Re: User space for lapic2

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Dong, Eddie wrote:
>> If we release a kernel with pic but not lapic, and userspace that
>> defaults to user-pic+lapic, then that kernel will not work
>> with a newer
>> userspace that defaults to in-kernel pic+lapic.
>>
>> We need to switch in one go.  I don't mind checking in patches to the
>> lapic2 branch, and continually rebasing it against master, but
>> a release
>> will only happen when everything works.
>>     
>
> I think the difference here is if we can leave the live migration to
> future, we all agree lapic should be with pic together and that is
> almost there.
>
> Does "everything works" here mean live migration works?
>
>   

Yes.

I don't think live migration is particularly difficult.  You need a APIs 
to read and write the PIC+LAPIC states, and you write the state into the 
qemu device model, which already supports migration.  You can even live 
migrate from a userspace PIC+LAPIC to a kernel PIC+LAPIC as the format 
is the same.  CPU registers work the same way in kvm/qemu.

-- 
error compiling committee.c: too many arguments to function


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