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