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 "monitor.h"
  28 #include "qjson.h"
  29 #include "qint.h"
  30 #include "cpu-common.h"
  31 #include "kvm.h"
  32 #include "balloon.h"
  33 #include "trace.h"
  34
  35 static QEMUBalloonEvent *balloon_event_fn;
  36 static QEMUBalloonStatus *balloon_stat_fn;
  37 static void *balloon_opaque;
  38
  39 int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
  40                              QEMUBalloonStatus *stat_func, void *opaque)
  41 {
  42     if (balloon_event_fn || balloon_stat_fn || balloon_opaque) {
  43         /* We're already registered one balloon handler.  How many can
  44          * a guest really have?
  45          */
  46         error_report("Another balloon device already registered");
  47         return -1;
  48     }
  49     balloon_event_fn = event_func;
  50     balloon_stat_fn = stat_func;
  51     balloon_opaque = opaque;
  52     return 0;
  53 }
  54
  55 void qemu_remove_balloon_handler(void *opaque)
  56 {
  57     if (balloon_opaque != opaque) {
  58         return;
  59     }
  60     balloon_event_fn = NULL;
  61     balloon_stat_fn = NULL;
  62     balloon_opaque = NULL;
  63 }
  64
  65 static int qemu_balloon(ram_addr_t target)
  66 {
  67     if (!balloon_event_fn) {
  68         return 0;
  69     }
  70     trace_balloon_event(balloon_opaque, target);
  71     balloon_event_fn(balloon_opaque, target);
  72     return 1;
  73 }
  74
  75 static int qemu_balloon_status(MonitorCompletion cb, void *opaque)
  76 {
  77     if (!balloon_stat_fn) {
  78         return 0;
  79     }
  80     balloon_stat_fn(balloon_opaque, cb, opaque);
  81     return 1;
  82 }
  83
  84 static void print_balloon_stat(const char *key, QObject *obj, void *opaque)
  85 {
  86     Monitor *mon = opaque;
  87
  88     if (strcmp(key, "actual")) {
  89         monitor_printf(mon, ",%s=%" PRId64, key,
  90                        qint_get_int(qobject_to_qint(obj)));
  91     }
  92 }
  93
  94 void monitor_print_balloon(Monitor *mon, const QObject *data)
  95 {
  96     QDict *qdict;
  97
  98     qdict = qobject_to_qdict(data);
  99     if (!qdict_haskey(qdict, "actual")) {
 100         return;
 101     }
 102     monitor_printf(mon, "balloon: actual=%" PRId64,
 103                    qdict_get_int(qdict, "actual") >> 20);
 104     qdict_iter(qdict, print_balloon_stat, mon);
 105     monitor_printf(mon, "\n");
 106 }
 107
 108 /**
 109  * do_info_balloon(): Balloon information
 110  *
 111  * Make an asynchronous request for balloon info.  When the request completes
 112  * a QDict will be returned according to the following specification:
 113  *
 114  * - "actual": current balloon value in bytes
 115  * The following fields may or may not be present:
 116  * - "mem_swapped_in": Amount of memory swapped in (bytes)
 117  * - "mem_swapped_out": Amount of memory swapped out (bytes)
 118  * - "major_page_faults": Number of major faults
 119  * - "minor_page_faults": Number of minor faults
 120  * - "free_mem": Total amount of free and unused memory (bytes)
 121  * - "total_mem": Total amount of available memory (bytes)
 122  *
 123  * Example:
 124  *
 125  * { "actual": 1073741824, "mem_swapped_in": 0, "mem_swapped_out": 0,
 126  *   "major_page_faults": 142, "minor_page_faults": 239245,
 127  *   "free_mem": 1014185984, "total_mem": 1044668416 }
 128  */
 129 int do_info_balloon(Monitor *mon, MonitorCompletion cb, void *opaque)
 130 {
 131     int ret;
 132
 133     if (kvm_enabled() && !kvm_has_sync_mmu()) {
 134         qerror_report(QERR_KVM_MISSING_CAP, "synchronous MMU", "balloon");
 135         return -1;
 136     }
 137
 138     ret = qemu_balloon_status(cb, opaque);
 139     if (!ret) {
 140         qerror_report(QERR_DEVICE_NOT_ACTIVE, "balloon");
 141         return -1;
 142     }
 143
 144     return 0;
 145 }
 146
 147 /**
 148  * do_balloon(): Request VM to change its memory allocation
 149  */
 150 int do_balloon(Monitor *mon, const QDict *params,
 151                MonitorCompletion cb, void *opaque)
 152 {
 153     int64_t target;
 154     int ret;
 155
 156     if (kvm_enabled() && !kvm_has_sync_mmu()) {
 157         qerror_report(QERR_KVM_MISSING_CAP, "synchronous MMU", "balloon");
 158         return -1;
 159     }
 160
 161     target = qdict_get_int(params, "value");
 162     if (target <= 0) {
 163         qerror_report(QERR_INVALID_PARAMETER_VALUE, "target", "a size");
 164         return -1;
 165     }
 166     ret = qemu_balloon(target);
 167     if (ret == 0) {
 168         qerror_report(QERR_DEVICE_NOT_ACTIVE, "balloon");
 169         return -1;
 170     }
 171
 172     cb(opaque, NULL);
 173     return 0;
 174 }