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/*

 * QEMU KVM support, paravirtual clock device

 *

 * Copyright (C) 2011 Siemens AG

 *

 * Authors:

 *  Jan Kiszka        <jan.kiszka@siemens.com>

 *

 * This work is licensed under the terms of the GNU GPL version 2.

 * See the COPYING file in the top-level directory.

 *

 * Contributions after 2012-01-13 are licensed under the terms of the

 * GNU GPL, version 2 or (at your option) any later version.

 */

#include "qemu-common.h"

#include "sysemu/sysemu.h"

#include "sysemu/kvm.h"

#include "hw/sysbus.h"

#include "hw/kvm/clock.h"

#include <linux/kvm.h>

#include <linux/kvm_para.h>

#define TYPE_KVM_CLOCK "kvmclock"

#define KVM_CLOCK(obj) OBJECT_CHECK(KVMClockState, (obj), TYPE_KVM_CLOCK)

typedef struct KVMClockState {

    /*< private >*/

    SysBusDevice busdev;

    /*< public >*/

    uint64_t clock;

    bool clock_valid;

} KVMClockState;

static void kvmclock_vm_state_change(void *opaque, int running,

                                     RunState state)

{

    KVMClockState *s = opaque;

    CPUState *cpu;

    int cap_clock_ctrl = kvm_check_extension(kvm_state, KVM_CAP_KVMCLOCK_CTRL);

    int ret;

    if (running) {

        struct kvm_clock_data data;

        s->clock_valid = false;

        data.clock = s->clock;

        data.flags = 0;

        ret = kvm_vm_ioctl(kvm_state, KVM_SET_CLOCK, &data);

        if (ret < 0) {

            fprintf(stderr, "KVM_SET_CLOCK failed: %s\n", strerror(ret));

            abort();

        }

        if (!cap_clock_ctrl) {

            return;

        }

        CPU_FOREACH(cpu) {

            ret = kvm_vcpu_ioctl(cpu, KVM_KVMCLOCK_CTRL, 0);

            if (ret) {

                if (ret != -EINVAL) {

                    fprintf(stderr, "%s: %s\n", __func__, strerror(-ret));

                }

                return;

            }

        }

    } else {

        struct kvm_clock_data data;

        int ret;

        if (s->clock_valid) {

            return;

        }

        ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);

        if (ret < 0) {

            fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));

            abort();

        }

        s->clock = data.clock;

        /*

         * If the VM is stopped, declare the clock state valid to

         * avoid re-reading it on next vmsave (which would return

         * a different value). Will be reset when the VM is continued.

         */

        s->clock_valid = true;

    }

}

static void kvmclock_realize(DeviceState *dev, Error **errp)

{

    KVMClockState *s = KVM_CLOCK(dev);

    qemu_add_vm_change_state_handler(kvmclock_vm_state_change, s);

}

static const VMStateDescription kvmclock_vmsd = {

    .name = "kvmclock",

    .version_id = 1,

    .minimum_version_id = 1,

    .minimum_version_id_old = 1,

    .fields = (VMStateField[]) {

        VMSTATE_UINT64(clock, KVMClockState),

        VMSTATE_END_OF_LIST()

    }

};

static void kvmclock_class_init(ObjectClass *klass, void *data)

{

    DeviceClass *dc = DEVICE_CLASS(klass);

    dc->realize = kvmclock_realize;

    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */

    dc->vmsd = &kvmclock_vmsd;

}

static const TypeInfo kvmclock_info = {

    .name          = TYPE_KVM_CLOCK,

    .parent        = TYPE_SYS_BUS_DEVICE,

    .instance_size = sizeof(KVMClockState),

    .class_init    = kvmclock_class_init,

};

/* Note: Must be called after VCPU initialization. */

void kvmclock_create(void)

{

    X86CPU *cpu = X86_CPU(first_cpu);

    if (kvm_enabled() &&

        cpu->env.features[FEAT_KVM] & ((1ULL << KVM_FEATURE_CLOCKSOURCE) |

                                       (1ULL << KVM_FEATURE_CLOCKSOURCE2))) {

        sysbus_create_simple(TYPE_KVM_CLOCK, -1, NULL);

    }

}

static void kvmclock_register_types(void)

{

    type_register_static(&kvmclock_info);

}

type_init(kvmclock_register_types)