[Qemu-devel] [PATCH 10/15] qmp event: Add COLO_EXIT event to notify users while exited from COLO

[zhanghailiang <zhang.zhanghailiang@huawei.com>]

If some errors happen during VM's COLO FT stage, it's important to
notify the users of this event. Together with 'x_colo_lost_heartbeat',
Users can intervene in COLO's failover work immediately.
If users don't want to get involved in COLO's failover verdict,
it is still necessary to notify users that we exited COLO mode.

Cc: Markus Armbruster <armbru@redhat.com>
Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 migration/colo.c | 19 +++++++++++++++++++
 qapi-schema.json | 14 ++++++++++++++
 qapi/event.json  | 21 +++++++++++++++++++++
 3 files changed, 54 insertions(+)

diff --git a/migration/colo.c b/migration/colo.c
index edb7f00..65d0802 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -468,6 +468,18 @@ out:
     }
 
     colo_compare_unregister_notifier(&packets_compare_notifier);
+    /*
+     * There are only two reasons we can go here, some error happened.
+     * Or the user triggered failover.
+     */
+    if (failover_get_state() == FAILOVER_STATUS_NONE) {
+        qapi_event_send_colo_exit(COLO_MODE_PRIMARY,
+                                  COLO_EXIT_REASON_ERROR, NULL);
+    } else {
+        qapi_event_send_colo_exit(COLO_MODE_PRIMARY,
+                                  COLO_EXIT_REASON_REQUEST, NULL);
+    }
+
     timer_del(s->colo_delay_timer);
 
     /* Hope this not to be too long to wait here */
@@ -708,6 +720,13 @@ out:
     if (local_err) {
         error_report_err(local_err);
     }
+    if (failover_get_state() == FAILOVER_STATUS_NONE) {
+        qapi_event_send_colo_exit(COLO_MODE_SECONDARY,
+                                  COLO_EXIT_REASON_ERROR, NULL);
+    } else {
+        qapi_event_send_colo_exit(COLO_MODE_SECONDARY,
+                                  COLO_EXIT_REASON_REQUEST, NULL);
+    }
 
     if (fb) {
         qemu_fclose(fb);
diff --git a/qapi-schema.json b/qapi-schema.json
index 0521054..bb73e8f 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1203,6 +1203,20 @@
   'data': [ 'none', 'require', 'active', 'completed', 'relaunch' ] }
 
 ##
+# @COLOExitReason:
+#
+# The reason for a COLO exit
+#
+# @request: COLO exit is due to an external request
+#
+# @error: COLO exit is due to an internal error
+#
+# Since: 2.9
+##
+{ 'enum': 'COLOExitReason',
+  'data': [ 'request', 'error' ] }
+
+##
 # @x-colo-lost-heartbeat:
 #
 # Tell qemu that heartbeat is lost, request it to do takeover procedures.
diff --git a/qapi/event.json b/qapi/event.json
index 970ff02..fe33628 100644
--- a/qapi/event.json
+++ b/qapi/event.json
@@ -441,6 +441,27 @@
   'data': { 'pass': 'int' } }
 
 ##
+# @COLO_EXIT:
+#
+# Emitted when VM finishes COLO mode due to some errors happening or
+# at the request of users.
+#
+# @mode: which COLO mode the VM was in when it exited.
+#
+# @reason: describes the reason for the COLO exit.
+#
+# Since: 2.9
+#
+# Example:
+#
+# <- { "timestamp": {"seconds": 2032141960, "microseconds": 417172},
+#      "event": "COLO_EXIT", "data": {"mode": "primary", "reason": "request" } }
+#
+##
+{ 'event': 'COLO_EXIT',
+  'data': {'mode': 'COLOMode', 'reason': 'COLOExitReason' } }
+
+##
 # @ACPI_DEVICE_OST:
 #
 # Emitted when guest executes ACPI _OST method.
-- 
1.8.3.1