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 <[email protected]>
  29  *   Based on QEMU and Xen.
  30  */
  31
  32 #define pr_fmt(fmt) "pit: " fmt
  33
  34 #include <linux/kvm_host.h>
  35
  36 #include "irq.h"
  37 #include "i8254.h"
  38
  39 #ifndef CONFIG_X86_64
  40 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
  41 #else
  42 #define mod_64(x, y) ((x) % (y))
  43 #endif
  44
  45 #define RW_STATE_LSB 1
  46 #define RW_STATE_MSB 2
  47 #define RW_STATE_WORD0 3
  48 #define RW_STATE_WORD1 4
  49
  50 /* Compute with 96 bit intermediate result: (a*b)/c */
  51 static u64 muldiv64(u64 a, u32 b, u32 c)
  52 {
  53         union {
  54                 u64 ll;
  55                 struct {
  56                         u32 low, high;
  57                 } l;
  58         } u, res;
  59         u64 rl, rh;
  60
  61         u.ll = a;
  62         rl = (u64)u.l.low * (u64)b;
  63         rh = (u64)u.l.high * (u64)b;
  64         rh += (rl >> 32);
  65         res.l.high = div64_u64(rh, c);
  66         res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
  67         return res.ll;
  68 }
  69
  70 static void pit_set_gate(struct kvm *kvm, int channel, u32 val)
  71 {
  72         struct kvm_kpit_channel_state *c =
  73                 &kvm->arch.vpit->pit_state.channels[channel];
  74
  75         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
  76
  77         switch (c->mode) {
  78         default:
  79         case 0:
  80         case 4:
  81                 /* XXX: just disable/enable counting */
  82                 break;
  83         case 1:
  84         case 2:
  85         case 3:
  86         case 5:
  87                 /* Restart counting on rising edge. */
  88                 if (c->gate < val)
  89                         c->count_load_time = ktime_get();
  90                 break;
  91         }
  92
  93         c->gate = val;
  94 }
  95
  96 static int pit_get_gate(struct kvm *kvm, int channel)
  97 {
  98         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
  99
 100         return kvm->arch.vpit->pit_state.channels[channel].gate;
 101 }
 102
 103 static s64 __kpit_elapsed(struct kvm *kvm)
 104 {
 105         s64 elapsed;
 106         ktime_t remaining;
 107         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 108
 109         if (!ps->pit_timer.period)
 110                 return 0;
 111
 112         /*
 113          * The Counter does not stop when it reaches zero. In
 114          * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
 115          * the highest count, either FFFF hex for binary counting
 116          * or 9999 for BCD counting, and continues counting.
 117          * Modes 2 and 3 are periodic; the Counter reloads
 118          * itself with the initial count and continues counting
 119          * from there.
 120          */
 121         remaining = hrtimer_get_remaining(&ps->pit_timer.timer);
 122         elapsed = ps->pit_timer.period - ktime_to_ns(remaining);
 123         elapsed = mod_64(elapsed, ps->pit_timer.period);
 124
 125         return elapsed;
 126 }
 127
 128 static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,
 129                         int channel)
 130 {
 131         if (channel == 0)
 132                 return __kpit_elapsed(kvm);
 133
 134         return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 135 }
 136
 137 static int pit_get_count(struct kvm *kvm, int channel)
 138 {
 139         struct kvm_kpit_channel_state *c =
 140                 &kvm->arch.vpit->pit_state.channels[channel];
 141         s64 d, t;
 142         int counter;
 143
 144         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 145
 146         t = kpit_elapsed(kvm, c, channel);
 147         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 148
 149         switch (c->mode) {
 150         case 0:
 151         case 1:
 152         case 4:
 153         case 5:
 154                 counter = (c->count - d) & 0xffff;
 155                 break;
 156         case 3:
 157                 /* XXX: may be incorrect for odd counts */
 158                 counter = c->count - (mod_64((2 * d), c->count));
 159                 break;
 160         default:
 161                 counter = c->count - mod_64(d, c->count);
 162                 break;
 163         }
 164         return counter;
 165 }
 166
 167 static int pit_get_out(struct kvm *kvm, int channel)
 168 {
 169         struct kvm_kpit_channel_state *c =
 170                 &kvm->arch.vpit->pit_state.channels[channel];
 171         s64 d, t;
 172         int out;
 173
 174         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 175
 176         t = kpit_elapsed(kvm, c, channel);
 177         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 178
 179         switch (c->mode) {
 180         default:
 181         case 0:
 182                 out = (d >= c->count);
 183                 break;
 184         case 1:
 185                 out = (d < c->count);
 186                 break;
 187         case 2:
 188                 out = ((mod_64(d, c->count) == 0) && (d != 0));
 189                 break;
 190         case 3:
 191                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
 192                 break;
 193         case 4:
 194         case 5:
 195                 out = (d == c->count);
 196                 break;
 197         }
 198
 199         return out;
 200 }
 201
 202 static void pit_latch_count(struct kvm *kvm, int channel)
 203 {
 204         struct kvm_kpit_channel_state *c =
 205                 &kvm->arch.vpit->pit_state.channels[channel];
 206
 207         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 208
 209         if (!c->count_latched) {
 210                 c->latched_count = pit_get_count(kvm, channel);
 211                 c->count_latched = c->rw_mode;
 212         }
 213 }
 214
 215 static void pit_latch_status(struct kvm *kvm, int channel)
 216 {
 217         struct kvm_kpit_channel_state *c =
 218                 &kvm->arch.vpit->pit_state.channels[channel];
 219
 220         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 221
 222         if (!c->status_latched) {
 223                 /* TODO: Return NULL COUNT (bit 6). */
 224                 c->status = ((pit_get_out(kvm, channel) << 7) |
 225                                 (c->rw_mode << 4) |
 226                                 (c->mode << 1) |
 227                                 c->bcd);
 228                 c->status_latched = 1;
 229         }
 230 }
 231
 232 int pit_has_pending_timer(struct kvm_vcpu *vcpu)
 233 {
 234         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 235
 236         if (pit && kvm_vcpu_is_bsp(vcpu) && pit->pit_state.irq_ack)
 237                 return atomic_read(&pit->pit_state.pit_timer.pending);
 238         return 0;
 239 }
 240
 241 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 242 {
 243         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 244                                                  irq_ack_notifier);
 245         spin_lock(&ps->inject_lock);
 246         if (atomic_dec_return(&ps->pit_timer.pending) < 0)
 247                 atomic_inc(&ps->pit_timer.pending);
 248         ps->irq_ack = 1;
 249         spin_unlock(&ps->inject_lock);
 250 }
 251
 252 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 253 {
 254         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 255         struct hrtimer *timer;
 256
 257         if (!kvm_vcpu_is_bsp(vcpu) || !pit)
 258                 return;
 259
 260         timer = &pit->pit_state.pit_timer.timer;
 261         if (hrtimer_cancel(timer))
 262                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 263 }
 264
 265 static void destroy_pit_timer(struct kvm_timer *pt)
 266 {
 267         pr_debug("execute del timer!\n");
 268         hrtimer_cancel(&pt->timer);
 269 }
 270
 271 static bool kpit_is_periodic(struct kvm_timer *ktimer)
 272 {
 273         struct kvm_kpit_state *ps = container_of(ktimer, struct kvm_kpit_state,
 274                                                  pit_timer);
 275         return ps->is_periodic;
 276 }
 277
 278 static struct kvm_timer_ops kpit_ops = {
 279         .is_periodic = kpit_is_periodic,
 280 };
 281
 282 static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
 283 {
 284         struct kvm_timer *pt = &ps->pit_timer;
 285         s64 interval;
 286
 287         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 288
 289         pr_debug("create pit timer, interval is %llu nsec\n", interval);
 290
 291         /* TODO The new value only affected after the retriggered */
 292         hrtimer_cancel(&pt->timer);
 293         pt->period = interval;
 294         ps->is_periodic = is_period;
 295
 296         pt->timer.function = kvm_timer_fn;
 297         pt->t_ops = &kpit_ops;
 298         pt->kvm = ps->pit->kvm;
 299         pt->vcpu = pt->kvm->bsp_vcpu;
 300
 301         atomic_set(&pt->pending, 0);
 302         ps->irq_ack = 1;
 303
 304         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
 305                       HRTIMER_MODE_ABS);
 306 }
 307
 308 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 309 {
 310         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 311
 312         WARN_ON(!mutex_is_locked(&ps->lock));
 313
 314         pr_debug("load_count val is %d, channel is %d\n", val, channel);
 315
 316         /*
 317          * The largest possible initial count is 0; this is equivalent
 318          * to 216 for binary counting and 104 for BCD counting.
 319          */
 320         if (val == 0)
 321                 val = 0x10000;
 322
 323         ps->channels[channel].count = val;
 324
 325         if (channel != 0) {
 326                 ps->channels[channel].count_load_time = ktime_get();
 327                 return;
 328         }
 329
 330         /* Two types of timer
 331          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 332         switch (ps->channels[0].mode) {
 333         case 0:
 334         case 1:
 335         /* FIXME: enhance mode 4 precision */
 336         case 4:
 337                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) {
 338                         create_pit_timer(ps, val, 0);
 339                 }
 340                 break;
 341         case 2:
 342         case 3:
 343                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){
 344                         create_pit_timer(ps, val, 1);
 345                 }
 346                 break;
 347         default:
 348                 destroy_pit_timer(&ps->pit_timer);
 349         }
 350 }
 351
 352 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
 353 {
 354         u8 saved_mode;
 355         if (hpet_legacy_start) {
 356                 /* save existing mode for later reenablement */
 357                 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
 358                 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
 359                 pit_load_count(kvm, channel, val);
 360                 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
 361         } else {
 362                 pit_load_count(kvm, channel, val);
 363         }
 364 }
 365
 366 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
 367 {
 368         return container_of(dev, struct kvm_pit, dev);
 369 }
 370
 371 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
 372 {
 373         return container_of(dev, struct kvm_pit, speaker_dev);
 374 }
 375
 376 static inline int pit_in_range(gpa_t addr)
 377 {
 378         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 379                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 380 }
 381
 382 static int pit_ioport_write(struct kvm_io_device *this,
 383                             gpa_t addr, int len, const void *data)
 384 {
 385         struct kvm_pit *pit = dev_to_pit(this);
 386         struct kvm_kpit_state *pit_state = &pit->pit_state;
 387         struct kvm *kvm = pit->kvm;
 388         int channel, access;
 389         struct kvm_kpit_channel_state *s;
 390         u32 val = *(u32 *) data;
 391         if (!pit_in_range(addr))
 392                 return -EOPNOTSUPP;
 393
 394         val  &= 0xff;
 395         addr &= KVM_PIT_CHANNEL_MASK;
 396
 397         mutex_lock(&pit_state->lock);
 398
 399         if (val != 0)
 400                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
 401                          (unsigned int)addr, len, val);
 402
 403         if (addr == 3) {
 404                 channel = val >> 6;
 405                 if (channel == 3) {
 406                         /* Read-Back Command. */
 407                         for (channel = 0; channel < 3; channel++) {
 408                                 s = &pit_state->channels[channel];
 409                                 if (val & (2 << channel)) {
 410                                         if (!(val & 0x20))
 411                                                 pit_latch_count(kvm, channel);
 412                                         if (!(val & 0x10))
 413                                                 pit_latch_status(kvm, channel);
 414                                 }
 415                         }
 416                 } else {
 417                         /* Select Counter <channel>. */
 418                         s = &pit_state->channels[channel];
 419                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 420                         if (access == 0) {
 421                                 pit_latch_count(kvm, channel);
 422                         } else {
 423                                 s->rw_mode = access;
 424                                 s->read_state = access;
 425                                 s->write_state = access;
 426                                 s->mode = (val >> 1) & 7;
 427                                 if (s->mode > 5)
 428                                         s->mode -= 4;
 429                                 s->bcd = val & 1;
 430                         }
 431                 }
 432         } else {
 433                 /* Write Count. */
 434                 s = &pit_state->channels[addr];
 435                 switch (s->write_state) {
 436                 default:
 437                 case RW_STATE_LSB:
 438                         pit_load_count(kvm, addr, val);
 439                         break;
 440                 case RW_STATE_MSB:
 441                         pit_load_count(kvm, addr, val << 8);
 442                         break;
 443                 case RW_STATE_WORD0:
 444                         s->write_latch = val;
 445                         s->write_state = RW_STATE_WORD1;
 446                         break;
 447                 case RW_STATE_WORD1:
 448                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 449                         s->write_state = RW_STATE_WORD0;
 450                         break;
 451                 }
 452         }
 453
 454         mutex_unlock(&pit_state->lock);
 455         return 0;
 456 }
 457
 458 static int pit_ioport_read(struct kvm_io_device *this,
 459                            gpa_t addr, int len, void *data)
 460 {
 461         struct kvm_pit *pit = dev_to_pit(this);
 462         struct kvm_kpit_state *pit_state = &pit->pit_state;
 463         struct kvm *kvm = pit->kvm;
 464         int ret, count;
 465         struct kvm_kpit_channel_state *s;
 466         if (!pit_in_range(addr))
 467                 return -EOPNOTSUPP;
 468
 469         addr &= KVM_PIT_CHANNEL_MASK;
 470         s = &pit_state->channels[addr];
 471
 472         mutex_lock(&pit_state->lock);
 473
 474         if (s->status_latched) {
 475                 s->status_latched = 0;
 476                 ret = s->status;
 477         } else if (s->count_latched) {
 478                 switch (s->count_latched) {
 479                 default:
 480                 case RW_STATE_LSB:
 481                         ret = s->latched_count & 0xff;
 482                         s->count_latched = 0;
 483                         break;
 484                 case RW_STATE_MSB:
 485                         ret = s->latched_count >> 8;
 486                         s->count_latched = 0;
 487                         break;
 488                 case RW_STATE_WORD0:
 489                         ret = s->latched_count & 0xff;
 490                         s->count_latched = RW_STATE_MSB;
 491                         break;
 492                 }
 493         } else {
 494                 switch (s->read_state) {
 495                 default:
 496                 case RW_STATE_LSB:
 497                         count = pit_get_count(kvm, addr);
 498                         ret = count & 0xff;
 499                         break;
 500                 case RW_STATE_MSB:
 501                         count = pit_get_count(kvm, addr);
 502                         ret = (count >> 8) & 0xff;
 503                         break;
 504                 case RW_STATE_WORD0:
 505                         count = pit_get_count(kvm, addr);
 506                         ret = count & 0xff;
 507                         s->read_state = RW_STATE_WORD1;
 508                         break;
 509                 case RW_STATE_WORD1:
 510                         count = pit_get_count(kvm, addr);
 511                         ret = (count >> 8) & 0xff;
 512                         s->read_state = RW_STATE_WORD0;
 513                         break;
 514                 }
 515         }
 516
 517         if (len > sizeof(ret))
 518                 len = sizeof(ret);
 519         memcpy(data, (char *)&ret, len);
 520
 521         mutex_unlock(&pit_state->lock);
 522         return 0;
 523 }
 524
 525 static int speaker_ioport_write(struct kvm_io_device *this,
 526                                 gpa_t addr, int len, const void *data)
 527 {
 528         struct kvm_pit *pit = speaker_to_pit(this);
 529         struct kvm_kpit_state *pit_state = &pit->pit_state;
 530         struct kvm *kvm = pit->kvm;
 531         u32 val = *(u32 *) data;
 532         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 533                 return -EOPNOTSUPP;
 534
 535         mutex_lock(&pit_state->lock);
 536         pit_state->speaker_data_on = (val >> 1) & 1;
 537         pit_set_gate(kvm, 2, val & 1);
 538         mutex_unlock(&pit_state->lock);
 539         return 0;
 540 }
 541
 542 static int speaker_ioport_read(struct kvm_io_device *this,
 543                                gpa_t addr, int len, void *data)
 544 {
 545         struct kvm_pit *pit = speaker_to_pit(this);
 546         struct kvm_kpit_state *pit_state = &pit->pit_state;
 547         struct kvm *kvm = pit->kvm;
 548         unsigned int refresh_clock;
 549         int ret;
 550         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 551                 return -EOPNOTSUPP;
 552
 553         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 554         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 555
 556         mutex_lock(&pit_state->lock);
 557         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 558                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 559         if (len > sizeof(ret))
 560                 len = sizeof(ret);
 561         memcpy(data, (char *)&ret, len);
 562         mutex_unlock(&pit_state->lock);
 563         return 0;
 564 }
 565
 566 void kvm_pit_reset(struct kvm_pit *pit)
 567 {
 568         int i;
 569         struct kvm_kpit_channel_state *c;
 570
 571         mutex_lock(&pit->pit_state.lock);
 572         pit->pit_state.flags = 0;
 573         for (i = 0; i < 3; i++) {
 574                 c = &pit->pit_state.channels[i];
 575                 c->mode = 0xff;
 576                 c->gate = (i != 2);
 577                 pit_load_count(pit->kvm, i, 0);
 578         }
 579         mutex_unlock(&pit->pit_state.lock);
 580
 581         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 582         pit->pit_state.irq_ack = 1;
 583 }
 584
 585 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 586 {
 587         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 588
 589         if (!mask) {
 590                 atomic_set(&pit->pit_state.pit_timer.pending, 0);
 591                 pit->pit_state.irq_ack = 1;
 592         }
 593 }
 594
 595 static const struct kvm_io_device_ops pit_dev_ops = {
 596         .read     = pit_ioport_read,
 597         .write    = pit_ioport_write,
 598 };
 599
 600 static const struct kvm_io_device_ops speaker_dev_ops = {
 601         .read     = speaker_ioport_read,
 602         .write    = speaker_ioport_write,
 603 };
 604
 605 /* Caller must have writers lock on slots_lock */
 606 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 607 {
 608         struct kvm_pit *pit;
 609         struct kvm_kpit_state *pit_state;
 610         int ret;
 611
 612         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 613         if (!pit)
 614                 return NULL;
 615
 616         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 617         if (pit->irq_source_id < 0) {
 618                 kfree(pit);
 619                 return NULL;
 620         }
 621
 622         mutex_init(&pit->pit_state.lock);
 623         mutex_lock(&pit->pit_state.lock);
 624         spin_lock_init(&pit->pit_state.inject_lock);
 625
 626         kvm->arch.vpit = pit;
 627         pit->kvm = kvm;
 628
 629         pit_state = &pit->pit_state;
 630         pit_state->pit = pit;
 631         hrtimer_init(&pit_state->pit_timer.timer,
 632                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 633         pit_state->irq_ack_notifier.gsi = 0;
 634         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 635         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 636         pit_state->pit_timer.reinject = true;
 637         mutex_unlock(&pit->pit_state.lock);
 638
 639         kvm_pit_reset(pit);
 640
 641         pit->mask_notifier.func = pit_mask_notifer;
 642         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 643
 644         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
 645         ret = __kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
 646         if (ret < 0)
 647                 goto fail;
 648
 649         if (flags & KVM_PIT_SPEAKER_DUMMY) {
 650                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 651                 ret = __kvm_io_bus_register_dev(&kvm->pio_bus,
 652                                                 &pit->speaker_dev);
 653                 if (ret < 0)
 654                         goto fail_unregister;
 655         }
 656
 657         return pit;
 658
 659 fail_unregister:
 660         __kvm_io_bus_unregister_dev(&kvm->pio_bus, &pit->dev);
 661
 662 fail:
 663         if (pit->irq_source_id >= 0)
 664                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
 665
 666         kfree(pit);
 667         return NULL;
 668 }
 669
 670 void kvm_free_pit(struct kvm *kvm)
 671 {
 672         struct hrtimer *timer;
 673
 674         if (kvm->arch.vpit) {
 675                 kvm_unregister_irq_mask_notifier(kvm, 0,
 676                                                &kvm->arch.vpit->mask_notifier);
 677                 kvm_unregister_irq_ack_notifier(kvm,
 678                                 &kvm->arch.vpit->pit_state.irq_ack_notifier);
 679                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 680                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
 681                 hrtimer_cancel(timer);
 682                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 683                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 684                 kfree(kvm->arch.vpit);
 685         }
 686 }
 687
 688 static void __inject_pit_timer_intr(struct kvm *kvm)
 689 {
 690         struct kvm_vcpu *vcpu;
 691         int i;
 692
 693         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
 694         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
 695
 696         /*
 697          * Provides NMI watchdog support via Virtual Wire mode.
 698          * The route is: PIT -> PIC -> LVT0 in NMI mode.
 699          *
 700          * Note: Our Virtual Wire implementation is simplified, only
 701          * propagating PIT interrupts to all VCPUs when they have set
 702          * LVT0 to NMI delivery. Other PIC interrupts are just sent to
 703          * VCPU0, and only if its LVT0 is in EXTINT mode.
 704          */
 705         if (kvm->arch.vapics_in_nmi_mode > 0)
 706                 kvm_for_each_vcpu(i, vcpu, kvm)
 707                         kvm_apic_nmi_wd_deliver(vcpu);
 708 }
 709
 710 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
 711 {
 712         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 713         struct kvm *kvm = vcpu->kvm;
 714         struct kvm_kpit_state *ps;
 715
 716         if (pit) {
 717                 int inject = 0;
 718                 ps = &pit->pit_state;
 719
 720                 /* Try to inject pending interrupts when
 721                  * last one has been acked.
 722                  */
 723                 spin_lock(&ps->inject_lock);
 724                 if (atomic_read(&ps->pit_timer.pending) && ps->irq_ack) {
 725                         ps->irq_ack = 0;
 726                         inject = 1;
 727                 }
 728                 spin_unlock(&ps->inject_lock);
 729                 if (inject)
 730                         __inject_pit_timer_intr(kvm);
 731         }
 732 }