[RFC V2 1/8] migration: stop vm earlier for cpr

[Steve Sistare]

Stop the vm earlier for cpr, before cpr_save_state which causes new QEMU
to proceed and initialize devices.  We must guarantee devices are stopped
in old QEMU, and all source notifiers called, before they are initialized
in new QEMU.

Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
---
 migration/migration.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 10c216d..2efe60a 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1662,6 +1662,7 @@ void migration_cancel(void)
                           MIGRATION_STATUS_CANCELLED);
         cpr_state_close();
         migrate_hup_delete(s);
+        vm_resume(s->vm_old_state);
     }
 }
 
@@ -2196,6 +2197,7 @@ void qmp_migrate(const char *uri, bool has_channels,
     MigrationAddress *addr = NULL;
     MigrationChannel *channelv[MIGRATION_CHANNEL_TYPE__MAX] = { NULL };
     MigrationChannel *cpr_channel = NULL;
+    bool stopped = false;
 
     /*
      * Having preliminary checks for uri and channel
@@ -2248,6 +2250,15 @@ void qmp_migrate(const char *uri, bool has_channels,
         return;
     }
 
+    if (migrate_mode_is_cpr(s)) {
+        int ret = migration_stop_vm(s, RUN_STATE_FINISH_MIGRATE);
+        if (ret < 0) {
+            error_setg(&local_err, "migration_stop_vm failed, error %d", -ret);
+            goto out;
+        }
+        stopped = true;
+    }
+
     if (cpr_state_save(cpr_channel, &local_err)) {
         goto out;
     }
@@ -2274,6 +2285,9 @@ out:
     if (local_err) {
         migration_connect_set_error(s, local_err);
         error_propagate(errp, local_err);
+        if (stopped) {
+            vm_resume(s->vm_old_state);
+        }
     }
 }
 
@@ -2319,6 +2333,9 @@ static void qmp_migrate_finish(MigrationAddress *addr, 
bool resume_requested,
         }
         migration_connect_set_error(s, local_err);
         error_propagate(errp, local_err);
+        if (migrate_mode_is_cpr(s)) {
+            vm_resume(s->vm_old_state);
+        }
         return;
     }
 }
@@ -3961,7 +3978,6 @@ void migration_connect(MigrationState *s, Error *error_in)
     Error *local_err = NULL;
     uint64_t rate_limit;
     bool resume = (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER_SETUP);
-    int ret;
 
     /*
      * If there's a previous error, free it and prepare for another one.
@@ -4033,14 +4049,6 @@ void migration_connect(MigrationState *s, Error 
*error_in)
         return;
     }
 
-    if (migrate_mode_is_cpr(s)) {
-        ret = migration_stop_vm(s, RUN_STATE_FINISH_MIGRATE);
-        if (ret < 0) {
-            error_setg(&local_err, "migration_stop_vm failed, error %d", -ret);
-            goto fail;
-        }
-    }
-
     /*
      * Take a refcount to make sure the migration object won't get freed by
      * the main thread already in migration_shutdown().
-- 
1.8.3.1