From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 1/6] target-arm: kvm: save/restore mp state Date: Tue, 03 Mar 2015 18:10:12 +0100 Message-ID: <54F5EAF4.2000206@redhat.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <87zj7u59hd.fsf@linaro.org> Sender: kvm-owner@vger.kernel.org To: =?UTF-8?B?QWxleCBCZW5uw6ll?= , Peter Maydell Cc: kvm-devel , Marc Zyngier , QEMU Developers , "kvmarm@lists.cs.columbia.edu" , arm-mail-list List-Id: kvmarm@lists.cs.columbia.edu On 03/03/2015 17:30, Alex Benn=C3=A9e 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