Re: [Qemu-devel] Qemu 2.6 => Qemu 2.7 migration: error while loading state for instance 0x0 of device '0000:00:03.0/virtio-balloon'

[Stefan Priebe - Profihost AG]

Am 15.11.2016 um 12:07 schrieb Ladi Prosek:
> Hi,
> 
> On Tue, Nov 15, 2016 at 11:37 AM, Stefan Priebe - Profihost AG
> <address@hidden> wrote:
>> Hello,
>>
>> Am 15.11.2016 um 11:30 schrieb Dr. David Alan Gilbert:
>>> * Stefan Priebe - Profihost AG (address@hidden) wrote:
>>>> Hello,
>>>>
>>>> today i did a first live migration from Qemu 2.6.2 to Qemu 2.7.0. The VM
>>>> is running windows and virtio-balloon and with machine type pc-i440fx-2.5.
>>>>
>>>> The output of the target qemu process was:
>>>> kvm_apic_post_load: Yeh
>>>> kvm_apic_post_load: Yeh
>>>> kvm_apic_post_load: Yeh
>>>> kvm_apic_post_load: Yeh
>>>> kvm: VQ 2 size 0x80 < last_avail_idx 0x1 - used_idx 0x4
>>>> kvm: error while loading state for instance 0x0 of device
>>>> '0000:00:03.0/virtio-balloon'
>>>> kvm: load of migration failed: Operation not permitted
>>>
>>> Yes that's a known bug; only seems to affect windows guests, and I believe
>>> doesn't even need to cross versions.
>>>
>>> There's a bunch of fixes that Stefan applied to virtio code
>>> that I think fix this; I see that he cc'd qemu-stable.
>>> I think it's 4b7f91ed, but I'm not sure if there are others needed.
>>
>> thanks for pointing to that commit.
>>
>> Stefan can you tell me whether it's enough to cherry-pick 4b7f91ed into
>> 2.7.0 ?
> 
> I don't believe that 4b7f91ed will help here (no device reset on
> migration). We've seen this error with QEMU running without:
> 
>   commit 4eae2a657d1ff5ada56eb9b4966eae0eff333b0b
>   Author: Ladi Prosek <address@hidden>
>   Date:   Tue Mar 1 12:14:03 2016 +0100
> 
>       balloon: fix segfault and harden the stats queue
> 
> 
> Is it possible that the VM has run on such a QEMU, then was
> live-migrated to 2.6.2, and then to 2.7.0?

Hi,

yes, it was started under Qemu 2.5.0. Was then migrated to 2.6.2 and
then to 2.7.0.

Greets,
Stefan

> 
> Thanks,
> Ladi
> 
>> Greets,
>> Stefan
>>
>>>
>>> Dave
>>>>
>>>> Greets,
>>>> Stefan
>>>>
>>> --
>>> Dr. David Alan Gilbert / address@hidden / Manchester, UK
>>>
>>