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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 754F4C4361B for ; Wed, 16 Dec 2020 10:24:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23C5D22D49 for ; Wed, 16 Dec 2020 10:24:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726146AbgLPKYN (ORCPT ); Wed, 16 Dec 2020 05:24:13 -0500 Received: from foss.arm.com ([217.140.110.172]:43876 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725820AbgLPKYN (ORCPT ); Wed, 16 Dec 2020 05:24:13 -0500 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 B934F1FB; Wed, 16 Dec 2020 02:23:27 -0800 (PST) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 03FF13F66B; Wed, 16 Dec 2020 02:23:25 -0800 (PST) Subject: Re: [PATCH v5 0/2] MTE support for KVM guest To: Haibo Xu Cc: Marc Zyngier , Andrew Jones , Catalin Marinas , Juan Quintela , Richard Henderson , QEMU Developers , "Dr. David Alan Gilbert" , arm-mail-list , kvmarm , Thomas Gleixner , Will Deacon , Dave Martin , lkml - Kernel Mailing List References: <20201119153901.53705-1-steven.price@arm.com> <20201119184248.4bycy6ouvaxqdiiy@kamzik.brq.redhat.com> <46fd98a2-ee39-0086-9159-b38c406935ab@arm.com> From: Steven Price Message-ID: <29a7229d-a1ff-98a5-3007-1addcc85aa04@arm.com> Date: Wed, 16 Dec 2020 10:22:52 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16/12/2020 07:31, Haibo Xu wrote: [...] > Hi Steve, Hi Haibo > I have finished verifying the POC on a FVP setup, and the MTE test case can > be migrated from one VM to another successfully. Since the test case is very > simple which just maps one page with MTE enabled and does some memory > access, so I can't say it's OK for other cases. That's great progress. > > BTW, I noticed that you have sent out patch set v6 which mentions that mapping > all the guest memory with PROT_MTE was not feasible. So what's the plan for the > next step? Will new KVM APIs which can facilitate the tag store and recover be > available? I'm currently rebasing on top of the KASAN MTE patch series. My plan for now is to switch back to not requiring the VMM to supply PROT_MTE (so KVM 'upgrades' the pages as necessary) and I'll add an RFC patch on the end of the series to add an KVM API for doing bulk read/write of tags. That way the VMM can map guest memory without PROT_MTE (so device 'DMA' accesses will be unchecked), and use the new API for migration. Thanks, Steve