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=-8.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 17FEBC433E2 for ; Thu, 10 Sep 2020 15:37:35 +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 AC8E22087C for ; Thu, 10 Sep 2020 15:37:34 +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="GKVS6dK7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC8E22087C 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]:41450 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kGOdh-0005uu-Oj for qemu-devel@archiver.kernel.org; Thu, 10 Sep 2020 11:37:33 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43828) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kGOd1-0005Un-04 for qemu-devel@nongnu.org; Thu, 10 Sep 2020 11:36:51 -0400 Received: from mail-pg1-x544.google.com ([2607:f8b0:4864:20::544]:42556) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kGOcz-0001j9-0g for qemu-devel@nongnu.org; Thu, 10 Sep 2020 11:36:50 -0400 Received: by mail-pg1-x544.google.com with SMTP id m5so4421056pgj.9 for ; Thu, 10 Sep 2020 08:36:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=+NphFAz+bbbGOLPoViKWvapYAGN08JtmjYnLzZIKOxo=; b=GKVS6dK77bx/0jZLujlXrhsPEnEfKJjffubPbjyONPpDBt8aKV+/WikhO98lFUcqBg fknNlKQUgg0UcuMI4rvH6oQicx7azui4MD9+lZC8HzP87Vi4TbpnL5wsy+KtaRvsh2LC 56er56VCnPG1cwnDpL+FZu4sdinoEO6m0lag595MpAp4J3HgJxKTp/ftgfAClZ5xpG9e IGh4od5fDmnNKVRLqhekiwgA0ji4hW/l6rP7Ub0rdSacgB+QsToPnSt5fJEOro/bh0y5 tfWDEo6mZ+GCGnCsbnFxd4FHFyfq+MjpuaQe3PdZTqbmYXIk7DHpN7njMs/8y0p1rs/E iOwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=+NphFAz+bbbGOLPoViKWvapYAGN08JtmjYnLzZIKOxo=; b=ZzFt6290lsEhjrd7hevjaVUgS4rzkUbH5BAgnfmFQ/5ES5psbBkjh95DX3ONjg2WXg X+Bv6NU2ITHfEm4iAkaQ/uP96kmL1nL6djynxrKNF2QxIY+vqcDaPAiOS9mBzMBtMWLo S+Pe3zK3PZvBfQ+A+nzotTtOlXEt4l5CjwKkHhFun9/rUJTNLih1Cm1IrwRZchmq0+hU i4xBEOQR7lx/p2C71hPM4B1YVbU2Z+jEBxT/yVIKIGOrumYmDPDklsu9EfeKk2obRlqI lkKmNUoomuUakacQBW1e9CwZdStQR/P7+pBmFW6YyCkdamuBnsuZLBd7Q/pnwUyQe+VW O+Tw== X-Gm-Message-State: AOAM532tlNHQ53LCkyLbURudCKezM0/J+/2FWy6YgNTNsDuUEG20/AHg J7w5s6s4vpwK18upbLBHBpWQoQ== X-Google-Smtp-Source: ABdhPJxIZ4y5XTc4IrXUnrqP73HVFyQx7PSmSplY3yEEr1jJKnjEfVZhyGyxvSD2g5MX5wlOI8kPiA== X-Received: by 2002:aa7:8bd4:0:b029:13c:1611:6538 with SMTP id s20-20020aa78bd40000b029013c16116538mr6137309pfd.10.1599752207202; Thu, 10 Sep 2020 08:36:47 -0700 (PDT) Received: from [192.168.1.11] ([71.212.141.89]) by smtp.gmail.com with ESMTPSA id s187sm6690150pfc.134.2020.09.10.08.36.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Sep 2020 08:36:46 -0700 (PDT) Subject: Re: [PATCH v2 0/2] MTE support for KVM guest To: Steven Price , Catalin Marinas , Marc Zyngier , Will Deacon References: <20200904160018.29481-1-steven.price@arm.com> <8e661984-70bc-790c-8636-39dcd8b00131@linaro.org> <842807ac-562a-36ce-8061-aa323341b605@arm.com> From: Richard Henderson Message-ID: Date: Thu, 10 Sep 2020 08:36:44 -0700 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: <842807ac-562a-36ce-8061-aa323341b605@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::544; envelope-from=richard.henderson@linaro.org; helo=mail-pg1-x544.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: -56 X-Spam_score: -5.7 X-Spam_bar: ----- X-Spam_report: (-5.7 / 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, NICE_REPLY_A=-3.576, 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" , Peter Maydell , Haibo Xu , Suzuki K Poulose , qemu-devel@nongnu.org, Juan Quintela , linux-kernel@vger.kernel.org, Dave Martin , James Morse , Julien Thierry , Thomas Gleixner , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 9/10/20 3:24 AM, Steven Price wrote: > It is a shame, however I suspect this is because to use those instructions you > need to know the block size held in GMID_EL1. And at least in theory that could > vary between CPUs. Which is no different from having to read DCZID_EL0 in order to implement memset, in my opinion. But, whatever. > When we have some real hardware it would be worth profiling this. At the moment > I've no idea whether the kernel entry overhead would make such an interface > useful from a performance perspective or not. Yep. r~