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 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 8DD68C433B4 for ; Mon, 12 Apr 2021 09:11:25 +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 2C7B26008E for ; Mon, 12 Apr 2021 09:11:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C7B26008E 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]:48588 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lVsbM-0005fM-2i for qemu-devel@archiver.kernel.org; Mon, 12 Apr 2021 05:11:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42414) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lVsYz-0004cy-77 for qemu-devel@nongnu.org; Mon, 12 Apr 2021 05:08:57 -0400 Received: from mail-ej1-x631.google.com ([2a00:1450:4864:20::631]:43782) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lVsYj-0001X2-7F for qemu-devel@nongnu.org; Mon, 12 Apr 2021 05:08:52 -0400 Received: by mail-ej1-x631.google.com with SMTP id l4so18983512ejc.10 for ; Mon, 12 Apr 2021 02:08:39 -0700 (PDT) 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=HkL117L0NGX6ld7vF/27lucS+P6ofJVh50IK/9dVZXg=; b=eXjMVVuYHQbvz28PTDJbdHk4axbRiQyc1mu+UL4fxTMGZ7f1CrGHdxoVG7dPv21u10 XFW2dgK4UDy93LdwTaKJxh7I3oY/EkVc4+eNhXtjvwV8WaqK1QmJlL1Kqyqo9zXrendn MygPYsQZl93nSsFSXez4uC+rIYmMXV3F51hAona1mdp4k8noQGKs5SBBtopV+jmMXB/L oc5bVUY8SyQlrcYsPLxnEOtYawayXB1+wWR3mNycsSyuF20sjs2gK4aNxtOoJxI1eMqR cqMv/59qF4ugzhr0ctc/+GDIuerUdHKfntY0QCVdRLt1COfRy4BefWXGfCTPIhQM0FyX srcA== 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=HkL117L0NGX6ld7vF/27lucS+P6ofJVh50IK/9dVZXg=; b=W7DIB+pk7V6MEwXvo8HaPui84z4gl3d5vqcLlq7fsctheYz2z+nH5B9rEEnlZEXkTa qOXP/LtF/x7aOAvPPLQ6RQeQCbCypjtTIjDT70L5Xss3iBepKfQ+5bwZ/vMnIlymeVox LaIDarbYYmkkIL2cgU6ex6c4qkTxPoT95MkQ2hx9Tt52iX1i2xCQkUDHmsGv8jh39Pua O04ADEarE3Qz2Vohk+hLrpd634J1Xs2U0tvk5vZZvIrx0MB1NQLufQs0WDM+V1Zei9gf TzoHFm9DOvPAAhn7T73DRNteK/FlrCT0U3hCDQ8jpXxYtk+KPIgOCiT26jEjeZmZYg4E +vHg== X-Gm-Message-State: AOAM531z7HfmHOabIRedFl/VUboaeXCbl2UMVVJegIuf8/ZcetbI35v4 pgja7ISIlUcvBXSRBk9uDUSJHJ0RLIK+2j8bOGAC2w== X-Google-Smtp-Source: ABdhPJxtZ2OWrAp20lT9cXhhGdBrO7E3xfegzrKgmu7/iA+gYaH7QMLu42yi4trTjglsI+TzsmZMGhuLAz7lDHkYIaQ= X-Received: by 2002:a17:906:1dd3:: with SMTP id v19mr26216693ejh.4.1618218518196; Mon, 12 Apr 2021 02:08:38 -0700 (PDT) MIME-Version: 1.0 References: <20210320220949.40965-1-mrolnik@gmail.com> <20210320220949.40965-2-mrolnik@gmail.com> In-Reply-To: From: Peter Maydell Date: Mon, 12 Apr 2021 10:07:54 +0100 Message-ID: Subject: Re: [PATCH 1/1] Set TARGET_PAGE_BITS to be 10 instead of 8 bits To: Richard Henderson Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2a00:1450:4864:20::631; envelope-from=peter.maydell@linaro.org; helo=mail-ej1-x631.google.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, 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=unavailable 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: Richard Henderson , Michael Rolnik , "Dr. David Alan Gilbert" , QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sun, 11 Apr 2021 at 16:15, Richard Henderson wrote: > > On 4/10/21 10:24 AM, Michael Rolnik wrote: > > Please review. > > > The first 256b is i/o, the next 768b are ram. But having changed the page > size, it should mean that the first 1k are now treated as i/o. > > We do have a path by which instructions in i/o pages can be executed. This > happens on some ARM board setups during cold boot. But we do not save those > translations, so they run much much slower than it should. > > But perhaps in the case of AVR, "much much slower" really isn't visible? > > In general, I think changing the page size is wrong. I also assume that > migration is largely irrelevant to this target. Migration is irrelevant, but every target benefits from snapshot save-and-restore, and I think that uses the same codepaths ? -- PMM