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References: <20171123190131.5138-1-ppandit@redhat.com>
	<20171123190131.5138-2-ppandit@redhat.com>
From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Fri, 24 Nov 2017 00:39:15 +0100
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Subject: Re: [Qemu-devel] [PATCH 1/2] virtio: check VirtQueue Vring object
 is set
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To: P J P <ppandit@redhat.com>, Qemu Developers <qemu-devel@nongnu.org>
Cc: zhangboxian <zhangboxian@huawei.com>, Stefan Hajnoczi <stefanha@redhat.com>, Prasad J Pandit <pjp@fedoraproject.org>

On 23/11/2017 20:01, P J P wrote:
> @@ -182,7 +182,7 @@ void virtio_queue_update_rings(VirtIODevice *vdev, int n)
>  {
>      VRing *vring = &vdev->vq[n].vring;
>  
> -    if (!vring->desc) {
> +    if (!vring->desc || !vring->align) {
>          /* not yet setup -> nothing to do */
>          return;
>      }
> @@ -1414,6 +1414,9 @@ void virtio_config_modern_writel(VirtIODevice *vdev,
>  
>  void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
>  {
> +    if (!vdev->vq[n].vring.num) {
> +        return;
> +    }

Why not check vring->num in virtio_queue_update_rings too?

Thanks,

Paolo

>      vdev->vq[n].vring.desc = addr;
>      virtio_queue_update_rings(vdev, n);
>  }