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Subject: Re: [PATCH v4 5/7] virtio_vdpa: setup correct vq size with callbacks
 get_vq_num_{max,min}
To:     Wu Zongyong <wuzongyong@linux.alibaba.com>,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, mst@redhat.com
Cc:     wei.yang1@linux.alibaba.com
References: <cover.1632313398.git.wuzongyong@linux.alibaba.com>
 <cover.1632882380.git.wuzongyong@linux.alibaba.com>
 <e971b011b9224a4da4fcab6e904fcee0b7393ac6.1632882380.git.wuzongyong@linux.alibaba.com>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <514a4a6e-89d5-3200-bb31-3660389f5315@redhat.com>
Date:   Mon, 11 Oct 2021 11:06:44 +0800
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?? 2021/9/29 ????2:11, Wu Zongyong д??:

> Signed-off-by: Wu Zongyong <wuzongyong@linux.alibaba.com>


Commit log please.


> ---
>   drivers/virtio/virtio_vdpa.c | 25 ++++++++++++++++++++-----
>   1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
> index 72eaef2caeb1..8aa4ebe2a2a2 100644
> --- a/drivers/virtio/virtio_vdpa.c
> +++ b/drivers/virtio/virtio_vdpa.c
> @@ -145,7 +145,8 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
>   	/* Assume split virtqueue, switch to packed if necessary */
>   	struct vdpa_vq_state state = {0};
>   	unsigned long flags;
> -	u32 align, num;
> +	u32 align, max_num, min_num = 0;
> +	bool may_reduce_num = true;
>   	int err;
>   
>   	if (!name)
> @@ -163,22 +164,36 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
>   	if (!info)
>   		return ERR_PTR(-ENOMEM);
>   
> -	num = ops->get_vq_num_max(vdpa);
> -	if (num == 0) {
> +	max_num = ops->get_vq_num_max(vdpa);
> +	if (max_num == 0) {
>   		err = -ENOENT;
>   		goto error_new_virtqueue;
>   	}
>   
> +	if (ops->get_vq_num_min)
> +		min_num = ops->get_vq_num_min(vdpa);
> +	if (min_num > max_num) {
> +		err = -ENOENT;
> +		goto error_new_virtqueue;
> +	}


If we really want to do this, let's move this to vdpa core during device 
probing.

Or just leave it as is (device risk itself).

Thanks


> +
> +	may_reduce_num = (max_num == min_num) ? false : true;
> +
>   	/* Create the vring */
>   	align = ops->get_vq_align(vdpa);
> -	vq = vring_create_virtqueue(index, num, align, vdev,
> -				    true, true, ctx,
> +	vq = vring_create_virtqueue(index, max_num, align, vdev,
> +				    true, may_reduce_num, ctx,
>   				    virtio_vdpa_notify, callback, name);
>   	if (!vq) {
>   		err = -ENOMEM;
>   		goto error_new_virtqueue;
>   	}
>   
> +	if (virtqueue_get_vring_size(vq) < min_num) {
> +		err = -EINVAL;
> +		goto err_vq;
> +	}
> +
>   	/* Setup virtqueue callback */
>   	cb.callback = virtio_vdpa_virtqueue_cb;
>   	cb.private = info;