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