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Date:   Wed, 2 Jun 2021 09:17:23 +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>, <kvm@vger.kernel.org>,
        <netdev@vger.kernel.org>, <eli@mellanox.com>
Subject: Re: [PATCH V2 4/4] virtio/vdpa: clear the virtqueue state during
 probe
Message-ID: <20210602061723.GB8662@mtl-vdi-166.wap.labs.mlnx>
References: <20210602021043.39201-1-jasowang@redhat.com>
 <20210602021043.39201-5-jasowang@redhat.com>
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On Wed, Jun 02, 2021 at 10:10:43AM +0800, Jason Wang wrote:
> From: Eli Cohen <elic@nvidia.com>
> 
> Clear the available index as part of the initialization process to
> clear and values that might be left from previous usage of the device.
> For example, if the device was previously used by vhost_vdpa and now
> probed by vhost_vdpa, you want to start with indices.
> 
> Fixes: c043b4a8cf3b ("virtio: introduce a vDPA based transport")
> Signed-off-by: Eli Cohen <elic@nvidia.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  drivers/virtio/virtio_vdpa.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
> index e28acf482e0c..e1a141135992 100644
> --- a/drivers/virtio/virtio_vdpa.c
> +++ b/drivers/virtio/virtio_vdpa.c
> @@ -142,6 +142,8 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
>  	struct vdpa_callback cb;
>  	struct virtqueue *vq;
>  	u64 desc_addr, driver_addr, device_addr;
> +	/* Assume split virtqueue, switch to packed if necessary */
> +	struct vdpa_vq_state state = {0};
>  	unsigned long flags;
>  	u32 align, num;
>  	int err;
> @@ -191,6 +193,19 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
>  		goto err_vq;
>  	}
>  
> +	/* reset virtqueue state index */
> +	if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
> +		struct vdpa_vq_state_packed *s = &state.packed;
> +
> +		s->last_avail_counter = 1;
> +		s->last_avail_idx = 0;

It's already 0

> +		s->last_used_counter = 1;
> +		s->last_used_idx = 0;

already 0

> +	}
> +	err = ops->set_vq_state(vdpa, index, &state);
> +	if (err)
> +		goto err_vq;
> +
>  	ops->set_vq_ready(vdpa, index, 1);
>  
>  	vq->priv = info;
> -- 
> 2.25.1
>