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Date:   Tue, 1 Jun 2021 06:42:38 +0300
From:   Eli Cohen <elic@nvidia.com>
To:     Jason Wang <jasowang@redhat.com>
CC:     <mst@redhat.com>, <virtualization@lists.linux-foundation.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] vdpa/mlx5: Only return vq ready if vq is initialized
Message-ID: <20210601034238.GB203469@mtl-vdi-166.wap.labs.mlnx>
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On Tue, Jun 01, 2021 at 10:18:04AM +0800, Jason Wang wrote:
> 
> 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@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.
> "

ok

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