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/timer.h"
  26 #include "sysemu/sysemu.h"
  27 #include "hw/timer/i8254.h"
  28 #include "hw/timer/i8254_internal.h"
  29 #include "sysemu/kvm.h"
  30
  31 #define KVM_PIT_REINJECT_BIT 0
  32
  33 #define CALIBRATION_ROUNDS   3
  34
  35 #define KVM_PIT(obj) OBJECT_CHECK(KVMPITState, (obj), TYPE_KVM_I8254)
  36 #define KVM_PIT_CLASS(class) \
  37     OBJECT_CLASS_CHECK(KVMPITClass, (class), TYPE_KVM_I8254)
  38 #define KVM_PIT_GET_CLASS(obj) \
  39     OBJECT_GET_CLASS(KVMPITClass, (obj), TYPE_KVM_I8254)
  40
  41 typedef struct KVMPITState {
  42     PITCommonState parent_obj;
  43
  44     LostTickPolicy lost_tick_policy;
  45     bool vm_stopped;
  46     int64_t kernel_clock_offset;
  47 } KVMPITState;
  48
  49 typedef struct KVMPITClass {
  50     PITCommonClass parent_class;
  51
  52     DeviceRealize parent_realize;
  53 } KVMPITClass;
  54
  55 static int64_t abs64(int64_t v)
  56 {
  57     return v < 0 ? -v : v;
  58 }
  59
  60 static void kvm_pit_update_clock_offset(KVMPITState *s)
  61 {
  62     int64_t offset, clock_offset;
  63     struct timespec ts;
  64     int i;
  65
  66     /*
  67      * Measure the delta between CLOCK_MONOTONIC, the base used for
  68      * kvm_pit_channel_state::count_load_time, and vm_clock. Take the
  69      * minimum of several samples to filter out scheduling noise.
  70      */
  71     clock_offset = INT64_MAX;
  72     for (i = 0; i < CALIBRATION_ROUNDS; i++) {
  73         offset = qemu_get_clock_ns(vm_clock);
  74         clock_gettime(CLOCK_MONOTONIC, &ts);
  75         offset -= ts.tv_nsec;
  76         offset -= (int64_t)ts.tv_sec * 1000000000;
  77         if (abs64(offset) < abs64(clock_offset)) {
  78             clock_offset = offset;
  79         }
  80     }
  81     s->kernel_clock_offset = clock_offset;
  82 }
  83
  84 static void kvm_pit_get(PITCommonState *pit)
  85 {
  86     KVMPITState *s = KVM_PIT(pit);
  87     struct kvm_pit_state2 kpit;
  88     struct kvm_pit_channel_state *kchan;
  89     struct PITChannelState *sc;
  90     int i, ret;
  91
  92     /* No need to re-read the state if VM is stopped. */
  93     if (s->vm_stopped) {
  94         return;
  95     }
  96
  97     if (kvm_has_pit_state2()) {
  98         ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit);
  99         if (ret < 0) {
 100             fprintf(stderr, "KVM_GET_PIT2 failed: %s\n", strerror(ret));
 101             abort();
 102         }
 103         pit->channels[0].irq_disabled = kpit.flags & KVM_PIT_FLAGS_HPET_LEGACY;
 104     } else {
 105         /*
 106          * kvm_pit_state2 is superset of kvm_pit_state struct,
 107          * so we can use it for KVM_GET_PIT as well.
 108          */
 109         ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT, &kpit);
 110         if (ret < 0) {
 111             fprintf(stderr, "KVM_GET_PIT failed: %s\n", strerror(ret));
 112             abort();
 113         }
 114     }
 115     for (i = 0; i < 3; i++) {
 116         kchan = &kpit.channels[i];
 117         sc = &pit->channels[i];
 118         sc->count = kchan->count;
 119         sc->latched_count = kchan->latched_count;
 120         sc->count_latched = kchan->count_latched;
 121         sc->status_latched = kchan->status_latched;
 122         sc->status = kchan->status;
 123         sc->read_state = kchan->read_state;
 124         sc->write_state = kchan->write_state;
 125         sc->write_latch = kchan->write_latch;
 126         sc->rw_mode = kchan->rw_mode;
 127         sc->mode = kchan->mode;
 128         sc->bcd = kchan->bcd;
 129         sc->gate = kchan->gate;
 130         sc->count_load_time = kchan->count_load_time + s->kernel_clock_offset;
 131     }
 132
 133     sc = &pit->channels[0];
 134     sc->next_transition_time =
 135         pit_get_next_transition_time(sc, sc->count_load_time);
 136 }
 137
 138 static void kvm_pit_put(PITCommonState *pit)
 139 {
 140     KVMPITState *s = KVM_PIT(pit);
 141     struct kvm_pit_state2 kpit;
 142     struct kvm_pit_channel_state *kchan;
 143     struct PITChannelState *sc;
 144     int i, ret;
 145
 146     /* The offset keeps changing as long as the VM is stopped. */
 147     if (s->vm_stopped) {
 148         kvm_pit_update_clock_offset(s);
 149     }
 150
 151     kpit.flags = pit->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0;
 152     for (i = 0; i < 3; i++) {
 153         kchan = &kpit.channels[i];
 154         sc = &pit->channels[i];
 155         kchan->count = sc->count;
 156         kchan->latched_count = sc->latched_count;
 157         kchan->count_latched = sc->count_latched;
 158         kchan->status_latched = sc->status_latched;
 159         kchan->status = sc->status;
 160         kchan->read_state = sc->read_state;
 161         kchan->write_state = sc->write_state;
 162         kchan->write_latch = sc->write_latch;
 163         kchan->rw_mode = sc->rw_mode;
 164         kchan->mode = sc->mode;
 165         kchan->bcd = sc->bcd;
 166         kchan->gate = sc->gate;
 167         kchan->count_load_time = sc->count_load_time - s->kernel_clock_offset;
 168     }
 169
 170     ret = kvm_vm_ioctl(kvm_state,
 171                        kvm_has_pit_state2() ? KVM_SET_PIT2 : KVM_SET_PIT,
 172                        &kpit);
 173     if (ret < 0) {
 174         fprintf(stderr, "%s failed: %s\n",
 175                 kvm_has_pit_state2() ? "KVM_SET_PIT2" : "KVM_SET_PIT",
 176                 strerror(ret));
 177         abort();
 178     }
 179 }
 180
 181 static void kvm_pit_set_gate(PITCommonState *s, PITChannelState *sc, int val)
 182 {
 183     kvm_pit_get(s);
 184
 185     switch (sc->mode) {
 186     default:
 187     case 0:
 188     case 4:
 189         /* XXX: just disable/enable counting */
 190         break;
 191     case 1:
 192     case 2:
 193     case 3:
 194     case 5:
 195         if (sc->gate < val) {
 196             /* restart counting on rising edge */
 197             sc->count_load_time = qemu_get_clock_ns(vm_clock);
 198         }
 199         break;
 200     }
 201     sc->gate = val;
 202
 203     kvm_pit_put(s);
 204 }
 205
 206 static void kvm_pit_get_channel_info(PITCommonState *s, PITChannelState *sc,
 207                                      PITChannelInfo *info)
 208 {
 209     kvm_pit_get(s);
 210
 211     pit_get_channel_info_common(s, sc, info);
 212 }
 213
 214 static void kvm_pit_reset(DeviceState *dev)
 215 {
 216     PITCommonState *s = PIT_COMMON(dev);
 217
 218     pit_reset_common(s);
 219
 220     kvm_pit_put(s);
 221 }
 222
 223 static void kvm_pit_irq_control(void *opaque, int n, int enable)
 224 {
 225     PITCommonState *pit = opaque;
 226     PITChannelState *s = &pit->channels[0];
 227
 228     kvm_pit_get(pit);
 229
 230     s->irq_disabled = !enable;
 231
 232     kvm_pit_put(pit);
 233 }
 234
 235 static void kvm_pit_vm_state_change(void *opaque, int running,
 236                                     RunState state)
 237 {
 238     KVMPITState *s = opaque;
 239
 240     if (running) {
 241         kvm_pit_update_clock_offset(s);
 242         s->vm_stopped = false;
 243     } else {
 244         kvm_pit_update_clock_offset(s);
 245         kvm_pit_get(PIT_COMMON(s));
 246         s->vm_stopped = true;
 247     }
 248 }
 249
 250 static void kvm_pit_realizefn(DeviceState *dev, Error **errp)
 251 {
 252     PITCommonState *pit = PIT_COMMON(dev);
 253     KVMPITClass *kpc = KVM_PIT_GET_CLASS(dev);
 254     KVMPITState *s = KVM_PIT(pit);
 255     struct kvm_pit_config config = {
 256         .flags = 0,
 257     };
 258     int ret;
 259
 260     if (kvm_check_extension(kvm_state, KVM_CAP_PIT2)) {
 261         ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT2, &config);
 262     } else {
 263         ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT);
 264     }
 265     if (ret < 0) {
 266         error_setg(errp, "Create kernel PIC irqchip failed: %s",
 267                    strerror(ret));
 268         return;
 269     }
 270     switch (s->lost_tick_policy) {
 271     case LOST_TICK_DELAY:
 272         break; /* enabled by default */
 273     case LOST_TICK_DISCARD:
 274         if (kvm_check_extension(kvm_state, KVM_CAP_REINJECT_CONTROL)) {
 275             struct kvm_reinject_control control = { .pit_reinject = 0 };
 276
 277             ret = kvm_vm_ioctl(kvm_state, KVM_REINJECT_CONTROL, &control);
 278             if (ret < 0) {
 279                 error_setg(errp,
 280                            "Can't disable in-kernel PIT reinjection: %s",
 281                            strerror(ret));
 282                 return;
 283             }
 284         }
 285         break;
 286     default:
 287         error_setg(errp, "Lost tick policy not supported.");
 288         return;
 289     }
 290
 291     memory_region_init_reservation(&pit->ioports, NULL, "kvm-pit", 4);
 292
 293     qdev_init_gpio_in(dev, kvm_pit_irq_control, 1);
 294
 295     qemu_add_vm_change_state_handler(kvm_pit_vm_state_change, s);
 296
 297     kpc->parent_realize(dev, errp);
 298 }
 299
 300 static Property kvm_pit_properties[] = {
 301     DEFINE_PROP_HEX32("iobase", PITCommonState, iobase,  -1),
 302     DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", KVMPITState,
 303                                lost_tick_policy, LOST_TICK_DELAY),
 304     DEFINE_PROP_END_OF_LIST(),
 305 };
 306
 307 static void kvm_pit_class_init(ObjectClass *klass, void *data)
 308 {
 309     KVMPITClass *kpc = KVM_PIT_CLASS(klass);
 310     PITCommonClass *k = PIT_COMMON_CLASS(klass);
 311     DeviceClass *dc = DEVICE_CLASS(klass);
 312
 313     kpc->parent_realize = dc->realize;
 314     dc->realize = kvm_pit_realizefn;
 315     k->set_channel_gate = kvm_pit_set_gate;
 316     k->get_channel_info = kvm_pit_get_channel_info;
 317     k->pre_save = kvm_pit_get;
 318     k->post_load = kvm_pit_put;
 319     dc->reset = kvm_pit_reset;
 320     dc->props = kvm_pit_properties;
 321 }
 322
 323 static const TypeInfo kvm_pit_info = {
 324     .name          = TYPE_KVM_I8254,
 325     .parent        = TYPE_PIT_COMMON,
 326     .instance_size = sizeof(KVMPITState),
 327     .class_init = kvm_pit_class_init,
 328     .class_size = sizeof(KVMPITClass),
 329 };
 330
 331 static void kvm_pit_register(void)
 332 {
 333     type_register_static(&kvm_pit_info);
 334 }
 335
 336 type_init(kvm_pit_register)