From mboxrd@z Thu Jan 1 00:00:00 1970 From: pbonzini@redhat.com (Paolo Bonzini) Date: Tue, 03 Mar 2015 18:10:12 +0100 Subject: [PATCH 1/6] target-arm: kvm: save/restore mp state In-Reply-To: <87zj7u59hd.fsf@linaro.org> References: <1424880159-29348-1-git-send-email-alex.bennee@linaro.org> <1424880159-29348-2-git-send-email-alex.bennee@linaro.org> <8761ai73j1.fsf@linaro.org> <54F595C0.5060004@redhat.com> <87zj7u59hd.fsf@linaro.org> Message-ID: <54F5EAF4.2000206@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/03/2015 17:30, Alex Benn?e 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