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Subject: Re: [PATCH v2] vdpa/mlx5: Clear vq ready indication upon device reset
To:     Eli Cohen <elic@nvidia.com>, mst@redhat.com,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
References: <20210606053128.170399-1-elic@nvidia.com>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <6f257eb1-c3ff-c17c-c937-7cc7f945f22d@redhat.com>
Date:   Mon, 7 Jun 2021 10:12:06 +0800
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?? 2021/6/6 ????1:31, Eli Cohen д??:
> After device reset, the virtqueues are not ready so clear the ready
> field.
>
> 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@nvidia.com>


Acked-by: Jason Wang <jasowang@redhat.com>


> ---
> v0 --> v1:
>     Make sure clear of ready is done only in reset flow
> v1 --> v2:
>     use ascending loop iterator to avoid confusion
>
>   drivers/vdpa/mlx5/net/mlx5_vnet.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 02a05492204c..a42db592e7bb 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1766,6 +1766,14 @@ static void teardown_driver(struct mlx5_vdpa_net *ndev)
>   	mutex_unlock(&ndev->reslock);
>   }
>   
> +static void clear_vqs_ready(struct mlx5_vdpa_net *ndev)
> +{
> +	int i;
> +
> +	for (i = 0; i < ndev->mvdev.max_vqs; i++)
> +		ndev->vqs[i].ready = false;
> +}
> +
>   static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
>   {
>   	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> @@ -1776,6 +1784,7 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
>   	if (!status) {
>   		mlx5_vdpa_info(mvdev, "performing device reset\n");
>   		teardown_driver(ndev);
> +		clear_vqs_ready(ndev);
>   		mlx5_vdpa_destroy_mr(&ndev->mvdev);
>   		ndev->mvdev.status = 0;
>   		ndev->mvdev.mlx_features = 0;