qemu/hw/kvmclock.c

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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.
*
*/
#include "qemu-common.h"
#include "sysemu.h"
#include "sysbus.h"
#include "kvm.h"
#include "kvmclock.h"
#include <linux/kvm.h>
#include <linux/kvm_para.h>
typedef struct KVMClockState {
SysBusDevice busdev;
uint64_t clock;
bool clock_valid;
} KVMClockState;
static void kvmclock_pre_save(void *opaque)
{
KVMClockState *s = opaque;
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));
data.clock = 0;
}
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 = !vm_running;
}
static int kvmclock_post_load(void *opaque, int version_id)
{
KVMClockState *s = opaque;
struct kvm_clock_data data;
data.clock = s->clock;
data.flags = 0;
return kvm_vm_ioctl(kvm_state, KVM_SET_CLOCK, &data);
}
static void kvmclock_vm_state_change(void *opaque, int running, int reason)
{
KVMClockState *s = opaque;
if (running) {
s->clock_valid = false;
}
}
static int kvmclock_init(SysBusDevice *dev)
{
KVMClockState *s = FROM_SYSBUS(KVMClockState, dev);
qemu_add_vm_change_state_handler(kvmclock_vm_state_change, s);
return 0;
}
static const VMStateDescription kvmclock_vmsd = {
.name = "kvmclock",
.version_id = 1,
.minimum_version_id = 1,
.minimum_version_id_old = 1,
.pre_save = kvmclock_pre_save,
.post_load = kvmclock_post_load,
.fields = (VMStateField[]) {
VMSTATE_UINT64(clock, KVMClockState),
VMSTATE_END_OF_LIST()
}
};
static SysBusDeviceInfo kvmclock_info = {
.qdev.name = "kvmclock",
.qdev.size = sizeof(KVMClockState),
.qdev.vmsd = &kvmclock_vmsd,
.qdev.no_user = 1,
.init = kvmclock_init,
};
/* Note: Must be called after VCPU initialization. */
void kvmclock_create(void)
{
if (kvm_enabled() &&
first_cpu->cpuid_kvm_features & ((1ULL << KVM_FEATURE_CLOCKSOURCE) |
(1ULL << KVM_FEATURE_CLOCKSOURCE2))) {
sysbus_create_simple("kvmclock", -1, NULL);
}
}
static void kvmclock_register_device(void)
{
if (kvm_enabled()) {
sysbus_register_withprop(&kvmclock_info);
}
}
device_init(kvmclock_register_device);