[Qemu-devel] [PATCH 1/1] vl: change QEMU state machine for system reset

[Denis V. Lunev]

This patch implements proposal from Paolo to handle system reset when
the guest is not running.

"After a reset, main_loop_should_exit should actually transition
to VM_STATE_PRELAUNCH (*not* RUN_STATE_PAUSED) for *all* states except
RUN_STATE_INMIGRATE, RUN_STATE_SAVE_VM (which I think cannot happen
there) and (of course) RUN_STATE_RUNNING."

Signed-off-by: Denis V. Lunev <address@hidden>
CC: Paolo Bonzini <address@hidden>
CC: Dmitry Andreev <address@hidden>
---
 vl.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/vl.c b/vl.c
index 0172e42..c9e47b0 100644
--- a/vl.c
+++ b/vl.c
@@ -583,6 +583,7 @@ static const RunStateTransition runstate_transitions_def[] 
= {
     /*     from      ->     to      */
     { RUN_STATE_DEBUG, RUN_STATE_RUNNING },
     { RUN_STATE_DEBUG, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_DEBUG, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_INMIGRATE, RUN_STATE_INTERNAL_ERROR },
     { RUN_STATE_INMIGRATE, RUN_STATE_IO_ERROR },
@@ -596,15 +597,19 @@ static const RunStateTransition 
runstate_transitions_def[] = {
 
     { RUN_STATE_INTERNAL_ERROR, RUN_STATE_PAUSED },
     { RUN_STATE_INTERNAL_ERROR, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_INTERNAL_ERROR, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_IO_ERROR, RUN_STATE_RUNNING },
     { RUN_STATE_IO_ERROR, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_IO_ERROR, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_PAUSED, RUN_STATE_RUNNING },
     { RUN_STATE_PAUSED, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_PAUSED, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_POSTMIGRATE, RUN_STATE_RUNNING },
     { RUN_STATE_POSTMIGRATE, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_POSTMIGRATE, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_PRELAUNCH, RUN_STATE_RUNNING },
     { RUN_STATE_PRELAUNCH, RUN_STATE_FINISH_MIGRATE },
@@ -612,8 +617,10 @@ static const RunStateTransition runstate_transitions_def[] 
= {
 
     { RUN_STATE_FINISH_MIGRATE, RUN_STATE_RUNNING },
     { RUN_STATE_FINISH_MIGRATE, RUN_STATE_POSTMIGRATE },
+    { RUN_STATE_FINISH_MIGRATE, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_RESTORE_VM, RUN_STATE_RUNNING },
+    { RUN_STATE_RESTORE_VM, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_RUNNING, RUN_STATE_DEBUG },
     { RUN_STATE_RUNNING, RUN_STATE_INTERNAL_ERROR },
@@ -627,20 +634,25 @@ static const RunStateTransition 
runstate_transitions_def[] = {
     { RUN_STATE_RUNNING, RUN_STATE_GUEST_PANICKED },
 
     { RUN_STATE_SAVE_VM, RUN_STATE_RUNNING },
+    { RUN_STATE_SAVE_VM, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_SHUTDOWN, RUN_STATE_PAUSED },
     { RUN_STATE_SHUTDOWN, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_SHUTDOWN, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_DEBUG, RUN_STATE_SUSPENDED },
     { RUN_STATE_RUNNING, RUN_STATE_SUSPENDED },
     { RUN_STATE_SUSPENDED, RUN_STATE_RUNNING },
     { RUN_STATE_SUSPENDED, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_SUSPENDED, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_WATCHDOG, RUN_STATE_RUNNING },
     { RUN_STATE_WATCHDOG, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_WATCHDOG, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_GUEST_PANICKED, RUN_STATE_RUNNING },
     { RUN_STATE_GUEST_PANICKED, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_GUEST_PANICKED, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE__MAX, RUN_STATE__MAX },
 };
@@ -1886,8 +1899,10 @@ static bool main_loop_should_exit(void)
         cpu_synchronize_all_states();
         qemu_system_reset(VMRESET_REPORT);
         resume_all_vcpus();
-        if (runstate_needs_reset()) {
-            runstate_set(RUN_STATE_PAUSED);
+        if (!runstate_check(RUN_STATE_RUNNING) &&
+                !runstate_check(RUN_STATE_INMIGRATE) &&
+                !runstate_check(RUN_STATE_SAVE_VM)) {
+            runstate_set(RUN_STATE_PRELAUNCH);
         }
     }
     if (qemu_wakeup_requested()) {
-- 
2.5.0