Re: [RFC PATCH v9 21/23] vdpa: Add vhost_vdpa_start_control_svq

[Jason Wang]

在 2022/7/7 02:40, Eugenio Pérez 写道:
> As a first step we only enable CVQ first than others. Future patches add
> state restore.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>   net/vhost-vdpa.c | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index e415cc8de5..77d013833f 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -370,6 +370,24 @@ static CVQElement 
> *vhost_vdpa_cvq_alloc_elem(VhostVDPAState *s,
>       return g_steal_pointer(&cvq_elem);
>   }
>   
> +static int vhost_vdpa_start_control_svq(VhostShadowVirtqueue *svq,
> +                                        void *opaque)
> +{
> +    struct vhost_vring_state state = {
> +        .index = virtio_get_queue_index(svq->vq),
> +        .num = 1,
> +    };
> +    VhostVDPAState *s = opaque;
> +    struct vhost_dev *dev = s->vhost_vdpa.dev;
> +    struct vhost_vdpa *v = dev->opaque;
> +    int r;
> +
> +    assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
> +
> +    r = ioctl(v->device_fd, VHOST_VDPA_SET_VRING_ENABLE, &state);
> +    return r < 0 ? -errno : r;
> +}
> +
>   /**
>    * iov_size with an upper limit. It's assumed UINT64_MAX is an invalid
>    * iov_size.
> @@ -554,6 +572,7 @@ static const VhostShadowVirtqueueOps vhost_vdpa_net_svq_ops 
> = {
>       .avail_handler = vhost_vdpa_net_handle_ctrl_avail,
>       .used_handler = vhost_vdpa_net_handle_ctrl_used,
>       .detach_handler = vhost_vdpa_net_handle_ctrl_detach,
> +    .start = vhost_vdpa_start_control_svq,
>   };


I wonder if vhost_net_start() is something better than here. It knows 
all virtqueues and it can do whatever it wants, we just need to make 
shadow virtqueue visible there?

Thanks


>   
>   static NetClientState *net_vhost_vdpa_init(NetClientState *peer,