qapi: Convert balloon

Note that the command being dropped uses the deprecated MONITOR_CMD_ASYNC
API, but the new command is a regular synchronous command. There shouldn't
be visible differences though, as MONITOR_CMD_ASYNC is internal only.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

balloon.c

@@ -100,31 +100,19 @@ BalloonInfo *qmp_query_balloon(Error **errp)
     return info;
 }
 
-/**
- * do_balloon(): Request VM to change its memory allocation
- */
-int do_balloon(Monitor *mon, const QDict *params,
-	       MonitorCompletion cb, void *opaque)
+void qmp_balloon(int64_t value, Error **errp)
 {
-    int64_t target;
-    int ret;
-
     if (kvm_enabled() && !kvm_has_sync_mmu()) {
-        qerror_report(QERR_KVM_MISSING_CAP, "synchronous MMU", "balloon");
-        return -1;
+        error_set(errp, QERR_KVM_MISSING_CAP, "synchronous MMU", "balloon");
+        return;
     }
 
-    target = qdict_get_int(params, "value");
-    if (target <= 0) {
+    if (value <= 0) {
         qerror_report(QERR_INVALID_PARAMETER_VALUE, "target", "a size");
-        return -1;
+        return;
     }
-    ret = qemu_balloon(target);
-    if (ret == 0) {
-        qerror_report(QERR_DEVICE_NOT_ACTIVE, "balloon");
-        return -1;
+    
+    if (qemu_balloon(value) == 0) {
+        error_set(errp, QERR_DEVICE_NOT_ACTIVE, "balloon");
     }
-
-    cb(opaque, NULL);
-    return 0;
 }

balloon.h

@@ -24,7 +24,4 @@ int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
 			     QEMUBalloonStatus *stat_func, void *opaque);
 void qemu_remove_balloon_handler(void *opaque);
 
-int do_balloon(Monitor *mon, const QDict *params,
-               MonitorCompletion cb, void *opaque);
-
 #endif

hmp-commands.hx

@@ -1022,9 +1022,7 @@ ETEXI
         .args_type  = "value:M",
         .params     = "target",
         .help       = "request VM to change its memory allocation (in MB)",
-        .user_print = monitor_user_noop,
-        .mhandler.cmd_async = do_balloon,
-        .flags      = MONITOR_CMD_ASYNC,
+        .mhandler.cmd = hmp_balloon,
     },
 
 STEXI

hmp.c

@@ -621,3 +621,15 @@ void hmp_block_passwd(Monitor *mon, const QDict *qdict)
     qmp_block_passwd(device, password, &errp);
     hmp_handle_error(mon, &errp);
 }
+
+void hmp_balloon(Monitor *mon, const QDict *qdict)
+{
+    int64_t value = qdict_get_int(qdict, "value");
+    Error *errp = NULL;
+
+    qmp_balloon(value, &errp);
+    if (error_is_set(&errp)) {
+        monitor_printf(mon, "balloon: %s\n", error_get_pretty(errp));
+        error_free(errp);
+    }
+}

hmp.h

@@ -43,5 +43,6 @@ void hmp_cont(Monitor *mon, const QDict *qdict);
 void hmp_inject_nmi(Monitor *mon, const QDict *qdict);
 void hmp_set_link(Monitor *mon, const QDict *qdict);
 void hmp_block_passwd(Monitor *mon, const QDict *qdict);
+void hmp_balloon(Monitor *mon, const QDict *qdict);
 
 #endif

qapi-schema.json

@@ -1032,3 +1032,23 @@
 # Since: 0.14.0
 ##
 { 'command': 'block_passwd', 'data': {'device': 'str', 'password': 'str'} }
+
+##
+# @balloon:
+#
+# Request the balloon driver to change its balloon size.
+#
+# @value: the target size of the balloon in bytes
+#
+# Returns: Nothing on success
+#          If the balloon driver is enabled but not functional because the KVM
+#            kernel module cannot support it, KvmMissingCap
+#          If no balloon device is present, DeviceNotActive
+#
+# Notes: This command just issues a request to the guest.  When it returns,
+#        the balloon size may not have changed.  A guest can change the balloon
+#        size independent of this command.
+#
+# Since: 0.14.0
+##
+{ 'command': 'balloon', 'data': {'value': 'int'} }

qmp-commands.hx

@@ -703,11 +703,7 @@ EQMP
     {
         .name       = "balloon",
         .args_type  = "value:M",
-        .params     = "target",
-        .help       = "request VM to change its memory allocation (in MB)",
-        .user_print = monitor_user_noop,
-        .mhandler.cmd_async = do_balloon,
-        .flags      = MONITOR_CMD_ASYNC,
+        .mhandler.cmd_new = qmp_marshal_input_balloon,
     },
 
 SQMP