Re: [PATCH 0/2] Make savevm versioning compatible with upstream QEMU

[Anthony Liguori <aliguori@us.ibm.com>]

Avi Kivity wrote:
> Anthony Liguori wrote:
>> Right now, there is no way savevm versioning can be compatible with 
>> upstream
>> QEMU because KVM adds fields to existing savevm structures without 
>> incrementing
>> the versions.
>>
>> If you assume that KVM will eventually merge into upstream QEMU, this 
>> means that
>> eventually KVM is going to have to break backwards compatibility with 
>> itself
>> to resolve this issue in a non-graceful way.
>>
>> So let's do that now instead of doing it later when the situation is 
>> only worse.
>>
>> I'm happy to allocate particular version identifiers for KVM to avoid 
>> future
>> conflicts.  I believe we should try to eliminate the existing 
>> differences so
>> that we can converge in the future on a common versioning scheme.
>>   
>
> Applied both, thanks.
>
> I think we can avoid the need to synchronize too much by saving 
> kvm-specific state for device "x" using id "x-kvm"; this allows the 
> two to evolve independently.

I need to add save/restore support to upstream QEMU so this is a good 
excuse to just merge the changes in KVM upstream.  So hopefully this 
will become a non issue.  If something arises and you need more savevm 
state, introduce a new section suffixed or prefixed with kvm.  
Alternatively, ask and I can reserve an ID upstream.

For virtio-net, we just need to get the vnet stuff merged upstream.

-- 
Regards,

Anthony Liguori