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         remaining = hrtimer_expires_remaining(&ps->pit_timer.timer);
 108         if (ktime_to_ns(remaining) < 0)
 109                 remaining = ktime_set(0, 0);
 110
 111         elapsed = ps->pit_timer.period;
 112         if (ktime_to_ns(remaining) <= ps->pit_timer.period)
 113                 elapsed = ps->pit_timer.period - ktime_to_ns(remaining);
 114
 115         return elapsed;
 116 }
 117
 118 static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,
 119                         int channel)
 120 {
 121         if (channel == 0)
 122                 return __kpit_elapsed(kvm);
 123
 124         return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 125 }
 126
 127 static int pit_get_count(struct kvm *kvm, int channel)
 128 {
 129         struct kvm_kpit_channel_state *c =
 130                 &kvm->arch.vpit->pit_state.channels[channel];
 131         s64 d, t;
 132         int counter;
 133
 134         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 135
 136         t = kpit_elapsed(kvm, c, channel);
 137         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 138
 139         switch (c->mode) {
 140         case 0:
 141         case 1:
 142         case 4:
 143         case 5:
 144                 counter = (c->count - d) & 0xffff;
 145                 break;
 146         case 3:
 147                 /* XXX: may be incorrect for odd counts */
 148                 counter = c->count - (mod_64((2 * d), c->count));
 149                 break;
 150         default:
 151                 counter = c->count - mod_64(d, c->count);
 152                 break;
 153         }
 154         return counter;
 155 }
 156
 157 static int pit_get_out(struct kvm *kvm, int channel)
 158 {
 159         struct kvm_kpit_channel_state *c =
 160                 &kvm->arch.vpit->pit_state.channels[channel];
 161         s64 d, t;
 162         int out;
 163
 164         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 165
 166         t = kpit_elapsed(kvm, c, channel);
 167         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 168
 169         switch (c->mode) {
 170         default:
 171         case 0:
 172                 out = (d >= c->count);
 173                 break;
 174         case 1:
 175                 out = (d < c->count);
 176                 break;
 177         case 2:
 178                 out = ((mod_64(d, c->count) == 0) && (d != 0));
 179                 break;
 180         case 3:
 181                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
 182                 break;
 183         case 4:
 184         case 5:
 185                 out = (d == c->count);
 186                 break;
 187         }
 188
 189         return out;
 190 }
 191
 192 static void pit_latch_count(struct kvm *kvm, int channel)
 193 {
 194         struct kvm_kpit_channel_state *c =
 195                 &kvm->arch.vpit->pit_state.channels[channel];
 196
 197         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 198
 199         if (!c->count_latched) {
 200                 c->latched_count = pit_get_count(kvm, channel);
 201                 c->count_latched = c->rw_mode;
 202         }
 203 }
 204
 205 static void pit_latch_status(struct kvm *kvm, int channel)
 206 {
 207         struct kvm_kpit_channel_state *c =
 208                 &kvm->arch.vpit->pit_state.channels[channel];
 209
 210         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 211
 212         if (!c->status_latched) {
 213                 /* TODO: Return NULL COUNT (bit 6). */
 214                 c->status = ((pit_get_out(kvm, channel) << 7) |
 215                                 (c->rw_mode << 4) |
 216                                 (c->mode << 1) |
 217                                 c->bcd);
 218                 c->status_latched = 1;
 219         }
 220 }
 221
 222 static int __pit_timer_fn(struct kvm_kpit_state *ps)
 223 {
 224         struct kvm_vcpu *vcpu0 = ps->pit->kvm->vcpus[0];
 225         struct kvm_kpit_timer *pt = &ps->pit_timer;
 226
 227         if (!atomic_inc_and_test(&pt->pending))
 228                 set_bit(KVM_REQ_PENDING_TIMER, &vcpu0->requests);
 229
 230         if (!pt->reinject)
 231                 atomic_set(&pt->pending, 1);
 232
 233         if (vcpu0 && waitqueue_active(&vcpu0->wq))
 234                 wake_up_interruptible(&vcpu0->wq);
 235
 236         hrtimer_add_expires_ns(&pt->timer, pt->period);
 237
 238         return (pt->period == 0 ? 0 : 1);
 239 }
 240
 241 int pit_has_pending_timer(struct kvm_vcpu *vcpu)
 242 {
 243         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 244
 245         if (pit && vcpu->vcpu_id == 0 && pit->pit_state.irq_ack)
 246                 return atomic_read(&pit->pit_state.pit_timer.pending);
 247         return 0;
 248 }
 249
 250 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 251 {
 252         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 253                                                  irq_ack_notifier);
 254         spin_lock(&ps->inject_lock);
 255         if (atomic_dec_return(&ps->pit_timer.pending) < 0)
 256                 atomic_inc(&ps->pit_timer.pending);
 257         ps->irq_ack = 1;
 258         spin_unlock(&ps->inject_lock);
 259 }
 260
 261 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 262 {
 263         struct kvm_kpit_state *ps;
 264         int restart_timer = 0;
 265
 266         ps = container_of(data, struct kvm_kpit_state, pit_timer.timer);
 267
 268         restart_timer = __pit_timer_fn(ps);
 269
 270         if (restart_timer)
 271                 return HRTIMER_RESTART;
 272         else
 273                 return HRTIMER_NORESTART;
 274 }
 275
 276 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 277 {
 278         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 279         struct hrtimer *timer;
 280
 281         if (vcpu->vcpu_id != 0 || !pit)
 282                 return;
 283
 284         timer = &pit->pit_state.pit_timer.timer;
 285         if (hrtimer_cancel(timer))
 286                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 287 }
 288
 289 static void destroy_pit_timer(struct kvm_kpit_timer *pt)
 290 {
 291         pr_debug("pit: execute del timer!\n");
 292         hrtimer_cancel(&pt->timer);
 293 }
 294
 295 static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
 296 {
 297         struct kvm_kpit_timer *pt = &ps->pit_timer;
 298         s64 interval;
 299
 300         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 301
 302         pr_debug("pit: create pit timer, interval is %llu nsec\n", interval);
 303
 304         /* TODO The new value only affected after the retriggered */
 305         hrtimer_cancel(&pt->timer);
 306         pt->period = (is_period == 0) ? 0 : interval;
 307         pt->timer.function = pit_timer_fn;
 308         atomic_set(&pt->pending, 0);
 309         ps->irq_ack = 1;
 310
 311         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
 312                       HRTIMER_MODE_ABS);
 313 }
 314
 315 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 316 {
 317         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 318
 319         WARN_ON(!mutex_is_locked(&ps->lock));
 320
 321         pr_debug("pit: load_count val is %d, channel is %d\n", val, channel);
 322
 323         /*
 324          * Though spec said the state of 8254 is undefined after power-up,
 325          * seems some tricky OS like Windows XP depends on IRQ0 interrupt
 326          * when booting up.
 327          * So here setting initialize rate for it, and not a specific number
 328          */
 329         if (val == 0)
 330                 val = 0x10000;
 331
 332         ps->channels[channel].count = val;
 333
 334         if (channel != 0) {
 335                 ps->channels[channel].count_load_time = ktime_get();
 336                 return;
 337         }
 338
 339         /* Two types of timer
 340          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 341         switch (ps->channels[0].mode) {
 342         case 1:
 343         /* FIXME: enhance mode 4 precision */
 344         case 4:
 345                 create_pit_timer(ps, val, 0);
 346                 break;
 347         case 2:
 348         case 3:
 349                 create_pit_timer(ps, val, 1);
 350                 break;
 351         default:
 352                 destroy_pit_timer(&ps->pit_timer);
 353         }
 354 }
 355
 356 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val)
 357 {
 358         mutex_lock(&kvm->arch.vpit->pit_state.lock);
 359         pit_load_count(kvm, channel, val);
 360         mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 361 }
 362
 363 static void pit_ioport_write(struct kvm_io_device *this,
 364                              gpa_t addr, int len, const void *data)
 365 {
 366         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 367         struct kvm_kpit_state *pit_state = &pit->pit_state;
 368         struct kvm *kvm = pit->kvm;
 369         int channel, access;
 370         struct kvm_kpit_channel_state *s;
 371         u32 val = *(u32 *) data;
 372
 373         val  &= 0xff;
 374         addr &= KVM_PIT_CHANNEL_MASK;
 375
 376         mutex_lock(&pit_state->lock);
 377
 378         if (val != 0)
 379                 pr_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
 380                           (unsigned int)addr, len, val);
 381
 382         if (addr == 3) {
 383                 channel = val >> 6;
 384                 if (channel == 3) {
 385                         /* Read-Back Command. */
 386                         for (channel = 0; channel < 3; channel++) {
 387                                 s = &pit_state->channels[channel];
 388                                 if (val & (2 << channel)) {
 389                                         if (!(val & 0x20))
 390                                                 pit_latch_count(kvm, channel);
 391                                         if (!(val & 0x10))
 392                                                 pit_latch_status(kvm, channel);
 393                                 }
 394                         }
 395                 } else {
 396                         /* Select Counter <channel>. */
 397                         s = &pit_state->channels[channel];
 398                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 399                         if (access == 0) {
 400                                 pit_latch_count(kvm, channel);
 401                         } else {
 402                                 s->rw_mode = access;
 403                                 s->read_state = access;
 404                                 s->write_state = access;
 405                                 s->mode = (val >> 1) & 7;
 406                                 if (s->mode > 5)
 407                                         s->mode -= 4;
 408                                 s->bcd = val & 1;
 409                         }
 410                 }
 411         } else {
 412                 /* Write Count. */
 413                 s = &pit_state->channels[addr];
 414                 switch (s->write_state) {
 415                 default:
 416                 case RW_STATE_LSB:
 417                         pit_load_count(kvm, addr, val);
 418                         break;
 419                 case RW_STATE_MSB:
 420                         pit_load_count(kvm, addr, val << 8);
 421                         break;
 422                 case RW_STATE_WORD0:
 423                         s->write_latch = val;
 424                         s->write_state = RW_STATE_WORD1;
 425                         break;
 426                 case RW_STATE_WORD1:
 427                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 428                         s->write_state = RW_STATE_WORD0;
 429                         break;
 430                 }
 431         }
 432
 433         mutex_unlock(&pit_state->lock);
 434 }
 435
 436 static void pit_ioport_read(struct kvm_io_device *this,
 437                             gpa_t addr, int len, void *data)
 438 {
 439         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 440         struct kvm_kpit_state *pit_state = &pit->pit_state;
 441         struct kvm *kvm = pit->kvm;
 442         int ret, count;
 443         struct kvm_kpit_channel_state *s;
 444
 445         addr &= KVM_PIT_CHANNEL_MASK;
 446         s = &pit_state->channels[addr];
 447
 448         mutex_lock(&pit_state->lock);
 449
 450         if (s->status_latched) {
 451                 s->status_latched = 0;
 452                 ret = s->status;
 453         } else if (s->count_latched) {
 454                 switch (s->count_latched) {
 455                 default:
 456                 case RW_STATE_LSB:
 457                         ret = s->latched_count & 0xff;
 458                         s->count_latched = 0;
 459                         break;
 460                 case RW_STATE_MSB:
 461                         ret = s->latched_count >> 8;
 462                         s->count_latched = 0;
 463                         break;
 464                 case RW_STATE_WORD0:
 465                         ret = s->latched_count & 0xff;
 466                         s->count_latched = RW_STATE_MSB;
 467                         break;
 468                 }
 469         } else {
 470                 switch (s->read_state) {
 471                 default:
 472                 case RW_STATE_LSB:
 473                         count = pit_get_count(kvm, addr);
 474                         ret = count & 0xff;
 475                         break;
 476                 case RW_STATE_MSB:
 477                         count = pit_get_count(kvm, addr);
 478                         ret = (count >> 8) & 0xff;
 479                         break;
 480                 case RW_STATE_WORD0:
 481                         count = pit_get_count(kvm, addr);
 482                         ret = count & 0xff;
 483                         s->read_state = RW_STATE_WORD1;
 484                         break;
 485                 case RW_STATE_WORD1:
 486                         count = pit_get_count(kvm, addr);
 487                         ret = (count >> 8) & 0xff;
 488                         s->read_state = RW_STATE_WORD0;
 489                         break;
 490                 }
 491         }
 492
 493         if (len > sizeof(ret))
 494                 len = sizeof(ret);
 495         memcpy(data, (char *)&ret, len);
 496
 497         mutex_unlock(&pit_state->lock);
 498 }
 499
 500 static int pit_in_range(struct kvm_io_device *this, gpa_t addr,
 501                         int len, int is_write)
 502 {
 503         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 504                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 505 }
 506
 507 static void speaker_ioport_write(struct kvm_io_device *this,
 508                                  gpa_t addr, int len, const void *data)
 509 {
 510         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 511         struct kvm_kpit_state *pit_state = &pit->pit_state;
 512         struct kvm *kvm = pit->kvm;
 513         u32 val = *(u32 *) data;
 514
 515         mutex_lock(&pit_state->lock);
 516         pit_state->speaker_data_on = (val >> 1) & 1;
 517         pit_set_gate(kvm, 2, val & 1);
 518         mutex_unlock(&pit_state->lock);
 519 }
 520
 521 static void speaker_ioport_read(struct kvm_io_device *this,
 522                                 gpa_t addr, int len, void *data)
 523 {
 524         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 525         struct kvm_kpit_state *pit_state = &pit->pit_state;
 526         struct kvm *kvm = pit->kvm;
 527         unsigned int refresh_clock;
 528         int ret;
 529
 530         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 531         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 532
 533         mutex_lock(&pit_state->lock);
 534         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 535                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 536         if (len > sizeof(ret))
 537                 len = sizeof(ret);
 538         memcpy(data, (char *)&ret, len);
 539         mutex_unlock(&pit_state->lock);
 540 }
 541
 542 static int speaker_in_range(struct kvm_io_device *this, gpa_t addr,
 543                             int len, int is_write)
 544 {
 545         return (addr == KVM_SPEAKER_BASE_ADDRESS);
 546 }
 547
 548 void kvm_pit_reset(struct kvm_pit *pit)
 549 {
 550         int i;
 551         struct kvm_kpit_channel_state *c;
 552
 553         mutex_lock(&pit->pit_state.lock);
 554         for (i = 0; i < 3; i++) {
 555                 c = &pit->pit_state.channels[i];
 556                 c->mode = 0xff;
 557                 c->gate = (i != 2);
 558                 pit_load_count(pit->kvm, i, 0);
 559         }
 560         mutex_unlock(&pit->pit_state.lock);
 561
 562         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 563         pit->pit_state.irq_ack = 1;
 564 }
 565
 566 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 567 {
 568         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 569
 570         if (!mask) {
 571                 atomic_set(&pit->pit_state.pit_timer.pending, 0);
 572                 pit->pit_state.irq_ack = 1;
 573         }
 574 }
 575
 576 struct kvm_pit *kvm_create_pit(struct kvm *kvm)
 577 {
 578         struct kvm_pit *pit;
 579         struct kvm_kpit_state *pit_state;
 580
 581         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 582         if (!pit)
 583                 return NULL;
 584
 585         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 586         if (pit->irq_source_id < 0) {
 587                 kfree(pit);
 588                 return NULL;
 589         }
 590
 591         mutex_init(&pit->pit_state.lock);
 592         mutex_lock(&pit->pit_state.lock);
 593         spin_lock_init(&pit->pit_state.inject_lock);
 594
 595         /* Initialize PIO device */
 596         pit->dev.read = pit_ioport_read;
 597         pit->dev.write = pit_ioport_write;
 598         pit->dev.in_range = pit_in_range;
 599         pit->dev.private = pit;
 600         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
 601
 602         pit->speaker_dev.read = speaker_ioport_read;
 603         pit->speaker_dev.write = speaker_ioport_write;
 604         pit->speaker_dev.in_range = speaker_in_range;
 605         pit->speaker_dev.private = pit;
 606         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->speaker_dev);
 607
 608         kvm->arch.vpit = pit;
 609         pit->kvm = kvm;
 610
 611         pit_state = &pit->pit_state;
 612         pit_state->pit = pit;
 613         hrtimer_init(&pit_state->pit_timer.timer,
 614                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 615         pit_state->irq_ack_notifier.gsi = 0;
 616         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 617         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 618         pit_state->pit_timer.reinject = true;
 619         mutex_unlock(&pit->pit_state.lock);
 620
 621         kvm_pit_reset(pit);
 622
 623         pit->mask_notifier.func = pit_mask_notifer;
 624         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 625
 626         return pit;
 627 }
 628
 629 void kvm_free_pit(struct kvm *kvm)
 630 {
 631         struct hrtimer *timer;
 632
 633         if (kvm->arch.vpit) {
 634                 kvm_unregister_irq_mask_notifier(kvm, 0,
 635                                                &kvm->arch.vpit->mask_notifier);
 636                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 637                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
 638                 hrtimer_cancel(timer);
 639                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 640                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 641                 kfree(kvm->arch.vpit);
 642         }
 643 }
 644
 645 static void __inject_pit_timer_intr(struct kvm *kvm)
 646 {
 647         struct kvm_vcpu *vcpu;
 648         int i;
 649
 650         mutex_lock(&kvm->lock);
 651         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
 652         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
 653         mutex_unlock(&kvm->lock);
 654
 655         /*
 656          * Provides NMI watchdog support via Virtual Wire mode.
 657          * The route is: PIT -> PIC -> LVT0 in NMI mode.
 658          *
 659          * Note: Our Virtual Wire implementation is simplified, only
 660          * propagating PIT interrupts to all VCPUs when they have set
 661          * LVT0 to NMI delivery. Other PIC interrupts are just sent to
 662          * VCPU0, and only if its LVT0 is in EXTINT mode.
 663          */
 664         if (kvm->arch.vapics_in_nmi_mode > 0)
 665                 for (i = 0; i < KVM_MAX_VCPUS; ++i) {
 666                         vcpu = kvm->vcpus[i];
 667                         if (vcpu)
 668                                 kvm_apic_nmi_wd_deliver(vcpu);
 669                 }
 670 }
 671
 672 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
 673 {
 674         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 675         struct kvm *kvm = vcpu->kvm;
 676         struct kvm_kpit_state *ps;
 677
 678         if (vcpu && pit) {
 679                 int inject = 0;
 680                 ps = &pit->pit_state;
 681
 682                 /* Try to inject pending interrupts when
 683                  * last one has been acked.
 684                  */
 685                 spin_lock(&ps->inject_lock);
 686                 if (atomic_read(&ps->pit_timer.pending) && ps->irq_ack) {
 687                         ps->irq_ack = 0;
 688                         inject = 1;
 689                 }
 690                 spin_unlock(&ps->inject_lock);
 691                 if (inject)
 692                         __inject_pit_timer_intr(kvm);
 693         }
 694 }