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