1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16#include "qemu/osdep.h"
17#include "qemu-common.h"
18#include "cpu.h"
19#include "qemu/host-utils.h"
20#include "sysemu/sysemu.h"
21#include "sysemu/kvm.h"
22#include "kvm_i386.h"
23#include "hw/sysbus.h"
24#include "hw/kvm/clock.h"
25
26#include <linux/kvm.h>
27#include <linux/kvm_para.h>
28
29#define TYPE_KVM_CLOCK "kvmclock"
30#define KVM_CLOCK(obj) OBJECT_CHECK(KVMClockState, (obj), TYPE_KVM_CLOCK)
31
32typedef struct KVMClockState {
33
34 SysBusDevice busdev;
35
36
37 uint64_t clock;
38 bool clock_valid;
39} KVMClockState;
40
41struct pvclock_vcpu_time_info {
42 uint32_t version;
43 uint32_t pad0;
44 uint64_t tsc_timestamp;
45 uint64_t system_time;
46 uint32_t tsc_to_system_mul;
47 int8_t tsc_shift;
48 uint8_t flags;
49 uint8_t pad[2];
50} __attribute__((__packed__));
51
52static uint64_t kvmclock_current_nsec(KVMClockState *s)
53{
54 CPUState *cpu = first_cpu;
55 CPUX86State *env = cpu->env_ptr;
56 hwaddr kvmclock_struct_pa = env->system_time_msr & ~1ULL;
57 uint64_t migration_tsc = env->tsc;
58 struct pvclock_vcpu_time_info time;
59 uint64_t delta;
60 uint64_t nsec_lo;
61 uint64_t nsec_hi;
62 uint64_t nsec;
63
64 if (!(env->system_time_msr & 1ULL)) {
65
66 return 0;
67 }
68
69 cpu_physical_memory_read(kvmclock_struct_pa, &time, sizeof(time));
70
71 assert(time.tsc_timestamp <= migration_tsc);
72 delta = migration_tsc - time.tsc_timestamp;
73 if (time.tsc_shift < 0) {
74 delta >>= -time.tsc_shift;
75 } else {
76 delta <<= time.tsc_shift;
77 }
78
79 mulu64(&nsec_lo, &nsec_hi, delta, time.tsc_to_system_mul);
80 nsec = (nsec_lo >> 32) | (nsec_hi << 32);
81 return nsec + time.system_time;
82}
83
84static void kvmclock_vm_state_change(void *opaque, int running,
85 RunState state)
86{
87 KVMClockState *s = opaque;
88 CPUState *cpu;
89 int cap_clock_ctrl = kvm_check_extension(kvm_state, KVM_CAP_KVMCLOCK_CTRL);
90 int ret;
91
92 if (running) {
93 struct kvm_clock_data data = {};
94 uint64_t time_at_migration = kvmclock_current_nsec(s);
95
96 s->clock_valid = false;
97
98
99 if (time_at_migration) {
100 s->clock = time_at_migration;
101 }
102
103 data.clock = s->clock;
104 ret = kvm_vm_ioctl(kvm_state, KVM_SET_CLOCK, &data);
105 if (ret < 0) {
106 fprintf(stderr, "KVM_SET_CLOCK failed: %s\n", strerror(ret));
107 abort();
108 }
109
110 if (!cap_clock_ctrl) {
111 return;
112 }
113 CPU_FOREACH(cpu) {
114 ret = kvm_vcpu_ioctl(cpu, KVM_KVMCLOCK_CTRL, 0);
115 if (ret) {
116 if (ret != -EINVAL) {
117 fprintf(stderr, "%s: %s\n", __func__, strerror(-ret));
118 }
119 return;
120 }
121 }
122 } else {
123 struct kvm_clock_data data;
124 int ret;
125
126 if (s->clock_valid) {
127 return;
128 }
129
130 kvm_synchronize_all_tsc();
131
132 ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
133 if (ret < 0) {
134 fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
135 abort();
136 }
137 s->clock = data.clock;
138
139
140
141
142
143
144 s->clock_valid = true;
145 }
146}
147
148static void kvmclock_realize(DeviceState *dev, Error **errp)
149{
150 KVMClockState *s = KVM_CLOCK(dev);
151
152 qemu_add_vm_change_state_handler(kvmclock_vm_state_change, s);
153}
154
155static const VMStateDescription kvmclock_vmsd = {
156 .name = "kvmclock",
157 .version_id = 1,
158 .minimum_version_id = 1,
159 .fields = (VMStateField[]) {
160 VMSTATE_UINT64(clock, KVMClockState),
161 VMSTATE_END_OF_LIST()
162 }
163};
164
165static void kvmclock_class_init(ObjectClass *klass, void *data)
166{
167 DeviceClass *dc = DEVICE_CLASS(klass);
168
169 dc->realize = kvmclock_realize;
170 dc->vmsd = &kvmclock_vmsd;
171}
172
173static const TypeInfo kvmclock_info = {
174 .name = TYPE_KVM_CLOCK,
175 .parent = TYPE_SYS_BUS_DEVICE,
176 .instance_size = sizeof(KVMClockState),
177 .class_init = kvmclock_class_init,
178};
179
180
181void kvmclock_create(void)
182{
183 X86CPU *cpu = X86_CPU(first_cpu);
184
185 if (kvm_enabled() &&
186 cpu->env.features[FEAT_KVM] & ((1ULL << KVM_FEATURE_CLOCKSOURCE) |
187 (1ULL << KVM_FEATURE_CLOCKSOURCE2))) {
188 sysbus_create_simple(TYPE_KVM_CLOCK, -1, NULL);
189 }
190}
191
192static void kvmclock_register_types(void)
193{
194 type_register_static(&kvmclock_info);
195}
196
197type_init(kvmclock_register_types)
198