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=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 87A97C2D0E4 for ; Mon, 23 Nov 2020 12:18:31 +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 A639D20728 for ; Mon, 23 Nov 2020 12:18:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Tz653Fyf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A639D20728 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:39616 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1khAnd-0004z3-6L for qemu-devel@archiver.kernel.org; Mon, 23 Nov 2020 07:18:29 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35242) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1khAmQ-0004YI-U5 for qemu-devel@nongnu.org; Mon, 23 Nov 2020 07:17:15 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:29042) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1khAmO-0006vz-8q for qemu-devel@nongnu.org; Mon, 23 Nov 2020 07:17:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606133828; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=RSa6axA8acXlN/nHzWzCr89Oo5Z355MEuIWkDZmMlas=; b=Tz653FyfTnDjBoLsc/aAESJ5AzbrMifWYsujGFpquFrKizF5V+QoSMUpg9XEhqOySYM71g MMeo7/mx3qhmSR9S+hc5PP0blr65DavMGOH8nupLfNXZYVMfG973L+KMv9drBm213+DPJo Yod5eI1/lb3ycRRh8oZH1FqPBKASusM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-446-OjmxZbq0PEacCG4qpdCK8w-1; Mon, 23 Nov 2020 07:16:20 -0500 X-MC-Unique: OjmxZbq0PEacCG4qpdCK8w-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CBE4A8AEA40; Mon, 23 Nov 2020 12:16:17 +0000 (UTC) Received: from work-vm (ovpn-114-158.ams2.redhat.com [10.36.114.158]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CC31B5D9CC; Mon, 23 Nov 2020 12:16:13 +0000 (UTC) Date: Mon, 23 Nov 2020 12:16:11 +0000 From: "Dr. David Alan Gilbert" To: Peter Maydell Subject: Re: [PATCH v5 0/2] MTE support for KVM guest Message-ID: <20201123121611.GG3022@work-vm> References: <20201119153901.53705-1-steven.price@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: Mark Rutland , Andrew Jones , Haibo Xu , Suzuki K Poulose , QEMU Developers , Catalin Marinas , Juan Quintela , Richard Henderson , lkml - Kernel Mailing List , Steven Price , James Morse , arm-mail-list , Marc Zyngier , Thomas Gleixner , Will Deacon , kvmarm , Julien Thierry , Dave Martin Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Peter Maydell (peter.maydell@linaro.org) wrote: > On Thu, 19 Nov 2020 at 15:39, Steven Price wrote: > > This series adds support for Arm's Memory Tagging Extension (MTE) to > > KVM, allowing KVM guests to make use of it. This builds on the existing > > user space support already in v5.10-rc1, see [1] for an overview. > > > The change to require the VMM to map all guest memory PROT_MTE is > > significant as it means that the VMM has to deal with the MTE tags even > > if it doesn't care about them (e.g. for virtual devices or if the VMM > > doesn't support migration). Also unfortunately because the VMM can > > change the memory layout at any time the check for PROT_MTE/VM_MTE has > > to be done very late (at the point of faulting pages into stage 2). > > I'm a bit dubious about requring the VMM to map the guest memory > PROT_MTE unless somebody's done at least a sketch of the design > for how this would work on the QEMU side. Currently QEMU just > assumes the guest memory is guest memory and it can access it > without special precautions... Although that is also changing because of the encrypted/protected memory in things like SEV. Dave > thanks > -- PMM > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK