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 972D3C0218A for ; Tue, 28 Jan 2025 09:18:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tchiZ-0004qb-Hb; Tue, 28 Jan 2025 04:17:11 -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 1tchiM-0004nV-Q8 for qemu-devel@nongnu.org; Tue, 28 Jan 2025 04:17:02 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tchiK-0001ho-Nj for qemu-devel@nongnu.org; Tue, 28 Jan 2025 04:16:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1738055813; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TqY5Ree3wNr3nCRHJo2viQbmCQ1/jaEuAagcwFuw6is=; b=C55lePRH+rVjdJ7DHbyi0VyCDQmKmp8G6q7Ua7F0ozIe3nnv18FzrmNZJqROitzlqtmkfA m5j4QPqS6rXbNPhbqsH1IL24VJMaW4Qp6Bv4GDF9gwrngGDt2lJz0KS8hAuyMU5ShqDFI8 mkAGWHaN9FGSQQGiZVU4UmpdN0l4UNI= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-517-Ewq93MytPA6u8-pLTBm6Lw-1; Tue, 28 Jan 2025 04:16:49 -0500 X-MC-Unique: Ewq93MytPA6u8-pLTBm6Lw-1 X-Mimecast-MFC-AGG-ID: Ewq93MytPA6u8-pLTBm6Lw Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7D9D81956083; Tue, 28 Jan 2025 09:16:47 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.75]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 58E371956094; Tue, 28 Jan 2025 09:16:43 +0000 (UTC) Date: Tue, 28 Jan 2025 09:16:40 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Alex =?utf-8?Q?Benn=C3=A9e?= Cc: Thomas Huth , Richard Henderson , qemu-devel@nongnu.org, peter.maydell@linaro.org, stefanha@redhat.com, pbonzini@redhat.com, philmd@linaro.org, mark.cave-ayland@ilande.co.uk, Liviu Ionescu Subject: Re: [PATCH 0/1] meson: Deprecate 32-bit host systems Message-ID: References: <20250128004254.33442-1-richard.henderson@linaro.org> <9a280789-9248-4eca-b50c-048fc58e3f53@redhat.com> <87plk72tvr.fsf@draig.linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87plk72tvr.fsf@draig.linaro.org> User-Agent: Mutt/2.2.13 (2024-03-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.3, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Jan 28, 2025 at 09:02:48AM +0000, Alex Bennée wrote: > Thomas Huth writes: > > > On 28/01/2025 01.42, Richard Henderson wrote: > >> Time for our biennial attempt to kill ancient hosts. > >> I've been re-working the tcg code generator a bit over the holidays. > >> One place that screams for a bit of cleanup is with 64-bit guest > >> addresses on 32-bit hosts. Of course the best "cleanup" is to not > >> have to handle such silliness at all. > >> Two years after Thomas' last attempt, > >> https://lore.kernel.org/qemu-devel/20230130114428.1297295-1-thuth@redhat.com/ > >> which resulted only in deprecation of i686 host for system > >> emulation. > >> By itself, this just isn't enough for large-scale cleanups. > >> I'll note that we've separately deprecated mips32, set to expire > >> with the end of Debian bookworm, set to enter LTS in June 2026. > >> I'll note that there is *already* no Debian support for ppc32, > >> and that I am currently unable to cross-compile that host at all. > > > > IIRC the biggest pushback that I got two years ago was with regards to > > 32-bit arm: The recommended version of Raspberry Pi OS is still > > 32-bit: > > > > https://lore.kernel.org/qemu-devel/F852C238-77B8-4E24-9494-8D060EB78F9F@livius.net/ > > > > And looking at https://www.raspberrypi.com/software/operating-systems/ > > this still seems to be the case... > > > > So I guess the main question is now: Would it be ok to kill support > > for 32-bit Raspberry Pi OS nowadays? > > I would argue yes for a few reasons. > > - you can't buy 32 bit only Pi's AFAICT, even the Pi Zero 2W can work > with a 64 bit OS. > > - It's not like the versions shipping in bullseye and bookworm will > stop working. > > - Even if we deprecate now there will likely be one more Debian > release cycle that gets 32 bit host support. > > >> Showing my hand a bit, I am willing to limit deprecation to > >> 64-bit guests on 32-bit hosts. But I'd prefer to go the whole hog: > >> unconditional support for TCG_TYPE_I64 would remove a *lot* of > >> 32-bit fallback code. > > I support going the whole hog. I would be curious what use cases still > exist for an up to date 32-on-32 QEMU based emulation? Last time we discussed this, we distinguished between system emulation and linux-user. I believe Richard is proposing to deprecated *both*, but lets call that out explicitly in any deprecation message to avoid mis-understandings. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|