arch/x86/kvm/i8254.c

   1 /*
   2  * 8253/8254 interval timer emulation
   3  *
   4  * Copyright (c) 2003-2004 Fabrice Bellard
   5  * Copyright (c) 2006 Intel Corporation
   6  * Copyright (c) 2007 Keir Fraser, XenSource Inc
   7  * Copyright (c) 2008 Intel Corporation
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a copy
  10  * of this software and associated documentation files (the "Software"), to deal
  11  * in the Software without restriction, including without limitation the rights
  12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13  * copies of the Software, and to permit persons to whom the Software is
  14  * furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25  * THE SOFTWARE.
  26  *
  27  * Authors:
  28  *   Sheng Yang <sheng.yang@intel.com>
  29  *   Based on QEMU and Xen.
  30  */
  31
  32 #include <linux/kvm_host.h>
  33
  34 #include "irq.h"
  35 #include "i8254.h"
  36
  37 #ifndef CONFIG_X86_64
  38 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
  39 #else
  40 #define mod_64(x, y) ((x) % (y))
  41 #endif
  42
  43 #define RW_STATE_LSB 1
  44 #define RW_STATE_MSB 2
  45 #define RW_STATE_WORD0 3
  46 #define RW_STATE_WORD1 4
  47
  48 /* Compute with 96 bit intermediate result: (a*b)/c */
  49 static u64 muldiv64(u64 a, u32 b, u32 c)
  50 {
  51         union {
  52                 u64 ll;
  53                 struct {
  54                         u32 low, high;
  55                 } l;
  56         } u, res;
  57         u64 rl, rh;
  58
  59         u.ll = a;
  60         rl = (u64)u.l.low * (u64)b;
  61         rh = (u64)u.l.high * (u64)b;
  62         rh += (rl >> 32);
  63         res.l.high = div64_u64(rh, c);
  64         res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
  65         return res.ll;
  66 }
  67
  68 static void pit_set_gate(struct kvm *kvm, int channel, u32 val)
  69 {
  70         struct kvm_kpit_channel_state *c =
  71                 &kvm->arch.vpit->pit_state.channels[channel];
  72
  73         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
  74
  75         switch (c->mode) {
  76         default:
  77         case 0:
  78         case 4:
  79                 /* XXX: just disable/enable counting */
  80                 break;
  81         case 1:
  82         case 2:
  83         case 3:
  84         case 5:
  85                 /* Restart counting on rising edge. */
  86                 if (c->gate < val)
  87                         c->count_load_time = ktime_get();
  88                 break;
  89         }
  90
  91         c->gate = val;
  92 }
  93
  94 static int pit_get_gate(struct kvm *kvm, int channel)
  95 {
  96         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
  97
  98         return kvm->arch.vpit->pit_state.channels[channel].gate;
  99 }
 100
 101 static s64 __kpit_elapsed(struct kvm *kvm)
 102 {
 103         s64 elapsed;
 104         ktime_t remaining;
 105         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 106
 107         if (!ps->pit_timer.period)
 108                 return 0;
 109
 110         /*
 111          * The Counter does not stop when it reaches zero. In
 112          * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
 113          * the highest count, either FFFF hex for binary counting
 114          * or 9999 for BCD counting, and continues counting.
 115          * Modes 2 and 3 are periodic; the Counter reloads
 116          * itself with the initial count and continues counting
 117          * from there.
 118          */
 119         remaining = hrtimer_expires_remaining(&ps->pit_timer.timer);
 120         elapsed = ps->pit_timer.period - ktime_to_ns(remaining);
 121         elapsed = mod_64(elapsed, ps->pit_timer.period);
 122
 123         return elapsed;
 124 }
 125
 126 static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,
 127                         int channel)
 128 {
 129         if (channel == 0)
 130                 return __kpit_elapsed(kvm);
 131
 132         return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 133 }
 134
 135 static int pit_get_count(struct kvm *kvm, int channel)
 136 {
 137         struct kvm_kpit_channel_state *c =
 138                 &kvm->arch.vpit->pit_state.channels[channel];
 139         s64 d, t;
 140         int counter;
 141
 142         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 143
 144         t = kpit_elapsed(kvm, c, channel);
 145         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 146
 147         switch (c->mode) {
 148         case 0:
 149         case 1:
 150         case 4:
 151         case 5:
 152                 counter = (c->count - d) & 0xffff;
 153                 break;
 154         case 3:
 155                 /* XXX: may be incorrect for odd counts */
 156                 counter = c->count - (mod_64((2 * d), c->count));
 157                 break;
 158         default:
 159                 counter = c->count - mod_64(d, c->count);
 160                 break;
 161         }
 162         return counter;
 163 }
 164
 165 static int pit_get_out(struct kvm *kvm, int channel)
 166 {
 167         struct kvm_kpit_channel_state *c =
 168                 &kvm->arch.vpit->pit_state.channels[channel];
 169         s64 d, t;
 170         int out;
 171
 172         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 173
 174         t = kpit_elapsed(kvm, c, channel);
 175         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 176
 177         switch (c->mode) {
 178         default:
 179         case 0:
 180                 out = (d >= c->count);
 181                 break;
 182         case 1:
 183                 out = (d < c->count);
 184                 break;
 185         case 2:
 186                 out = ((mod_64(d, c->count) == 0) && (d != 0));
 187                 break;
 188         case 3:
 189                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
 190                 break;
 191         case 4:
 192         case 5:
 193                 out = (d == c->count);
 194                 break;
 195         }
 196
 197         return out;
 198 }
 199
 200 static void pit_latch_count(struct kvm *kvm, int channel)
 201 {
 202         struct kvm_kpit_channel_state *c =
 203                 &kvm->arch.vpit->pit_state.channels[channel];
 204
 205         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 206
 207         if (!c->count_latched) {
 208                 c->latched_count = pit_get_count(kvm, channel);
 209                 c->count_latched = c->rw_mode;
 210         }
 211 }
 212
 213 static void pit_latch_status(struct kvm *kvm, int channel)
 214 {
 215         struct kvm_kpit_channel_state *c =
 216                 &kvm->arch.vpit->pit_state.channels[channel];
 217
 218         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 219
 220         if (!c->status_latched) {
 221                 /* TODO: Return NULL COUNT (bit 6). */
 222                 c->status = ((pit_get_out(kvm, channel) << 7) |
 223                                 (c->rw_mode << 4) |
 224                                 (c->mode << 1) |
 225                                 c->bcd);
 226                 c->status_latched = 1;
 227         }
 228 }
 229
 230 int pit_has_pending_timer(struct kvm_vcpu *vcpu)
 231 {
 232         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 233
 234         if (pit && kvm_vcpu_is_bsp(vcpu) && pit->pit_state.irq_ack)
 235                 return atomic_read(&pit->pit_state.pit_timer.pending);
 236         return 0;
 237 }
 238
 239 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 240 {
 241         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 242                                                  irq_ack_notifier);
 243         spin_lock(&ps->inject_lock);
 244         if (atomic_dec_return(&ps->pit_timer.pending) < 0)
 245                 atomic_inc(&ps->pit_timer.pending);
 246         ps->irq_ack = 1;
 247         spin_unlock(&ps->inject_lock);
 248 }
 249
 250 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 251 {
 252         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 253         struct hrtimer *timer;
 254
 255         if (!kvm_vcpu_is_bsp(vcpu) || !pit)
 256                 return;
 257
 258         timer = &pit->pit_state.pit_timer.timer;
 259         if (hrtimer_cancel(timer))
 260                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 261 }
 262
 263 static void destroy_pit_timer(struct kvm_timer *pt)
 264 {
 265         pr_debug("pit: execute del timer!\n");
 266         hrtimer_cancel(&pt->timer);
 267 }
 268
 269 static bool kpit_is_periodic(struct kvm_timer *ktimer)
 270 {
 271         struct kvm_kpit_state *ps = container_of(ktimer, struct kvm_kpit_state,
 272                                                  pit_timer);
 273         return ps->is_periodic;
 274 }
 275
 276 static struct kvm_timer_ops kpit_ops = {
 277         .is_periodic = kpit_is_periodic,
 278 };
 279
 280 static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
 281 {
 282         struct kvm_timer *pt = &ps->pit_timer;
 283         s64 interval;
 284
 285         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 286
 287         pr_debug("pit: create pit timer, interval is %llu nsec\n", interval);
 288
 289         /* TODO The new value only affected after the retriggered */
 290         hrtimer_cancel(&pt->timer);
 291         pt->period = interval;
 292         ps->is_periodic = is_period;
 293
 294         pt->timer.function = kvm_timer_fn;
 295         pt->t_ops = &kpit_ops;
 296         pt->kvm = ps->pit->kvm;
 297         pt->vcpu = pt->kvm->bsp_vcpu;
 298
 299         atomic_set(&pt->pending, 0);
 300         ps->irq_ack = 1;
 301
 302         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
 303                       HRTIMER_MODE_ABS);
 304 }
 305
 306 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 307 {
 308         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 309
 310         WARN_ON(!mutex_is_locked(&ps->lock));
 311
 312         pr_debug("pit: load_count val is %d, channel is %d\n", val, channel);
 313
 314         /*
 315          * The largest possible initial count is 0; this is equivalent
 316          * to 216 for binary counting and 104 for BCD counting.
 317          */
 318         if (val == 0)
 319                 val = 0x10000;
 320
 321         ps->channels[channel].count = val;
 322
 323         if (channel != 0) {
 324                 ps->channels[channel].count_load_time = ktime_get();
 325                 return;
 326         }
 327
 328         /* Two types of timer
 329          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 330         switch (ps->channels[0].mode) {
 331         case 0:
 332         case 1:
 333         /* FIXME: enhance mode 4 precision */
 334         case 4:
 335                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) {
 336                         create_pit_timer(ps, val, 0);
 337                 }
 338                 break;
 339         case 2:
 340         case 3:
 341                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){
 342                         create_pit_timer(ps, val, 1);
 343                 }
 344                 break;
 345         default:
 346                 destroy_pit_timer(&ps->pit_timer);
 347         }
 348 }
 349
 350 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
 351 {
 352         u8 saved_mode;
 353         if (hpet_legacy_start) {
 354                 /* save existing mode for later reenablement */
 355                 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
 356                 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
 357                 pit_load_count(kvm, channel, val);
 358                 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
 359         } else {
 360                 pit_load_count(kvm, channel, val);
 361         }
 362 }
 363
 364 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
 365 {
 366         return container_of(dev, struct kvm_pit, dev);
 367 }
 368
 369 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
 370 {
 371         return container_of(dev, struct kvm_pit, speaker_dev);
 372 }
 373
 374 static inline int pit_in_range(gpa_t addr)
 375 {
 376         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 377                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 378 }
 379
 380 static int pit_ioport_write(struct kvm_io_device *this,
 381                             gpa_t addr, int len, const void *data)
 382 {
 383         struct kvm_pit *pit = dev_to_pit(this);
 384         struct kvm_kpit_state *pit_state = &pit->pit_state;
 385         struct kvm *kvm = pit->kvm;
 386         int channel, access;
 387         struct kvm_kpit_channel_state *s;
 388         u32 val = *(u32 *) data;
 389         if (!pit_in_range(addr))
 390                 return -EOPNOTSUPP;
 391
 392         val  &= 0xff;
 393         addr &= KVM_PIT_CHANNEL_MASK;
 394
 395         mutex_lock(&pit_state->lock);
 396
 397         if (val != 0)
 398                 pr_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
 399                           (unsigned int)addr, len, val);
 400
 401         if (addr == 3) {
 402                 channel = val >> 6;
 403                 if (channel == 3) {
 404                         /* Read-Back Command. */
 405                         for (channel = 0; channel < 3; channel++) {
 406                                 s = &pit_state->channels[channel];
 407                                 if (val & (2 << channel)) {
 408                                         if (!(val & 0x20))
 409                                                 pit_latch_count(kvm, channel);
 410                                         if (!(val & 0x10))
 411                                                 pit_latch_status(kvm, channel);
 412                                 }
 413                         }
 414                 } else {
 415                         /* Select Counter <channel>. */
 416                         s = &pit_state->channels[channel];
 417                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 418                         if (access == 0) {
 419                                 pit_latch_count(kvm, channel);
 420                         } else {
 421                                 s->rw_mode = access;
 422                                 s->read_state = access;
 423                                 s->write_state = access;
 424                                 s->mode = (val >> 1) & 7;
 425                                 if (s->mode > 5)
 426                                         s->mode -= 4;
 427                                 s->bcd = val & 1;
 428                         }
 429                 }
 430         } else {
 431                 /* Write Count. */
 432                 s = &pit_state->channels[addr];
 433                 switch (s->write_state) {
 434                 default:
 435                 case RW_STATE_LSB:
 436                         pit_load_count(kvm, addr, val);
 437                         break;
 438                 case RW_STATE_MSB:
 439                         pit_load_count(kvm, addr, val << 8);
 440                         break;
 441                 case RW_STATE_WORD0:
 442                         s->write_latch = val;
 443                         s->write_state = RW_STATE_WORD1;
 444                         break;
 445                 case RW_STATE_WORD1:
 446                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 447                         s->write_state = RW_STATE_WORD0;
 448                         break;
 449                 }
 450         }
 451
 452         mutex_unlock(&pit_state->lock);
 453         return 0;
 454 }
 455
 456 static int pit_ioport_read(struct kvm_io_device *this,
 457                            gpa_t addr, int len, void *data)
 458 {
 459         struct kvm_pit *pit = dev_to_pit(this);
 460         struct kvm_kpit_state *pit_state = &pit->pit_state;
 461         struct kvm *kvm = pit->kvm;
 462         int ret, count;
 463         struct kvm_kpit_channel_state *s;
 464         if (!pit_in_range(addr))
 465                 return -EOPNOTSUPP;
 466
 467         addr &= KVM_PIT_CHANNEL_MASK;
 468         s = &pit_state->channels[addr];
 469
 470         mutex_lock(&pit_state->lock);
 471
 472         if (s->status_latched) {
 473                 s->status_latched = 0;
 474                 ret = s->status;
 475         } else if (s->count_latched) {
 476                 switch (s->count_latched) {
 477                 default:
 478                 case RW_STATE_LSB:
 479                         ret = s->latched_count & 0xff;
 480                         s->count_latched = 0;
 481                         break;
 482                 case RW_STATE_MSB:
 483                         ret = s->latched_count >> 8;
 484                         s->count_latched = 0;
 485                         break;
 486                 case RW_STATE_WORD0:
 487                         ret = s->latched_count & 0xff;
 488                         s->count_latched = RW_STATE_MSB;
 489                         break;
 490                 }
 491         } else {
 492                 switch (s->read_state) {
 493                 default:
 494                 case RW_STATE_LSB:
 495                         count = pit_get_count(kvm, addr);
 496                         ret = count & 0xff;
 497                         break;
 498                 case RW_STATE_MSB:
 499                         count = pit_get_count(kvm, addr);
 500                         ret = (count >> 8) & 0xff;
 501                         break;
 502                 case RW_STATE_WORD0:
 503                         count = pit_get_count(kvm, addr);
 504                         ret = count & 0xff;
 505                         s->read_state = RW_STATE_WORD1;
 506                         break;
 507                 case RW_STATE_WORD1:
 508                         count = pit_get_count(kvm, addr);
 509                         ret = (count >> 8) & 0xff;
 510                         s->read_state = RW_STATE_WORD0;
 511                         break;
 512                 }
 513         }
 514
 515         if (len > sizeof(ret))
 516                 len = sizeof(ret);
 517         memcpy(data, (char *)&ret, len);
 518
 519         mutex_unlock(&pit_state->lock);
 520         return 0;
 521 }
 522
 523 static int speaker_ioport_write(struct kvm_io_device *this,
 524                                 gpa_t addr, int len, const void *data)
 525 {
 526         struct kvm_pit *pit = speaker_to_pit(this);
 527         struct kvm_kpit_state *pit_state = &pit->pit_state;
 528         struct kvm *kvm = pit->kvm;
 529         u32 val = *(u32 *) data;
 530         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 531                 return -EOPNOTSUPP;
 532
 533         mutex_lock(&pit_state->lock);
 534         pit_state->speaker_data_on = (val >> 1) & 1;
 535         pit_set_gate(kvm, 2, val & 1);
 536         mutex_unlock(&pit_state->lock);
 537         return 0;
 538 }
 539
 540 static int speaker_ioport_read(struct kvm_io_device *this,
 541                                gpa_t addr, int len, void *data)
 542 {
 543         struct kvm_pit *pit = speaker_to_pit(this);
 544         struct kvm_kpit_state *pit_state = &pit->pit_state;
 545         struct kvm *kvm = pit->kvm;
 546         unsigned int refresh_clock;
 547         int ret;
 548         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 549                 return -EOPNOTSUPP;
 550
 551         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 552         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 553
 554         mutex_lock(&pit_state->lock);
 555         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 556                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 557         if (len > sizeof(ret))
 558                 len = sizeof(ret);
 559         memcpy(data, (char *)&ret, len);
 560         mutex_unlock(&pit_state->lock);
 561         return 0;
 562 }
 563
 564 void kvm_pit_reset(struct kvm_pit *pit)
 565 {
 566         int i;
 567         struct kvm_kpit_channel_state *c;
 568
 569         mutex_lock(&pit->pit_state.lock);
 570         pit->pit_state.flags = 0;
 571         for (i = 0; i < 3; i++) {
 572                 c = &pit->pit_state.channels[i];
 573                 c->mode = 0xff;
 574                 c->gate = (i != 2);
 575                 pit_load_count(pit->kvm, i, 0);
 576         }
 577         mutex_unlock(&pit->pit_state.lock);
 578
 579         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 580         pit->pit_state.irq_ack = 1;
 581 }
 582
 583 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 584 {
 585         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 586
 587         if (!mask) {
 588                 atomic_set(&pit->pit_state.pit_timer.pending, 0);
 589                 pit->pit_state.irq_ack = 1;
 590         }
 591 }
 592
 593 static const struct kvm_io_device_ops pit_dev_ops = {
 594         .read     = pit_ioport_read,
 595         .write    = pit_ioport_write,
 596 };
 597
 598 static const struct kvm_io_device_ops speaker_dev_ops = {
 599         .read     = speaker_ioport_read,
 600         .write    = speaker_ioport_write,
 601 };
 602
 603 /* Caller must have writers lock on slots_lock */
 604 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 605 {
 606         struct kvm_pit *pit;
 607         struct kvm_kpit_state *pit_state;
 608         int ret;
 609
 610         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 611         if (!pit)
 612                 return NULL;
 613
 614         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 615         if (pit->irq_source_id < 0) {
 616                 kfree(pit);
 617                 return NULL;
 618         }
 619
 620         mutex_init(&pit->pit_state.lock);
 621         mutex_lock(&pit->pit_state.lock);
 622         spin_lock_init(&pit->pit_state.inject_lock);
 623
 624         kvm->arch.vpit = pit;
 625         pit->kvm = kvm;
 626
 627         pit_state = &pit->pit_state;
 628         pit_state->pit = pit;
 629         hrtimer_init(&pit_state->pit_timer.timer,
 630                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 631         pit_state->irq_ack_notifier.gsi = 0;
 632         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 633         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 634         pit_state->pit_timer.reinject = true;
 635         mutex_unlock(&pit->pit_state.lock);
 636
 637         kvm_pit_reset(pit);
 638
 639         pit->mask_notifier.func = pit_mask_notifer;
 640         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 641
 642         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
 643         ret = __kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
 644         if (ret < 0)
 645                 goto fail;
 646
 647         if (flags & KVM_PIT_SPEAKER_DUMMY) {
 648                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 649                 ret = __kvm_io_bus_register_dev(&kvm->pio_bus,
 650                                                 &pit->speaker_dev);
 651                 if (ret < 0)
 652                         goto fail_unregister;
 653         }
 654
 655         return pit;
 656
 657 fail_unregister:
 658         __kvm_io_bus_unregister_dev(&kvm->pio_bus, &pit->dev);
 659
 660 fail:
 661         if (pit->irq_source_id >= 0)
 662                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
 663
 664         kfree(pit);
 665         return NULL;
 666 }
 667
 668 void kvm_free_pit(struct kvm *kvm)
 669 {
 670         struct hrtimer *timer;
 671
 672         if (kvm->arch.vpit) {
 673                 kvm_unregister_irq_mask_notifier(kvm, 0,
 674                                                &kvm->arch.vpit->mask_notifier);
 675                 kvm_unregister_irq_ack_notifier(kvm,
 676                                 &kvm->arch.vpit->pit_state.irq_ack_notifier);
 677                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 678                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
 679                 hrtimer_cancel(timer);
 680                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 681                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 682                 kfree(kvm->arch.vpit);
 683         }
 684 }
 685
 686 static void __inject_pit_timer_intr(struct kvm *kvm)
 687 {
 688         struct kvm_vcpu *vcpu;
 689         int i;
 690
 691         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
 692         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
 693
 694         /*
 695          * Provides NMI watchdog support via Virtual Wire mode.
 696          * The route is: PIT -> PIC -> LVT0 in NMI mode.
 697          *
 698          * Note: Our Virtual Wire implementation is simplified, only
 699          * propagating PIT interrupts to all VCPUs when they have set
 700          * LVT0 to NMI delivery. Other PIC interrupts are just sent to
 701          * VCPU0, and only if its LVT0 is in EXTINT mode.
 702          */
 703         if (kvm->arch.vapics_in_nmi_mode > 0)
 704                 kvm_for_each_vcpu(i, vcpu, kvm)
 705                         kvm_apic_nmi_wd_deliver(vcpu);
 706 }
 707
 708 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
 709 {
 710         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 711         struct kvm *kvm = vcpu->kvm;
 712         struct kvm_kpit_state *ps;
 713
 714         if (pit) {
 715                 int inject = 0;
 716                 ps = &pit->pit_state;
 717
 718                 /* Try to inject pending interrupts when
 719                  * last one has been acked.
 720                  */
 721                 spin_lock(&ps->inject_lock);
 722                 if (atomic_read(&ps->pit_timer.pending) && ps->irq_ack) {
 723                         ps->irq_ack = 0;
 724                         inject = 1;
 725                 }
 726                 spin_unlock(&ps->inject_lock);
 727                 if (inject)
 728                         __inject_pit_timer_intr(kvm);
 729         }
 730 }