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=-0.8 required=3.0 tests=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 225B7ECDE3D for ; Fri, 19 Oct 2018 11:47:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CC1A4205F4 for ; Fri, 19 Oct 2018 11:47:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CC1A4205F4 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-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727427AbeJSTxH (ORCPT ); Fri, 19 Oct 2018 15:53:07 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:50984 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726784AbeJSTxH (ORCPT ); Fri, 19 Oct 2018 15:53:07 -0400 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 6FB9A80D; Fri, 19 Oct 2018 04:47:23 -0700 (PDT) Received: from [10.1.196.62] (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 015F93F71D; Fri, 19 Oct 2018 04:47:17 -0700 (PDT) Subject: Re: [PATCH v5 11/17] arm64: docs: document pointer authentication To: Catalin Marinas , Kristina Martsenko Cc: Ramana Radhakrishnan , "linux-arm-kernel@lists.infradead.org" , Mark Rutland , "linux-arch@vger.kernel.org" , Andrew Jones , Jacob Bramley , Arnd Bergmann , Ard Biesheuvel , Adam Wallis , Suzuki Poulose , Will Deacon , Christoffer Dall , "kvmarm@lists.cs.columbia.edu" , Amit Kachhap , Dave P Martin , "linux-kernel@vger.kernel.org" , Kees Cook References: <20181005084754.20950-1-kristina.martsenko@arm.com> <20181005084754.20950-12-kristina.martsenko@arm.com> <9acb0cd2-66b0-1c41-b1a8-7c70608e9a9b@foss.arm.com> <7b0de19b-45b9-f4df-25d1-c7e80fab49dc@arm.com> <20181019113556.ljbdmjo5pdw7muvz@mbp> From: Marc Zyngier Openpgp: preference=signencrypt Autocrypt: addr=marc.zyngier@arm.com; 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Linux aarch64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181019113556.ljbdmjo5pdw7muvz@mbp> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/10/18 12:35, Catalin Marinas wrote: > On Tue, Oct 16, 2018 at 05:14:39PM +0100, Kristina Martsenko wrote: >> On 05/10/2018 10:04, Ramana Radhakrishnan wrote: >>> On 05/10/2018 09:47, Kristina Martsenko wrote: [...] >> The other option is to turn off trapping entirely. However then on a >> big.LITTLE system with mismatched pointer authentication support >> instructions will work intermittently on some CPUs but not others. > > That's another case but let's assume we never see such configurations ;). I'd like to put it on the record that I'm not willing to support such a configuration. So my ask is that if we detect a system where only some of the CPUs have pointer authentication support, we either: 1) prevent some of the CPUs from booting (that's harsh) 2) disable KVM (that's easy) I'm perfectly happy with (2). Thanks, M. -- Jazz is not dead. It just smells funny... From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH v5 11/17] arm64: docs: document pointer authentication Date: Fri, 19 Oct 2018 12:47:16 +0100 Message-ID: <05738017-5886-fe4d-e8fd-a834da6b1576@arm.com> References: <20181005084754.20950-1-kristina.martsenko@arm.com> <20181005084754.20950-12-kristina.martsenko@arm.com> <9acb0cd2-66b0-1c41-b1a8-7c70608e9a9b@foss.arm.com> <7b0de19b-45b9-f4df-25d1-c7e80fab49dc@arm.com> <20181019113556.ljbdmjo5pdw7muvz@mbp> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181019113556.ljbdmjo5pdw7muvz@mbp> Content-Language: en-GB Sender: linux-kernel-owner@vger.kernel.org To: Catalin Marinas , Kristina Martsenko Cc: Ramana Radhakrishnan , "linux-arm-kernel@lists.infradead.org" , Mark Rutland , "linux-arch@vger.kernel.org" , Andrew Jones , Jacob Bramley , Arnd Bergmann , Ard Biesheuvel , Adam Wallis , Suzuki Poulose , Will Deacon , Christoffer Dall , "kvmarm@lists.cs.columbia.edu" , Amit Kachhap , Dave P Martin , "linux-kernel@vger.kernel.org" , Kees Cook List-Id: linux-arch.vger.kernel.org On 19/10/18 12:35, Catalin Marinas wrote: > On Tue, Oct 16, 2018 at 05:14:39PM +0100, Kristina Martsenko wrote: >> On 05/10/2018 10:04, Ramana Radhakrishnan wrote: >>> On 05/10/2018 09:47, Kristina Martsenko wrote: [...] >> The other option is to turn off trapping entirely. However then on a >> big.LITTLE system with mismatched pointer authentication support >> instructions will work intermittently on some CPUs but not others. > > That's another case but let's assume we never see such configurations ;). I'd like to put it on the record that I'm not willing to support such a configuration. So my ask is that if we detect a system where only some of the CPUs have pointer authentication support, we either: 1) prevent some of the CPUs from booting (that's harsh) 2) disable KVM (that's easy) I'm perfectly happy with (2). Thanks, M. -- Jazz is not dead. It just smells funny... From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:50984 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726784AbeJSTxH (ORCPT ); Fri, 19 Oct 2018 15:53:07 -0400 Subject: Re: [PATCH v5 11/17] arm64: docs: document pointer authentication References: <20181005084754.20950-1-kristina.martsenko@arm.com> <20181005084754.20950-12-kristina.martsenko@arm.com> <9acb0cd2-66b0-1c41-b1a8-7c70608e9a9b@foss.arm.com> <7b0de19b-45b9-f4df-25d1-c7e80fab49dc@arm.com> <20181019113556.ljbdmjo5pdw7muvz@mbp> From: Marc Zyngier Message-ID: <05738017-5886-fe4d-e8fd-a834da6b1576@arm.com> Date: Fri, 19 Oct 2018 12:47:16 +0100 MIME-Version: 1.0 In-Reply-To: <20181019113556.ljbdmjo5pdw7muvz@mbp> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Catalin Marinas , Kristina Martsenko Cc: Ramana Radhakrishnan , "linux-arm-kernel@lists.infradead.org" , Mark Rutland , "linux-arch@vger.kernel.org" , Andrew Jones , Jacob Bramley , Arnd Bergmann , Ard Biesheuvel , Adam Wallis , Suzuki Poulose , Will Deacon , Christoffer Dall , "kvmarm@lists.cs.columbia.edu" , Amit Kachhap , Dave P Martin , "linux-kernel@vger.kernel.org" , Kees Cook Message-ID: <20181019114716.O4C3h6BdEnv_Pb2EkGU07_0_EBb77KRcG1LCmzmmaaw@z> On 19/10/18 12:35, Catalin Marinas wrote: > On Tue, Oct 16, 2018 at 05:14:39PM +0100, Kristina Martsenko wrote: >> On 05/10/2018 10:04, Ramana Radhakrishnan wrote: >>> On 05/10/2018 09:47, Kristina Martsenko wrote: [...] >> The other option is to turn off trapping entirely. However then on a >> big.LITTLE system with mismatched pointer authentication support >> instructions will work intermittently on some CPUs but not others. > > That's another case but let's assume we never see such configurations ;). I'd like to put it on the record that I'm not willing to support such a configuration. So my ask is that if we detect a system where only some of the CPUs have pointer authentication support, we either: 1) prevent some of the CPUs from booting (that's harsh) 2) disable KVM (that's easy) I'm perfectly happy with (2). Thanks, M. -- Jazz is not dead. It just smells funny... From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Fri, 19 Oct 2018 12:47:16 +0100 Subject: [PATCH v5 11/17] arm64: docs: document pointer authentication In-Reply-To: <20181019113556.ljbdmjo5pdw7muvz@mbp> References: <20181005084754.20950-1-kristina.martsenko@arm.com> <20181005084754.20950-12-kristina.martsenko@arm.com> <9acb0cd2-66b0-1c41-b1a8-7c70608e9a9b@foss.arm.com> <7b0de19b-45b9-f4df-25d1-c7e80fab49dc@arm.com> <20181019113556.ljbdmjo5pdw7muvz@mbp> Message-ID: <05738017-5886-fe4d-e8fd-a834da6b1576@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 19/10/18 12:35, Catalin Marinas wrote: > On Tue, Oct 16, 2018 at 05:14:39PM +0100, Kristina Martsenko wrote: >> On 05/10/2018 10:04, Ramana Radhakrishnan wrote: >>> On 05/10/2018 09:47, Kristina Martsenko wrote: [...] >> The other option is to turn off trapping entirely. However then on a >> big.LITTLE system with mismatched pointer authentication support >> instructions will work intermittently on some CPUs but not others. > > That's another case but let's assume we never see such configurations ;). I'd like to put it on the record that I'm not willing to support such a configuration. So my ask is that if we detect a system where only some of the CPUs have pointer authentication support, we either: 1) prevent some of the CPUs from booting (that's harsh) 2) disable KVM (that's easy) I'm perfectly happy with (2). Thanks, M. -- Jazz is not dead. It just smells funny...