Merge remote-tracking branch 'remotes/kraxel/tags/pull-vga-20170103-1' into staging
[qemu.git] / balloon.c
1 /*
2 * Generic Balloon handlers and management
3 *
4 * Copyright (c) 2003-2008 Fabrice Bellard
5 * Copyright (C) 2011 Red Hat, Inc.
6 * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
7 *
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:
14 *
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
17 *
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.
25 */
26
27 #include "qemu/osdep.h"
28 #include "qemu-common.h"
29 #include "exec/cpu-common.h"
30 #include "sysemu/kvm.h"
31 #include "sysemu/balloon.h"
32 #include "trace.h"
33 #include "qmp-commands.h"
34 #include "qapi/qmp/qerror.h"
35 #include "qapi/qmp/qjson.h"
36
37 static QEMUBalloonEvent *balloon_event_fn;
38 static QEMUBalloonStatus *balloon_stat_fn;
39 static void *balloon_opaque;
40 static bool balloon_inhibited;
41
42 bool qemu_balloon_is_inhibited(void)
43 {
44 return balloon_inhibited;
45 }
46
47 void qemu_balloon_inhibit(bool state)
48 {
49 balloon_inhibited = state;
50 }
51
52 static bool have_balloon(Error **errp)
53 {
54 if (kvm_enabled() && !kvm_has_sync_mmu()) {
55 error_set(errp, ERROR_CLASS_KVM_MISSING_CAP,
56 "Using KVM without synchronous MMU, balloon unavailable");
57 return false;
58 }
59 if (!balloon_event_fn) {
60 error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
61 "No balloon device has been activated");
62 return false;
63 }
64 return true;
65 }
66
67 int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
68 QEMUBalloonStatus *stat_func, void *opaque)
69 {
70 if (balloon_event_fn || balloon_stat_fn || balloon_opaque) {
71 /* We're already registered one balloon handler. How many can
72 * a guest really have?
73 */
74 return -1;
75 }
76 balloon_event_fn = event_func;
77 balloon_stat_fn = stat_func;
78 balloon_opaque = opaque;
79 return 0;
80 }
81
82 void qemu_remove_balloon_handler(void *opaque)
83 {
84 if (balloon_opaque != opaque) {
85 return;
86 }
87 balloon_event_fn = NULL;
88 balloon_stat_fn = NULL;
89 balloon_opaque = NULL;
90 }
91
92 BalloonInfo *qmp_query_balloon(Error **errp)
93 {
94 BalloonInfo *info;
95
96 if (!have_balloon(errp)) {
97 return NULL;
98 }
99
100 info = g_malloc0(sizeof(*info));
101 balloon_stat_fn(balloon_opaque, info);
102 return info;
103 }
104
105 void qmp_balloon(int64_t target, Error **errp)
106 {
107 if (!have_balloon(errp)) {
108 return;
109 }
110
111 if (target <= 0) {
112 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "target", "a size");
113 return;
114 }
115
116 trace_balloon_event(balloon_opaque, target);
117 balloon_event_fn(balloon_opaque, target);
118 }