balloon.c 3.44 KB
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/*
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 * Generic Balloon handlers and management
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 *
 * Copyright (c) 2003-2008 Fabrice Bellard
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 * Copyright (C) 2011 Red Hat, Inc.
 * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
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 *
 * 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.
 */

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#include "monitor/monitor.h"
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#include "exec/cpu-common.h"
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#include "sysemu/kvm.h"
#include "sysemu/balloon.h"
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#include "trace.h"
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#include "qmp-commands.h"
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#include "qapi/qmp/qjson.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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int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
                             QEMUBalloonStatus *stat_func, void *opaque)
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{
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    if (balloon_event_fn || balloon_stat_fn || balloon_opaque) {
        /* We're already registered one balloon handler.  How many can
         * a guest really have?
         */
        error_report("Another balloon device already registered");
        return -1;
    }
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    balloon_event_fn = event_func;
    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)
{
    if (balloon_opaque != opaque) {
        return;
    }
    balloon_event_fn = NULL;
    balloon_stat_fn = NULL;
    balloon_opaque = NULL;
}

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static int qemu_balloon(ram_addr_t target)
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{
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    if (!balloon_event_fn) {
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        return 0;
    }
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    trace_balloon_event(balloon_opaque, target);
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    balloon_event_fn(balloon_opaque, target);
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    return 1;
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}

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static int qemu_balloon_status(BalloonInfo *info)
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{
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    if (!balloon_stat_fn) {
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        return 0;
    }
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    balloon_stat_fn(balloon_opaque, info);
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    return 1;
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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 (kvm_enabled() && !kvm_has_sync_mmu()) {
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        error_set(errp, QERR_KVM_MISSING_CAP, "synchronous MMU", "balloon");
        return NULL;
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    }

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    info = g_malloc0(sizeof(*info));

    if (qemu_balloon_status(info) == 0) {
        error_set(errp, QERR_DEVICE_NOT_ACTIVE, "balloon");
        qapi_free_BalloonInfo(info);
        return NULL;
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    }

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    return info;
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}

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void qmp_balloon(int64_t value, Error **errp)
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{
    if (kvm_enabled() && !kvm_has_sync_mmu()) {
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        error_set(errp, QERR_KVM_MISSING_CAP, "synchronous MMU", "balloon");
        return;
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    }

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    if (value <= 0) {
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        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "target", "a size");
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        return;
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    }
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    if (qemu_balloon(value) == 0) {
        error_set(errp, QERR_DEVICE_NOT_ACTIVE, "balloon");
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    }
}