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Re: [Qemu-devel] [PATCH] vhost: fix invalid downcast
From: |
Jia He |
Subject: |
Re: [Qemu-devel] [PATCH] vhost: fix invalid downcast |
Date: |
Sat, 14 Jul 2018 12:09:30 +0800 |
User-agent: |
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 |
On 7/14/2018 12:15 AM, Michael S. Tsirkin Wrote:
> 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
>
yes, it is a bug introduced by fb20fbb764aa1
Acked-by: Jia He <address@hidden>
--
Cheers,
Jia