From: Paolo Bonzini <pbonzini@redhat.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: imammedo@redhat.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] kvm/apic: fix 2.2->2.1 migration
Date: Fri, 12 Dec 2014 19:42:18 +0100 [thread overview]
Message-ID: <548B370A.9070107@redhat.com> (raw)
In-Reply-To: <20141212173044.GD2328@work-vm>
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.
Paolo
next prev parent reply other threads:[~2014-12-12 18:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-10 15:57 [Qemu-devel] [PATCH] kvm/apic: fix 2.2->2.1 migration Paolo Bonzini
2014-12-12 17:30 ` Dr. David Alan Gilbert
2014-12-12 18:42 ` Paolo Bonzini [this message]
2014-12-12 19:32 ` Dr. David Alan Gilbert
2015-01-20 9:53 ` Markus Armbruster
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