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 lists1p.gnu.org (lists1p.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 6DABCCA5FDD for ; Fri, 2 Oct 2026 16:36:27 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xCgEW-0005rG-SV; Fri, 02 Oct 2026 12:35:40 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xCgEP-0005no-Fg for qemu-devel@nongnu.org; Fri, 02 Oct 2026 12:35:33 -0400 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 1xCgEN-00071J-B1 for qemu-devel@nongnu.org; Fri, 02 Oct 2026 12:35:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1790958930; 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=8baB70HUph5PBf8rsxiiTG7cUswoEvhNq/gzpYM/r8s=; b=TnoNSDb3qQkFDSyG6bdPsaO3/TT8vX19wbqZJXTg8+iccjEuKb0HRL0FbMBflyuv4i+1sN 8ZezIWrDV8JZBc1OkHbAq95CnwlSlpVLoVmLPXbuzFwc7stxs/WRhmAyZxXT6LbWPe51fu KVHm8fOolfiSLmC3c2VnD8IxZZazbOM= 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-125-2FKyEoBcN96i92nrtxwRtg-1; Fri, 02 Oct 2026 12:35:26 -0400 X-MC-Unique: 2FKyEoBcN96i92nrtxwRtg-1 X-Mimecast-MFC-AGG-ID: 2FKyEoBcN96i92nrtxwRtg_1790958924 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 04D1D1912C49; Fri, 2 Oct 2026 16:35:21 +0000 (UTC) Received: from redhat.com (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E252E1800361; Fri, 2 Oct 2026 16:35:15 +0000 (UTC) Date: Fri, 2 Oct 2026 17:34:51 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Yonggang Luo Cc: Pierrick Bouvier , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , qemu-devel@nongnu.org, Chao Liu , Eric Blake , qemu-arm@nongnu.org, Paolo Bonzini , Markus Armbruster , Alistair Francis , Brian Cain , Stafford Horne , Peter Maydell , Jiaxun Yang , Fabiano Rosas , Daniel Henrique Barboza , qemu-riscv@nongnu.org, Laurent Vivier , Max Filippov , Song Gao <17746591750@163.com>, Philippe Mathieu-Daude , Palmer Dabbelt , Laurent Vivier , Weiwei Li , Zhao Liu Subject: Re: [PATCH v3 01/10] machine: allow -M name to differ from QOM type Message-ID: References: <26b0d44d-0322-4ceb-a47b-747fc52c61b7@oss.qualcomm.com> <6bf4dad5-4fa2-4df1-b6b8-d594dbd3842c@oss.qualcomm.com> <557262df-b8e7-49b5-a245-ae46b8885b30@oss.qualcomm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.4.2 (2026-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 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: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.336, 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_H2=0.001, SPF_HELO_PASS=-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: qemu development 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, Oct 03, 2026 at 12:27:08AM +0800, Yonggang Luo wrote: > On Sat, Oct 3, 2026 at 12:14 AM Daniel P. Berrangé wrote: > > > > On Thu, Oct 01, 2026 at 11:56:13AM -0700, Pierrick Bouvier wrote: > > > On 10/1/2026 11:26 AM, Daniel P. Berrangé wrote: > > > > On Thu, Oct 01, 2026 at 11:08:17AM -0700, Pierrick Bouvier wrote: > > > >> On 10/1/2026 10:40 AM, Daniel P. Berrangé wrote: > > > >>> Even with the current per-target binaries there are countless > > > >>> devices linked in which are incompatible / not usable with > > > >>> certain machine types. A new multi-target binary with a union > > > >>> of all devices will just be a bigger example of a scenario that > > > >>> already has to be dealt with for today's binaries. > > > >>> > > > >>> So if we have that assumption that we don't need to do device > > > >>> filtering, at that point, a --target option doesn't have as > > > >>> big of a role to play. The machine type code knows what target(s) > > > >>> it wants (1 or 2 targets depending on if there are 32 + 64 bit > > > >>> varaints. The CPU model the user requests (if the CPU is not > > > >>> hardcoded by the machine), determines 32 bit vs 64 bit. > > > >>> > > > >> > > > >> How can we deduce this information (bitness or target for existing > > > >> machines/cpus)? > > > > > > > > It would require that we introduce a new field in MachineClass > > > > that returned that information about what target a machine is > > > > associated with. > > > > > > > > I note the SysEmuTarget covers both 32-bit and 64-bit variants. > > > > > > > > It might be better use QEMU_ARCH which correlates directly to > > > > the TCG targets, rather than the traditional binary target > > > > names ? > > > > > > > > Likely the CPU class would also want to declare its list of > > > > supported targets. > > > > > > > > > > QEMU_ARCH only represents base architectures, and not variant, so > > > SysEmuTarget is the right choice. > > > > > > So, we would need a list of SysEmuTarget for every cpu/machine that is > > > target specific, since one could be available for variants of base arch? > > > > Ok > > > > > @Daniel: how do we deal with machines available for all targets like > > > null? We would need a way to ensure all machines/cpus are tagged > > > correctly, in an independent way from "available for all", without > > > having to repeat all existing SysEmuTarget. > > > > Or could the 'none' machine simply report '0xffffffff' for the > > list of targets so it includes everything today & in the future, > > or specialize "0" to mean everything ? > I think for is_avaible give a > bool target_is_any(const TargetInfo *ti) > { > (void)ti; > return true; > } > is enough. then we iterate the target list we will found every target > support for it. Yep, that would work. > > One idea I had was that when define the 'virt' class type we could > > have a way to identify whether it is linked into the traditional > > binaries, or linked into the multi-target binary, and from > > that choose what name to register it under. eg > > > > "extern bool multi_target;" > > This idea already resolved, see commit > https://gitlab.com/lygstate-qemu/qemu/-/commit/3342c04451bb21174e6bd53a7040e4929008b9d0 > The idea is > bool target_combined_binary(void) > { > return true; > } > for multi-target binary, and stub for single-target binary > for single-target binary > bool target_combined_binary(void) > { > return false; > } Ok, yes, that works, even if that feels a bit like overkill vs a global variable ! > > and have two .c files, one setting it 'true' and one 'false', > > and link each to the respective binaries. So we know statically > > before main() has even run, what mode this binary is intended > > to operate in. > > > > > Also, for compatibility with existing binaries, should we accept -M > > > $arch-virt also? I feel like it does not hurt and would make thing > > > simpler to switch between existing and new binary. > > > > Yes, that's another viable option. Always register '$arch-virt' and > > only register 'virt' for traditional binaries. > Oh, I see, for single-target binary, the "virt" is QOM name, and for > multi-target binary. > "$arch-virt" is the QOM name? So this series needs to consider this. made sense. With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|