Re: [PATCH 2/3] vdpa/mlx5: Only return vq ready if vq is initialized

[Jason Wang]

在 2021/6/1 上午12:04, Eli Cohen 写道:
> Only return the value of the ready field if the VQ is initialized in
> which case the value of the field is valid.
>
> Failing to do so can result in virtio_vdpa failing to load if the device
> was previously used by vhost_vdpa and the old values are ready.
> virtio_vdpa expects to find VQs in "not ready" state.
>
> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
> Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
> ---
>   drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 02a05492204c..f6b680d2ab1c 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1407,7 +1407,7 @@ static bool mlx5_vdpa_get_vq_ready(struct vdpa_device *vdev, u16 idx)
>   	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
>   	struct mlx5_vdpa_virtqueue *mvq = &ndev->vqs[idx];
>   
> -	return mvq->ready;
> +	return mvq->initialized && mvq->ready;


I think the more suitable fix is to reset mvq->ready during reset. The 
vq_ready should follow the queue_enable semantic in virtio-pci:

"
The device MUST present a 0 in queue_enable on reset.
"

Thanks


>   }
>   
>   static int mlx5_vdpa_set_vq_state(struct vdpa_device *vdev, u16 idx,