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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 DEF6BC43381 for ; Wed, 17 Mar 2021 14:40:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A06C864F26 for ; Wed, 17 Mar 2021 14:40:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231952AbhCQOk1 (ORCPT ); Wed, 17 Mar 2021 10:40:27 -0400 Received: from foss.arm.com ([217.140.110.172]:34576 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232228AbhCQOkN (ORCPT ); Wed, 17 Mar 2021 10:40:13 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AE30EED1; Wed, 17 Mar 2021 07:40:09 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 08F8F3F792; Wed, 17 Mar 2021 07:40:08 -0700 (PDT) Date: Wed, 17 Mar 2021 14:40:04 +0000 From: Lorenzo Pieralisi To: Marc Zyngier Cc: linux-kernel@vger.kernel.org, LAKML , KVM Subject: Re: [PATCH v3 1/1] irqchip/gic-v4.1: Disable vSGI upon (GIC CPUIF < v4.1) detection Message-ID: <20210317144004.GA6593@e121166-lin.cambridge.arm.com> References: <20210302102744.12692-1-lorenzo.pieralisi@arm.com> <20210317100719.3331-1-lorenzo.pieralisi@arm.com> <20210317100719.3331-2-lorenzo.pieralisi@arm.com> <87blbhj2q3.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87blbhj2q3.wl-maz@kernel.org> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 17, 2021 at 02:04:36PM +0000, Marc Zyngier wrote: > Hi Lorenzo, > > Wed, 17 Mar 2021 10:07:19 +0000, > Lorenzo Pieralisi wrote: > > > > GIC CPU interfaces versions predating GIC v4.1 were not built to > > accommodate vINTID within the vSGI range; as reported in the GIC > > specifications (8.2 "Changes to the CPU interface"), it is > > CONSTRAINED UNPREDICTABLE to deliver a vSGI to a PE with > > ID_AA64PFR0_EL1.GIC < b0011. > > > > Check the GIC CPUIF version by reading the SYS_ID_AA64_PFR0_EL1. > > > > Disable vSGIs if a CPUIF version < 4.1 is detected to prevent using > > vSGIs on systems where they may misbehave. > > > > Signed-off-by: Lorenzo Pieralisi > > Cc: Marc Zyngier > > Does it need to go in as a fix? or can it just be pushed into 5.13? > Given that there is no such HW in the wild just yet, I'm inclined to > do the latter... I agree with you; it is to make the driver/vgic robust against HW misconfigurations (because that's what they are and I am not aware of any _existing_ HW with such a misconfiguration - yet), 5.13 will perfectly do. Thanks a lot. Lorenzo