From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752846AbeBELJC (ORCPT ); Mon, 5 Feb 2018 06:09:02 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:48936 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751705AbeBELIy (ORCPT ); Mon, 5 Feb 2018 06:08:54 -0500 Subject: Re: [PATCH v3 08/18] arm/arm64: KVM: Add PSCI version selection API To: Christoffer Dall Cc: Andrew Jones , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, Catalin Marinas , Will Deacon , Peter Maydell , Lorenzo Pieralisi , Mark Rutland , Robin Murphy , Ard Biesheuvel , Hanjun Guo , Jayachandran C , Jon Masters , Russell King - ARM Linux References: <20180201114657.7323-1-marc.zyngier@arm.com> <20180201114657.7323-9-marc.zyngier@arm.com> <20180202201706.dj6jmff7lh7bleze@kamzik.brq.redhat.com> <20180203115932.24c4bcfb@why.wild-wind.fr.eu.org> <20180204123701.GK21802@cbox> <6b0d5f23-950c-b2a6-3cc8-63c3145893b4@arm.com> <20180205095823.r5vlfkovrgksykxh@hawk.localdomain> <7eb71dd4-c06b-9680-0280-03569925283b@arm.com> <20180205105031.GV21802@cbox> From: Marc Zyngier Organization: ARM Ltd Message-ID: <3089d003-5904-94a2-c62a-e2c0f512e803@arm.com> Date: Mon, 5 Feb 2018 11:08:50 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180205105031.GV21802@cbox> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/02/18 10:50, Christoffer Dall wrote: > On Mon, Feb 05, 2018 at 10:42:44AM +0000, Marc Zyngier wrote: >> On 05/02/18 09:58, Andrew Jones wrote: >>> On Mon, Feb 05, 2018 at 09:24:33AM +0000, Marc Zyngier wrote: >>>> On 04/02/18 12:37, Christoffer Dall wrote: >> >> [...] >> >>>>> Given the urgency of adding mitigation towards variant 2 which is the >>>>> driver for this work, I think we should drop the compat functionality in >>>>> this series and work this out later on if needed. I think we can just >>>>> tweak the previous patch to enable PSCI 1.0 by default and drop this >>>>> patch for the current merge window. >>>> >>>> I'd be fine with that, as long as we have a clear agreement on the >>>> impact of such a move. >>> >>> Yeah, that's what I was trying to figure out with my fancy tables. I might >>> be coming around more to your approach now, though. Ensuring the new->old >>> migration fails is a nice feature of this series. It would be good if >>> we could preserve that behavior without committing to a new userspace >>> interface, but I'm not sure how. Maybe I should just apologize for the >>> noise, and this patch be left as is... >> >> How about we don't decide now? >> >> I can remove this patch from the series so that the core stuff can make >> it into the arm64 tree ASAP (I think Catalin wants to queue something >> early this week so that it can hit Linus' tree before the end of the >> merge window), and then repost this single patch on its own (with fixes >> for the things that Christoffer found in his review) after -rc1. >> >> It leaves us time to haggle over the userspace ABI (which is >> realistically not going to affect anyone), and we get the core stuff in >> place for SoC vendors to start updating their firmware. >> > I agree, that's what I tried to suggest in my e-mail as well. Just > remember to tweak the previous patch to actually enable PSCI 1.0 by > default. Yup. I'll move the KVM_ARM_PSCI_LATEST hunk to that patch, and return it unconditionally from kvm_psci_version. M. -- Jazz is not dead. It just smells funny...