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=-13.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SIGNED_OFF_BY,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 3F9D1C433E7 for ; Tue, 20 Oct 2020 01:28:02 +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 68C3F22244 for ; Tue, 20 Oct 2020 01:28:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="QiVdwyQk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 68C3F22244 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]:46870 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kUgRU-0006fp-8p for qemu-devel@archiver.kernel.org; Mon, 19 Oct 2020 21:28:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46872) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kUgQp-0006GC-0G for qemu-devel@nongnu.org; Mon, 19 Oct 2020 21:27:19 -0400 Received: from mail-pj1-x1042.google.com ([2607:f8b0:4864:20::1042]:53102) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kUgQm-0000Ts-G8 for qemu-devel@nongnu.org; Mon, 19 Oct 2020 21:27:18 -0400 Received: by mail-pj1-x1042.google.com with SMTP id gm14so27865pjb.2 for ; Mon, 19 Oct 2020 18:27:15 -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=QLJDrFxDj4IHa3Ky07kLPgy3yaagFUrARkpDuqHrbDk=; b=QiVdwyQkDY8uXkUFV1GsBsaDSFeC/RRuYVOwhLUtTjxsGzILxdUFe33j9i9M1Ml8ZQ wPERq4dftbdoUFpWCUJL3o+/SMohhFhTiJgQAknSo3CaKiz5ruivQhFe3O2aIhPIxl1C rbeJPK3ftOPWjBb0zrsrmzNBsI/2AQSC7od8YewF9FIfeeeEJdcLb6g8RrcOYkvcHsOe u2wnoOccAJUZO/LWtKopjgs6Y3YkuFrcN8CtvvdxDyLTlvKO6Vw8I+F6K9d05H7+mP6b te6PLrdblFYCTQb6cVcbSgXDPCem8jcvT5Y49UpkXXrEPw1cu4cvtalLlc8vMILoqevo SkfA== 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=QLJDrFxDj4IHa3Ky07kLPgy3yaagFUrARkpDuqHrbDk=; b=tzfTo09tczN/fB+A4u54FlhuzqezGflhkisahrf2+FhYqiMVWh84F9+OqwHo/SfJSX y2xtyeKWYtAQ/haTBHrDKmDFFALE/jhpwAAXDOeP0PTjxnAqWiDJiVyRLkQ9YujwEiUj YlV1rOb67kBg4nkMjbKZWzKvRmBCFE+aFW/VKK7cZuxBcrZM9a5QEVNU0apVMFf6XzMk gO6jdcsFXtcaQGvW89u5suV+Kf8qDe5dKt+7vLrTRYw7fbfVolflwLLcidcMw9XHJgmx uAD9/voxG3eHWfBkS4x+fZpFUhE6jJFlJ81EBHbMajS+XMX3CS+VswwP5Y/JcK+i3sGe IJRw== X-Gm-Message-State: AOAM530i7asy3sXRtIYwKGJ1q51f9+yulp/6KPp+pfIwdW+wr90oBMXa Te3VIPidg9y4IdG6Kxb3aL6YZw== X-Google-Smtp-Source: ABdhPJzpmgUPDZaKWmKRGPaz/xsyyRbeRyVog1lEumgNSA0g2frtWdmNUdsoWQVJ0mrGJjzzr8czsg== X-Received: by 2002:a17:902:ee52:b029:d5:dd2d:df92 with SMTP id 18-20020a170902ee52b02900d5dd2ddf92mr504034plo.37.1603157234697; Mon, 19 Oct 2020 18:27:14 -0700 (PDT) Received: from [192.168.1.11] ([71.212.141.89]) by smtp.gmail.com with ESMTPSA id nm11sm93064pjb.24.2020.10.19.18.27.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 19 Oct 2020 18:27:13 -0700 (PDT) Subject: Re: [PATCH v2 7/9] tcg: mirror mapping RWX pages for iOS optional To: Joelle van Dyne , qemu-devel@nongnu.org References: <20201019013928.72770-1-j@getutm.app> <20201019013928.72770-8-j@getutm.app> From: Richard Henderson Message-ID: Date: Mon, 19 Oct 2020 18:27:11 -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: <20201019013928.72770-8-j@getutm.app> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::1042; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x1042.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, NICE_REPLY_A=-0.001, 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: Paolo Bonzini , Laurent Vivier , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10/18/20 6:39 PM, Joelle van Dyne wrote: > From: osy > > This allows jailbroken devices with entitlements to switch the option off. > > Signed-off-by: Joelle van Dyne > --- I can guess why this performs better: half the page table entries and thus half the tlb entries required. Which for any non-trivially sized jit arena is going to add up. [*] In line with my comments re patch 6, and making this feature available everywhere (or at least non-windows), the ifdefs would go away. I might also suggest default on for CONFIG_DEBUG_TCG and otherwise default off (when the host os allows). r~ * Which makes me wonder how much we should use the "const TranslationBlock *" version of that structure in the rx mapping, so that we're using a tlb entry that is more likely to be present, since we've just branched from the code (or just about to branch to the code) on the same page.