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=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 21E5AC169C4 for ; Mon, 11 Feb 2019 16:37:41 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E5367218D8 for ; Mon, 11 Feb 2019 16:37:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="tHjHoyJE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5367218D8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=sx9rbuKhHOXAykRL9ofggpYIMnXWDqNaJq1zF25VhSE=; b=tHjHoyJETIJ1H2cEGj0HM0qe7 rE8u7LW+FzLQ2E+zxdS4Hr/+4i88BCe6l5/St8itdGaSoLHrsyUnWuqd3hjZrXCWuiRaG7bLMJX3M gLEbPNPJCPmf2VH0lTh5lRP6ADACh7KGsVD8ZnXya6G2rFDHGcJHCKMsxDf7aPR5rst4lHg6HHLZ4 +Nch/omNVG0ydKHtpo57ZXuIzR/3dv447ruqmBcI3rGcHcYaQW5TRqs8sMzXPGPTEAfNghtMKrNDi X8e0yn8ZAKexhp6AM+iGpSM7Dnjv/fc1ZtmnycgRreo9qMti4HMytWl+NlJDGHJVLKW4ltVjOUT1b invw5zpog==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gtEaK-0004oa-J0; Mon, 11 Feb 2019 16:37:32 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gtEaE-0004mY-Eb for linux-arm-kernel@lists.infradead.org; Mon, 11 Feb 2019 16:37:29 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BA88F80D; Mon, 11 Feb 2019 08:37:25 -0800 (PST) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3A0BA3F675; Mon, 11 Feb 2019 08:37:24 -0800 (PST) Subject: Re: [PATCH] arm64/io: Don't use WZR in writel To: Marc Zyngier , AngeloGioacchino Del Regno , Will Deacon References: <68b71c15f32341468a868f6418e4fcb375bc49ba.camel@gmail.com> <20190211105755.GB30880@fuggles.cambridge.arm.com> <38d8965a-cd41-17cf-1b95-8dd58c079be4@arm.com> <874c702b8af760aa8fae38d478c79e3ecba00515.camel@gmail.com> <235d20ef-3054-69d9-975d-25aebf32aad3@arm.com> From: Robin Murphy Message-ID: <0dcc636d-236f-6211-4bf4-5c20f2aeefc2@arm.com> Date: Mon, 11 Feb 2019 16:37:22 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <235d20ef-3054-69d9-975d-25aebf32aad3@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190211_083726_757695_99758865 X-CRM114-Status: GOOD ( 18.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Catalin Marinas , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 11/02/2019 14:59, Marc Zyngier wrote: > On 11/02/2019 14:29, AngeloGioacchino Del Regno wrote: > > [...] > >> Also, just one more thing: yes this thing is going ARM64-wide and >> - from my findings - it's targeting certain Qualcomm SoCs, but... >> I'm not sure that only QC is affected by that, others may as well >> have the same stupid bug. >> > > At the moment, only QC SoCs seem to be affected, probably because > everyone else has debugged their hypervisor (or most likely doesn't > bother with shipping one). > > In all honesty, we need some information from QC here: which SoCs are > affected, what is the exact nature of the bug, can it be triggered from > EL0. Randomly papering over symptoms is not something I really like > doing, and is likely to generate problems on unaffected systems. And even if we *were* to just try papering over the observed extent of the issue, I'd still be inclined to confine it to arm-smmu.c where the impact is finite and minimal - of the 4 instances of writel(0) there, 3 of them don't care what the data is (so could just reuse the base register or similar) and the other one already has a zero in a GPR to hand by construction. Robin. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel