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 6F2EDC636CD for ; Mon, 30 Jan 2023 20:49:35 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pMb5Y-0003NG-TR; Mon, 30 Jan 2023 15:49:16 -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 1pMb5S-0003Mw-Cr for qemu-devel@nongnu.org; Mon, 30 Jan 2023 15:49:15 -0500 Received: from mail-wr1-x42b.google.com ([2a00:1450:4864:20::42b]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1pMb5Q-0003Sz-M5 for qemu-devel@nongnu.org; Mon, 30 Jan 2023 15:49:09 -0500 Received: by mail-wr1-x42b.google.com with SMTP id o18so2896341wrj.3 for ; Mon, 30 Jan 2023 12:49:08 -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=6rV9xwlANCC1x56K8iV1huOC7rWqV7yM04ksBL92ptU=; b=OsdgQXYg1/SAt10v+jtWLb47R/0OE2dQ5kpKU5TJL5WekOMRy3BN4yoIUtWrxVGfqQ tucCY1szRnf5GshAXgDhXvgNmMLqPFJVRiE9apEo27+dFFGta9CpeP6SObadZSy6pMva 3OaBV70VxOAEzzyAfSnCckRjGt/G1/kqWlJYuH93DL/1FgPdNjThe7nrce4Bx+KLgyYb LWEe0mofHFXRDGv/yWYf1dh8NaYLtnkm1bq0Dc9TcXaf5BEOBtFBVjUah+zhyjjI/eh9 CRpmCHlYn15oaMX84G1kd1X4wBlNQBsEcxPyo4Fb2Mf0t4YCo7k97NzC0ghYh0K6YcjL Qv5g== 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=6rV9xwlANCC1x56K8iV1huOC7rWqV7yM04ksBL92ptU=; b=xg1Wnud20Smmzkj/+JSbjTehtmsh8VSGBDt1i/KogKLR7IrXeSfsqFZahO8SZElfFW IluNkoykM2yKyUJIG4+CLAo7grXlY97Bz2HVdaSpxLaQHNpyJSj5UzGeGTG5fF9Y6+L/ bnorCpS+ia6yqVy3AI17+R/WO85WbBLBOezW5HZrR18N97yNXHGiG2g6B0amaN+srcQC 13DPTdYDRS4EjyKzfRGt3CU7F+hlhrAgazK/bzilBlF5JptrDIiyjE5+XmDK7IW+Pe3u viIqxkDJ+82FwOu+f+w9q87CwNuEM57BZrxW4dEE+CLAPthOEw2AYg9+hxPq05ad74e1 +NVg== X-Gm-Message-State: AO0yUKV84BQS9VWYVJHGRIZdxgYuhJYBLqbY/32XqAxASL8bCV5fOoV+ 0Yo/01HYBQmfAjqgopGgyhdNcw== X-Google-Smtp-Source: AK7set82myOWnRJjRIIUFIGn4TLJcHTrtx3JgnKZGhnKFFYnZoSqF7j7VjMDQE6aueQM7a2A4UQMCA== X-Received: by 2002:adf:a1ce:0:b0:2bf:cfc2:2eae with SMTP id v14-20020adfa1ce000000b002bfcfc22eaemr12272699wrv.69.1675111747197; Mon, 30 Jan 2023 12:49:07 -0800 (PST) Received: from zen.linaroharston ([185.81.254.11]) by smtp.gmail.com with ESMTPSA id t19-20020a1c7713000000b003dc48a2f997sm8478918wmi.17.2023.01.30.12.49.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Jan 2023 12:49:06 -0800 (PST) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id 44C541FFB7; Mon, 30 Jan 2023 20:49:06 +0000 (GMT) References: <20230130114428.1297295-1-thuth@redhat.com> User-agent: mu4e 1.9.18; emacs 29.0.60 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: =?utf-8?Q?Daniel_P=2E_Berrang=C3=A9?= Cc: Peter Maydell , Thomas Huth , Stefan Hajnoczi , Richard Henderson , libvir-list@redhat.com, Paolo Bonzini , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Reinoud Zandijk , Ryo ONODERA , Brad Smith , Stefan Weil , qemu-devel@nongnu.org Subject: Re: [RFC PATCH] docs/about/deprecated: Deprecate 32-bit host systems Date: Mon, 30 Jan 2023 20:45:47 +0000 In-reply-to: Message-ID: <87h6w7694t.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::42b; envelope-from=alex.bennee@linaro.org; helo=mail-wr1-x42b.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 Daniel P. Berrang=C3=A9 writes: > On Mon, Jan 30, 2023 at 11:47:02AM +0000, Peter Maydell wrote: >> On Mon, 30 Jan 2023 at 11:44, Thomas Huth wrote: >> > >> > Testing 32-bit host OS support takes a lot of precious time during the= QEMU >> > contiguous integration tests, and considering that many OS vendors sto= pped >> > shipping 32-bit variants of their OS distributions and most hardware f= rom >> > the past >10 years is capable of 64-bit >>=20 >> True for x86, not necessarily true for other architectures. >> Are you proposing to deprecate x86 32-bit, or all 32-bit? >> I'm not entirely sure about whether we're yet at a point where >> I'd want to deprecate-and-drop 32-bit arm host support. > > Do we have a feeling on which aspects of 32-bit cause us the support > burden ? The boring stuff like compiler errors from mismatched integer > sizes is mostly quick & easy to detect simply through a cross compile. > > I vaguely recall someone mentioned problems with atomic ops in the past, > or was it 128-bit ints, caused implications for the codebase ? Atomic operations on > TARGET_BIT_SIZE and cputlb when TCG_OVERSIZED_GUEST is set. Also the core TCG code and a bunch of the backends have TARGET_LONG_BITS > TCG_TARGET_REG_BITS ifdefs peppered throughout. > > With regards, > Daniel --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro