Re: [RFC PATCH 07/12] vhost: Add VhostVDPAStartOp operation

[Jason Wang]

On Sat, Jul 16, 2022 at 7:34 PM Eugenio Pérez <eperezma@redhat.com> wrote:
>
> It allows to run commands at start of the device, before it have enabled
> any queue.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
>  hw/virtio/vhost-shadow-virtqueue.h | 3 +++
>  include/hw/virtio/vhost-vdpa.h     | 5 +++++
>  hw/virtio/vhost-vdpa.c             | 8 ++++++++
>  3 files changed, 16 insertions(+)
>
> diff --git a/hw/virtio/vhost-shadow-virtqueue.h 
> b/hw/virtio/vhost-shadow-virtqueue.h
> index 03eb7ff670..210fe393cd 100644
> --- a/hw/virtio/vhost-shadow-virtqueue.h
> +++ b/hw/virtio/vhost-shadow-virtqueue.h
> @@ -26,6 +26,8 @@ typedef struct SVQDescState {
>  } SVQDescState;
>
>  typedef struct VhostShadowVirtqueue VhostShadowVirtqueue;
> +typedef int (*ShadowVirtQueueStart)(VhostShadowVirtqueue *svq,
> +                                    void *opaque);
>
>  /**
>   * Callback to handle an avail buffer.
> @@ -43,6 +45,7 @@ typedef int (*VirtQueueAvailCallback)(VhostShadowVirtqueue 
> *svq,
>                                        void *vq_callback_opaque);
>
>  typedef struct VhostShadowVirtqueueOps {
> +    ShadowVirtQueueStart start;

What's the difference between this and start_op?

Thanks

>      VirtQueueAvailCallback avail_handler;
>  } VhostShadowVirtqueueOps;
>
> diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> index d10a89303e..b7d18b4e30 100644
> --- a/include/hw/virtio/vhost-vdpa.h
> +++ b/include/hw/virtio/vhost-vdpa.h
> @@ -24,6 +24,10 @@ typedef struct VhostVDPAHostNotifier {
>      void *addr;
>  } VhostVDPAHostNotifier;
>
> +struct vhost_vdpa;
> +/* Called after send DRIVER_OK but after enabling vrings */
> +typedef int (*VhostVDPAStartOp)(struct vhost_vdpa *v);
> +
>  typedef struct vhost_vdpa {
>      int device_fd;
>      int index;
> @@ -39,6 +43,7 @@ typedef struct vhost_vdpa {
>      GPtrArray *shadow_vqs;
>      const VhostShadowVirtqueueOps *shadow_vq_ops;
>      void *shadow_vq_ops_opaque;
> +    VhostVDPAStartOp start_op;
>      struct vhost_dev *dev;
>      VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
>  } VhostVDPA;
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index 1d8829c619..48f031b8c0 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -1136,6 +1136,14 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, 
> bool started)
>          if (unlikely(r)) {
>              return r;
>          }
> +
> +        if (v->start_op) {
> +            r = v->start_op(v);
> +            if (unlikely(r)) {
> +                return r;
> +            }
> +        }
> +
>          vhost_vdpa_set_vring_ready(dev);
>      } else {
>          vhost_vdpa_reset_device(dev);
> --
> 2.31.1
>