aboutsummaryrefslogtreecommitdiff
path: root/hw/i386/kvm/clock.c
blob: 383938d1bc3058be9925e942b519b4aa231c232a (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
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
/*
 * 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->no_user = 1;
    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)