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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 F0036C433F5 for ; Tue, 7 Sep 2021 12:52:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9A4D6109D for ; Tue, 7 Sep 2021 12:52:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344511AbhIGMxQ (ORCPT ); Tue, 7 Sep 2021 08:53:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232913AbhIGMxK (ORCPT ); Tue, 7 Sep 2021 08:53:10 -0400 Received: from mail-wm1-x336.google.com (mail-wm1-x336.google.com [IPv6:2a00:1450:4864:20::336]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F37AC061575 for ; Tue, 7 Sep 2021 05:52:04 -0700 (PDT) Received: by mail-wm1-x336.google.com with SMTP id c8-20020a7bc008000000b002e6e462e95fso1751703wmb.2 for ; Tue, 07 Sep 2021 05:52:04 -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=wovuk/YJ4ZzxTgEM/WTOLuXvX25Yjntehj+QQBKkeck=; b=K76J8SyL+1jOA8UfApaeCDLxztO+LZ8h4Nx9PbBNYsr+paYOiEqK9OIn2ldFs+7jzC YEttCcgHMvN3u1/0AVrT+pgr4UyIN1fY0TWDjPrCpijQjVadGHS6qCJxNRMRydMpbkpe vklWQApsPXT85SJjEbrr4whDc3f1MVpzfNFQ7ks6sAhOJgokRCkk4axYWPqo9Gq8UOEF jTjR2dGFy5N5XLZ6yElzSZACsjQFOUeQqAW9Htb6vbipQslVAql4L3mbDnFLy8aIY//W PjA+HrI7kjxQ45KDdftoS1ecm4AaCZ37azSPgx8Nz0Y44zMdL0lD1CCofVVAd3cPXEKz fYsg== 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=wovuk/YJ4ZzxTgEM/WTOLuXvX25Yjntehj+QQBKkeck=; b=s09m8162lysf2dMi2graipTo2psQGi9nlWCS9nDaAJt3AHoulTwe+KFGkmRXQ1cgMf vseQ7nUc0PGvNSysysnFDwFTWafG5lbYdmqmJPXPa8OxeY7kdXruylCAB38cAcpDtNYk cgCf7Y70GRSyyTkLANBf9EkjxsVQKcrn8nhtVu8ZSsPCcQ0ny56eXsKEtTKdgyS41SeV ZE6+BYpWr+d1/yDgWajM5LGziBE4tijRD0gyzybxsAsc/FQHLpTpWwdPG9WdRXrn6lI6 QjHglmztHym2m/4VOVzwEZ2w0OyMR6FrMMjxgWSzTVg2ZAT+rqDAf4fRB1PBj7cZIax+ Hp2Q== X-Gm-Message-State: AOAM530Fbf7fahEWM1btiKTuZcgr8lTjw31nQjoN5J5ciXvOHbT0dK7X BVPQJb6GjqirU1hK4X+TAfOc8edgLbsbkIL8Q4rgU6jdbXc= X-Google-Smtp-Source: ABdhPJzN1k5vdacf8pXMz+PcUOlliO8oElhlm9+Wxx2tO4deEucQ0q5nA8yws4gRRyTPG0HwiEfKkeMxeGbJ78NSUUM= X-Received: by 2002:a05:600c:4fcd:: with SMTP id o13mr3850083wmq.32.1631019122955; Tue, 07 Sep 2021 05:52:02 -0700 (PDT) MIME-Version: 1.0 References: <20210822144441.1290891-1-maz@kernel.org> <20210822144441.1290891-4-maz@kernel.org> In-Reply-To: <20210822144441.1290891-4-maz@kernel.org> From: Peter Maydell Date: Tue, 7 Sep 2021 13:51:13 +0100 Message-ID: Subject: Re: [PATCH 3/3] docs/system/arm/virt: Fix documentation for the 'highmem' option To: Marc Zyngier Cc: QEMU Developers , Andrew Jones , Eric Auger , kvmarm , kvm-devel , Android Kernel Team Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Sun, 22 Aug 2021 at 15:45, Marc Zyngier wrote: > > The documentation for the 'highmem' option indicates that it controls > the placement of both devices and RAM. The actual behaviour of QEMU > seems to be that RAM is allowed to go beyond the 4GiB limit, and > that only devices are constraint by this option. > > Align the documentation with the actual behaviour. I think it would be better to align the behaviour with the documentation. The intent of 'highmem' is to allow a configuration for use with guests that can't address more than 32 bits (originally, 32-bit guests without LPAE support compiled in). It seems like a bug that we allow the user to specify more RAM than will fit into that 32-bit range. We should instead make QEMU exit with an error if the user tries to specify both highmem=off and a memory size that's too big to fit. thanks -- PMM 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 447DCC433EF for ; Tue, 7 Sep 2021 12:52:07 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id AA85C610C9 for ; Tue, 7 Sep 2021 12:52:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org AA85C610C9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 28EA04B24D; Tue, 7 Sep 2021 08:52:06 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@linaro.org Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id NWa1VbzWEe9s; Tue, 7 Sep 2021 08:52:05 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2B24D4B1FC; Tue, 7 Sep 2021 08:52:05 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E15E64B1B0 for ; Tue, 7 Sep 2021 08:52:04 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Tdf609a1gcd2 for ; Tue, 7 Sep 2021 08:52:04 -0400 (EDT) Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id EEAE84B19D for ; Tue, 7 Sep 2021 08:52:03 -0400 (EDT) Received: by mail-wm1-f50.google.com with SMTP id k5-20020a05600c1c8500b002f76c42214bso1739884wms.3 for ; Tue, 07 Sep 2021 05:52:03 -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=wovuk/YJ4ZzxTgEM/WTOLuXvX25Yjntehj+QQBKkeck=; b=K76J8SyL+1jOA8UfApaeCDLxztO+LZ8h4Nx9PbBNYsr+paYOiEqK9OIn2ldFs+7jzC YEttCcgHMvN3u1/0AVrT+pgr4UyIN1fY0TWDjPrCpijQjVadGHS6qCJxNRMRydMpbkpe vklWQApsPXT85SJjEbrr4whDc3f1MVpzfNFQ7ks6sAhOJgokRCkk4axYWPqo9Gq8UOEF jTjR2dGFy5N5XLZ6yElzSZACsjQFOUeQqAW9Htb6vbipQslVAql4L3mbDnFLy8aIY//W PjA+HrI7kjxQ45KDdftoS1ecm4AaCZ37azSPgx8Nz0Y44zMdL0lD1CCofVVAd3cPXEKz fYsg== 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=wovuk/YJ4ZzxTgEM/WTOLuXvX25Yjntehj+QQBKkeck=; b=fUspkS3FlwST2JTT7oY5zYT6Coj7w6X1JO6zIfPyN21SQ8mVAGqwNHgCnqYq9irsMG VEB1UYVHMT3FUUEEp0mk5P9VLyYW5hVkcD6f450MxKh9BTs3m8WgIvpU84klAhOQkrNP cG8eke08Y7LmuO3FKGkZfSPKOZkxxyBdoi1GBHTkeZyK+UI7d3Wlg4vMhpWkke43hKQH ZIlaTct89OyE9z3Qs6CLX9mroCqYOyil1tQ9nSyDGcwPnDU8Ui0rbsFFYJ5+rHJDkF3L 7CXeL9NV5t4k2QOIO1zz9622QwhNLbiJK6LUD4OxQWUISNVvceFQz1fpbk1bGhpoBvM8 pzHA== X-Gm-Message-State: AOAM530VBZjeIJyPCZVtYfLCB/I9uQY3YesaI3eOH3zBaDdELkXHc+IA FFg3AtQ5mKFjaTX0KWBjgdGexS/0x56uRUhzUMB8YQ== X-Google-Smtp-Source: ABdhPJzN1k5vdacf8pXMz+PcUOlliO8oElhlm9+Wxx2tO4deEucQ0q5nA8yws4gRRyTPG0HwiEfKkeMxeGbJ78NSUUM= X-Received: by 2002:a05:600c:4fcd:: with SMTP id o13mr3850083wmq.32.1631019122955; Tue, 07 Sep 2021 05:52:02 -0700 (PDT) MIME-Version: 1.0 References: <20210822144441.1290891-1-maz@kernel.org> <20210822144441.1290891-4-maz@kernel.org> In-Reply-To: <20210822144441.1290891-4-maz@kernel.org> From: Peter Maydell Date: Tue, 7 Sep 2021 13:51:13 +0100 Message-ID: Subject: Re: [PATCH 3/3] docs/system/arm/virt: Fix documentation for the 'highmem' option To: Marc Zyngier Cc: kvm-devel , QEMU Developers , Android Kernel Team , kvmarm X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Sun, 22 Aug 2021 at 15:45, Marc Zyngier wrote: > > The documentation for the 'highmem' option indicates that it controls > the placement of both devices and RAM. The actual behaviour of QEMU > seems to be that RAM is allowed to go beyond the 4GiB limit, and > that only devices are constraint by this option. > > Align the documentation with the actual behaviour. I think it would be better to align the behaviour with the documentation. The intent of 'highmem' is to allow a configuration for use with guests that can't address more than 32 bits (originally, 32-bit guests without LPAE support compiled in). It seems like a bug that we allow the user to specify more RAM than will fit into that 32-bit range. We should instead make QEMU exit with an error if the user tries to specify both highmem=off and a memory size that's too big to fit. thanks -- PMM _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm 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=-3.6 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 42227C433EF for ; Tue, 7 Sep 2021 13:20:13 +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 D335E610E9 for ; Tue, 7 Sep 2021 13:20:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D335E610E9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:33270 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mNb1G-0004cU-4z for qemu-devel@archiver.kernel.org; Tue, 07 Sep 2021 09:20:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51022) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mNaa7-0000U3-1r for qemu-devel@nongnu.org; Tue, 07 Sep 2021 08:52:08 -0400 Received: from mail-wm1-x330.google.com ([2a00:1450:4864:20::330]:39873) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1mNaa4-0001RU-E3 for qemu-devel@nongnu.org; Tue, 07 Sep 2021 08:52:06 -0400 Received: by mail-wm1-x330.google.com with SMTP id u26-20020a05600c441a00b002f66b2d8603so1733722wmn.4 for ; Tue, 07 Sep 2021 05:52:03 -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=wovuk/YJ4ZzxTgEM/WTOLuXvX25Yjntehj+QQBKkeck=; b=K76J8SyL+1jOA8UfApaeCDLxztO+LZ8h4Nx9PbBNYsr+paYOiEqK9OIn2ldFs+7jzC YEttCcgHMvN3u1/0AVrT+pgr4UyIN1fY0TWDjPrCpijQjVadGHS6qCJxNRMRydMpbkpe vklWQApsPXT85SJjEbrr4whDc3f1MVpzfNFQ7ks6sAhOJgokRCkk4axYWPqo9Gq8UOEF jTjR2dGFy5N5XLZ6yElzSZACsjQFOUeQqAW9Htb6vbipQslVAql4L3mbDnFLy8aIY//W PjA+HrI7kjxQ45KDdftoS1ecm4AaCZ37azSPgx8Nz0Y44zMdL0lD1CCofVVAd3cPXEKz fYsg== 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=wovuk/YJ4ZzxTgEM/WTOLuXvX25Yjntehj+QQBKkeck=; b=FnZVdSGXssf1W1xdEs3XGodBVKLwVO84Bo1yjUT0qJCQbipmJhRWr/1eI77fSRINDT MDNvm2aEtcDU7Q2luPKV8yWiv/sXQ3Ftjw47NVgp6SNzDPWvc5bUmwqSKVcFtPqvrJVW SQWt/du1o88DwNl2EDoVm+k3qaFX+5CImT4C1b1MiZx7NfRxdDCndQkshNF5xUbD1mgc HHDTEN+B9AMYYoi4+twabTw6GyD/J2kYcaTSb82s13nmiiFZXbLlGbHDODYoJIvDIYyO IoBt238Dv2XUWzUIb9twVhwHDL4ogMKU6kRtwnaMBqBhyTTS2njiWOPvaefuddGM9j3U DETw== X-Gm-Message-State: AOAM531JZl4aNs9ycKQVRZV23DDiOE5iy/yKYSeJVAzru+512dHalVqu yJUrOC78WtCjMF/Kw6EAJFSS2zeYktVPhc0rtbLQfw== X-Google-Smtp-Source: ABdhPJzN1k5vdacf8pXMz+PcUOlliO8oElhlm9+Wxx2tO4deEucQ0q5nA8yws4gRRyTPG0HwiEfKkeMxeGbJ78NSUUM= X-Received: by 2002:a05:600c:4fcd:: with SMTP id o13mr3850083wmq.32.1631019122955; Tue, 07 Sep 2021 05:52:02 -0700 (PDT) MIME-Version: 1.0 References: <20210822144441.1290891-1-maz@kernel.org> <20210822144441.1290891-4-maz@kernel.org> In-Reply-To: <20210822144441.1290891-4-maz@kernel.org> From: Peter Maydell Date: Tue, 7 Sep 2021 13:51:13 +0100 Message-ID: Subject: Re: [PATCH 3/3] docs/system/arm/virt: Fix documentation for the 'highmem' option To: Marc Zyngier Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2a00:1450:4864:20::330; envelope-from=peter.maydell@linaro.org; helo=mail-wm1-x330.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=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: Andrew Jones , kvm-devel , QEMU Developers , Eric Auger , Android Kernel Team , kvmarm Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sun, 22 Aug 2021 at 15:45, Marc Zyngier wrote: > > The documentation for the 'highmem' option indicates that it controls > the placement of both devices and RAM. The actual behaviour of QEMU > seems to be that RAM is allowed to go beyond the 4GiB limit, and > that only devices are constraint by this option. > > Align the documentation with the actual behaviour. I think it would be better to align the behaviour with the documentation. The intent of 'highmem' is to allow a configuration for use with guests that can't address more than 32 bits (originally, 32-bit guests without LPAE support compiled in). It seems like a bug that we allow the user to specify more RAM than will fit into that 32-bit range. We should instead make QEMU exit with an error if the user tries to specify both highmem=off and a memory size that's too big to fit. thanks -- PMM