fd
> to -1 in vhost_virtqueue_start.
> The patch doesn't set vring call fd to -1 for vhost-user.
>
> Signed-off-by: ZhiPeng Lu <lu.zhipeng@zte.com.cn>
> ---
>   hw/virtio/vhost.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 6eddb09..bb8db7d 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -1098,7 +1098,8 @@ static int vhost_virtqueue_start(struct vhost_dev *dev,
>   
>       if (k->query_guest_notifiers &&
>           k->query_guest_notifiers(qbus->parent) &&
> -        virtio_queue_vector(vdev, idx) == VIRTIO_NO_VECTOR) {
> +        virtio_queue_vector(vdev, idx) == VIRTIO_NO_VECTOR &&
> +        vdev->use_guest_notifier_mask) {
>           file.fd = -1;
>           r = dev->vhost_ops->vhost_set_vring_call(dev, &file);
>           if (r) {

Hi:

Which kind/version of vhost-user bakcend did you use? What happen if we 
don't do vhost_set_vring_call for it? Is this a bug of vhost-user 
backend instead of qemu?

Thanks