cpus: vm_resume

Define the vm_resume helper, for use in subsequent patches.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/1704312341-66640-5-git-send-email-steven.sistare@oracle.com
Signed-off-by: Peter Xu <peterx@redhat.com>

include/sysemu/runstate.h

@@ -57,6 +57,15 @@ void vm_start(void);
  * @step_pending: whether any of the CPUs is about to be single-stepped by gdb
  */
 int vm_prepare_start(bool step_pending);
+
+/**
+ * vm_resume: If @state is a live state, start the vm and set the state,
+ * else just set the state.
+ *
+ * @state: the state to restore
+ */
+void vm_resume(RunState state);
+
 int vm_stop(RunState state);
 int vm_stop_force_state(RunState state);
 int vm_shutdown(void);

system/cpus.c

@@ -748,6 +748,15 @@ void vm_start(void)
     }
 }
 
+void vm_resume(RunState state)
+{
+    if (runstate_is_live(state)) {
+        vm_start();
+    } else {
+        runstate_set(state);
+    }
+}
+
 /* does a state transition even if the VM is already stopped,
    current state is forgotten forever */
 int vm_stop_force_state(RunState state)