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 "target/i386/kvm/kvm_i386.h" 38 #include "qom/object.h" 39 40 #define KVM_PIT_REINJECT_BIT 0 41 42 #define CALIBRATION_ROUNDS 3 43 44 typedef struct KVMPITClass KVMPITClass; 45 typedef struct KVMPITState KVMPITState; 46 DECLARE_OBJ_CHECKERS(KVMPITState, KVMPITClass, 47 KVM_PIT, TYPE_KVM_I8254) 48 49 struct KVMPITState { 50 PITCommonState parent_obj; 51 52 LostTickPolicy lost_tick_policy; 53 bool vm_stopped; 54 int64_t kernel_clock_offset; 55 }; 56 57 struct KVMPITClass { 58 PITCommonClass parent_class; 59 60 DeviceRealize parent_realize; 61 }; 62 63 static void kvm_pit_update_clock_offset(KVMPITState *s) 64 { 65 int64_t offset, clock_offset; 66 struct timespec ts; 67 int i; 68 69 /* 70 * Measure the delta between CLOCK_MONOTONIC, the base used for 71 * kvm_pit_channel_state::count_load_time, and QEMU_CLOCK_VIRTUAL. Take the 72 * minimum of several samples to filter out scheduling noise. 73 */ 74 clock_offset = INT64_MAX; 75 for (i = 0; i < CALIBRATION_ROUNDS; i++) { 76 offset = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 77 clock_gettime(CLOCK_MONOTONIC, &ts); 78 offset -= ts.tv_nsec; 79 offset -= (int64_t)ts.tv_sec * 1000000000; 80 if (uabs64(offset) < uabs64(clock_offset)) { 81 clock_offset = offset; 82 } 83 } 84 s->kernel_clock_offset = clock_offset; 85 } 86 87 static void kvm_pit_get(PITCommonState *pit) 88 { 89 KVMPITState *s = KVM_PIT(pit); 90 struct kvm_pit_state2 kpit; 91 struct kvm_pit_channel_state *kchan; 92 struct PITChannelState *sc; 93 int i, ret; 94 95 /* No need to re-read the state if VM is stopped. */ 96 if (s->vm_stopped) { 97 return; 98 } 99 100 if (kvm_has_pit_state2()) { 101 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit); 102 if (ret < 0) { 103 fprintf(stderr, "KVM_GET_PIT2 failed: %s\n", strerror(-ret)); 104 abort(); 105 } 106 pit->channels[0].irq_disabled = kpit.flags & KVM_PIT_FLAGS_HPET_LEGACY; 107 } else { 108 /* 109 * kvm_pit_state2 is superset of kvm_pit_state struct, 110 * so we can use it for KVM_GET_PIT as well. 111 */ 112 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT, &kpit); 113 if (ret < 0) { 114 fprintf(stderr, "KVM_GET_PIT failed: %s\n", strerror(-ret)); 115 abort(); 116 } 117 } 118 for (i = 0; i < 3; i++) { 119 kchan = &kpit.channels[i]; 120 sc = &pit->channels[i]; 121 sc->count = kchan->count; 122 sc->latched_count = kchan->latched_count; 123 sc->count_latched = kchan->count_latched; 124 sc->status_latched = kchan->status_latched; 125 sc->status = kchan->status; 126 sc->read_state = kchan->read_state; 127 sc->write_state = kchan->write_state; 128 sc->write_latch = kchan->write_latch; 129 sc->rw_mode = kchan->rw_mode; 130 sc->mode = kchan->mode; 131 sc->bcd = kchan->bcd; 132 sc->gate = kchan->gate; 133 sc->count_load_time = kchan->count_load_time + s->kernel_clock_offset; 134 } 135 136 sc = &pit->channels[0]; 137 sc->next_transition_time = 138 pit_get_next_transition_time(sc, sc->count_load_time); 139 } 140 141 static void kvm_pit_put(PITCommonState *pit) 142 { 143 KVMPITState *s = KVM_PIT(pit); 144 struct kvm_pit_state2 kpit = {}; 145 struct kvm_pit_channel_state *kchan; 146 struct PITChannelState *sc; 147 int i, ret; 148 149 /* The offset keeps changing as long as the VM is stopped. */ 150 if (s->vm_stopped) { 151 kvm_pit_update_clock_offset(s); 152 } 153 154 kpit.flags = pit->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0; 155 for (i = 0; i < 3; i++) { 156 kchan = &kpit.channels[i]; 157 sc = &pit->channels[i]; 158 kchan->count = sc->count; 159 kchan->latched_count = sc->latched_count; 160 kchan->count_latched = sc->count_latched; 161 kchan->status_latched = sc->status_latched; 162 kchan->status = sc->status; 163 kchan->read_state = sc->read_state; 164 kchan->write_state = sc->write_state; 165 kchan->write_latch = sc->write_latch; 166 kchan->rw_mode = sc->rw_mode; 167 kchan->mode = sc->mode; 168 kchan->bcd = sc->bcd; 169 kchan->gate = sc->gate; 170 kchan->count_load_time = sc->count_load_time - s->kernel_clock_offset; 171 } 172 173 ret = kvm_vm_ioctl(kvm_state, 174 kvm_has_pit_state2() ? KVM_SET_PIT2 : KVM_SET_PIT, 175 &kpit); 176 if (ret < 0) { 177 fprintf(stderr, "%s failed: %s\n", 178 kvm_has_pit_state2() ? "KVM_SET_PIT2" : "KVM_SET_PIT", 179 strerror(-ret)); 180 abort(); 181 } 182 } 183 184 static void kvm_pit_set_gate(PITCommonState *s, PITChannelState *sc, int val) 185 { 186 kvm_pit_get(s); 187 188 switch (sc->mode) { 189 default: 190 case 0: 191 case 4: 192 /* XXX: just disable/enable counting */ 193 break; 194 case 1: 195 case 2: 196 case 3: 197 case 5: 198 if (sc->gate < val) { 199 /* restart counting on rising edge */ 200 sc->count_load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 201 } 202 break; 203 } 204 sc->gate = val; 205 206 kvm_pit_put(s); 207 } 208 209 static void kvm_pit_get_channel_info(PITCommonState *s, PITChannelState *sc, 210 PITChannelInfo *info) 211 { 212 kvm_pit_get(s); 213 214 pit_get_channel_info_common(s, sc, info); 215 } 216 217 static void kvm_pit_reset(DeviceState *dev) 218 { 219 PITCommonState *s = PIT_COMMON(dev); 220 221 pit_reset_common(s); 222 223 kvm_pit_put(s); 224 } 225 226 static void kvm_pit_irq_control(void *opaque, int n, int enable) 227 { 228 PITCommonState *pit = opaque; 229 PITChannelState *s = &pit->channels[0]; 230 231 kvm_pit_get(pit); 232 233 s->irq_disabled = !enable; 234 235 kvm_pit_put(pit); 236 } 237 238 static void kvm_pit_vm_state_change(void *opaque, bool running, 239 RunState state) 240 { 241 KVMPITState *s = opaque; 242 243 if (running) { 244 kvm_pit_update_clock_offset(s); 245 kvm_pit_put(PIT_COMMON(s)); 246 s->vm_stopped = false; 247 } else { 248 kvm_pit_update_clock_offset(s); 249 kvm_pit_get(PIT_COMMON(s)); 250 s->vm_stopped = true; 251 } 252 } 253 254 static void kvm_pit_realizefn(DeviceState *dev, Error **errp) 255 { 256 PITCommonState *pit = PIT_COMMON(dev); 257 KVMPITClass *kpc = KVM_PIT_GET_CLASS(dev); 258 KVMPITState *s = KVM_PIT(pit); 259 struct kvm_pit_config config = { 260 .flags = 0, 261 }; 262 int ret; 263 264 if (kvm_check_extension(kvm_state, KVM_CAP_PIT2)) { 265 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT2, &config); 266 } else { 267 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT); 268 } 269 if (ret < 0) { 270 error_setg(errp, "Create kernel PIC irqchip failed: %s", 271 strerror(-ret)); 272 return; 273 } 274 switch (s->lost_tick_policy) { 275 case LOST_TICK_POLICY_DELAY: 276 break; /* enabled by default */ 277 case LOST_TICK_POLICY_DISCARD: 278 if (kvm_check_extension(kvm_state, KVM_CAP_REINJECT_CONTROL)) { 279 struct kvm_reinject_control control = { .pit_reinject = 0 }; 280 281 ret = kvm_vm_ioctl(kvm_state, KVM_REINJECT_CONTROL, &control); 282 if (ret < 0) { 283 error_setg(errp, 284 "Can't disable in-kernel PIT reinjection: %s", 285 strerror(-ret)); 286 return; 287 } 288 } 289 break; 290 default: 291 error_setg(errp, "Lost tick policy not supported."); 292 return; 293 } 294 295 memory_region_init_io(&pit->ioports, OBJECT(dev), NULL, NULL, "kvm-pit", 4); 296 297 qdev_init_gpio_in(dev, kvm_pit_irq_control, 1); 298 299 qemu_add_vm_change_state_handler(kvm_pit_vm_state_change, s); 300 301 kpc->parent_realize(dev, errp); 302 } 303 304 static Property kvm_pit_properties[] = { 305 DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", KVMPITState, 306 lost_tick_policy, LOST_TICK_POLICY_DELAY), 307 DEFINE_PROP_END_OF_LIST(), 308 }; 309 310 static void kvm_pit_class_init(ObjectClass *klass, void *data) 311 { 312 KVMPITClass *kpc = KVM_PIT_CLASS(klass); 313 PITCommonClass *k = PIT_COMMON_CLASS(klass); 314 DeviceClass *dc = DEVICE_CLASS(klass); 315 316 device_class_set_parent_realize(dc, kvm_pit_realizefn, 317 &kpc->parent_realize); 318 k->set_channel_gate = kvm_pit_set_gate; 319 k->get_channel_info = kvm_pit_get_channel_info; 320 dc->reset = kvm_pit_reset; 321 device_class_set_props(dc, kvm_pit_properties); 322 } 323 324 static const TypeInfo kvm_pit_info = { 325 .name = TYPE_KVM_I8254, 326 .parent = TYPE_PIT_COMMON, 327 .instance_size = sizeof(KVMPITState), 328 .class_init = kvm_pit_class_init, 329 .class_size = sizeof(KVMPITClass), 330 }; 331 332 static void kvm_pit_register(void) 333 { 334 type_register_static(&kvm_pit_info); 335 } 336 337 type_init(kvm_pit_register) 338