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Re: [Qemu-devel] [PATCH] vhost: fix invalid downcast
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH] vhost: fix invalid downcast |
Date: |
Fri, 13 Jul 2018 19:15:56 +0300 |
On Fri, Jul 13, 2018 at 05:04:05PM +0300, Yury Kotov wrote:
> virtio_queue_get_desc_addr returns 64-bit hwaddr while int is usually 32-bit.
> If returned hwaddr is not equal to 0 but least-significant 32 bits are
> equal to 0 then this code will not actually stop running queue.
>
> Signed-off-by: Yury Kotov <address@hidden>
So IIUC
Fixes: fb20fbb764aa1 ("vhost: avoid to start/stop virtqueue which is not ready")
And
Cc: address@hidden
> ---
> hw/virtio/vhost.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index b129cb9..7edeee7 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -1071,10 +1071,8 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev,
> .index = vhost_vq_index,
> };
> int r;
> - int a;
>
> - a = virtio_queue_get_desc_addr(vdev, idx);
> - if (a == 0) {
> + if (virtio_queue_get_desc_addr(vdev, idx) == 0) {
> /* Don't stop the virtqueue which might have not been started */
> return;
> }
> --
> 2.7.4