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 C0EB2D0C5F4 for ; Fri, 25 Oct 2024 09:26:37 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t4GZf-0004Ns-CJ; Fri, 25 Oct 2024 05:25:39 -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 1t4GZd-0004NV-N9 for qemu-devel@nongnu.org; Fri, 25 Oct 2024 05:25:37 -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 1t4GZa-0001WA-Pq for qemu-devel@nongnu.org; Fri, 25 Oct 2024 05:25:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1729848333; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Hn9dLSsy2ZmrYYt6a3x8pCr3JGkLSAnQ0CDdX5NQXrA=; b=gK4F2g6ZeTKEotNMf/PUx+k02Ic0DUVVo4V2IMA9zDBvFGRCIyAVb8k0PEGVbb6NVqUhlE ZdI8L5X+4icr/gDYeik03lYMJilQHaljUwtIju2DyryhV6fsBLIFYKQVojN9Vfnf4slSLp vciTGFL6JqpuAG/VbNfi57ULwvdsPJY= Received: from mx-prod-mc-04.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-258-85fShx9mOKec45GD2sS9CA-1; Fri, 25 Oct 2024 05:25:28 -0400 X-MC-Unique: 85fShx9mOKec45GD2sS9CA-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1F3AD19560AB; Fri, 25 Oct 2024 09:25:26 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.150]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 716A3300018D; Fri, 25 Oct 2024 09:25:25 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 1A5DB21E6A28; Fri, 25 Oct 2024 11:25:23 +0200 (CEST) From: Markus Armbruster To: Peter Xu Cc: qemu-devel@nongnu.org, Fabiano Rosas , Igor Mammedov , Juraj Marcin , "Michael S . Tsirkin" , "Dr . David Alan Gilbert" , =?utf-8?Q?C=C3=A9dric?= Le Goater , Eduardo Habkost , Daniel P . =?utf-8?Q?Berrang=C3=A9?= , Alex Williamson , Paolo Bonzini , Peter Maydell Subject: Re: [PATCH 2/4] x86/iommu: Make x86-iommu a singleton object In-Reply-To: <20241024165627.1372621-3-peterx@redhat.com> (Peter Xu's message of "Thu, 24 Oct 2024 12:56:25 -0400") References: <20241024165627.1372621-1-peterx@redhat.com> <20241024165627.1372621-3-peterx@redhat.com> Date: Fri, 25 Oct 2024 11:25:23 +0200 Message-ID: <87jzdwlekc.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@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=-0.263, 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_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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Peter Xu writes: > X86 IOMMUs cannot be created more than one on a system yet. Make it a > singleton so it guards the system from accidentally create yet another > IOMMU object when one already presents. > > Now if someone tries to create more than one, e.g., via: > > ./qemu -M q35 -device intel-iommu -device intel-iommu > > The error will change from: > > qemu-system-x86_64: -device intel-iommu: QEMU does not support multiple vIOMMUs for x86 yet. > > To: > > qemu-system-x86_64: -device intel-iommu: Class 'intel-iommu' only supports one instance > > Unfortunately, yet we can't remove the singleton check in the machine > hook (pc_machine_device_pre_plug_cb), because there can also be > virtio-iommu involved, which doesn't share a common parent class yet. > > But with this, it should be closer to reach that goal to check singleton by > QOM one day. > > Signed-off-by: Peter Xu $ qemu-system-x86_64 -device amd-iommu,help /work/armbru/qemu/include/hw/boards.h:24:MACHINE: Object 0x56473906f960 is not an instance of type machine Aborted (core dumped) (gdb) bt #0 0x00007ffff4e43834 in __pthread_kill_implementation () at /lib64/libc.so.6 #1 0x00007ffff4df18ee in raise () at /lib64/libc.so.6 #2 0x00007ffff4dd98ff in abort () at /lib64/libc.so.6 #3 0x0000555555f75ef3 in object_dynamic_cast_assert (obj=0x555557e03960, typename=0x5555563c403e "machine", file=0x5555563c4018 "/work/armbru/qemu/include/hw/boards.h", line=24, func=0x5555563c4290 <__func__.7> "MACHINE") at ../qom/object.c:936 #4 0x0000555555d5db0f in MACHINE (obj=0x555557e03960) at /work/armbru/qemu/include/hw/boards.h:24 #5 0x0000555555d5e030 in x86_iommu_get_default () at ../hw/i386/x86-iommu.c:83 #6 0x0000555555d5e262 in x86_iommu_get_instance (errp=0x5555573d4918 ) at ../hw/i386/x86-iommu.c:139 #7 0x0000555555f7c27c in singleton_get_instance (class=0x555557e00320) at ../qom/object_interfaces.c:371 #8 0x000055555612a842 in qmp_device_list_properties (typename=0x555557e001d0 "amd-iommu", errp=0x7fffffffda38) at ../qom/qom-qmp-cmds.c:147 #9 0x0000555555bf20b2 in qdev_device_help (opts=0x555557e001f0) at ../system/qdev-monitor.c:314 #10 0x0000555555bfe06d in device_help_func (opaque=0x0, opts=0x555557e001f0, errp=0x0) at ../system/vl.c:1208 #11 0x0000555556217186 in qemu_opts_foreach (list=0x55555729e5c0 , func=0x555555bfe04d , opaque=0x0, errp=0x0) at ../util/qemu-option.c:1135 #12 0x0000555555c01d56 in qemu_process_help_options () at ../system/vl.c:2555 #13 0x0000555555c04d81 in qemu_init (argc=3, argv=0x7fffffffde28) at ../system/vl.c:3654 #14 0x000055555612ffae in main (argc=3, argv=0x7fffffffde28) at ../system/main.c:47