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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 3D096C636D6 for ; Wed, 22 Feb 2023 13:39:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pUpLH-00029d-S2; Wed, 22 Feb 2023 08:39:31 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pUpLE-00029H-Ii for qemu-devel@nongnu.org; Wed, 22 Feb 2023 08:39:28 -0500 Received: from mail-wr1-x433.google.com ([2a00:1450:4864:20::433]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1pUpLC-00067d-RX for qemu-devel@nongnu.org; Wed, 22 Feb 2023 08:39:28 -0500 Received: by mail-wr1-x433.google.com with SMTP id p8so7882687wrt.12 for ; Wed, 22 Feb 2023 05:39:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:from:to:cc:subject:date :message-id:reply-to; bh=jEQtF3safae3+1s9H+6M1cB5EIZCXqjy+l54lB0sxUY=; b=jnYfTkxxUbP3LiqQmVSW4hTc0izzzhu8fGtQB+RNOZjYWs7Q9jml3fJq8R+Vj05JOP MwlGoPtsvHhMwBsO/OEWVWpfLuD9TiTTyOcTox4V1pqRfFF1al4u/F6PqWAgqgT6rM2l wHnOA9pU1uZviHbh6/paGoPoyvMO/64ZCLwmWU+q3E7YT5SeC2qbeAx+WRiaOh1QxII9 YCHojN+21BSF4WqUtafXcUEvB+iANSo1Ho1T+0/GraR//J2hevkR1YkXphQKZ3BYVSsL 5pG1rxROgZQJM9nZvfjXjM3oOYe5J8HVxsVc9nI7fg5ik/CJaBFs9hyxQlCrjE4S/tp2 iHGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=jEQtF3safae3+1s9H+6M1cB5EIZCXqjy+l54lB0sxUY=; b=N1+h8oH1EPUlngZV4WOS4h2QgARK3Q2KgIeWoUkOdQNc0v1BLn5nr+yadG6MsnG7r1 OZjQ6AbR6KaM6zOsB1+b950lliM7ptBNXTe9rjMMuH6CtP/L+gdeOiMZaZAKO/jCvrqN +AQLiDFLiUyPaPeVZvvxGUDY63jDb6NuiV0VKfurTcRrmR1Pfv/3tlSEXSM0cFUuj7Am oUzSnax2/ZADc7RBEsIlcdbmDL0Iibj4vMZN0SWujSi5sPqLqZd9C4zZZMU8m8UZAJ1s tAv3pSb+dDqD90PBN5vwVLoXLDdj8tUnRsjPsPrIJZe1a9yca+8DUvC8P6eJGsgQlTYj Yz1Q== X-Gm-Message-State: AO0yUKVY38eHf/1JQPmC2TE/5Zx9EwmPajYLlEEoPN5d6flUMf6LPeL6 fNHVx2vjyzyfWjt2jqXZDPvJ3g== X-Google-Smtp-Source: AK7set9F+vQ8iUOF/BH8H42lUReYTQ/PTCYetNexb1/Dia8I8pjo9XZl2baAKo0UhkZQJHa5U2SOFg== X-Received: by 2002:adf:eec6:0:b0:2c3:e5e6:f0d8 with SMTP id a6-20020adfeec6000000b002c3e5e6f0d8mr7335831wrp.11.1677073165020; Wed, 22 Feb 2023 05:39:25 -0800 (PST) Received: from zen.linaroharston ([85.9.250.243]) by smtp.gmail.com with ESMTPSA id a8-20020adfed08000000b002c55cdb1de5sm7126146wro.116.2023.02.22.05.39.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Feb 2023 05:39:24 -0800 (PST) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id 4A6C01FFB7; Wed, 22 Feb 2023 13:39:24 +0000 (GMT) References: <20230130114428.1297295-1-thuth@redhat.com> <87h6w7694t.fsf@linaro.org> <45EE5F9E-B9B8-4DA4-809E-A95FC618E7BE@gmail.com> User-agent: mu4e 1.9.21; emacs 29.0.60 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Reinoud Zandijk Cc: =?utf-8?Q?Daniel_P=2E_Berrang=C3=A9?= , Bernhard Beschow , qemu-devel@nongnu.org, Peter Maydell , Thomas Huth , Stefan Hajnoczi , Richard Henderson , libvir-list@redhat.com, Paolo Bonzini , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Ryo ONODERA , Brad Smith , Stefan Weil Subject: Re: [RFC PATCH] docs/about/deprecated: Deprecate 32-bit host systems Date: Wed, 22 Feb 2023 13:37:54 +0000 In-reply-to: Message-ID: <87wn49q0oj.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::433; envelope-from=alex.bennee@linaro.org; helo=mail-wr1-x433.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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Reinoud Zandijk writes: > On Wed, Feb 22, 2023 at 09:51:57AM +0000, Daniel P. Berrang=C3=A9 wrote: >> On Wed, Feb 22, 2023 at 09:11:13AM +0000, Bernhard Beschow wrote: >> > Are there any plans or ideas to support 128 bit architectures >> > such as CHERI in the future? There is already a QEMU fork >> > implementing CHERI for RISC V [1]. Also ARM has developed an >> > experimental hardware implementation of CHERI within the Morello >> > project where Linaro is involved as well, although the QEMU >> > implementation is performed by the University of Cambridge [2]. >>=20 >> If 128 bit hardware exists and has real world non-toy usage, >> then a request to support it in QEMU is essentially inevitable. >>=20 >> > I'm asking because once we deeply bake in the assumption that >> > host size >=3D guest size then adding such architectures will >> > become much harder. >>=20 >> Yep, that is a risk. > > I can second that. Better keep it in the code and deal with it. Maybe tho= se > specific parts can be implemented in such a way that it can easily become= a > noop on host size >=3D guest size. AIUI these don't expose bigger addresses or natural atomic sizes which is where things get tricky for the TCG. All the extra bits are used for authentication or permission checks. --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro