hw/i386/kvm/i8254.c

   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 #include "qemu/osdep.h"
  26 #include "qapi/error.h"
  27 #include "qemu/timer.h"
  28 #include "sysemu/sysemu.h"
  29 #include "hw/timer/i8254.h"
  30 #include "hw/timer/i8254_internal.h"
  31 #include "sysemu/kvm.h"
  32
  33 #define KVM_PIT_REINJECT_BIT 0
  34
  35 #define CALIBRATION_ROUNDS   3
  36
  37 #define KVM_PIT(obj) OBJECT_CHECK(KVMPITState, (obj), TYPE_KVM_I8254)
  38 #define KVM_PIT_CLASS(class) \
  39     OBJECT_CLASS_CHECK(KVMPITClass, (class), TYPE_KVM_I8254)
  40 #define KVM_PIT_GET_CLASS(obj) \
  41     OBJECT_GET_CLASS(KVMPITClass, (obj), TYPE_KVM_I8254)
  42
  43 typedef struct KVMPITState {
  44     PITCommonState parent_obj;
  45
  46     LostTickPolicy lost_tick_policy;
  47     bool vm_stopped;
  48     int64_t kernel_clock_offset;
  49 } KVMPITState;
  50
  51 typedef struct KVMPITClass {
  52     PITCommonClass parent_class;
  53
  54     DeviceRealize parent_realize;
  55 } KVMPITClass;
  56
  57 static int64_t abs64(int64_t v)
  58 {
  59     return v < 0 ? -v : v;
  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 (abs64(offset) < abs64(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, int 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_reservation(&pit->ioports, 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     kpc->parent_realize = dc->realize;
 317     dc->realize = kvm_pit_realizefn;
 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     dc->props = 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)