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