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Re: [Qemu-devel] [PATCH] kvm/apic: fix 2.2->2.1 migration
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH] kvm/apic: fix 2.2->2.1 migration |
Date: |
Fri, 12 Dec 2014 19:32:43 +0000 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
* Paolo Bonzini (address@hidden) wrote:
>
>
> On 12/12/2014 18:30, Dr. David Alan Gilbert wrote:
> > OK, let me just check that I get this....
> >
> > It gets reset to 0 already in kvm_apic_realize
>
> (before this patch -- after this patch it's only done in reset)
>
> > then we do the common init
>
> Then as part of starting up auxiliary processors we send an INIT
> interrupt, that resets the APIC and...
>
> > that sets it to !bsp - so 1 for most CPUs
> > then you're adding this so that a specific APIC implementation (kvm)
> > can nobble it back to 0 again?
>
> Yes. That's needed because this APIC implementation does not use the
> field at all.
>
> > and on the load side it's forced to zero by apic_pre_load.
>
> Yes. That's the common case for the !APIC implementation because it
> gets to zero as soon as te OS starts.
OK; yep, that's OK.
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
>
> Paolo
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK