Re: [PATCH v1 08/10] vhost: implement vhost_dev_start method

[Laurent Vivier <lvivier@redhat.com>]

On 22/06/2020 17:37, Cindy Lu wrote:
> use the vhost_dev_start callback to send the status to backend

I agree with Jason, squash this patch with the previous one.

> Signed-off-by: Cindy Lu <lulu@redhat.com>
> ---
>  hw/virtio/vhost.c         | 17 +++++++++++++++++
>  include/hw/virtio/vhost.h |  2 ++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 01ebe12f28..bfd7f9ce1f 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -744,6 +744,7 @@ static void vhost_iommu_region_del(MemoryListener *listener,
>      }
>  }
>  
> +
>  static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
>                                      struct vhost_virtqueue *vq,
>                                      unsigned idx, bool enable_log)
> @@ -1661,6 +1662,11 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
>          }
>      }
>  
> +    r = vhost_set_start(hdev, true);

Perhaps you can use the same kind of name we have for the queue
(queue_set_started()) and use something like vhost_dev_set_started()?

> +    if (r) {
> +        goto fail_log;
> +    }
> +
>      if (vhost_dev_has_iommu(hdev)) {
>          hdev->vhost_ops->vhost_set_iotlb_callback(hdev, true);
>  
> @@ -1697,6 +1703,8 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
>      /* should only be called after backend is connected */
>      assert(hdev->vhost_ops);
>  
> +    vhost_set_start(hdev, false);
> +
>      for (i = 0; i < hdev->nvqs; ++i) {
>          vhost_virtqueue_stop(hdev,
>                               vdev,
> @@ -1722,3 +1730,12 @@ int vhost_net_set_backend(struct vhost_dev *hdev,
>  
>      return -1;
>  }
> +
> +int vhost_set_start(struct vhost_dev *hdev, bool started)
> +{
> +
> +    if (hdev->vhost_ops->vhost_dev_start) {
> +        hdev->vhost_ops->vhost_dev_start(hdev, started);

The "return" is missing.

And generally a function that only embeds a call to a hook has the same
as the hook.

> +    }
> +    return 0;
> +}

so something like:

    int vhost_dev_set_started(struct vhost_dev *hdev, bool started)
    {
        if (hdev->vhost_ops->dev_set_started) {
            return hdev->vhost_ops->dev_set_started(hdev, started);
        }
        return 0;
    }


> diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> index 085450c6f8..59ea53f8c2 100644
> --- a/include/hw/virtio/vhost.h
> +++ b/include/hw/virtio/vhost.h
> @@ -92,6 +92,7 @@ struct vhost_dev {
>      const VhostDevConfigOps *config_ops;
>  };
>  
> +
>  int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
>                     VhostBackendType backend_type,
>                     uint32_t busyloop_timeout);
> @@ -137,4 +138,5 @@ int vhost_dev_set_inflight(struct vhost_dev *dev,
>                             struct vhost_inflight *inflight);
>  int vhost_dev_get_inflight(struct vhost_dev *dev, uint16_t queue_size,
>                             struct vhost_inflight *inflight);
> +int vhost_set_start(struct vhost_dev *dev, bool started);

There is no need to export it, so set it "static" in hw/virtio/vhost.c
and move the definition before the use.

Thanks,
Laurent