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-machine.h" 29 #include "qapi/error.h" 30 #include "qemu/module.h" 31 #include "qemu/timer.h" 32 #include "sysemu/runstate.h" 33 #include "hw/timer/i8254.h" 34 #include "hw/timer/i8254_internal.h" 35 #include "hw/qdev-properties-system.h" 36 #include "sysemu/kvm.h" 37 #include "qom/object.h" 38 39 #define KVM_PIT_REINJECT_BIT 0 40 41 #define CALIBRATION_ROUNDS 3 42 43 typedef struct KVMPITClass KVMPITClass; 44 typedef struct KVMPITState KVMPITState; 45 DECLARE_OBJ_CHECKERS(KVMPITState, KVMPITClass, 46 KVM_PIT, TYPE_KVM_I8254) 47 48 struct KVMPITState { 49 PITCommonState parent_obj; 50 51 LostTickPolicy lost_tick_policy; 52 bool vm_stopped; 53 int64_t kernel_clock_offset; 54 }; 55 56 struct KVMPITClass { 57 PITCommonClass parent_class; 58 59 DeviceRealize parent_realize; 60 }; 61 62 static int64_t abs64(int64_t v) 63 { 64 return v < 0 ? -v : v; 65 } 66 67 static void kvm_pit_update_clock_offset(KVMPITState *s) 68 { 69 int64_t offset, clock_offset; 70 struct timespec ts; 71 int i; 72 73 /* 74 * Measure the delta between CLOCK_MONOTONIC, the base used for 75 * kvm_pit_channel_state::count_load_time, and QEMU_CLOCK_VIRTUAL. Take the 76 * minimum of several samples to filter out scheduling noise. 77 */ 78 clock_offset = INT64_MAX; 79 for (i = 0; i < CALIBRATION_ROUNDS; i++) { 80 offset = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 81 clock_gettime(CLOCK_MONOTONIC, &ts); 82 offset -= ts.tv_nsec; 83 offset -= (int64_t)ts.tv_sec * 1000000000; 84 if (abs64(offset) < abs64(clock_offset)) { 85 clock_offset = offset; 86 } 87 } 88 s->kernel_clock_offset = clock_offset; 89 } 90 91 static void kvm_pit_get(PITCommonState *pit) 92 { 93 KVMPITState *s = KVM_PIT(pit); 94 struct kvm_pit_state2 kpit; 95 struct kvm_pit_channel_state *kchan; 96 struct PITChannelState *sc; 97 int i, ret; 98 99 /* No need to re-read the state if VM is stopped. */ 100 if (s->vm_stopped) { 101 return; 102 } 103 104 if (kvm_has_pit_state2()) { 105 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit); 106 if (ret < 0) { 107 fprintf(stderr, "KVM_GET_PIT2 failed: %s\n", strerror(ret)); 108 abort(); 109 } 110 pit->channels[0].irq_disabled = kpit.flags & KVM_PIT_FLAGS_HPET_LEGACY; 111 } else { 112 /* 113 * kvm_pit_state2 is superset of kvm_pit_state struct, 114 * so we can use it for KVM_GET_PIT as well. 115 */ 116 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT, &kpit); 117 if (ret < 0) { 118 fprintf(stderr, "KVM_GET_PIT failed: %s\n", strerror(ret)); 119 abort(); 120 } 121 } 122 for (i = 0; i < 3; i++) { 123 kchan = &kpit.channels[i]; 124 sc = &pit->channels[i]; 125 sc->count = kchan->count; 126 sc->latched_count = kchan->latched_count; 127 sc->count_latched = kchan->count_latched; 128 sc->status_latched = kchan->status_latched; 129 sc->status = kchan->status; 130 sc->read_state = kchan->read_state; 131 sc->write_state = kchan->write_state; 132 sc->write_latch = kchan->write_latch; 133 sc->rw_mode = kchan->rw_mode; 134 sc->mode = kchan->mode; 135 sc->bcd = kchan->bcd; 136 sc->gate = kchan->gate; 137 sc->count_load_time = kchan->count_load_time + s->kernel_clock_offset; 138 } 139 140 sc = &pit->channels[0]; 141 sc->next_transition_time = 142 pit_get_next_transition_time(sc, sc->count_load_time); 143 } 144 145 static void kvm_pit_put(PITCommonState *pit) 146 { 147 KVMPITState *s = KVM_PIT(pit); 148 struct kvm_pit_state2 kpit = {}; 149 struct kvm_pit_channel_state *kchan; 150 struct PITChannelState *sc; 151 int i, ret; 152 153 /* The offset keeps changing as long as the VM is stopped. */ 154 if (s->vm_stopped) { 155 kvm_pit_update_clock_offset(s); 156 } 157 158 kpit.flags = pit->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0; 159 for (i = 0; i < 3; i++) { 160 kchan = &kpit.channels[i]; 161 sc = &pit->channels[i]; 162 kchan->count = sc->count; 163 kchan->latched_count = sc->latched_count; 164 kchan->count_latched = sc->count_latched; 165 kchan->status_latched = sc->status_latched; 166 kchan->status = sc->status; 167 kchan->read_state = sc->read_state; 168 kchan->write_state = sc->write_state; 169 kchan->write_latch = sc->write_latch; 170 kchan->rw_mode = sc->rw_mode; 171 kchan->mode = sc->mode; 172 kchan->bcd = sc->bcd; 173 kchan->gate = sc->gate; 174 kchan->count_load_time = sc->count_load_time - s->kernel_clock_offset; 175 } 176 177 ret = kvm_vm_ioctl(kvm_state, 178 kvm_has_pit_state2() ? KVM_SET_PIT2 : KVM_SET_PIT, 179 &kpit); 180 if (ret < 0) { 181 fprintf(stderr, "%s failed: %s\n", 182 kvm_has_pit_state2() ? "KVM_SET_PIT2" : "KVM_SET_PIT", 183 strerror(ret)); 184 abort(); 185 } 186 } 187 188 static void kvm_pit_set_gate(PITCommonState *s, PITChannelState *sc, int val) 189 { 190 kvm_pit_get(s); 191 192 switch (sc->mode) { 193 default: 194 case 0: 195 case 4: 196 /* XXX: just disable/enable counting */ 197 break; 198 case 1: 199 case 2: 200 case 3: 201 case 5: 202 if (sc->gate < val) { 203 /* restart counting on rising edge */ 204 sc->count_load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 205 } 206 break; 207 } 208 sc->gate = val; 209 210 kvm_pit_put(s); 211 } 212 213 static void kvm_pit_get_channel_info(PITCommonState *s, PITChannelState *sc, 214 PITChannelInfo *info) 215 { 216 kvm_pit_get(s); 217 218 pit_get_channel_info_common(s, sc, info); 219 } 220 221 static void kvm_pit_reset(DeviceState *dev) 222 { 223 PITCommonState *s = PIT_COMMON(dev); 224 225 pit_reset_common(s); 226 227 kvm_pit_put(s); 228 } 229 230 static void kvm_pit_irq_control(void *opaque, int n, int enable) 231 { 232 PITCommonState *pit = opaque; 233 PITChannelState *s = &pit->channels[0]; 234 235 kvm_pit_get(pit); 236 237 s->irq_disabled = !enable; 238 239 kvm_pit_put(pit); 240 } 241 242 static void kvm_pit_vm_state_change(void *opaque, int running, 243 RunState state) 244 { 245 KVMPITState *s = opaque; 246 247 if (running) { 248 kvm_pit_update_clock_offset(s); 249 kvm_pit_put(PIT_COMMON(s)); 250 s->vm_stopped = false; 251 } else { 252 kvm_pit_update_clock_offset(s); 253 kvm_pit_get(PIT_COMMON(s)); 254 s->vm_stopped = true; 255 } 256 } 257 258 static void kvm_pit_realizefn(DeviceState *dev, Error **errp) 259 { 260 PITCommonState *pit = PIT_COMMON(dev); 261 KVMPITClass *kpc = KVM_PIT_GET_CLASS(dev); 262 KVMPITState *s = KVM_PIT(pit); 263 struct kvm_pit_config config = { 264 .flags = 0, 265 }; 266 int ret; 267 268 if (kvm_check_extension(kvm_state, KVM_CAP_PIT2)) { 269 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT2, &config); 270 } else { 271 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT); 272 } 273 if (ret < 0) { 274 error_setg(errp, "Create kernel PIC irqchip failed: %s", 275 strerror(ret)); 276 return; 277 } 278 switch (s->lost_tick_policy) { 279 case LOST_TICK_POLICY_DELAY: 280 break; /* enabled by default */ 281 case LOST_TICK_POLICY_DISCARD: 282 if (kvm_check_extension(kvm_state, KVM_CAP_REINJECT_CONTROL)) { 283 struct kvm_reinject_control control = { .pit_reinject = 0 }; 284 285 ret = kvm_vm_ioctl(kvm_state, KVM_REINJECT_CONTROL, &control); 286 if (ret < 0) { 287 error_setg(errp, 288 "Can't disable in-kernel PIT reinjection: %s", 289 strerror(ret)); 290 return; 291 } 292 } 293 break; 294 default: 295 error_setg(errp, "Lost tick policy not supported."); 296 return; 297 } 298 299 memory_region_init_io(&pit->ioports, OBJECT(dev), NULL, NULL, "kvm-pit", 4); 300 301 qdev_init_gpio_in(dev, kvm_pit_irq_control, 1); 302 303 qemu_add_vm_change_state_handler(kvm_pit_vm_state_change, s); 304 305 kpc->parent_realize(dev, errp); 306 } 307 308 static Property kvm_pit_properties[] = { 309 DEFINE_PROP_UINT32("iobase", PITCommonState, iobase, -1), 310 DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", KVMPITState, 311 lost_tick_policy, LOST_TICK_POLICY_DELAY), 312 DEFINE_PROP_END_OF_LIST(), 313 }; 314 315 static void kvm_pit_class_init(ObjectClass *klass, void *data) 316 { 317 KVMPITClass *kpc = KVM_PIT_CLASS(klass); 318 PITCommonClass *k = PIT_COMMON_CLASS(klass); 319 DeviceClass *dc = DEVICE_CLASS(klass); 320 321 device_class_set_parent_realize(dc, kvm_pit_realizefn, 322 &kpc->parent_realize); 323 k->set_channel_gate = kvm_pit_set_gate; 324 k->get_channel_info = kvm_pit_get_channel_info; 325 dc->reset = kvm_pit_reset; 326 device_class_set_props(dc, kvm_pit_properties); 327 } 328 329 static const TypeInfo kvm_pit_info = { 330 .name = TYPE_KVM_I8254, 331 .parent = TYPE_PIT_COMMON, 332 .instance_size = sizeof(KVMPITState), 333 .class_init = kvm_pit_class_init, 334 .class_size = sizeof(KVMPITClass), 335 }; 336 337 static void kvm_pit_register(void) 338 { 339 type_register_static(&kvm_pit_info); 340 } 341 342 type_init(kvm_pit_register) 343