aboutsummaryrefslogtreecommitdiffstats
path: root/hw/kvm/clock.c
blob: bb28c088db6b5b02b25484b32791d76146ae0790 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
/*
 * 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.h"
#include "kvm.h"
#include "hw/sysbus.h"
#include "hw/kvm/clock.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 = !runstate_is_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,
                                     RunState state)
{
    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);