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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,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 77026C63697 for ; Thu, 19 Nov 2020 16:03:29 +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 D20DC206D5 for ; Thu, 19 Nov 2020 16:03:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="yd+dDD5s" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D20DC206D5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:52660 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kfmP9-0007dJ-QJ for qemu-devel@archiver.kernel.org; Thu, 19 Nov 2020 11:03:27 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:43254) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kfm8D-0006v5-Oq for qemu-devel@nongnu.org; Thu, 19 Nov 2020 10:45:59 -0500 Received: from mail-ej1-x642.google.com ([2a00:1450:4864:20::642]:33509) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kfm8A-0003hD-Vw for qemu-devel@nongnu.org; Thu, 19 Nov 2020 10:45:57 -0500 Received: by mail-ej1-x642.google.com with SMTP id 7so8586538ejm.0 for ; Thu, 19 Nov 2020 07:45:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=45e0VgNBbvYnn00UZUV/75YCSw3FH7awq7f1yZmGnIA=; b=yd+dDD5sCyrZHocr/ApiPlXl8Vodq1TGFhwOHBFO8f6IhOtQwsioH35yKK7UONHdH5 TitQsHK6lA8fYRer+u4YnGR1szOVLD1j7PQF214pS7Ce6d2fyplN4xEO63Z0fMf+eo5F +D7s7HaiYkc1/gXas5BwAL1r0YHLx3mzjYUBJ3VVkquNN71MOzWoSStwN2EHOedXyFIr Ro9F1WQY4P81qMbCgNbC/Ev/imG/WmHAd4i9hs/qUPN2WgCzFgjiXtJGT7k0K/b08nuD 3c0yMqnN3mBXKuySRziRYw0DuO4lMXk7AGWqZHMjPIhhmOGjOj8ao0ADRhK4NexKY+xa jw1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=45e0VgNBbvYnn00UZUV/75YCSw3FH7awq7f1yZmGnIA=; b=nIhH73G3a+20nm5xeODLx7zVWtC2cRb7GkhvWSR337xBK0KNEsyYdTsBZNJsnftOfT cKIgNPPIMP6KCmOpsirr2gMleHoMP4Jf23tTEDMjnodLMBIGHqV3uzNm10CJ0d9YCjJA DRdDRuh2YQYLnv9cJ9fY4KcHfAhJhBeH6qVEv4jYkHxH7OAGsNWk0q4xX518nkHSdiLM BMfj1vk9sBgIv7O+oCu57krPyRvUldBIxk3i41SLQPGhCy2Tpe2L+oBGzjXKPgDCpyYN iLWk9Mw18Wrdk3oEQ/6x/i+IwcRGpjfN2hlrfMsqHygC8Q9ezl+19Jhpg9H2++VAe/Bv LsXw== X-Gm-Message-State: AOAM5330NkGkUm7frBU3YwEV1cT2YZwsbwchxkpTmtMKMnFtYfi2Uh8B nELi+2GNn3XSXpFZiDaxpDNY1ex7jcP8rJvswT5wcw== X-Google-Smtp-Source: ABdhPJwerYJJayn5lWpV2YdXL6eFXH1urcMvWimgMV3daCqtLlvmtu4pEM2RJAtpVko5A8pZi6+uXKrICI4dBfpc4FU= X-Received: by 2002:a17:906:6896:: with SMTP id n22mr30365553ejr.56.1605800751989; Thu, 19 Nov 2020 07:45:51 -0800 (PST) MIME-Version: 1.0 References: <20201119153901.53705-1-steven.price@arm.com> In-Reply-To: <20201119153901.53705-1-steven.price@arm.com> From: Peter Maydell Date: Thu, 19 Nov 2020 15:45:40 +0000 Message-ID: Subject: Re: [PATCH v5 0/2] MTE support for KVM guest To: Steven Price Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2a00:1450:4864:20::642; envelope-from=peter.maydell@linaro.org; helo=mail-ej1-x642.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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 , "Dr. David Alan Gilbert" , Andrew Jones , Haibo Xu , Suzuki K Poulose , QEMU Developers , Catalin Marinas , Juan Quintela , Richard Henderson , lkml - Kernel Mailing List , Dave Martin , James Morse , arm-mail-list , Marc Zyngier , Thomas Gleixner , Will Deacon , kvmarm , Julien Thierry Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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... thanks -- PMM