2 * Generic Balloon handlers and management
4 * Copyright (c) 2003-2008 Fabrice Bellard
5 * Copyright (C) 2011 Red Hat, Inc.
6 * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions:
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
27 #include "qemu/osdep.h"
28 #include "qemu/atomic.h"
29 #include "sysemu/kvm.h"
30 #include "sysemu/balloon.h"
31 #include "qapi/error.h"
32 #include "qapi/qapi-commands-machine.h"
33 #include "qapi/qmp/qerror.h"
36 static QEMUBalloonEvent *balloon_event_fn;
37 static QEMUBalloonStatus *balloon_stat_fn;
38 static void *balloon_opaque;
40 static bool have_balloon(Error **errp)
42 if (kvm_enabled() && !kvm_has_sync_mmu()) {
43 error_set(errp, ERROR_CLASS_KVM_MISSING_CAP,
44 "Using KVM without synchronous MMU, balloon unavailable");
47 if (!balloon_event_fn) {
48 error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
49 "No balloon device has been activated");
55 int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
56 QEMUBalloonStatus *stat_func, void *opaque)
58 if (balloon_event_fn || balloon_stat_fn || balloon_opaque) {
59 /* We're already registered one balloon handler. How many can
60 * a guest really have?
64 balloon_event_fn = event_func;
65 balloon_stat_fn = stat_func;
66 balloon_opaque = opaque;
70 void qemu_remove_balloon_handler(void *opaque)
72 if (balloon_opaque != opaque) {
75 balloon_event_fn = NULL;
76 balloon_stat_fn = NULL;
77 balloon_opaque = NULL;
80 BalloonInfo *qmp_query_balloon(Error **errp)
84 if (!have_balloon(errp)) {
88 info = g_malloc0(sizeof(*info));
89 balloon_stat_fn(balloon_opaque, info);
93 void qmp_balloon(int64_t target, Error **errp)
95 if (!have_balloon(errp)) {
100 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "target", "a size");
104 trace_balloon_event(balloon_opaque, target);
105 balloon_event_fn(balloon_opaque, target);