i8254.c (10129B)
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 void kvm_pit_update_clock_offset(KVMPITState *s) 63 { 64 int64_t offset, clock_offset; 65 struct timespec ts; 66 int i; 67 68 /* 69 * Measure the delta between CLOCK_MONOTONIC, the base used for 70 * kvm_pit_channel_state::count_load_time, and QEMU_CLOCK_VIRTUAL. Take the 71 * minimum of several samples to filter out scheduling noise. 72 */ 73 clock_offset = INT64_MAX; 74 for (i = 0; i < CALIBRATION_ROUNDS; i++) { 75 offset = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 76 clock_gettime(CLOCK_MONOTONIC, &ts); 77 offset -= ts.tv_nsec; 78 offset -= (int64_t)ts.tv_sec * 1000000000; 79 if (uabs64(offset) < uabs64(clock_offset)) { 80 clock_offset = offset; 81 } 82 } 83 s->kernel_clock_offset = clock_offset; 84 } 85 86 static void kvm_pit_get(PITCommonState *pit) 87 { 88 KVMPITState *s = KVM_PIT(pit); 89 struct kvm_pit_state2 kpit; 90 struct kvm_pit_channel_state *kchan; 91 struct PITChannelState *sc; 92 int i, ret; 93 94 /* No need to re-read the state if VM is stopped. */ 95 if (s->vm_stopped) { 96 return; 97 } 98 99 if (kvm_has_pit_state2()) { 100 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit); 101 if (ret < 0) { 102 fprintf(stderr, "KVM_GET_PIT2 failed: %s\n", strerror(-ret)); 103 abort(); 104 } 105 pit->channels[0].irq_disabled = kpit.flags & KVM_PIT_FLAGS_HPET_LEGACY; 106 } else { 107 /* 108 * kvm_pit_state2 is superset of kvm_pit_state struct, 109 * so we can use it for KVM_GET_PIT as well. 110 */ 111 ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT, &kpit); 112 if (ret < 0) { 113 fprintf(stderr, "KVM_GET_PIT failed: %s\n", strerror(-ret)); 114 abort(); 115 } 116 } 117 for (i = 0; i < 3; i++) { 118 kchan = &kpit.channels[i]; 119 sc = &pit->channels[i]; 120 sc->count = kchan->count; 121 sc->latched_count = kchan->latched_count; 122 sc->count_latched = kchan->count_latched; 123 sc->status_latched = kchan->status_latched; 124 sc->status = kchan->status; 125 sc->read_state = kchan->read_state; 126 sc->write_state = kchan->write_state; 127 sc->write_latch = kchan->write_latch; 128 sc->rw_mode = kchan->rw_mode; 129 sc->mode = kchan->mode; 130 sc->bcd = kchan->bcd; 131 sc->gate = kchan->gate; 132 sc->count_load_time = kchan->count_load_time + s->kernel_clock_offset; 133 } 134 135 sc = &pit->channels[0]; 136 sc->next_transition_time = 137 pit_get_next_transition_time(sc, sc->count_load_time); 138 } 139 140 static void kvm_pit_put(PITCommonState *pit) 141 { 142 KVMPITState *s = KVM_PIT(pit); 143 struct kvm_pit_state2 kpit = {}; 144 struct kvm_pit_channel_state *kchan; 145 struct PITChannelState *sc; 146 int i, ret; 147 148 /* The offset keeps changing as long as the VM is stopped. */ 149 if (s->vm_stopped) { 150 kvm_pit_update_clock_offset(s); 151 } 152 153 kpit.flags = pit->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0; 154 for (i = 0; i < 3; i++) { 155 kchan = &kpit.channels[i]; 156 sc = &pit->channels[i]; 157 kchan->count = sc->count; 158 kchan->latched_count = sc->latched_count; 159 kchan->count_latched = sc->count_latched; 160 kchan->status_latched = sc->status_latched; 161 kchan->status = sc->status; 162 kchan->read_state = sc->read_state; 163 kchan->write_state = sc->write_state; 164 kchan->write_latch = sc->write_latch; 165 kchan->rw_mode = sc->rw_mode; 166 kchan->mode = sc->mode; 167 kchan->bcd = sc->bcd; 168 kchan->gate = sc->gate; 169 kchan->count_load_time = sc->count_load_time - s->kernel_clock_offset; 170 } 171 172 ret = kvm_vm_ioctl(kvm_state, 173 kvm_has_pit_state2() ? KVM_SET_PIT2 : KVM_SET_PIT, 174 &kpit); 175 if (ret < 0) { 176 fprintf(stderr, "%s failed: %s\n", 177 kvm_has_pit_state2() ? "KVM_SET_PIT2" : "KVM_SET_PIT", 178 strerror(-ret)); 179 abort(); 180 } 181 } 182 183 static void kvm_pit_set_gate(PITCommonState *s, PITChannelState *sc, int val) 184 { 185 kvm_pit_get(s); 186 187 switch (sc->mode) { 188 default: 189 case 0: 190 case 4: 191 /* XXX: just disable/enable counting */ 192 break; 193 case 1: 194 case 2: 195 case 3: 196 case 5: 197 if (sc->gate < val) { 198 /* restart counting on rising edge */ 199 sc->count_load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 200 } 201 break; 202 } 203 sc->gate = val; 204 205 kvm_pit_put(s); 206 } 207 208 static void kvm_pit_get_channel_info(PITCommonState *s, PITChannelState *sc, 209 PITChannelInfo *info) 210 { 211 kvm_pit_get(s); 212 213 pit_get_channel_info_common(s, sc, info); 214 } 215 216 static void kvm_pit_reset(DeviceState *dev) 217 { 218 PITCommonState *s = PIT_COMMON(dev); 219 220 pit_reset_common(s); 221 222 kvm_pit_put(s); 223 } 224 225 static void kvm_pit_irq_control(void *opaque, int n, int enable) 226 { 227 PITCommonState *pit = opaque; 228 PITChannelState *s = &pit->channels[0]; 229 230 kvm_pit_get(pit); 231 232 s->irq_disabled = !enable; 233 234 kvm_pit_put(pit); 235 } 236 237 static void kvm_pit_vm_state_change(void *opaque, bool running, 238 RunState state) 239 { 240 KVMPITState *s = opaque; 241 242 if (running) { 243 kvm_pit_update_clock_offset(s); 244 kvm_pit_put(PIT_COMMON(s)); 245 s->vm_stopped = false; 246 } else { 247 kvm_pit_update_clock_offset(s); 248 kvm_pit_get(PIT_COMMON(s)); 249 s->vm_stopped = true; 250 } 251 } 252 253 static void kvm_pit_realizefn(DeviceState *dev, Error **errp) 254 { 255 PITCommonState *pit = PIT_COMMON(dev); 256 KVMPITClass *kpc = KVM_PIT_GET_CLASS(dev); 257 KVMPITState *s = KVM_PIT(pit); 258 struct kvm_pit_config config = { 259 .flags = 0, 260 }; 261 int ret; 262 263 if (kvm_check_extension(kvm_state, KVM_CAP_PIT2)) { 264 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT2, &config); 265 } else { 266 ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT); 267 } 268 if (ret < 0) { 269 error_setg(errp, "Create kernel PIC irqchip failed: %s", 270 strerror(-ret)); 271 return; 272 } 273 switch (s->lost_tick_policy) { 274 case LOST_TICK_POLICY_DELAY: 275 break; /* enabled by default */ 276 case LOST_TICK_POLICY_DISCARD: 277 if (kvm_check_extension(kvm_state, KVM_CAP_REINJECT_CONTROL)) { 278 struct kvm_reinject_control control = { .pit_reinject = 0 }; 279 280 ret = kvm_vm_ioctl(kvm_state, KVM_REINJECT_CONTROL, &control); 281 if (ret < 0) { 282 error_setg(errp, 283 "Can't disable in-kernel PIT reinjection: %s", 284 strerror(-ret)); 285 return; 286 } 287 } 288 break; 289 default: 290 error_setg(errp, "Lost tick policy not supported."); 291 return; 292 } 293 294 memory_region_init_io(&pit->ioports, OBJECT(dev), NULL, NULL, "kvm-pit", 4); 295 296 qdev_init_gpio_in(dev, kvm_pit_irq_control, 1); 297 298 qemu_add_vm_change_state_handler(kvm_pit_vm_state_change, s); 299 300 kpc->parent_realize(dev, errp); 301 } 302 303 static Property kvm_pit_properties[] = { 304 DEFINE_PROP_UINT32("iobase", PITCommonState, iobase, -1), 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)