[Qemu-devel] [PATCH v2] vl: change runstate only if new state is different from current state

[Li Zhijian]

Previously, qemu will abort at following scenario:
(qemu) stop
(qemu) system_reset
(qemu) system_reset
(qemu) 2016-04-13T20:54:38.979158Z qemu-system-x86_64: invalid runstate 
transition: 'prelaunch' -> 'prelaunch'

Signed-off-by: Li Zhijian <lizhij...@cn.fujitsu.com>
Acked-by: Paolo Bonzini <pbonz...@redhat.com>
---
from v1
- fix patch title typo 'chanage' -> 'change'
- coding sytle: 'return ;' -> 'return;'
- add Acked tag
 vl.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/vl.c b/vl.c
index 9df534f..039a353 100644
--- a/vl.c
+++ b/vl.c
@@ -692,6 +692,10 @@ void runstate_set(RunState new_state)
 {
     assert(new_state < RUN_STATE__MAX);
 
+    if (current_run_state == new_state) {
+        return;
+    }
+
     if (!runstate_valid_transitions[current_run_state][new_state]) {
         error_report("invalid runstate transition: '%s' -> '%s'",
                      RunState_lookup[current_run_state],
-- 
2.5.0