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Subject: Re: [Qemu-devel] [PATCH 1/6] target-arm: kvm: save/restore mp state
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Cc: Marc Zyngier <marc.zyngier@arm.com>, arm-mail-list <linux-arm-kernel@lists.infradead.org>, QEMU Developers <qemu-devel@nongnu.org>, kvm-devel <kvm@vger.kernel.org>, "kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>



On 03/03/2015 17:30, Alex Bennée wrote:
>> >
>>> >>  Right now this is not migrated on ARM if I remember correctly, but
>>> >> perhaps you'll want to add it in the future.
>> >
>> > ...which is why we don't need to migrate this: it just means
>> > that migration during WFI causes an unnecessary-wakeup, which
>> > is architecturally fine.
> What happens when you boot a SMP system but only ever power up one of the
> CPUs? You can't just randomly start the second CPU if it's in the
> powered off state, who knows what it would do?

The second CPU would not be in the WFI state, which is what Peter is
talking about.

I agree that this state should be saved/restored.  I'm just saying that
HALTED is not the right constant to use.

Paolo