From: Christian Brauner <brauner@kernel.org> Add functional tests that exercise dynamic monitor hotplug with real socket connections: - Hotplug cycle: chardev-add a unix socket, object-add, connect to the socket, receive the QMP greeting, negotiate capabilities, send query-version, disconnect, remove the monitor and chardev, then repeat the entire cycle a second time to verify cleanup and reuse. - Self-removal: a dynamically-added monitor sends object-del targeting itself, verifying that the request is rejected - Large response: send query-qmp-schema on a dynamic monitor to exercise the output buffer flush path with a large response payload. - Events after negotiation: trigger STOP/RESUME events via the main monitor and verify they are delivered on the dynamic monitor. This complements the qtest unit tests by verifying that a real QMP client can connect to a dynamically-added monitor and exchange messages. Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> [DB: modified to use object-add/object-del; adjust self-removal test to validate rejection of request] Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Tested-by: Peter Krempa <pkrempa@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> --- MAINTAINERS | 1 + tests/functional/generic/meson.build | 1 + .../generic/test_monitor_hotplug.py | 168 ++++++++++++++++++ 3 files changed, 170 insertions(+) create mode 100755 tests/functional/generic/test_monitor_hotplug.py diff --git a/MAINTAINERS b/MAINTAINERS index 2ecfd7159d..a0166f8257 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3638,6 +3638,7 @@ F: docs/interop/*qmp-* F: scripts/qmp/ F: tests/qtest/qmp-test.c F: tests/qtest/qmp-cmd-test.c +F: tests/functional/generic/test_monitor_hotplug.py T: git https://repo.or.cz/qemu/armbru.git qapi-next qtest diff --git a/tests/functional/generic/meson.build b/tests/functional/generic/meson.build index 09763c5d22..c94105c62e 100644 --- a/tests/functional/generic/meson.build +++ b/tests/functional/generic/meson.build @@ -4,6 +4,7 @@ tests_generic_system = [ 'empty_cpu_model', 'info_usernet', 'linters', + 'monitor_hotplug', 'version', 'vnc', ] diff --git a/tests/functional/generic/test_monitor_hotplug.py b/tests/functional/generic/test_monitor_hotplug.py new file mode 100755 index 0000000000..5d8a159eb0 --- /dev/null +++ b/tests/functional/generic/test_monitor_hotplug.py @@ -0,0 +1,168 @@ +#!/usr/bin/env python3 +# +# SPDX-License-Identifier: GPL-2.0-or-later +# +# Functional test for dynamic QMP monitor hotplug +# +# Copyright (c) 2026 Christian Brauner + +import os + +from qemu_test import QemuSystemTest + +from qemu.qmp.legacy import QEMUMonitorProtocol + + +class MonitorHotplug(QemuSystemTest): + + def setUp(self): + super().setUp() + sock_dir = self.socket_dir() + self._sock_path = os.path.join(sock_dir.name, 'hotplug.sock') + + def _add_monitor(self): + """Create a chardev + monitor and return the socket path.""" + sock = self._sock_path + self.vm.cmd('chardev-add', id='hotplug-chr', backend={ + 'type': 'socket', + 'data': { + 'addr': { + 'type': 'unix', + 'data': {'path': sock} + }, + 'server': True, + 'wait': False, + } + }) + self.vm.cmd('object-add', id='hotplug-mon', + qom_type='monitor-qmp', + chardev='hotplug-chr') + return sock + + def _remove_monitor(self): + """Remove the monitor + chardev.""" + self.vm.cmd('object-del', id='hotplug-mon') + self.vm.cmd('chardev-remove', id='hotplug-chr') + + def _connect_and_handshake(self, sock_path): + """ + Connect to the dynamic monitor socket, perform the QMP + greeting and capability negotiation, send a command, then + disconnect. + """ + qmp = QEMUMonitorProtocol(sock_path) + + # connect(negotiate=True) receives the greeting, validates it, + # and sends qmp_capabilities automatically. + greeting = qmp.connect(negotiate=True) + self.assertIn('QMP', greeting) + self.assertIn('version', greeting['QMP']) + self.assertIn('capabilities', greeting['QMP']) + + # Send a real command to prove the session is fully functional + resp = qmp.cmd_obj({'execute': 'query-version'}) + self.assertIn('return', resp) + self.assertIn('qemu', resp['return']) + + qmp.close() + + def test_hotplug_cycle(self): + """ + Hotplug a monitor, do the full QMP handshake, unplug it, + then repeat the whole cycle a second time. + """ + self.set_machine('none') + self.vm.add_args('-nodefaults') + self.vm.launch() + + # First cycle + sock = self._add_monitor() + self._connect_and_handshake(sock) + self._remove_monitor() + + # Second cycle -- same ids, same path, must work + sock = self._add_monitor() + self._connect_and_handshake(sock) + self._remove_monitor() + + def test_self_removal(self): + """ + A dynamically-added monitor sends object-del targeting + itself. Verify the request is rejected, but the monitor + can still be deleted from outside its own context. + """ + self.set_machine('none') + self.vm.add_args('-nodefaults') + self.vm.launch() + + sock = self._add_monitor() + + qmp = QEMUMonitorProtocol(sock) + greeting = qmp.connect(negotiate=True) + self.assertIn('QMP', greeting) + + # Self-removal: the dynamic monitor raises error + resp = qmp.cmd_obj({'execute': 'object-del', + 'arguments': {'id': 'hotplug-mon'}}) + self.assertIn('error', resp) + + qmp.close() + + resp = self.vm.cmd('object-del', id='hotplug-mon') + + # Clean up the chardev + self.vm.cmd('chardev-remove', id='hotplug-chr') + + def test_large_response(self): + """ + Send a command with a large response (query-qmp-schema) on a + dynamically-added monitor to exercise the output buffer flush + path. + """ + self.set_machine('none') + self.vm.add_args('-nodefaults') + self.vm.launch() + + sock = self._add_monitor() + + qmp = QEMUMonitorProtocol(sock) + qmp.connect(negotiate=True) + + resp = qmp.cmd_obj({'execute': 'query-qmp-schema'}) + self.assertIn('return', resp) + self.assertIsInstance(resp['return'], list) + self.assertGreater(len(resp['return']), 0) + + qmp.close() + self._remove_monitor() + + def test_events_after_negotiation(self): + """ + Verify that QMP events are delivered on a dynamically-added + monitor after capability negotiation completes. + """ + self.set_machine('none') + self.vm.add_args('-nodefaults') + self.vm.launch() + + sock = self._add_monitor() + + qmp = QEMUMonitorProtocol(sock) + qmp.connect(negotiate=True) + + # Trigger a STOP event via the main monitor, then read it + # from the dynamic monitor. + self.vm.cmd('stop') + resp = qmp.pull_event(wait=True) + self.assertEqual(resp['event'], 'STOP') + + self.vm.cmd('cont') + resp = qmp.pull_event(wait=True) + self.assertEqual(resp['event'], 'RESUME') + + qmp.close() + self._remove_monitor() + + +if __name__ == '__main__': + QemuSystemTest.main() -- 2.54.0