dump-guest-memory: add qmp event DUMP_COMPLETED

One new QMP event DUMP_COMPLETED is added. When a dump finishes, one
DUMP_COMPLETED event will occur to notify the user.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by:   Fam Zheng <famz@redhat.com>
Message-Id: <1455772616-8668-12-git-send-email-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

docs/qmp-events.txt

@@ -220,6 +220,24 @@ Data:
   },
   "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
 
+DUMP_COMPLETED
+--------------
+
+Emitted when the guest has finished one memory dump.
+
+Data:
+
+- "result": DumpQueryResult type described in qapi-schema.json
+- "error": Error message when dump failed. This is only a
+  human-readable string provided when dump failed. It should not be
+  parsed in any way (json-string, optional)
+
+Example:
+
+{ "event": "DUMP_COMPLETED",
+  "data": {"result": {"total": 1090650112, "status": "completed",
+                      "completed": 1090650112} } }
+
 GUEST_PANICKED
 --------------
 

dump.c

@@ -25,6 +25,7 @@
 #include "sysemu/cpus.h"
 #include "qapi/qmp/qerror.h"
 #include "qmp-commands.h"
+#include "qapi-event.h"
 
 #include <zlib.h>
 #ifdef CONFIG_LZO
@@ -1662,6 +1663,7 @@ cleanup:
 static void dump_process(DumpState *s, Error **errp)
 {
     Error *local_err = NULL;
+    DumpQueryResult *result = NULL;
 
     if (s->has_format && s->format != DUMP_GUEST_MEMORY_FORMAT_ELF) {
         create_kdump_vmcore(s, &local_err);
@@ -1674,6 +1676,15 @@ static void dump_process(DumpState *s, Error **errp)
     atomic_set(&s->status,
                (local_err ? DUMP_STATUS_FAILED : DUMP_STATUS_COMPLETED));
 
+    /* send DUMP_COMPLETED message (unconditionally) */
+    result = qmp_query_dump(NULL);
+    /* should never fail */
+    assert(result);
+    qapi_event_send_dump_completed(result, !!local_err, (local_err ? \
+                                   error_get_pretty(local_err) : NULL),
+                                   &error_abort);
+    qapi_free_DumpQueryResult(result);
+
     error_propagate(errp, local_err);
     dump_cleanup(s);
 }
@@ -1682,13 +1693,8 @@ static void *dump_thread(void *data)
 {
     Error *err = NULL;
     DumpState *s = (DumpState *)data;
-
     dump_process(s, &err);
-
-    if (err) {
-        /* TODO: notify user the error */
-        error_free(err);
-    }
+    error_free(err);
     return NULL;
 }
 

qapi/event.json

@@ -369,3 +369,19 @@
 ##
 { 'event': 'MEM_UNPLUG_ERROR',
   'data': { 'device': 'str', 'msg': 'str' } }
+
+##
+# @DUMP_COMPLETED
+#
+# Emitted when background dump has completed
+#
+# @result: DumpQueryResult type described in qapi-schema.json.
+#
+# @error: #optional human-readable error string that provides
+#         hint on why dump failed. Only presents on failure. The
+#         user should not try to interpret the error string.
+#
+# Since: 2.6
+##
+{ 'event': 'DUMP_COMPLETED' ,
+  'data': { 'result': 'DumpQueryResult', '*error': 'str' } }