Re: [Qemu-devel] Re: [PATCH 0/8] kvm: Fixes, cleanups and live migration

[Gleb Natapov]

On Sun, May 03, 2009 at 10:50:12AM +0300, Avi Kivity wrote:
> Gleb Natapov wrote:
>
>  
>
>>> Maybe we should unexecute the software interrupt instruction on Intel 
>>>  and get the same effect.
>>>
>>>     
>> We don't need to unexecute anything. We get exit with RIP pointing to
>> the offending instruction. The right thing on VMX to do is to inject
>> software interrupt with correct instruction length. Processor will do
>> the rest. Remind me please why do we try to find problems where there is
>> none? We will do right thing and fix migration code to do right thing.
>>
>>   
>
> I don't want the migration protocol to encode vendor specific  
> information. The architectural state is complicated enough, we don't  
> want microarchitectural state as well.
Then I don't see how migration can work correctly. How do you expect
migration to work if you don't migrate part of a processor state? Why
not drop non migratable state immediately after exit then? (that is
essentially what happens if we don't migrate it).

--
                        Gleb.