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 6994DC43458 for ; Wed, 1 Jul 2026 13:42:06 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wevC7-00043L-IS; Wed, 01 Jul 2026 09:41:39 -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 1wevC5-00042u-JM for qemu-devel@nongnu.org; Wed, 01 Jul 2026 09:41:37 -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 1wevC3-0005Nn-Oa for qemu-devel@nongnu.org; Wed, 01 Jul 2026 09:41:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782913294; 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=qZThTu9Ed/AICfoo2zchGGtcBETGBvqIqCacme2T0sQ=; b=LQ2dhzQ6z35ITjrhsfqHjHpZbg5iIy9QBpu/rZKqABnFkFdtmfeeZjHC//LMu37jhczqOG GMmEZKsNL5npxX4Ijfd4TkB5v9oQJzbM86fYEsjkqEMBfg5qron1IYJl33tqXDIHQYa8Sz c9S1+H8M+mZD8DguSOuxxa9ggHZIH3w= 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-693-BGk9UrgJP_CYKeNcvK0m0g-1; Wed, 01 Jul 2026 09:41:31 -0400 X-MC-Unique: BGk9UrgJP_CYKeNcvK0m0g-1 X-Mimecast-MFC-AGG-ID: BGk9UrgJP_CYKeNcvK0m0g_1782913290 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 BC17418795A5; Wed, 1 Jul 2026 13:41:29 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.4]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E6CB4180076D; Wed, 1 Jul 2026 13:41:28 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 7022D21E6920; Wed, 01 Jul 2026 15:41:26 +0200 (CEST) From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Cc: qemu-devel@nongnu.org, devel@lists.libvirt.org, =?utf-8?Q?Marc-Andr?= =?utf-8?Q?=C3=A9?= Lureau , Paolo Bonzini , "Dr. David Alan Gilbert" , Alex =?utf-8?Q?Benn=C3=A9e?= , Christian Brauner , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PATCH v5 00/35] monitor: turn QMP and HMP into QOM objects In-Reply-To: ("Daniel P. =?utf-8?Q?Berrang?= =?utf-8?Q?=C3=A9=22's?= message of "Wed, 1 Jul 2026 09:21:47 +0100") References: <20260624173752.2928717-1-berrange@redhat.com> <87fr236t9v.fsf@pond.sub.org> Date: Wed, 01 Jul 2026 15:41:26 +0200 Message-ID: <87ik6y4yk9.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 10.30.177.111 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: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, 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, 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: , 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 Wed, Jul 01, 2026 at 09:52:44AM +0200, Markus Armbruster wrote: >> Daniel P. Berrang=C3=A9 writes: >>=20 >> > Conceptually -object and object_add/object_del should be sufficient >> > for essentially all QEMU configuration....if only we ported all our >> > internal custom backends/devices/etc to QOM. That is of course a big >> > job which is why it hasn't happened. >> > >> > This series started with the premise that the monitor is one of the >> > easier areas to convert since we have no more than three classes, >> > a common base, and QMP and HMP subclasses[1]. So why not give it a >> > go and thus unlock the ability to dynamically create/delete monitors >> > in QMP/HMP. >> > >> > This series does the conversion in a great many small steps to better >> > understand the implications at each stage. >> > >> > The high level outcome of this series is >> > >> > * HMP and QMP monitors are QOM objects, 'monitor-hmp' and >> > 'monitor-qmp' respectively >> > >> > * Both can be cold plugged and hot plugged. QMP only, can >> > also be hot unplugged. >> > >> > * '-mon' is obsolete, deprecated and replaced by '-object', >> > but -monitor, -qmp and kept as high level syntax sugar >>=20 >> Possible additional work: change monitor_parse() to build a >> MonitorOptions instead of a QemuOpts, so it call monitor_new() directly >> instead of via monitor_new_opts(). Observation, not a demand. >>=20 >> > >> > * QMP gains a concept of "close-action" which makes it >> > possible to mark a monitor for auto-delete. >>=20 >> I'm not quite convinced this is warranted. I'd like to hear more about >> use cases. > > Replied about that inline to the patch. IMHO without this facility > the series does not fully address the needs of systemd that motivated > the original patches: > > https://lists.nongnu.org/archive/html/qemu-devel/2026-04/msg01349.html > >> Is libvirt going to make use of it? > > This wasn't motivated by libvirt's needs, but indeed it could be > useful for libvirt. Currently if apps want to access QMP, they > need to use libvirt's QMP passthrough, which means they need > special client code to talk to libvirt APIs. > > With this libvirt could dynamically add a monitor, with auto > close, open it and pass the open FD back to the client app. > libvirt would not need to watch for when the client app is > gone as dropping the FD would cleanup the monitor. Alright, that's fair. The management application doesn't spawn something that wants a dedicated monitor, it makes one for a client. Would this fit into a commit message somewhere? [...]