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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 4AA75C2BA19 for ; Wed, 15 Apr 2020 13:23:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 254C42074F for ; Wed, 15 Apr 2020 13:23:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586957013; bh=OGayslbKapewkz6Bc/D54llvfloiJR74nivh6TEICRI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=r4nZ/9F4aiHy6STmmBqcGaZG+5Y50XKqDNsR1zld6gehS2uIEyJyTH9ppURzw8Nju /ZA4IMdi6K3jDOslLM+hdvaK7BEUhyyERBOfWDp86F29g509zXzzf79F1z07epPxeM kOlvD86L5lgBw2yk8NC4TGiQKD0aQyUAKRXUnWXo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2636022AbgDONXa (ORCPT ); Wed, 15 Apr 2020 09:23:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:58766 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2506354AbgDONWl (ORCPT ); Wed, 15 Apr 2020 09:22:41 -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 044662074F; Wed, 15 Apr 2020 13:22:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586956961; bh=OGayslbKapewkz6Bc/D54llvfloiJR74nivh6TEICRI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=vWzSb68xwI0CVPV2HbKsVakamCAe0aYTaQk3f9Bd14jLx9xVSI5wY/PSKQg033/D1 Syn57itZL+GUSzKjCjZA/qhALbKdusg/OVryuLj7PyY4VLJT3nL+W1XLMwwhNZ8eAC mIx0zlZq4xY2rpZXbHdJhktAh1vwHXBt+rt5MbdM= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jOhzz-003XXy-2k; Wed, 15 Apr 2020 14:22:39 +0100 Date: Wed, 15 Apr 2020 14:22:37 +0100 From: Marc Zyngier To: Suzuki K Poulose Cc: will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, mark.rutland@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, saiprakash.ranjan@codeaurora.org, dianders@chromium.org, kernel-team@android.com Subject: Re: [PATCH 3/8] arm64: cpufeature: Add CPU capability for AArch32 EL1 support Message-ID: <20200415142237.651114f7@why> In-Reply-To: <7978a5a9-463e-5e96-7ea9-d8472b7b051c@arm.com> References: <20200414213114.2378-1-will@kernel.org> <20200414213114.2378-4-will@kernel.org> <20200415101444.GC12621@willie-the-truck> <7978a5a9-463e-5e96-7ea9-d8472b7b051c@arm.com> Organization: Approximate X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: suzuki.poulose@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, mark.rutland@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, saiprakash.ranjan@codeaurora.org, dianders@chromium.org, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 15 Apr 2020 14:15:51 +0100 Suzuki K Poulose wrote: > On 04/15/2020 11:14 AM, Will Deacon wrote: > > On Wed, Apr 15, 2020 at 11:13:54AM +0100, Suzuki K Poulose wrote: > >> On 04/14/2020 10:31 PM, Will Deacon wrote: > >>> Although we emit a "SANITY CHECK" warning and taint the kernel if we > >>> detect a CPU mismatch for AArch32 support at EL1, we still online the > >>> CPU with disastrous consequences for any running 32-bit VMs. > >>> > >>> Introduce a capability for AArch32 support at EL1 so that late onlining > >>> of incompatible CPUs is forbidden. > >>> > >>> Signed-off-by: Will Deacon > >> > >> One of the other important missing sanity check for KVM is the VMID width > >> check. I will code something up. > > > > Cheers! Do we handle things like the IPA size already? > > Good point. No, we don't. I will include this too. There is also the question of the ARMv8.5-GTG extension. I have a patch that treats it as non-strict, but that approach would fail with KVM if we online a late CPU without support for the right page size at S2. M. -- Jazz is not dead. It just smells funny...