On 05/01/2022 13:38, Daniel P. Berrangé wrote:
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 no unusable for its purpose, so
Not sure to understand: do you mean "now unusable"?
we add a new 'json-cli-hotplug' feature to indicate the
-device supports JSON without breaking hotplug.
Fixes: https://gitlab.com/qemu-project/qemu/-/issues/802
Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
---
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 d9e4c619d3..b1fc7da104 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -2684,6 +2684,7 @@ 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
@@ -2692,7 +2693,8 @@ 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);
You can use qpci_unplug_acpi_device_test() to process the request... but I see this is
done like that too in test_pci_unplug_request()
+ 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",
Reviewed-by: Laurent Vivier <lviv...@redhat.com>
