migration/hmp: add migrate_pause command

Wrapper for QMP command "migrate-pause".
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Message-Id: <20180502104740.12123-25-peterx@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

hmp-commands.hx

@@ -971,6 +971,20 @@ STEXI
 @item migrate_recover @var{uri}
 @findex migrate_recover
 Continue a paused incoming postcopy migration using the @var{uri}.
+ETEXI
+
+    {
+        .name       = "migrate_pause",
+        .args_type  = "",
+        .params     = "",
+        .help       = "Pause an ongoing migration (postcopy-only)",
+        .cmd        = hmp_migrate_pause,
+    },
+
+STEXI
+@item migrate_pause
+@findex migrate_pause
+Pause an ongoing migration.  Currently it only supports postcopy.
 ETEXI
 
     {

hmp.c

@@ -1527,6 +1527,15 @@ void hmp_migrate_recover(Monitor *mon, const QDict *qdict)
     hmp_handle_error(mon, &err);
 }
 
+void hmp_migrate_pause(Monitor *mon, const QDict *qdict)
+{
+    Error *err = NULL;
+
+    qmp_migrate_pause(&err);
+
+    hmp_handle_error(mon, &err);
+}
+
 /* Kept for backwards compatibility */
 void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict)
 {

hmp.h

@@ -69,6 +69,7 @@ void hmp_migrate_cancel(Monitor *mon, const QDict *qdict);
 void hmp_migrate_continue(Monitor *mon, const QDict *qdict);
 void hmp_migrate_incoming(Monitor *mon, const QDict *qdict);
 void hmp_migrate_recover(Monitor *mon, const QDict *qdict);
+void hmp_migrate_pause(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_capability(Monitor *mon, const QDict *qdict);