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/runstate.h" 33 #include "hw/timer/i8254.h" 34 #include "hw/timer/i8254_internal.h" 35 #include "sysemu/kvm.h" 36 #include "qom/object.h" 37 38 #define KVM_PIT_REINJECT_BIT 0 39 40 #define CALIBRATION_ROUNDS 3 41 42 typedef struct KVMPITClass KVMPITClass; 43 typedef struct KVMPITState KVMPITState; 44 #define KVM_PIT(obj) OBJECT_CHECK(KVMPITState, (obj), TYPE_KVM_I8254) 45 #define KVM_PIT_CLASS(class) \ 46 OBJECT_CLASS_CHECK(KVMPITClass, (class), TYPE_KVM_I8254) 47 #define KVM_PIT_GET_CLASS(obj) \ 48 OBJECT_GET_CLASS(KVMPITClass, (obj), TYPE_KVM_I8254) 49 50 struct KVMPITState { 51 PITCommonState parent_obj; 52 53 LostTickPolicy lost_tick_policy; 54 bool vm_stopped; 55 int64_t kernel_clock_offset; 56 }; 57 58 struct KVMPITClass { 59 PITCommonClass parent_class; 60 61 DeviceRealize parent_realize; 62 }; 63 64 static int64_t abs64(int64_t v) 65 { 66 return v < 0 ? -v : v; 67 } 68 69 static void kvm_pit_update_clock_offset(KVMPITState *s) 70 { 71 int64_t offset, clock_offset; 72 struct timespec ts; 73 int i; 74 75 /* 76 * Measure the delta between CLOCK_MONOTONIC, the base used for 77 * kvm_pit_channel_state::count_load_time, and QEMU_CLOCK_VIRTUAL. Take the 78 * minimum of several samples to filter out scheduling noise. 79 */ 80 clock_offset = INT64_MAX; 81 for (i = 0; i < CALIBRATION_ROUNDS; i++) { 82 offset = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 83 clock_gettime(CLOCK_MONOTONIC, &ts); 84 offset -= ts.tv_nsec; 85 offset -= (int64_t)ts.tv_sec * 1000000000; 86 if (abs64(offset) < abs64(clock_offset)) { 87 clock_offset = offset; 88 } 89 } 90 s->kernel_clock_offset = clock_offset; 91 } 92 93 static void kvm_pit_get(PITCommonState *pit) 94 { 95 KVMPITState *s = KVM_PIT(pit); 96 struct kvm_pit_state2 kpit; 97 struct kvm_pit_channel_state *kchan; 98 struct PITChannelState *sc; 99 int i, ret; 100 101 /* No need to re-read the state if VM is stopped. */ 102 if (s->vm_stopped) { 103 return; 104 } 105 106 if (kvm_has_pit_state2()) { 107 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit); 108 if (ret < 0) { 109 fprintf(stderr, "KVM_GET_PIT2 failed: %s\n", strerror(ret)); 110 abort(); 111 } 112 pit->channels[0].irq_disabled = kpit.flags & KVM_PIT_FLAGS_HPET_LEGACY; 113 } else { 114 /* 115 * kvm_pit_state2 is superset of kvm_pit_state struct, 116 * so we can use it for KVM_GET_PIT as well. 117 */ 118 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT, &kpit); 119 if (ret < 0) { 120 fprintf(stderr, "KVM_GET_PIT failed: %s\n", strerror(ret)); 121 abort(); 122 } 123 } 124 for (i = 0; i < 3; i++) { 125 kchan = &kpit.channels[i]; 126 sc = &pit->channels[i]; 127 sc->count = kchan->count; 128 sc->latched_count = kchan->latched_count; 129 sc->count_latched = kchan->count_latched; 130 sc->status_latched = kchan->status_latched; 131 sc->status = kchan->status; 132 sc->read_state = kchan->read_state; 133 sc->write_state = kchan->write_state; 134 sc->write_latch = kchan->write_latch; 135 sc->rw_mode = kchan->rw_mode; 136 sc->mode = kchan->mode; 137 sc->bcd = kchan->bcd; 138 sc->gate = kchan->gate; 139 sc->count_load_time = kchan->count_load_time + s->kernel_clock_offset; 140 } 141 142 sc = &pit->channels[0]; 143 sc->next_transition_time = 144 pit_get_next_transition_time(sc, sc->count_load_time); 145 } 146 147 static void kvm_pit_put(PITCommonState *pit) 148 { 149 KVMPITState *s = KVM_PIT(pit); 150 struct kvm_pit_state2 kpit = {}; 151 struct kvm_pit_channel_state *kchan; 152 struct PITChannelState *sc; 153 int i, ret; 154 155 /* The offset keeps changing as long as the VM is stopped. */ 156 if (s->vm_stopped) { 157 kvm_pit_update_clock_offset(s); 158 } 159 160 kpit.flags = pit->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0; 161 for (i = 0; i < 3; i++) { 162 kchan = &kpit.channels[i]; 163 sc = &pit->channels[i]; 164 kchan->count = sc->count; 165 kchan->latched_count = sc->latched_count; 166 kchan->count_latched = sc->count_latched; 167 kchan->status_latched = sc->status_latched; 168 kchan->status = sc->status; 169 kchan->read_state = sc->read_state; 170 kchan->write_state = sc->write_state; 171 kchan->write_latch = sc->write_latch; 172 kchan->rw_mode = sc->rw_mode; 173 kchan->mode = sc->mode; 174 kchan->bcd = sc->bcd; 175 kchan->gate = sc->gate; 176 kchan->count_load_time = sc->count_load_time - s->kernel_clock_offset; 177 } 178 179 ret = kvm_vm_ioctl(kvm_state, 180 kvm_has_pit_state2() ? KVM_SET_PIT2 : KVM_SET_PIT, 181 &kpit); 182 if (ret < 0) { 183 fprintf(stderr, "%s failed: %s\n", 184 kvm_has_pit_state2() ? "KVM_SET_PIT2" : "KVM_SET_PIT", 185 strerror(ret)); 186 abort(); 187 } 188 } 189 190 static void kvm_pit_set_gate(PITCommonState *s, PITChannelState *sc, int val) 191 { 192 kvm_pit_get(s); 193 194 switch (sc->mode) { 195 default: 196 case 0: 197 case 4: 198 /* XXX: just disable/enable counting */ 199 break; 200 case 1: 201 case 2: 202 case 3: 203 case 5: 204 if (sc->gate < val) { 205 /* restart counting on rising edge */ 206 sc->count_load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 207 } 208 break; 209 } 210 sc->gate = val; 211 212 kvm_pit_put(s); 213 } 214 215 static void kvm_pit_get_channel_info(PITCommonState *s, PITChannelState *sc, 216 PITChannelInfo *info) 217 { 218 kvm_pit_get(s); 219 220 pit_get_channel_info_common(s, sc, info); 221 } 222 223 static void kvm_pit_reset(DeviceState *dev) 224 { 225 PITCommonState *s = PIT_COMMON(dev); 226 227 pit_reset_common(s); 228 229 kvm_pit_put(s); 230 } 231 232 static void kvm_pit_irq_control(void *opaque, int n, int enable) 233 { 234 PITCommonState *pit = opaque; 235 PITChannelState *s = &pit->channels[0]; 236 237 kvm_pit_get(pit); 238 239 s->irq_disabled = !enable; 240 241 kvm_pit_put(pit); 242 } 243 244 static void kvm_pit_vm_state_change(void *opaque, int running, 245 RunState state) 246 { 247 KVMPITState *s = opaque; 248 249 if (running) { 250 kvm_pit_update_clock_offset(s); 251 kvm_pit_put(PIT_COMMON(s)); 252 s->vm_stopped = false; 253 } else { 254 kvm_pit_update_clock_offset(s); 255 kvm_pit_get(PIT_COMMON(s)); 256 s->vm_stopped = true; 257 } 258 } 259 260 static void kvm_pit_realizefn(DeviceState *dev, Error **errp) 261 { 262 PITCommonState *pit = PIT_COMMON(dev); 263 KVMPITClass *kpc = KVM_PIT_GET_CLASS(dev); 264 KVMPITState *s = KVM_PIT(pit); 265 struct kvm_pit_config config = { 266 .flags = 0, 267 }; 268 int ret; 269 270 if (kvm_check_extension(kvm_state, KVM_CAP_PIT2)) { 271 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT2, &config); 272 } else { 273 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT); 274 } 275 if (ret < 0) { 276 error_setg(errp, "Create kernel PIC irqchip failed: %s", 277 strerror(ret)); 278 return; 279 } 280 switch (s->lost_tick_policy) { 281 case LOST_TICK_POLICY_DELAY: 282 break; /* enabled by default */ 283 case LOST_TICK_POLICY_DISCARD: 284 if (kvm_check_extension(kvm_state, KVM_CAP_REINJECT_CONTROL)) { 285 struct kvm_reinject_control control = { .pit_reinject = 0 }; 286 287 ret = kvm_vm_ioctl(kvm_state, KVM_REINJECT_CONTROL, &control); 288 if (ret < 0) { 289 error_setg(errp, 290 "Can't disable in-kernel PIT reinjection: %s", 291 strerror(ret)); 292 return; 293 } 294 } 295 break; 296 default: 297 error_setg(errp, "Lost tick policy not supported."); 298 return; 299 } 300 301 memory_region_init_io(&pit->ioports, OBJECT(dev), NULL, NULL, "kvm-pit", 4); 302 303 qdev_init_gpio_in(dev, kvm_pit_irq_control, 1); 304 305 qemu_add_vm_change_state_handler(kvm_pit_vm_state_change, s); 306 307 kpc->parent_realize(dev, errp); 308 } 309 310 static Property kvm_pit_properties[] = { 311 DEFINE_PROP_UINT32("iobase", PITCommonState, iobase, -1), 312 DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", KVMPITState, 313 lost_tick_policy, LOST_TICK_POLICY_DELAY), 314 DEFINE_PROP_END_OF_LIST(), 315 }; 316 317 static void kvm_pit_class_init(ObjectClass *klass, void *data) 318 { 319 KVMPITClass *kpc = KVM_PIT_CLASS(klass); 320 PITCommonClass *k = PIT_COMMON_CLASS(klass); 321 DeviceClass *dc = DEVICE_CLASS(klass); 322 323 device_class_set_parent_realize(dc, kvm_pit_realizefn, 324 &kpc->parent_realize); 325 k->set_channel_gate = kvm_pit_set_gate; 326 k->get_channel_info = kvm_pit_get_channel_info; 327 dc->reset = kvm_pit_reset; 328 device_class_set_props(dc, kvm_pit_properties); 329 } 330 331 static const TypeInfo kvm_pit_info = { 332 .name = TYPE_KVM_I8254, 333 .parent = TYPE_PIT_COMMON, 334 .instance_size = sizeof(KVMPITState), 335 .class_init = kvm_pit_class_init, 336 .class_size = sizeof(KVMPITClass), 337 }; 338 339 static void kvm_pit_register(void) 340 { 341 type_register_static(&kvm_pit_info); 342 } 343 344 type_init(kvm_pit_register) 345