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 7D41EC36010 for ; Fri, 11 Apr 2025 13:43:29 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1u3Ef2-0003fS-KK; Fri, 11 Apr 2025 09:43:12 -0400 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 1u3Eex-0003a9-BJ for qemu-devel@nongnu.org; Fri, 11 Apr 2025 09:43:08 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1u3Eev-0002Fd-C9 for qemu-devel@nongnu.org; Fri, 11 Apr 2025 09:43:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744378983; 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=YY5PXsRQnhJ7B1iL8CIo54wGcbPHxm2sNzMZy+ip5Rk=; b=QRRF9n09CoDGSOOUwrMVePBHz2k3Dvu9mmBnKZja8JfhSyhUZms+Eb0bC9BGrI6bc4vEEB A3EXbS7culwp9uioOzUOeF9e79Gmw2WCwrRpsy/Xk6laHB1Bum6zR7GrbeKKLyyUCsTCp9 2Ai4KC1JaqhlyIPesVHOfLJqzWHPx7M= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-680-C9bko7iVOoCIpcNppKMu6g-1; Fri, 11 Apr 2025 09:43:00 -0400 X-MC-Unique: C9bko7iVOoCIpcNppKMu6g-1 X-Mimecast-MFC-AGG-ID: C9bko7iVOoCIpcNppKMu6g_1744378979 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 42A541809CA5; Fri, 11 Apr 2025 13:42:59 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.63]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id BFC651809B65; Fri, 11 Apr 2025 13:42:56 +0000 (UTC) Date: Fri, 11 Apr 2025 14:42:53 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Richard Henderson Cc: qemu-devel@nongnu.org, Thomas Huth , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PULL 8/9] meson: Disallow 64-bit on 32-bit emulation Message-ID: References: <20250208205725.568631-1-richard.henderson@linaro.org> <20250208205725.568631-9-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250208205725.568631-9-richard.henderson@linaro.org> User-Agent: Mutt/2.2.13 (2024-03-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.681, 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 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 Sat, Feb 08, 2025 at 12:57:23PM -0800, Richard Henderson wrote: > For system mode, we can rarely support the amount of RAM that > the guest requires. TCG emulation is restricted to round-robin > mode, which solves many of the atomicity issues, but not those > associated with virtio. In any case, round-robin does nothing > to help the speed of emulation. > > For user mode, most emulation does not succeed at all. Most > of the time we cannot even load 64-bit non-PIE binaries due > to lack of a 64-bit address space. Threads are run in > parallel, not round-robin, which means that atomicity > is not handled. > > Reviewed-by: Thomas Huth > Reviewed-by: Philippe Mathieu-Daudé > Signed-off-by: Richard Henderson > --- > meson.build | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) Shouldn't this patch and the earlier ones in this series have added something to removed-features.rst, as this is a significant feature removal which is impacting downstream users, and distros in particular. > > diff --git a/meson.build b/meson.build > index 85317cd63f..ec51827f40 100644 > --- a/meson.build > +++ b/meson.build > @@ -3185,6 +3185,9 @@ if host_os == 'windows' > endif > endif > > +# Detect host pointer size for the target configuration loop. > +host_long_bits = cc.sizeof('void *') * 8 > + > ######################## > # Target configuration # > ######################## > @@ -3277,8 +3280,14 @@ foreach target : target_dirs > } > endif > > + config_target += keyval.load('configs/targets' / target + '.mak') > + > target_kconfig = [] > foreach sym: accelerators > + # Disallow 64-bit on 32-bit emulation and virtualization > + if host_long_bits < config_target['TARGET_LONG_BITS'].to_int() > + continue > + endif > if sym == 'CONFIG_TCG' or target in accelerator_targets.get(sym, []) > config_target += { sym: 'y' } > config_all_accel += { sym: 'y' } > @@ -3292,9 +3301,6 @@ foreach target : target_dirs > error('No accelerator available for target @0@'.format(target)) > endif > > - config_target += keyval.load('configs/targets' / target + '.mak') > - config_target += { 'TARGET_' + config_target['TARGET_ARCH'].to_upper(): 'y' } > - > if 'TARGET_NEED_FDT' in config_target and not fdt.found() > if default_targets > warning('Disabling ' + target + ' due to missing libfdt') > @@ -3307,6 +3313,7 @@ foreach target : target_dirs > actual_target_dirs += target > > # Add default keys > + config_target += { 'TARGET_' + config_target['TARGET_ARCH'].to_upper(): 'y' } > if 'TARGET_BASE_ARCH' not in config_target > config_target += {'TARGET_BASE_ARCH': config_target['TARGET_ARCH']} > endif > -- > 2.43.0 > > 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 :|