Re: [Qemu-devel] [Qemu-stable] [ANNOUNCE] QEMU 2.6.1 Stable released

[Peter Lieven]

> Am 13.09.2016 um 17:42 schrieb Stefan Hajnoczi <address@hidden>:
> 
>> On Thu, Sep 08, 2016 at 03:58:26PM -0500, Michael Roth wrote:
>> Quoting Stefan Hajnoczi (2016-09-05 12:54:35)
>>>> On Fri, Aug 26, 2016 at 01:45:56PM +0200, Peter Lieven wrote:
>>>>> Am 25.08.2016 um 19:23 schrieb Michael Roth:
>>>>> Quoting Peter Lieven (2016-08-25 01:38:13)
>>>>>> 7c509d1 virtio: decrement vq->inuse in virtqueue_discard()
>>>>>> 700f26b virtio: recalculate vq->inuse after migration
>>>>> Looks like these got posted during the freeze :(
>>>>> 
>>>>>> The virtio thing is important because live migration is broken without
>>>>>> the fix as  86cc089 is in 2.6.1.
>>>>> Not sure I understand the relation to 86cc089. Wouldn't the check
>>>>> introduced there always pass due to target initializing inuse to 0?
>>>>> 
>>>>> Or is the issue that the fix introduced in 86cc089 is only partially
>>>>> effective due to inuse not being recalculated properly on target? That 
>>>>> might
>>>>> warrant a 2.6.1.1...
>>>> 
>>>> This is what Stefan wrote in the cover letter to the series:
>>>> 
>>>> "I should mention this is for QEMU 2.7. These fixes are needed if the
>>>> CVE-2016-5403 patch has been applied. Without these patches any device 
>>>> that holds VirtQueueElements acros
>>>> live migration will terminate with a "Virtqueue size exceeded" error 
>>>> message. virtio-balloon and virtio-scsi are affected. virtio-bl
>>>> probably too but I haven't tested it."
>>>> 
>>>> Maybe
>>> 
>>> The virtio inuse fixes are needed for stable (v2.6.2?) so that the
>>> spurious "Virtqueue size exceeded" on migration is solved.
>>> 
>>> The error can be reproduced when there is a VirtQueueElement pending
>>> across migration (e.g. virtio-blk s->rq failed request list).
>> 
>> Thanks for clarifying. I'm planning to do a 2.6.2 to capture these, the
>> patches Peter mentioned, and some other fixes that came during 2.7 RC
>> phase.
>> 
>> I have an initial staging tree at:
>> 
>>  https://github.com/mdroth/qemu/commits/stable-2.6-staging
>> 
>> There's still a few PULLs in flight with patches I plan to pull in, but
>> hoping to send out the patch round-up early next week and a release the
>> following week.
> 
> Two more candidates for stable:
> 
> 4b7f91e virtio: zero vq->inuse in virtio_reset()
> 104e70c virtio-balloon: discard virtqueue element on reset
> 
> They also deal with "Virtqueue size exceeded" errors.
> 
> Stefan

There also seems to be an regression (segfault) in the VNC server in 2.6.1, but 
i am still investigating.

Peter