Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 2/3] vdpa/mlx5: Only return vq ready if vq is initialized
To:     Eli Cohen <elic@nvidia.com>, mst@redhat.com,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
References: <20210531160448.31537-1-elic@nvidia.com>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <0fbd8484-9e8b-d7cc-4996-74306e6e2867@redhat.com>
Date:   Tue, 1 Jun 2021 10:18:04 +0800
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0)
 Gecko/20100101 Thunderbird/78.10.2
MIME-Version: 1.0
In-Reply-To: <20210531160448.31537-1-elic@nvidia.com>
Content-Type: text/plain; charset=gbk; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: en-US
Precedence: bulk


?? 2021/6/1 ????12:04, Eli Cohen д??:
> 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@nvidia.com>
> ---
>   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,