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28c28973 1/*
73428a8e 2 * Generic Balloon handlers and management
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3 *
4 * Copyright (c) 2003-2008 Fabrice Bellard
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5 * Copyright (C) 2011 Red Hat, Inc.
6 * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
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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
d38ea87a 27#include "qemu/osdep.h"
a0b1a66e 28#include "qemu-common.h"
022c62cb 29#include "exec/cpu-common.h"
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30#include "sysemu/kvm.h"
31#include "sysemu/balloon.h"
0ab8ed18 32#include "trace-root.h"
e688df6b 33#include "qapi/error.h"
112ed241 34#include "qapi/qapi-commands-misc.h"
cc7a8ea7 35#include "qapi/qmp/qerror.h"
28c28973 36
0a2a30d5 37static QEMUBalloonEvent *balloon_event_fn;
30fb2ca6 38static QEMUBalloonStatus *balloon_stat_fn;
0a2a30d5 39static void *balloon_opaque;
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40static bool balloon_inhibited;
41
42bool qemu_balloon_is_inhibited(void)
43{
44 return balloon_inhibited;
45}
46
47void qemu_balloon_inhibit(bool state)
48{
49 balloon_inhibited = state;
50}
28c28973 51
438e8289 52static bool have_balloon(Error **errp)
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53{
54 if (kvm_enabled() && !kvm_has_sync_mmu()) {
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55 error_set(errp, ERROR_CLASS_KVM_MISSING_CAP,
56 "Using KVM without synchronous MMU, balloon unavailable");
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57 return false;
58 }
59 if (!balloon_event_fn) {
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60 error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
61 "No balloon device has been activated");
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62 return false;
63 }
64 return true;
65}
66
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67int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
68 QEMUBalloonStatus *stat_func, void *opaque)
28c28973 69{
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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 */
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74 return -1;
75 }
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76 balloon_event_fn = event_func;
77 balloon_stat_fn = stat_func;
0a2a30d5 78 balloon_opaque = opaque;
6c6ec182 79 return 0;
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80}
81
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82void 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
96637bcd 92BalloonInfo *qmp_query_balloon(Error **errp)
28c28973 93{
96637bcd 94 BalloonInfo *info;
28c28973 95
438e8289 96 if (!have_balloon(errp)) {
96637bcd 97 return NULL;
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98 }
99
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100 info = g_malloc0(sizeof(*info));
101 balloon_stat_fn(balloon_opaque, info);
96637bcd 102 return info;
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103}
104
6502a147 105void qmp_balloon(int64_t target, Error **errp)
28c28973 106{
438e8289 107 if (!have_balloon(errp)) {
d72f3264 108 return;
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109 }
110
6502a147 111 if (target <= 0) {
c6bd8c70 112 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "target", "a size");
d72f3264 113 return;
514e73ec 114 }
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115
116 trace_balloon_event(balloon_opaque, target);
117 balloon_event_fn(balloon_opaque, target);
28c28973 118}