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/*
* Generic Balloon handlers and management
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (C) 2011 Red Hat, Inc.
* Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/atomic.h"
#include "exec/cpu-common.h"
#include "sysemu/kvm.h"
#include "sysemu/balloon.h"
#include "trace-root.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-misc.h"
#include "qapi/qmp/qerror.h"
static QEMUBalloonEvent *balloon_event_fn;
static QEMUBalloonStatus *balloon_stat_fn;
static void *balloon_opaque;
static int balloon_inhibit_count;
bool qemu_balloon_is_inhibited(void)
{
return atomic_read(&balloon_inhibit_count) > 0;
}
void qemu_balloon_inhibit(bool state)
{
if (state) {
atomic_inc(&balloon_inhibit_count);
} else {
atomic_dec(&balloon_inhibit_count);
}
assert(atomic_read(&balloon_inhibit_count) >= 0);
}
static bool have_balloon(Error **errp)
{
if (kvm_enabled() && !kvm_has_sync_mmu()) {
error_set(errp, ERROR_CLASS_KVM_MISSING_CAP,
"Using KVM without synchronous MMU, balloon unavailable");
return false;
}
if (!balloon_event_fn) {
error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
"No balloon device has been activated");
return false;
}
return true;
}
int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
QEMUBalloonStatus *stat_func, void *opaque)
{
if (balloon_event_fn || balloon_stat_fn || balloon_opaque) {
/* We're already registered one balloon handler. How many can
* a guest really have?
*/
return -1;
}
balloon_event_fn = event_func;
balloon_stat_fn = stat_func;
balloon_opaque = opaque;
return 0;
}
void qemu_remove_balloon_handler(void *opaque)
{
if (balloon_opaque != opaque) {
return;
}
balloon_event_fn = NULL;
balloon_stat_fn = NULL;
balloon_opaque = NULL;
}
BalloonInfo *qmp_query_balloon(Error **errp)
{
BalloonInfo *info;
if (!have_balloon(errp)) {
return NULL;
}
info = g_malloc0(sizeof(*info));
balloon_stat_fn(balloon_opaque, info);
return info;
}
void qmp_balloon(int64_t target, Error **errp)
{
if (!have_balloon(errp)) {
return;
}
if (target <= 0) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "target", "a size");
return;
}
trace_balloon_event(balloon_opaque, target);
balloon_event_fn(balloon_opaque, target);
}
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