hw/net: fix vmxnet3 live migration
[qemu/ar7.git] / balloon.c
blob914b3662db39d6e825dbf8b19873935ff52f8af4
1 /*
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
24 * THE SOFTWARE.
27 #include "qemu/osdep.h"
28 #include "qemu/atomic.h"
29 #include "exec/cpu-common.h"
30 #include "sysemu/kvm.h"
31 #include "sysemu/balloon.h"
32 #include "trace-root.h"
33 #include "qapi/error.h"
34 #include "qapi/qapi-commands-misc.h"
35 #include "qapi/qmp/qerror.h"
37 static QEMUBalloonEvent *balloon_event_fn;
38 static QEMUBalloonStatus *balloon_stat_fn;
39 static void *balloon_opaque;
40 static int balloon_inhibit_count;
42 bool qemu_balloon_is_inhibited(void)
44 return atomic_read(&balloon_inhibit_count) > 0;
47 void qemu_balloon_inhibit(bool state)
49 if (state) {
50 atomic_inc(&balloon_inhibit_count);
51 } else {
52 atomic_dec(&balloon_inhibit_count);
55 assert(atomic_read(&balloon_inhibit_count) >= 0);
58 static bool have_balloon(Error **errp)
60 if (kvm_enabled() && !kvm_has_sync_mmu()) {
61 error_set(errp, ERROR_CLASS_KVM_MISSING_CAP,
62 "Using KVM without synchronous MMU, balloon unavailable");
63 return false;
65 if (!balloon_event_fn) {
66 error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
67 "No balloon device has been activated");
68 return false;
70 return true;
73 int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
74 QEMUBalloonStatus *stat_func, void *opaque)
76 if (balloon_event_fn || balloon_stat_fn || balloon_opaque) {
77 /* We're already registered one balloon handler. How many can
78 * a guest really have?
80 return -1;
82 balloon_event_fn = event_func;
83 balloon_stat_fn = stat_func;
84 balloon_opaque = opaque;
85 return 0;
88 void qemu_remove_balloon_handler(void *opaque)
90 if (balloon_opaque != opaque) {
91 return;
93 balloon_event_fn = NULL;
94 balloon_stat_fn = NULL;
95 balloon_opaque = NULL;
98 BalloonInfo *qmp_query_balloon(Error **errp)
100 BalloonInfo *info;
102 if (!have_balloon(errp)) {
103 return NULL;
106 info = g_malloc0(sizeof(*info));
107 balloon_stat_fn(balloon_opaque, info);
108 return info;
111 void qmp_balloon(int64_t target, Error **errp)
113 if (!have_balloon(errp)) {
114 return;
117 if (target <= 0) {
118 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "target", "a size");
119 return;
122 trace_balloon_event(balloon_opaque, target);
123 balloon_event_fn(balloon_opaque, target);