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=-4.0 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A7694C433FE for ; Tue, 8 Dec 2020 10:02:40 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 F1954217A0 for ; Tue, 8 Dec 2020 10:02:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F1954217A0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35622 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kmZpO-0007xm-JV for qemu-devel@archiver.kernel.org; Tue, 08 Dec 2020 05:02:38 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:52502) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kmZoW-0007VC-Sv for qemu-devel@nongnu.org; Tue, 08 Dec 2020 05:01:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:57220) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kmZoU-00053m-Qb for qemu-devel@nongnu.org; Tue, 08 Dec 2020 05:01:44 -0500 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 6E8F9217A0; Tue, 8 Dec 2020 10:01:40 +0000 (UTC) Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94) (envelope-from ) id 1kmZoQ-00H3In-Bb; Tue, 08 Dec 2020 10:01:38 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 08 Dec 2020 10:01:38 +0000 From: Marc Zyngier To: Haibo Xu Subject: Re: [PATCH v5 0/2] MTE support for KVM guest In-Reply-To: References: <20201119153901.53705-1-steven.price@arm.com> <20201119184248.4bycy6ouvaxqdiiy@kamzik.brq.redhat.com> <46fd98a2-ee39-0086-9159-b38c406935ab@arm.com> User-Agent: Roundcube Webmail/1.4.9 Message-ID: X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: haibo.xu@linaro.org, steven.price@arm.com, drjones@redhat.com, catalin.marinas@arm.com, quintela@redhat.com, richard.henderson@linaro.org, qemu-devel@nongnu.org, dgilbert@redhat.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, tglx@linutronix.de, will@kernel.org, Dave.Martin@arm.com, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Received-SPF: pass client-ip=198.145.29.99; envelope-from=maz@kernel.org; helo=mail.kernel.org X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Jones , lkml - Kernel Mailing List , Juan Quintela , Catalin Marinas , Richard Henderson , QEMU Developers , Steven Price , arm-mail-list , Thomas Gleixner , Will Deacon , kvmarm , "Dr. David Alan Gilbert" , Dave Martin Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020-12-08 09:51, Haibo Xu wrote: > On Mon, 7 Dec 2020 at 22:48, Steven Price wrote: >> [...] >> Sounds like you are making good progress - thanks for the update. Have >> you thought about how the PROT_MTE mappings might work if QEMU itself >> were to use MTE? My worry is that we end up with MTE in a guest >> preventing QEMU from using MTE itself (because of the PROT_MTE >> mappings). I'm hoping QEMU can wrap its use of guest memory in a >> sequence which disables tag checking (something similar will be needed >> for the "protected VM" use case anyway), but this isn't something I've >> looked into. > > As far as I can see, to map all the guest memory with PROT_MTE in VMM > is a little weird, and lots of APIs have to be changed to include this > flag. > IMHO, it would be better if the KVM can provide new APIs to load/store > the > guest memory tag which may make it easier to enable the Qemu migration > support. On what granularity? To what storage? How do you plan to synchronise this with the dirty-log interface? Thanks, M. -- Jazz is not dead. It just smells funny...