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 E79DBC43458 for ; Fri, 26 Jun 2026 13:36:10 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wd6ib-0004Mn-C3; Fri, 26 Jun 2026 09:35:41 -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 1wd6iZ-0004MY-23 for qemu-devel@nongnu.org; Fri, 26 Jun 2026 09:35:39 -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 1wd6iW-0006l7-RW for qemu-devel@nongnu.org; Fri, 26 Jun 2026 09:35:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782480933; 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=Q0hhE7Pq2hM9NxLS5N0QKeUdQIeUbKrqY11OufozFwc=; b=ckBNOzanr6+TEaoeJmnMQyvxOG0nLmMOoWjfF+rndj3iudabZ3E4jLxZFrySl7tMqLe5ea /yH785EyKK9dgwpKa/uUfA6zDUy0WexwdhPI5oitrFEWFQCfJy+DPJ/C4mzlG4sF6ac8Vl RIJT4r/rmx/EkLg5IkAkE27bkdZaNBI= 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-665-FOI3BWk9M3uqKxftAzH0bg-1; Fri, 26 Jun 2026 09:35:29 -0400 X-MC-Unique: FOI3BWk9M3uqKxftAzH0bg-1 X-Mimecast-MFC-AGG-ID: FOI3BWk9M3uqKxftAzH0bg_1782480926 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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 3792718004D4; Fri, 26 Jun 2026 13:35:26 +0000 (UTC) Received: from redhat.com (unknown [10.44.50.5]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CB511195608A; Fri, 26 Jun 2026 13:35:22 +0000 (UTC) Date: Fri, 26 Jun 2026 14:35:19 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: qemu-devel@nongnu.org, Markus Armbruster Cc: devel@lists.libvirt.org, =?utf-8?Q?Marc-Andr=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 Message-ID: References: <20260624173752.2928717-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260624173752.2928717-1-berrange@redhat.com> User-Agent: Mutt/2.3.2 (2026-04-26) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 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: -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: , 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 Markus, This series is fully reviewed now by multiple people. Do you have any plans to do reviews and/or queue this as maintainer, or will you ack it for me to send a pull request. I would like to get this merged before soft freeze which is fast approaching. On Wed, Jun 24, 2026 at 06:37:16PM +0100, Daniel P. Berrangé wrote: > 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 > > * QMP gains a concept of "close-action" which makes it > possible to mark a monitor for auto-delete. > > The monitor hot-unplug code and the qtest and functional testing > code is heavily derived from a series sent by Christian Brauner > which proposed new monitor_add/monitor_del commands: > > https://lists.nongnu.org/archive/html/qemu-devel/2026-04/msg01349.html > > I left Christian's authorship & SoB on the patches which were > derived from his code, though the code has been refactored quite > a bit in places, so bugs are quite possibly my own. > > Note that Christian's series allowed the use of "monitor_del" > commands against the current monitor session. ie a client could > delete the very monitor it was using. This is an awkward concept > as it needs special casing to delay the deletion to happen in > the background, such that that the QMP response to 'monitor_del' > could still be sent back. This also left the chardev was orphaned > as there's no way to run 'chardev_dev' in that usage pattern. > > To provide an alternative mechanism to address the same use case, > this series introduces the 'close-action' concept mentioned above, > that allows hotplugging a monitor to service a specific task, > with the monitor being purged when the script closes its connection. > This avoids the special casing that an explicit "self deletion" > paradigm required. > > While supporting hotplug of HMP was trivial, I didn't do any work > to think about hotunplug of HMP, since IMHO it is of limited value > given HMP's typical use cases. > > [1] ~~~ we did all this not because it was easy, > but because we thought it would be easy ~~~ > > Changed in v5: > > - Address another race when looking up monitor by ID > - Refer to "line editting" when talking about HMP > readline feature > - Misc typos > - Fix mis-placed setting of 'delete_pending' > - Add test case to validate reconnecting to QMP > > Changed in v4: > > - Hold reference into BH to avoid race with auto-delete > > Changed in v3: > > - Removed unused 'dead' struct field > - Make use of 'setup_pending' struct field across BH > - Add missing free of chardev_id > - Add missnig ERRP_GUARD in monitor_new_qmp > - Misc docs typos / rephrasing > - Moved docs patch to the end > - Fixed docs about the default QOM ID naming for legacy > monitor syntax > - Fixed random sleep time calculation in tests > > Christian Brauner (6): > monitor: convert from oneshot BH to persistent BH > monitor: reject attempts to delete the current monitor > monitor: protect qemu_chr_fe_accept_input with monitor lock > monitor: implement support for deleting QMP objects > tests/qtest: add tests for dynamic monitor add/remove > tests/functional: add e2e test for dynamic QMP monitor hotplug > > Daniel P. Berrangé (29): > qom: replace 'can_be_deleted' with 'prepare_delete' > monitor: replace 'common' with 'parent_obj' in MonitorHMP > monitor: replace 'common' with 'parent_obj' in MonitorQMP > monitor: rename monitor_init* to monitor_new* > monitor: minimal conversion of monitors to QOM > monitor: add 'chardev' property to Monitor base class > monitor: add 'readline' property to HMP Monitor class > monitor: add 'pretty' property to QMP Monitor class > monitor: remove 'skip_flush' field > monitor: move monitor_data_(init|destroy) into QOM init/finalize > monitor: use class methods for monitor_vprintf > monitor: use class methods for monitor_qapi_event_emit > monitor: use class methods for monitor_accept_input > monitor: use class method for I/O thread request > monitor: use dynamic cast in monitor_qmp_requests_pop_any_with_lock > util: use dynamic cast in error vreport > monitor: drop unused monitor_cur_is_qmp > monitor: use dynamic cast in QMP commands > monitor: use dynamic cast in monitor_is_hmp_non_interactive > monitor: drop unused monitor_is_qmp method > monitor: eliminate monitor_is_hmp_non_interactive method > monitor: implement "user creatable" interface for adding monitors > tests/functional: add a stress test for monitor hot unplug > qom: add method for getting the "id" of a QOM object > qom: add trace events for user creatable create/delete APIs > monitor: add support for auto-deleting monitors upon close > tests: switch from -mon to -object monitor-qmp > qemu-options: document new monitor-hmp and monitor-qmp objects > docs: mark '-mon' as deprecated in favour of -object > > MAINTAINERS | 1 + > backends/cryptodev.c | 10 +- > backends/hostmem.c | 5 +- > backends/iommufd.c | 10 +- > block/throttle-groups.c | 10 +- > chardev/char.c | 3 +- > docs/about/deprecated.rst | 10 + > docs/devel/writing-monitor-commands.rst | 4 +- > docs/system/arm/xenpvh.rst | 4 +- > docs/system/i386/xen.rst | 3 +- > docs/system/i386/xenpvh.rst | 4 +- > event-loop-base.c | 8 +- > gdbstub/system.c | 4 +- > include/monitor/monitor.h | 23 +- > include/qom/object.h | 10 + > include/qom/object_interfaces.h | 26 +- > include/system/event-loop-base.h | 2 +- > migration/migration-hmp-cmds.c | 5 +- > monitor/hmp-cmds.c | 7 +- > monitor/hmp.c | 181 ++++++++-- > monitor/monitor-internal.h | 73 ++-- > monitor/monitor.c | 262 +++++++------- > monitor/qmp-cmds-control.c | 12 +- > monitor/qmp-cmds.c | 14 +- > monitor/qmp.c | 319 +++++++++++++++--- > net/can/can_core.c | 5 +- > python/qemu/machine/machine.py | 4 +- > qapi/qom.json | 62 ++++ > qemu-options.hx | 56 ++- > qom/object.c | 17 + > qom/object_interfaces.c | 20 +- > qom/trace-events | 5 + > storage-daemon/qemu-storage-daemon.c | 2 +- > stubs/monitor-core.c | 5 - > stubs/monitor-internal.c | 3 +- > system/vl.c | 12 +- > tests/functional/generic/meson.build | 1 + > .../generic/test_monitor_hotplug.py | 305 +++++++++++++++++ > tests/qemu-iotests/245 | 4 +- > tests/qtest/libqtest.c | 2 +- > tests/qtest/qmp-test.c | 174 ++++++++++ > tests/unit/test-util-sockets.c | 1 - > tools/qemu-vnc/stubs.c | 5 - > ui/ui-hmp-cmds.c | 2 +- > util/error-report.c | 13 +- > util/main-loop.c | 5 +- > 46 files changed, 1386 insertions(+), 327 deletions(-) > create mode 100755 tests/functional/generic/test_monitor_hotplug.py > > -- > 2.54.0 > 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 :|