[libvirt] [PATCH v4] qdev: DEVICE_DELETED event
libvirt has a long-standing bug: when removing the device,
it can request removal but does not know when the
removal completes. Add an event so we can fix this in a robust way.
Signed-off-by: Michael S. Tsirkin <mst(a)redhat.com>
---
At Anthony's request, reposting with a corrected subject.
Sorry about the noise.
Changes from v3:
- Document that we only emit events for devices with
and ID, as suggested by Markus
Changes from v2:
- move event toward the end of device_unparent,
so that parents are reported after their children,
as suggested by Paolo
Changes from v1:
- move to device_unparent
- address comments by Andreas and Eric
QMP/qmp-events.txt | 17 +++++++++++++++++
hw/qdev.c | 6 ++++++
include/monitor/monitor.h | 1 +
monitor.c | 1 +
qapi-schema.json | 4 +++-
5 files changed, 28 insertions(+), 1 deletion(-)
diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
index b2698e4..0ab5017 100644
--- a/QMP/qmp-events.txt
+++ b/QMP/qmp-events.txt
@@ -136,6 +136,23 @@ Example:
Note: The "ready to complete" status is always reset by a BLOCK_JOB_ERROR
event.
+DEVICE_DELETED
+-----------------
+
+Emitted whenever the device removal completion is acknowledged
+by the guest. This event is only emitted for devices with
+a user-specified ID.
+At this point, it's safe to reuse the specified device ID.
+Device removal can be initiated by the guest or by HMP/QMP commands.
+
+Data:
+
+- "device": device name (json-string)
+
+{ "event": "DEVICE_DELETED",
+ "data": { "device": "virtio-net-pci-0" },
+ "timestamp": { "seconds": 1265044230, "microseconds":
450486 } }
+
DEVICE_TRAY_MOVED
-----------------
diff --git a/hw/qdev.c b/hw/qdev.c
index 689cd54..393e83e 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -29,6 +29,7 @@
#include "sysemu/sysemu.h"
#include "qapi/error.h"
#include "qapi/visitor.h"
+#include "qapi/qmp/qjson.h"
int qdev_hotplug = 0;
static bool qdev_hot_added = false;
@@ -778,6 +779,11 @@ static void device_unparent(Object *obj)
object_unref(OBJECT(dev->parent_bus));
dev->parent_bus = NULL;
}
+ if (dev->id) {
+ QObject *data = qobject_from_jsonf("{ 'device': %s }",
dev->id);
+ monitor_protocol_event(QEVENT_DEVICE_DELETED, data);
+ qobject_decref(data);
+ }
}
static void device_class_init(ObjectClass *class, void *data)
diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h
index 87fb49c..b868760 100644
--- a/include/monitor/monitor.h
+++ b/include/monitor/monitor.h
@@ -39,6 +39,7 @@ typedef enum MonitorEvent {
QEVENT_BLOCK_JOB_CANCELLED,
QEVENT_BLOCK_JOB_ERROR,
QEVENT_BLOCK_JOB_READY,
+ QEVENT_DEVICE_DELETED,
QEVENT_DEVICE_TRAY_MOVED,
QEVENT_SUSPEND,
QEVENT_SUSPEND_DISK,
diff --git a/monitor.c b/monitor.c
index 32a6e74..2a5e7b6 100644
--- a/monitor.c
+++ b/monitor.c
@@ -457,6 +457,7 @@ static const char *monitor_event_names[] = {
[QEVENT_BLOCK_JOB_CANCELLED] = "BLOCK_JOB_CANCELLED",
[QEVENT_BLOCK_JOB_ERROR] = "BLOCK_JOB_ERROR",
[QEVENT_BLOCK_JOB_READY] = "BLOCK_JOB_READY",
+ [QEVENT_DEVICE_DELETED] = "DEVICE_DELETED",
[QEVENT_DEVICE_TRAY_MOVED] = "DEVICE_TRAY_MOVED",
[QEVENT_SUSPEND] = "SUSPEND",
[QEVENT_SUSPEND_DISK] = "SUSPEND_DISK",
diff --git a/qapi-schema.json b/qapi-schema.json
index 28b070f..bb361e1 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2354,7 +2354,9 @@
# Notes: When this command completes, the device may not be removed from the
# guest. Hot removal is an operation that requires guest cooperation.
# This command merely requests that the guest begin the hot removal
-# process.
+# process. Completion of the device removal process is signaled with a
+# DEVICE_DELETED event. Guest reset will automatically complete removal
+# for all devices.
#
# Since: 0.14.0
##
--
MST