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 8D838C4345F for ; Tue, 30 Apr 2024 07:38:03 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1s1i2c-0000TJ-17; Tue, 30 Apr 2024 03:36:42 -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 1s1i2K-0000SF-24 for qemu-devel@nongnu.org; Tue, 30 Apr 2024 03:36:27 -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 1s1i2F-00041j-Vo for qemu-devel@nongnu.org; Tue, 30 Apr 2024 03:36:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1714462577; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CRwvZv5W4b9sr9KIyZCYA0fPwcvOhPMI97ef33cQdfQ=; b=LGIXsfIvd0ZKrdB6q3jpA/j6pDLy0ahi4S3TGmMleHNE5Wg+RtaIpNoqPccgCQAOWK3D+i BC9aPjt9blq2TkY/ujipbbCBYpdLpgm1DelkaQ1RXLa32BPgUhlhZq98kNUEvWwF/SV2MB NLmKiVa819cxeKj2+U6wEyYwgDjuw1Y= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-549-LRGHqIWQOz61XkIxhys96A-1; Tue, 30 Apr 2024 03:36:13 -0400 X-MC-Unique: LRGHqIWQOz61XkIxhys96A-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id B4174803505; Tue, 30 Apr 2024 07:36:11 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.247]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 85FF440C5C2; Tue, 30 Apr 2024 07:36:08 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 7935B21E6811; Tue, 30 Apr 2024 09:36:07 +0200 (CEST) From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Cc: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , QEMU Developers , Daniil Tatianin , Alex =?utf-8?Q?Benn=C3=A9e?= , afaerber@suse.de, ale@rev.ng, alistair.francis@wdc.com, Anton Johansson , bbauman@redhat.com, bcain@quicinc.com, Chao Peng , cjia@nvidia.com, clg@kaod.org, cw@f00f.org, Damien Hedde , eblake@redhat.com, edgar.iglesias@gmail.com, eduardo@habkost.net, Elena Ufimtseva , eric.auger@redhat.com, felipe@nutanix.com, iggy@theiggy.com, imp@bsdimp.com, jan.kiszka@web.de, jgg@nvidia.com, jidong.xiao@gmail.com, jim.shu@sifive.com, jjherne@linux.vnet.ibm.com, Joao Martins , konrad.wilk@oracle.com, Luc Michel , mburton@qti.qualcomm.com, mdean@redhat.com, mimu@linux.vnet.ibm.com, paul.walmsley@sifive.com, pbonzini@redhat.com, Peter Maydell , Richard Henderson , Shameerali Kolothum Thodi , shentey@gmail.com, stefanha@gmail.com, wei.w.wang@intel.com, z.huo@139.com, LIU Zhiwei , zwu.kernel@gmail.com, eblot@rivosinc.com, max.chou@sifive.com Subject: Re: QEMU Community Call Agenda Items (April 30th, 2024) In-Reply-To: ("Daniel P. =?utf-8?Q?Berrang?= =?utf-8?Q?=C3=A9=22's?= message of "Mon, 29 Apr 2024 16:55:43 +0100") References: Date: Tue, 30 Apr 2024 09:36:07 +0200 Message-ID: <87v83zcnfc.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.987, 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_H4=0.001, RCVD_IN_MSPIKE_WL=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 Daniel P. Berrang=C3=A9 writes: > On Mon, Apr 29, 2024 at 05:06:36PM +0200, Philippe Mathieu-Daud=C3=A9 wro= te: >> Hi, >>=20 >> On 29/4/24 00:25, Philippe Mathieu-Daud=C3=A9 wrote: >> > Hi, >> >=20 >> > The KVM/QEMU community call is at: >> >=20 >> > =C2=A0 https://meet.jit.si/kvmcallmeeting >> > =C2=A0 @ >> > =C2=A0 30/4/2024 14:00 UTC >> >=20 >> > Are there any agenda items for the sync-up? >>=20 >> I'd like to discuss two issues: >>=20 >> 1/ Stability of QOM path >> --------------------- >>=20 >> Currently we have 3 QOM containers: >> - /machine >> QOM objects properly parented go there >> - /machine/unattached >> Orphan QOM objects. Missing parent is usually easy >> to figure out, but we need to post patches to fix them. >> - /machine/peripheral[-anon] >> Devices created at runtime with CLI -device or QAPI device_add. >> (-anon is for devices with no explicit bus ID). >> See "Problem 4: The /machine/unattached/ orphanage" in [1]. >>=20 >> The /machine and /machine/unattached trees are stable, although >> by adding parent to orphan objects, their path will change. >>=20 >> Objects in /machine/peripheral[-anon] depend on the order of >> the device_add commands / arguments used. >>=20 >> In a dynamically created machine, everything depend on how the >> device_add commands are processed. >>=20 >> How can be expect to easily reference a QOM object by its path? > > FYI, for reference libvirt uses a couple of QOM paths > > * "/machine/unattached/device[0]" - path of first vCPU, but > this is an historical artifact - nowdays we query the > paths from query-cpus-fast This is the only iffy use. The numbering of devices in /machine/unattached/ is not stable in practice. #0 may well be stable enough, though. > * "/machine/peripheral/%s/virtio-backend" where '%s' is the > ID we give the virtio device, for virtio-blk disks > > * /machine/peripheral/%s/%s.0/legacy[0] where both '%s' are > the ID we give the USB defvice, for USB disks > > * /machine/peripheral when enumerating devices we've > assigned ID aliases to. /machine/peripheral/ID is ABI. No worries. > * /machine to get the rtc-time property value This is an alias to the RTC device's "rtc-time" property. Only some machines define it. Useful because the actual property depends on machine type and configuration. For q35, it's /machine/unattached/device[N]/rtc/date, where N can vary. If we moved the southbridge out of the /machine/unattached dump, we'd have something like /machine/q35/ich9-lpc/rtc/date. Stable, but you have to know the machine type to find it. [...]