[Qemu-devel] [PULL 6/6] migration: We also want to store the global state for savevm

[Juan Quintela <quintela@redhat.com>]

Commit df4b1024526cae3479da3492d6371fd4a7324a03 introduced global_state
section.  But it only filled the state while doing migration.  While
doing a savevm, we stored an empty string as state.  So when we did a
loadvm, it complained that state was invalid.

Fedora 21, 4.1.1, qemu 2.4.0-rc0
> ../../configure --target-list="x86_64-softmmu"

068 2s ... - output mismatch (see 068.out.bad)
--- /home/bos/jhuston/src/qemu/tests/qemu-iotests/068.out	2015-07-08
17:56:18.588164979 -0400
+++ 068.out.bad	2015-07-09 17:39:58.636651317 -0400
@@ -6,6 +6,8 @@
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm 0
 (qemu) quit
+qemu-system-x86_64: Unknown savevm section or instance 'globalstate' 0
+qemu-system-x86_64: Error -22 while loading VM state
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) quit
 *** done
Failures: 068
Failed 1 of 1 tests

Actually, there were two problems here:
- we registered global_state too late for load_vm (fixed on another
  patch on the list)
- we didn't store a valid state for savevm (fixed by this patch).

Reported-by: John Snow <jsnow@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Tested-by:  Christian Borntraeger <borntraeger@de.ibm.com>
---
 include/migration/migration.h | 1 +
 migration/migration.c         | 2 +-
 migration/savevm.c            | 6 ++++++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/migration/migration.h b/include/migration/migration.h
index b2711ef..a2f8ed0 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -202,4 +202,5 @@ void savevm_skip_section_footers(void);
 void register_global_state(void);
 void global_state_set_optional(void);
 void savevm_skip_configuration(void);
+int global_state_store(void);
 #endif
diff --git a/migration/migration.c b/migration/migration.c
index ba82ff6..86ca099 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -110,7 +110,7 @@ typedef struct {

 static GlobalState global_state;

-static int global_state_store(void)
+int global_state_store(void)
 {
     if (!runstate_store((char *)global_state.runstate,
                         sizeof(global_state.runstate))) {
diff --git a/migration/savevm.c b/migration/savevm.c
index 86735fc..81dbe58 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1315,6 +1315,12 @@ void hmp_savevm(Monitor *mon, const QDict *qdict)
     }

     saved_vm_running = runstate_is_running();
+
+    ret = global_state_store();
+    if (ret) {
+        monitor_printf(mon, "Error saving global state\n");
+        return;
+    }
     vm_stop(RUN_STATE_SAVE_VM);

     memset(sn, 0, sizeof(*sn));
-- 
2.4.3