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 * '-mon' is obsolete, deprecated and replaced by '-object', 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 :|
