From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA970C433DB for ; Mon, 15 Mar 2021 14:38:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE8D96502B for ; Mon, 15 Mar 2021 14:38:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237288AbhCOOg4 (ORCPT ); Mon, 15 Mar 2021 10:36:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:32822 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236423AbhCOOgk (ORCPT ); Mon, 15 Mar 2021 10:36:40 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3788465012; Mon, 15 Mar 2021 14:36:39 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1lLoKg-001hZH-Dt; Mon, 15 Mar 2021 14:36:36 +0000 Date: Mon, 15 Mar 2021 14:36:33 +0000 Message-ID: <87czw0fpqm.wl-maz@kernel.org> From: Marc Zyngier To: Shameerali Kolothum Thodi Cc: Paolo Bonzini , Alexandru Elisei , Andre Przywara , Andrew Scull , Catalin Marinas , Christoffer Dall , Howard Zhang , Jia He , Mark Rutland , Quentin Perret , Suzuki K Poulose , Will Deacon , James Morse , Julien Thierry , "kernel-team@android.com" , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.cs.columbia.edu" , "kvm@vger.kernel.org" Subject: Re: [PATCH 7/8] KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility In-Reply-To: References: <87eegtzbch.wl-maz@kernel.org> <20210305185254.3730990-1-maz@kernel.org> <20210305185254.3730990-8-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: shameerali.kolothum.thodi@huawei.com, pbonzini@redhat.com, alexandru.elisei@arm.com, andre.przywara@arm.com, ascull@google.com, catalin.marinas@arm.com, christoffer.dall@arm.com, Howard.Zhang@arm.com, justin.he@arm.com, mark.rutland@arm.com, qperret@google.com, suzuki.poulose@arm.com, will@kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, kernel-team@android.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, 15 Mar 2021 12:55:42 +0000, Shameerali Kolothum Thodi wrote: > > > > > -----Original Message----- > > From: Marc Zyngier [mailto:maz@kernel.org] > > Sent: 05 March 2021 18:53 > > To: Paolo Bonzini > > Cc: Alexandru Elisei ; Andre Przywara > > ; Andrew Scull ; Catalin > > Marinas ; Christoffer Dall > > ; Howard Zhang ; Jia > > He ; Mark Rutland ; Quentin > > Perret ; Shameerali Kolothum Thodi > > ; Suzuki K Poulose > > ; Will Deacon ; James Morse > > ; Julien Thierry ; > > kernel-team@android.com; linux-arm-kernel@lists.infradead.org; > > kvmarm@lists.cs.columbia.edu; kvm@vger.kernel.org > > Subject: [PATCH 7/8] KVM: arm64: Workaround firmware wrongly advertising > > GICv2-on-v3 compatibility > > > > It looks like we have broken firmware out there that wrongly advertises > > a GICv2 compatibility interface, despite the CPUs not being able to deal > > with it. > > > > To work around this, check that the CPU initialising KVM is actually able > > to switch to MMIO instead of system registers, and use that as a > > precondition to enable GICv2 compatibility in KVM. > > > > Note that the detection happens on a single CPU. If the firmware is > > lying *and* that the CPUs are asymetric, all hope is lost anyway. > > > > Reported-by: Shameerali Kolothum Thodi > > > > Tested-by: Shameer Kolothum > > Signed-off-by: Marc Zyngier > > Is it possible to add stable tag for this? Looks like we do have > systems out there and reports issues. It is already merged. Which kernel versions do you need that for? In any case, please submit the backports, and I'll review them. Thanks, M. -- Without deviation from the norm, progress is not possible.