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=-8.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 1015EC43461 for ; Thu, 10 Sep 2020 15:38:20 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 918E12087C for ; Thu, 10 Sep 2020 15:38:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="MrUEXfr1"; 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 918E12087C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=itSubIFnrMLpx+WnmQuWSSxdc8AOT9pfJhgOszPXwMo=; b=MrUEXfr1tePwWsIXcu0vtGerb RITsT/YCO86lczEhs85dG9Ows+U5d5PrRT30pXjN2SwK3wFUt4jcMecA7vvAMD4jTZjansCQKhV2R nVKBrSnFd4vq43NxSfBYMH5f6MV3aZ7xiuLbsIGQodfX7FCz734UOzlZMe7y4zUWf2OaExRIMIhvi 9msKG6y+8dCsAVm0Q7A/n5mV6yJZQU8CtE30xcRqHU082dHWIzU2EQlV+XaZ1MvByBIJ409prKdar OwVEozSuVYe3kqQbSg8f7iWYHWAVJPxDy4mqg2CgScxnxZ2dVvn0z2HRT3iCmFW+4uksowA61FYjO 06vXp/cBw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kGOd3-0003wp-GO; Thu, 10 Sep 2020 15:36:53 +0000 Received: from mail-pf1-x441.google.com ([2607:f8b0:4864:20::441]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kGOcz-0003wK-TI for linux-arm-kernel@lists.infradead.org; Thu, 10 Sep 2020 15:36:51 +0000 Received: by mail-pf1-x441.google.com with SMTP id f18so4832475pfa.10 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=ncf+ZvYNtYbNxSb/BpU7GwrdllPrFE/tain8W47raFIzrWYmWBYgQXy0Exa8Ba+Hjg 4PBzcYYqtBgyyY7L3rCeykITl3mov+TemmIWtIB4he6w0MbxGmappENsTIiVnfC6UWDE XHGqg0gT4zj9AxevGsYVeY9cn0CnPSw4F5ibmhxhHkumCKPgvzG4WACqHaWhaQdCoR2Y QDUNY7PkCoiPz3UbZ/IvlH/OnHRQjm5jv43aCnfh54hvUyRTeSIiuK+2crAVnuxzrRJo tqUVopWvfgeRE3/+hEZmYDUElt6k1VHYSHKWI0YICv5MHR3BCix+W7UpwNn2j2m+RmDz PzPQ== X-Gm-Message-State: AOAM53154XAheMqUhdccKXYnWZaMWQdheGF14DiU5gkmN9Bmb/wTbib3 aUN8cyIjofv5Q+puVyba6W4HaA== 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-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200910_113650_242322_77BA349D X-CRM114-Status: GOOD ( 15.76 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 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 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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~ _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel