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 A51A5CA5FD2 for ; Thu, 1 Oct 2026 18:27:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xCLUH-0006Gf-KD; Thu, 01 Oct 2026 14:26:35 -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 1xCLUG-0006G9-2A for qemu-arm@nongnu.org; Thu, 01 Oct 2026 14:26:32 -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 1xCLUD-0005bQ-MI for qemu-arm@nongnu.org; Thu, 01 Oct 2026 14:26:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1790879189; 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=ZosECNOQKpGVZKJoWB6P0QvFscC8v6W+szCipwajEXs=; b=VBYaoORPgi9tvGyFVCr52Jc+SjLDGVm8dEC8pIATw8DyPXVbrJQPnUnL1U503Oq0A7iXL+ xo2TFgjDtiJP1bnc7sojQXofsZD9+BnmLW8aWUsD+SNCU3ZtdAwAz1ptqCnRsJAdQyHVvN 9of8agRC56xzWAYYMnCgzgELbNETM4s= Received: from mx-prod-mc-01.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-634-ivnWBlaEMbOlFQk30hYZ3w-1; Thu, 01 Oct 2026 14:26:25 -0400 X-MC-Unique: ivnWBlaEMbOlFQk30hYZ3w-1 X-Mimecast-MFC-AGG-ID: ivnWBlaEMbOlFQk30hYZ3w_1790879181 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7561819776DA; Thu, 1 Oct 2026 18:26:21 +0000 (UTC) Received: from redhat.com (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C242618002B6; Thu, 1 Oct 2026 18:26:14 +0000 (UTC) Date: Thu, 1 Oct 2026 19:26:11 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Pierrick Bouvier Cc: luoyonggang@gmail.com, 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: <82250296-78bc-4345-9e57-1fcac485d18a@oss.qualcomm.com> <74853ef8-7315-466a-99ac-41c8182f9b13@oss.qualcomm.com> <26b0d44d-0322-4ceb-a47b-747fc52c61b7@oss.qualcomm.com> <6bf4dad5-4fa2-4df1-b6b8-d594dbd3842c@oss.qualcomm.com> MIME-Version: 1.0 In-Reply-To: <6bf4dad5-4fa2-4df1-b6b8-d594dbd3842c@oss.qualcomm.com> User-Agent: Mutt/2.4.2 (2026-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Mimecast-MFC-PROC-ID: AHOLuvcxKfAagXxXzhyRgPgJQhOshPrNZEqKcxpQu4Y_1790879181 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit 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: 9 X-Spam_score: 0.9 X-Spam_bar: / X-Spam_report: (0.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.331, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-arm@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-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org Sender: qemu-arm-bounces+qemu-arm=archiver.kernel.org@nongnu.org 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. > Also, how to deal with devices that are only available for some targets, > but not others, depending on various Kconfig knobs? IMHO just leave devices to raise an error when passed to '-device' if not compatible with the requested machine. eg this example from x86 world: $ qemu-system-x86_64 -M microvm -device xen-disk qemu-system-x86_64: -device xen-disk: No 'xen-bus' bus found for device 'xen-disk' $ qemu-system-x86_64 -M isapc -device virtio-net-pci qemu-system-x86_64: -device virtio-net-pci: No 'PCI' bus found for device 'virtio-net-pci' Hopefully most devices have sane error reporting when they find a dependancy they have is not satisfied by the machine, but if some end up asserting with crashes that's not a blocker. Those asserts can be turned into pretty error messages at our leisure by whomever cares about improving error diagnosis. > > A --target option (or similar -machine name,target=xxx) could > > be used to dis-ambiguate between 'virt' machines if keeping > > their user facing machine names as-is, or it could be used as > > a way to be more explicit about the 32-bit vs 64-bit choice > > and sanity checked against the CPU model choice. > > > > We could also not register them as virt if more than one target is > detected, so people have to call explicitly aarch64-virt. > Would that be a possible way to move forward? Yes, we could diverge in the naming of the machines for the existing binary, vs the new multi-binary, and that could well be the sanest & simplest option in fact. 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 :|