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@redhat.com>

diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
index b2698e415377cc8572d68c4727bae156809fd984..24cf3e8aa3c680609b3395fda80c91da4dbba724 100644 (file)
--- a/QMP/qmp-events.txt
+++ b/QMP/qmp-events.txt
@@ -136,6 +136,22 @@ 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.
+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, optional)
+
+{ "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 0b20280133ce28ea60edc5407f5b7d4acda12095..5e8a89c06e3e3a0a94a31920342a96f880f5b03b 100644 (file)
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -30,6 +30,8 @@
 #include "qapi/error.h"
 #include "qapi/qmp/qerror.h"
 #include "qapi/visitor.h"
+#include "qapi/qmp/qjson.h"
+#include "monitor/monitor.h"
 
 int qdev_hotplug = 0;
 static bool qdev_hot_added = false;
@@ -761,6 +763,7 @@ static void device_unparent(Object *obj)
     DeviceState *dev = DEVICE(obj);
     DeviceClass *dc = DEVICE_GET_CLASS(dev);
     BusState *bus;
+    QObject *event_data;
 
     while (dev->num_child_bus) {
         bus = QLIST_FIRST(&dev->child_bus);
@@ -779,6 +782,14 @@ static void device_unparent(Object *obj)
         object_unref(OBJECT(dev->parent_bus));
         dev->parent_bus = NULL;
     }
+
+    if (dev->id) {
+        event_data = qobject_from_jsonf("{ 'device': %s }", dev->id);
+    } else {
+        event_data = qobject_from_jsonf("{ }");
+    }
+    monitor_protocol_event(QEVENT_DEVICE_DELETED, event_data);
+    qobject_decref(event_data);
 }
 
 static void device_class_init(ObjectClass *class, void *data)

diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h
index 87fb49c09266b90190e6dbb9475360cfa272d846..b868760d7c550c226bdeba5f9cebac11ba9a8220 100644 (file)
--- 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 112e92064d4cc957805127c67f114100adbfade0..2fdfb79cabc8bec594e244feb58e7fc123fc8179 100644 (file)
--- a/monitor.c
+++ b/monitor.c
@@ -458,6 +458,7 @@ 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 fdaa9da1337bbc74eefea8ef46a4b116416a1406..080dc39784391533aafb750f2a509f20ca65fe58 100644 (file)
--- 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
 ##