1 /* 2 * KVM in-kernel PIT (i8254) support 3 * 4 * Copyright (c) 2003-2004 Fabrice Bellard 5 * Copyright (c) 2012 Jan Kiszka, Siemens AG 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy 8 * of this software and associated documentation files (the "Software"), to deal 9 * in the Software without restriction, including without limitation the rights 10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11 * copies of the Software, and to permit persons to whom the Software is 12 * furnished to do so, subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 23 * THE SOFTWARE. 24 */ 25 26 #include "qemu/osdep.h" 27 #include <linux/kvm.h> 28 #include "qapi/qapi-types-misc.h" 29 #include "qapi/error.h" 30 #include "qemu/module.h" 31 #include "qemu/timer.h" 32 #include "sysemu/sysemu.h" 33 #include "hw/timer/i8254.h" 34 #include "hw/timer/i8254_internal.h" 35 #include "sysemu/kvm.h" 36 37 #define KVM_PIT_REINJECT_BIT 0 38 39 #define CALIBRATION_ROUNDS 3 40 41 #define KVM_PIT(obj) OBJECT_CHECK(KVMPITState, (obj), TYPE_KVM_I8254) 42 #define KVM_PIT_CLASS(class) \ 43 OBJECT_CLASS_CHECK(KVMPITClass, (class), TYPE_KVM_I8254) 44 #define KVM_PIT_GET_CLASS(obj) \ 45 OBJECT_GET_CLASS(KVMPITClass, (obj), TYPE_KVM_I8254) 46 47 typedef struct KVMPITState { 48 PITCommonState parent_obj; 49 50 LostTickPolicy lost_tick_policy; 51 bool vm_stopped; 52 int64_t kernel_clock_offset; 53 } KVMPITState; 54 55 typedef struct KVMPITClass { 56 PITCommonClass parent_class; 57 58 DeviceRealize parent_realize; 59 } KVMPITClass; 60 61 static int64_t abs64(int64_t v) 62 { 63 return v < 0 ? -v : v; 64 } 65 66 static void kvm_pit_update_clock_offset(KVMPITState *s) 67 { 68 int64_t offset, clock_offset; 69 struct timespec ts; 70 int i; 71 72 /* 73 * Measure the delta between CLOCK_MONOTONIC, the base used for 74 * kvm_pit_channel_state::count_load_time, and QEMU_CLOCK_VIRTUAL. Take the 75 * minimum of several samples to filter out scheduling noise. 76 */ 77 clock_offset = INT64_MAX; 78 for (i = 0; i < CALIBRATION_ROUNDS; i++) { 79 offset = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 80 clock_gettime(CLOCK_MONOTONIC, &ts); 81 offset -= ts.tv_nsec; 82 offset -= (int64_t)ts.tv_sec * 1000000000; 83 if (abs64(offset) < abs64(clock_offset)) { 84 clock_offset = offset; 85 } 86 } 87 s->kernel_clock_offset = clock_offset; 88 } 89 90 static void kvm_pit_get(PITCommonState *pit) 91 { 92 KVMPITState *s = KVM_PIT(pit); 93 struct kvm_pit_state2 kpit; 94 struct kvm_pit_channel_state *kchan; 95 struct PITChannelState *sc; 96 int i, ret; 97 98 /* No need to re-read the state if VM is stopped. */ 99 if (s->vm_stopped) { 100 return; 101 } 102 103 if (kvm_has_pit_state2()) { 104 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit); 105 if (ret < 0) { 106 fprintf(stderr, "KVM_GET_PIT2 failed: %s\n", strerror(ret)); 107 abort(); 108 } 109 pit->channels[0].irq_disabled = kpit.flags & KVM_PIT_FLAGS_HPET_LEGACY; 110 } else { 111 /* 112 * kvm_pit_state2 is superset of kvm_pit_state struct, 113 * so we can use it for KVM_GET_PIT as well. 114 */ 115 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT, &kpit); 116 if (ret < 0) { 117 fprintf(stderr, "KVM_GET_PIT failed: %s\n", strerror(ret)); 118 abort(); 119 } 120 } 121 for (i = 0; i < 3; i++) { 122 kchan = &kpit.channels[i]; 123 sc = &pit->channels[i]; 124 sc->count = kchan->count; 125 sc->latched_count = kchan->latched_count; 126 sc->count_latched = kchan->count_latched; 127 sc->status_latched = kchan->status_latched; 128 sc->status = kchan->status; 129 sc->read_state = kchan->read_state; 130 sc->write_state = kchan->write_state; 131 sc->write_latch = kchan->write_latch; 132 sc->rw_mode = kchan->rw_mode; 133 sc->mode = kchan->mode; 134 sc->bcd = kchan->bcd; 135 sc->gate = kchan->gate; 136 sc->count_load_time = kchan->count_load_time + s->kernel_clock_offset; 137 } 138 139 sc = &pit->channels[0]; 140 sc->next_transition_time = 141 pit_get_next_transition_time(sc, sc->count_load_time); 142 } 143 144 static void kvm_pit_put(PITCommonState *pit) 145 { 146 KVMPITState *s = KVM_PIT(pit); 147 struct kvm_pit_state2 kpit = {}; 148 struct kvm_pit_channel_state *kchan; 149 struct PITChannelState *sc; 150 int i, ret; 151 152 /* The offset keeps changing as long as the VM is stopped. */ 153 if (s->vm_stopped) { 154 kvm_pit_update_clock_offset(s); 155 } 156 157 kpit.flags = pit->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0; 158 for (i = 0; i < 3; i++) { 159 kchan = &kpit.channels[i]; 160 sc = &pit->channels[i]; 161 kchan->count = sc->count; 162 kchan->latched_count = sc->latched_count; 163 kchan->count_latched = sc->count_latched; 164 kchan->status_latched = sc->status_latched; 165 kchan->status = sc->status; 166 kchan->read_state = sc->read_state; 167 kchan->write_state = sc->write_state; 168 kchan->write_latch = sc->write_latch; 169 kchan->rw_mode = sc->rw_mode; 170 kchan->mode = sc->mode; 171 kchan->bcd = sc->bcd; 172 kchan->gate = sc->gate; 173 kchan->count_load_time = sc->count_load_time - s->kernel_clock_offset; 174 } 175 176 ret = kvm_vm_ioctl(kvm_state, 177 kvm_has_pit_state2() ? KVM_SET_PIT2 : KVM_SET_PIT, 178 &kpit); 179 if (ret < 0) { 180 fprintf(stderr, "%s failed: %s\n", 181 kvm_has_pit_state2() ? "KVM_SET_PIT2" : "KVM_SET_PIT", 182 strerror(ret)); 183 abort(); 184 } 185 } 186 187 static void kvm_pit_set_gate(PITCommonState *s, PITChannelState *sc, int val) 188 { 189 kvm_pit_get(s); 190 191 switch (sc->mode) { 192 default: 193 case 0: 194 case 4: 195 /* XXX: just disable/enable counting */ 196 break; 197 case 1: 198 case 2: 199 case 3: 200 case 5: 201 if (sc->gate < val) { 202 /* restart counting on rising edge */ 203 sc->count_load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 204 } 205 break; 206 } 207 sc->gate = val; 208 209 kvm_pit_put(s); 210 } 211 212 static void kvm_pit_get_channel_info(PITCommonState *s, PITChannelState *sc, 213 PITChannelInfo *info) 214 { 215 kvm_pit_get(s); 216 217 pit_get_channel_info_common(s, sc, info); 218 } 219 220 static void kvm_pit_reset(DeviceState *dev) 221 { 222 PITCommonState *s = PIT_COMMON(dev); 223 224 pit_reset_common(s); 225 226 kvm_pit_put(s); 227 } 228 229 static void kvm_pit_irq_control(void *opaque, int n, int enable) 230 { 231 PITCommonState *pit = opaque; 232 PITChannelState *s = &pit->channels[0]; 233 234 kvm_pit_get(pit); 235 236 s->irq_disabled = !enable; 237 238 kvm_pit_put(pit); 239 } 240 241 static void kvm_pit_vm_state_change(void *opaque, int running, 242 RunState state) 243 { 244 KVMPITState *s = opaque; 245 246 if (running) { 247 kvm_pit_update_clock_offset(s); 248 kvm_pit_put(PIT_COMMON(s)); 249 s->vm_stopped = false; 250 } else { 251 kvm_pit_update_clock_offset(s); 252 kvm_pit_get(PIT_COMMON(s)); 253 s->vm_stopped = true; 254 } 255 } 256 257 static void kvm_pit_realizefn(DeviceState *dev, Error **errp) 258 { 259 PITCommonState *pit = PIT_COMMON(dev); 260 KVMPITClass *kpc = KVM_PIT_GET_CLASS(dev); 261 KVMPITState *s = KVM_PIT(pit); 262 struct kvm_pit_config config = { 263 .flags = 0, 264 }; 265 int ret; 266 267 if (kvm_check_extension(kvm_state, KVM_CAP_PIT2)) { 268 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT2, &config); 269 } else { 270 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT); 271 } 272 if (ret < 0) { 273 error_setg(errp, "Create kernel PIC irqchip failed: %s", 274 strerror(ret)); 275 return; 276 } 277 switch (s->lost_tick_policy) { 278 case LOST_TICK_POLICY_DELAY: 279 break; /* enabled by default */ 280 case LOST_TICK_POLICY_DISCARD: 281 if (kvm_check_extension(kvm_state, KVM_CAP_REINJECT_CONTROL)) { 282 struct kvm_reinject_control control = { .pit_reinject = 0 }; 283 284 ret = kvm_vm_ioctl(kvm_state, KVM_REINJECT_CONTROL, &control); 285 if (ret < 0) { 286 error_setg(errp, 287 "Can't disable in-kernel PIT reinjection: %s", 288 strerror(ret)); 289 return; 290 } 291 } 292 break; 293 default: 294 error_setg(errp, "Lost tick policy not supported."); 295 return; 296 } 297 298 memory_region_init_io(&pit->ioports, OBJECT(dev), NULL, NULL, "kvm-pit", 4); 299 300 qdev_init_gpio_in(dev, kvm_pit_irq_control, 1); 301 302 qemu_add_vm_change_state_handler(kvm_pit_vm_state_change, s); 303 304 kpc->parent_realize(dev, errp); 305 } 306 307 static Property kvm_pit_properties[] = { 308 DEFINE_PROP_UINT32("iobase", PITCommonState, iobase, -1), 309 DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", KVMPITState, 310 lost_tick_policy, LOST_TICK_POLICY_DELAY), 311 DEFINE_PROP_END_OF_LIST(), 312 }; 313 314 static void kvm_pit_class_init(ObjectClass *klass, void *data) 315 { 316 KVMPITClass *kpc = KVM_PIT_CLASS(klass); 317 PITCommonClass *k = PIT_COMMON_CLASS(klass); 318 DeviceClass *dc = DEVICE_CLASS(klass); 319 320 device_class_set_parent_realize(dc, kvm_pit_realizefn, 321 &kpc->parent_realize); 322 k->set_channel_gate = kvm_pit_set_gate; 323 k->get_channel_info = kvm_pit_get_channel_info; 324 dc->reset = kvm_pit_reset; 325 dc->props = kvm_pit_properties; 326 } 327 328 static const TypeInfo kvm_pit_info = { 329 .name = TYPE_KVM_I8254, 330 .parent = TYPE_PIT_COMMON, 331 .instance_size = sizeof(KVMPITState), 332 .class_init = kvm_pit_class_init, 333 .class_size = sizeof(KVMPITClass), 334 }; 335 336 static void kvm_pit_register(void) 337 { 338 type_register_static(&kvm_pit_info); 339 } 340 341 type_init(kvm_pit_register) 342