From 005339f7deaee639c38d30e5bf2235c292ce3937 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Wed, 5 Jan 2022 12:38:47 +0000 Subject: [PATCH 3/3] softmmu: fix device deletion events with -device JSON syntax MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Kevin Wolf RH-MergeRequest: 62: Fix hot unplug of devices created with -device JSON syntax RH-Commit: [1/1] 980e505ba215b5f9324c107481c5bb257ae03f42 (kmwolf/centos-qemu-kvm) RH-Bugzilla: 2036669 RH-Acked-by: Daniel P. Berrangé RH-Acked-by: Laurent Vivier RH-Acked-by: Jano Tomko The -device JSON syntax impl leaks a reference on the created DeviceState instance. As a result when you hot-unplug the device, the device_finalize method won't be called and thus it will fail to emit the required DEVICE_DELETED event. A 'json-cli' feature was previously added against the 'device_add' QMP command QAPI schema to indicated to mgmt apps that -device supported JSON syntax. Given the hotplug bug that feature flag is not usable for its purpose, so we add a new 'json-cli-hotplug' feature to indicate the -device supports JSON without breaking hotplug. Fixes: 5dacda5167560b3af8eadbce5814f60ba44b467e Resolves: https://gitlab.com/qemu-project/qemu/-/issues/802 Signed-off-by: Daniel P. Berrangé Message-Id: <20220105123847.4047954-2-berrange@redhat.com> Reviewed-by: Laurent Vivier Tested-by: Ján Tomko Reviewed-by: Thomas Huth Signed-off-by: Kevin Wolf (cherry picked from commit 64b4529a432507ee84a924be69a03432639e87ba) Signed-off-by: Kevin Wolf --- qapi/qdev.json | 5 ++++- softmmu/vl.c | 4 +++- tests/qtest/device-plug-test.c | 19 +++++++++++++++++++ 3 files changed, 26 insertions(+), 2 deletions(-) diff --git a/qapi/qdev.json b/qapi/qdev.json index 69656b14df..26cd10106b 100644 --- a/qapi/qdev.json +++ b/qapi/qdev.json @@ -44,6 +44,9 @@ # @json-cli: If present, the "-device" command line option supports JSON # syntax with a structure identical to the arguments of this # command. +# @json-cli-hotplug: If present, the "-device" command line option supports JSON +# syntax without the reference counting leak that broke +# hot-unplug # # Notes: # @@ -74,7 +77,7 @@ { 'command': 'device_add', 'data': {'driver': 'str', '*bus': 'str', '*id': 'str'}, 'gen': false, # so we can get the additional arguments - 'features': ['json-cli'] } + 'features': ['json-cli', 'json-cli-hotplug'] } ## # @device_del: diff --git a/softmmu/vl.c b/softmmu/vl.c index d46b8fb4ab..b3829e2edd 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -2690,6 +2690,7 @@ static void qemu_create_cli_devices(void) qemu_opts_foreach(qemu_find_opts("device"), device_init_func, NULL, &error_fatal); QTAILQ_FOREACH(opt, &device_opts, next) { + DeviceState *dev; loc_push_restore(&opt->loc); /* * TODO Eventually we should call qmp_device_add() here to make sure it @@ -2698,7 +2699,8 @@ static void qemu_create_cli_devices(void) * from the start, so call qdev_device_add_from_qdict() directly for * now. */ - qdev_device_add_from_qdict(opt->opts, true, &error_fatal); + dev = qdev_device_add_from_qdict(opt->opts, true, &error_fatal); + object_unref(OBJECT(dev)); loc_pop(&opt->loc); } rom_reset_order_override(); diff --git a/tests/qtest/device-plug-test.c b/tests/qtest/device-plug-test.c index 559d47727a..ad79bd4c14 100644 --- a/tests/qtest/device-plug-test.c +++ b/tests/qtest/device-plug-test.c @@ -77,6 +77,23 @@ static void test_pci_unplug_request(void) qtest_quit(qtest); } +static void test_pci_unplug_json_request(void) +{ + QTestState *qtest = qtest_initf( + "-device '{\"driver\": \"virtio-mouse-pci\", \"id\": \"dev0\"}'"); + + /* + * Request device removal. As the guest is not running, the request won't + * be processed. However during system reset, the removal will be + * handled, removing the device. + */ + device_del(qtest, "dev0"); + system_reset(qtest); + wait_device_deleted_event(qtest, "dev0"); + + qtest_quit(qtest); +} + static void test_ccw_unplug(void) { QTestState *qtest = qtest_initf("-device virtio-balloon-ccw,id=dev0"); @@ -145,6 +162,8 @@ int main(int argc, char **argv) */ qtest_add_func("/device-plug/pci-unplug-request", test_pci_unplug_request); + qtest_add_func("/device-plug/pci-unplug-json-request", + test_pci_unplug_json_request); if (!strcmp(arch, "s390x")) { qtest_add_func("/device-plug/ccw-unplug", -- 2.27.0