[PATCH v4 05/10] tests/qtest: switch to using event callbacks for STOP event

["Daniel P. Berrangé" <berrange@redhat.com>]

Change the migration test to use the new qtest event callback to watch
for the stop event. This ensures that we only watch for the STOP event
on the source QEMU. The previous code would set the single 'got_stop'
flag when either source or dest QEMU got the STOP event.

Reviewed-by: Juan Quintela <quintela@redhat.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 tests/qtest/migration-helpers.c | 19 +++++++++----------
 tests/qtest/migration-helpers.h |  3 ++-
 tests/qtest/migration-test.c    |  4 ++++
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/tests/qtest/migration-helpers.c b/tests/qtest/migration-helpers.c
index e26fdcb132..7ceadecf84 100644
--- a/tests/qtest/migration-helpers.c
+++ b/tests/qtest/migration-helpers.c
@@ -23,15 +23,17 @@
  */
 #define MIGRATION_STATUS_WAIT_TIMEOUT 120
 
-bool got_stop;
-
-static void check_stop_event(QTestState *who)
+bool migrate_watch_for_stop(QTestState *who, const char *name,
+                            QDict *event, void *opaque)
 {
-    QDict *event = qtest_qmp_event_ref(who, "STOP");
-    if (event) {
-        got_stop = true;
-        qobject_unref(event);
+    bool *seen = opaque;
+
+    if (g_str_equal(name, "STOP")) {
+        *seen = true;
+        return true;
     }
+
+    return false;
 }
 
 #ifndef _WIN32
@@ -48,7 +50,6 @@ QDict *wait_command_fd(QTestState *who, int fd, const char *command, ...)
     va_end(ap);
 
     resp = qtest_qmp_receive(who);
-    check_stop_event(who);
 
     g_assert(!qdict_haskey(resp, "error"));
     g_assert(qdict_haskey(resp, "return"));
@@ -73,8 +74,6 @@ QDict *wait_command(QTestState *who, const char *command, ...)
     resp = qtest_vqmp(who, command, ap);
     va_end(ap);
 
-    check_stop_event(who);
-
     g_assert(!qdict_haskey(resp, "error"));
     g_assert(qdict_haskey(resp, "return"));
 
diff --git a/tests/qtest/migration-helpers.h b/tests/qtest/migration-helpers.h
index 2e51a6e195..fa69d1780a 100644
--- a/tests/qtest/migration-helpers.h
+++ b/tests/qtest/migration-helpers.h
@@ -15,7 +15,8 @@
 
 #include "libqtest.h"
 
-extern bool got_stop;
+bool migrate_watch_for_stop(QTestState *who, const char *name,
+                            QDict *event, void *opaque);
 
 #ifndef _WIN32
 G_GNUC_PRINTF(3, 4)
diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
index 822516286d..0af72c37c2 100644
--- a/tests/qtest/migration-test.c
+++ b/tests/qtest/migration-test.c
@@ -43,6 +43,7 @@
 unsigned start_address;
 unsigned end_address;
 static bool uffd_feature_thread_id;
+static bool got_stop;
 
 /*
  * Dirtylimit stop working if dirty page rate error
@@ -703,6 +704,9 @@ static int test_migrate_start(QTestState **from, QTestState **to,
                                  ignore_stderr);
     if (!args->only_target) {
         *from = qtest_init(cmd_source);
+        qtest_qmp_set_event_callback(*from,
+                                     migrate_watch_for_stop,
+                                     &got_stop);
     }
 
     cmd_target = g_strdup_printf("-accel kvm%s -accel tcg%s%s "
-- 
2.40.1