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  * Copyright 2009 Red Hat, Inc. and/or its affiliates.
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  26  * THE SOFTWARE.
  27  *
  28  * Authors:
  29  *   Sheng Yang <sheng.yang@intel.com>
  30  *   Based on QEMU and Xen.
  31  */
  32
  33 #define pr_fmt(fmt) "pit: " fmt
  34
  35 #include <linux/kvm_host.h>
  36 #include <linux/slab.h>
  37
  38 #include "irq.h"
  39 #include "i8254.h"
  40 #include "x86.h"
  41
  42 #ifndef CONFIG_X86_64
  43 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
  44 #else
  45 #define mod_64(x, y) ((x) % (y))
  46 #endif
  47
  48 #define RW_STATE_LSB 1
  49 #define RW_STATE_MSB 2
  50 #define RW_STATE_WORD0 3
  51 #define RW_STATE_WORD1 4
  52
  53 /* Compute with 96 bit intermediate result: (a*b)/c */
  54 static u64 muldiv64(u64 a, u32 b, u32 c)
  55 {
  56         union {
  57                 u64 ll;
  58                 struct {
  59                         u32 low, high;
  60                 } l;
  61         } u, res;
  62         u64 rl, rh;
  63
  64         u.ll = a;
  65         rl = (u64)u.l.low * (u64)b;
  66         rh = (u64)u.l.high * (u64)b;
  67         rh += (rl >> 32);
  68         res.l.high = div64_u64(rh, c);
  69         res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
  70         return res.ll;
  71 }
  72
  73 static void pit_set_gate(struct kvm *kvm, int channel, u32 val)
  74 {
  75         struct kvm_kpit_channel_state *c =
  76                 &kvm->arch.vpit->pit_state.channels[channel];
  77
  78         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
  79
  80         switch (c->mode) {
  81         default:
  82         case 0:
  83         case 4:
  84                 /* XXX: just disable/enable counting */
  85                 break;
  86         case 1:
  87         case 2:
  88         case 3:
  89         case 5:
  90                 /* Restart counting on rising edge. */
  91                 if (c->gate < val)
  92                         c->count_load_time = ktime_get();
  93                 break;
  94         }
  95
  96         c->gate = val;
  97 }
  98
  99 static int pit_get_gate(struct kvm *kvm, int channel)
 100 {
 101         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 102
 103         return kvm->arch.vpit->pit_state.channels[channel].gate;
 104 }
 105
 106 static s64 __kpit_elapsed(struct kvm *kvm)
 107 {
 108         s64 elapsed;
 109         ktime_t remaining;
 110         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 111
 112         if (!ps->period)
 113                 return 0;
 114
 115         /*
 116          * The Counter does not stop when it reaches zero. In
 117          * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
 118          * the highest count, either FFFF hex for binary counting
 119          * or 9999 for BCD counting, and continues counting.
 120          * Modes 2 and 3 are periodic; the Counter reloads
 121          * itself with the initial count and continues counting
 122          * from there.
 123          */
 124         remaining = hrtimer_get_remaining(&ps->timer);
 125         elapsed = ps->period - ktime_to_ns(remaining);
 126
 127         return elapsed;
 128 }
 129
 130 static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,
 131                         int channel)
 132 {
 133         if (channel == 0)
 134                 return __kpit_elapsed(kvm);
 135
 136         return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 137 }
 138
 139 static int pit_get_count(struct kvm *kvm, int channel)
 140 {
 141         struct kvm_kpit_channel_state *c =
 142                 &kvm->arch.vpit->pit_state.channels[channel];
 143         s64 d, t;
 144         int counter;
 145
 146         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 147
 148         t = kpit_elapsed(kvm, c, channel);
 149         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 150
 151         switch (c->mode) {
 152         case 0:
 153         case 1:
 154         case 4:
 155         case 5:
 156                 counter = (c->count - d) & 0xffff;
 157                 break;
 158         case 3:
 159                 /* XXX: may be incorrect for odd counts */
 160                 counter = c->count - (mod_64((2 * d), c->count));
 161                 break;
 162         default:
 163                 counter = c->count - mod_64(d, c->count);
 164                 break;
 165         }
 166         return counter;
 167 }
 168
 169 static int pit_get_out(struct kvm *kvm, int channel)
 170 {
 171         struct kvm_kpit_channel_state *c =
 172                 &kvm->arch.vpit->pit_state.channels[channel];
 173         s64 d, t;
 174         int out;
 175
 176         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 177
 178         t = kpit_elapsed(kvm, c, channel);
 179         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 180
 181         switch (c->mode) {
 182         default:
 183         case 0:
 184                 out = (d >= c->count);
 185                 break;
 186         case 1:
 187                 out = (d < c->count);
 188                 break;
 189         case 2:
 190                 out = ((mod_64(d, c->count) == 0) && (d != 0));
 191                 break;
 192         case 3:
 193                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
 194                 break;
 195         case 4:
 196         case 5:
 197                 out = (d == c->count);
 198                 break;
 199         }
 200
 201         return out;
 202 }
 203
 204 static void pit_latch_count(struct kvm *kvm, int channel)
 205 {
 206         struct kvm_kpit_channel_state *c =
 207                 &kvm->arch.vpit->pit_state.channels[channel];
 208
 209         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 210
 211         if (!c->count_latched) {
 212                 c->latched_count = pit_get_count(kvm, channel);
 213                 c->count_latched = c->rw_mode;
 214         }
 215 }
 216
 217 static void pit_latch_status(struct kvm *kvm, int channel)
 218 {
 219         struct kvm_kpit_channel_state *c =
 220                 &kvm->arch.vpit->pit_state.channels[channel];
 221
 222         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 223
 224         if (!c->status_latched) {
 225                 /* TODO: Return NULL COUNT (bit 6). */
 226                 c->status = ((pit_get_out(kvm, channel) << 7) |
 227                                 (c->rw_mode << 4) |
 228                                 (c->mode << 1) |
 229                                 c->bcd);
 230                 c->status_latched = 1;
 231         }
 232 }
 233
 234 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 235 {
 236         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 237                                                  irq_ack_notifier);
 238         int value;
 239
 240         spin_lock(&ps->inject_lock);
 241         value = atomic_dec_return(&ps->pending);
 242         if (value < 0)
 243                 /* spurious acks can be generated if, for example, the
 244                  * PIC is being reset.  Handle it gracefully here
 245                  */
 246                 atomic_inc(&ps->pending);
 247         else if (value > 0 && ps->reinject)
 248                 /* in this case, we had multiple outstanding pit interrupts
 249                  * that we needed to inject.  Reinject
 250                  */
 251                 queue_kthread_work(&ps->pit->worker, &ps->pit->expired);
 252         ps->irq_ack = 1;
 253         spin_unlock(&ps->inject_lock);
 254 }
 255
 256 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 257 {
 258         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 259         struct hrtimer *timer;
 260
 261         if (!kvm_vcpu_is_bsp(vcpu) || !pit)
 262                 return;
 263
 264         timer = &pit->pit_state.timer;
 265         mutex_lock(&pit->pit_state.lock);
 266         if (hrtimer_cancel(timer))
 267                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 268         mutex_unlock(&pit->pit_state.lock);
 269 }
 270
 271 static void destroy_pit_timer(struct kvm_pit *pit)
 272 {
 273         hrtimer_cancel(&pit->pit_state.timer);
 274         flush_kthread_work(&pit->expired);
 275 }
 276
 277 static void pit_do_work(struct kthread_work *work)
 278 {
 279         struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
 280         struct kvm *kvm = pit->kvm;
 281         struct kvm_vcpu *vcpu;
 282         int i;
 283         struct kvm_kpit_state *ps = &pit->pit_state;
 284         int inject = 0;
 285
 286         /* Try to inject pending interrupts when
 287          * last one has been acked.
 288          */
 289         spin_lock(&ps->inject_lock);
 290         if (!ps->reinject)
 291                 inject = 1;
 292         else if (ps->irq_ack) {
 293                 ps->irq_ack = 0;
 294                 inject = 1;
 295         }
 296         spin_unlock(&ps->inject_lock);
 297         if (inject) {
 298                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1, false);
 299                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0, false);
 300
 301                 /*
 302                  * Provides NMI watchdog support via Virtual Wire mode.
 303                  * The route is: PIT -> PIC -> LVT0 in NMI mode.
 304                  *
 305                  * Note: Our Virtual Wire implementation is simplified, only
 306                  * propagating PIT interrupts to all VCPUs when they have set
 307                  * LVT0 to NMI delivery. Other PIC interrupts are just sent to
 308                  * VCPU0, and only if its LVT0 is in EXTINT mode.
 309                  */
 310                 if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0)
 311                         kvm_for_each_vcpu(i, vcpu, kvm)
 312                                 kvm_apic_nmi_wd_deliver(vcpu);
 313         }
 314 }
 315
 316 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 317 {
 318         struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer);
 319         struct kvm_pit *pt = ps->kvm->arch.vpit;
 320
 321         if (ps->reinject)
 322                 atomic_inc(&ps->pending);
 323
 324         queue_kthread_work(&pt->worker, &pt->expired);
 325
 326         if (ps->is_periodic) {
 327                 hrtimer_add_expires_ns(&ps->timer, ps->period);
 328                 return HRTIMER_RESTART;
 329         } else
 330                 return HRTIMER_NORESTART;
 331 }
 332
 333 static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
 334 {
 335         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 336         s64 interval;
 337
 338         if (!irqchip_in_kernel(kvm) || ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
 339                 return;
 340
 341         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 342
 343         pr_debug("create pit timer, interval is %llu nsec\n", interval);
 344
 345         /* TODO The new value only affected after the retriggered */
 346         hrtimer_cancel(&ps->timer);
 347         flush_kthread_work(&ps->pit->expired);
 348         ps->period = interval;
 349         ps->is_periodic = is_period;
 350
 351         ps->timer.function = pit_timer_fn;
 352         ps->kvm = ps->pit->kvm;
 353
 354         atomic_set(&ps->pending, 0);
 355         ps->irq_ack = 1;
 356
 357         /*
 358          * Do not allow the guest to program periodic timers with small
 359          * interval, since the hrtimers are not throttled by the host
 360          * scheduler.
 361          */
 362         if (ps->is_periodic) {
 363                 s64 min_period = min_timer_period_us * 1000LL;
 364
 365                 if (ps->period < min_period) {
 366                         pr_info_ratelimited(
 367                             "kvm: requested %lld ns "
 368                             "i8254 timer period limited to %lld ns\n",
 369                             ps->period, min_period);
 370                         ps->period = min_period;
 371                 }
 372         }
 373
 374         hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
 375                       HRTIMER_MODE_ABS);
 376 }
 377
 378 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 379 {
 380         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 381
 382         WARN_ON(!mutex_is_locked(&ps->lock));
 383
 384         pr_debug("load_count val is %d, channel is %d\n", val, channel);
 385
 386         /*
 387          * The largest possible initial count is 0; this is equivalent
 388          * to 216 for binary counting and 104 for BCD counting.
 389          */
 390         if (val == 0)
 391                 val = 0x10000;
 392
 393         ps->channels[channel].count = val;
 394
 395         if (channel != 0) {
 396                 ps->channels[channel].count_load_time = ktime_get();
 397                 return;
 398         }
 399
 400         /* Two types of timer
 401          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 402         switch (ps->channels[0].mode) {
 403         case 0:
 404         case 1:
 405         /* FIXME: enhance mode 4 precision */
 406         case 4:
 407                 create_pit_timer(kvm, val, 0);
 408                 break;
 409         case 2:
 410         case 3:
 411                 create_pit_timer(kvm, val, 1);
 412                 break;
 413         default:
 414                 destroy_pit_timer(kvm->arch.vpit);
 415         }
 416 }
 417
 418 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
 419 {
 420         u8 saved_mode;
 421         if (hpet_legacy_start) {
 422                 /* save existing mode for later reenablement */
 423                 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
 424                 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
 425                 pit_load_count(kvm, channel, val);
 426                 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
 427         } else {
 428                 pit_load_count(kvm, channel, val);
 429         }
 430 }
 431
 432 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
 433 {
 434         return container_of(dev, struct kvm_pit, dev);
 435 }
 436
 437 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
 438 {
 439         return container_of(dev, struct kvm_pit, speaker_dev);
 440 }
 441
 442 static inline int pit_in_range(gpa_t addr)
 443 {
 444         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 445                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 446 }
 447
 448 static int pit_ioport_write(struct kvm_vcpu *vcpu,
 449                                 struct kvm_io_device *this,
 450                             gpa_t addr, int len, const void *data)
 451 {
 452         struct kvm_pit *pit = dev_to_pit(this);
 453         struct kvm_kpit_state *pit_state = &pit->pit_state;
 454         struct kvm *kvm = pit->kvm;
 455         int channel, access;
 456         struct kvm_kpit_channel_state *s;
 457         u32 val = *(u32 *) data;
 458         if (!pit_in_range(addr))
 459                 return -EOPNOTSUPP;
 460
 461         val  &= 0xff;
 462         addr &= KVM_PIT_CHANNEL_MASK;
 463
 464         mutex_lock(&pit_state->lock);
 465
 466         if (val != 0)
 467                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
 468                          (unsigned int)addr, len, val);
 469
 470         if (addr == 3) {
 471                 channel = val >> 6;
 472                 if (channel == 3) {
 473                         /* Read-Back Command. */
 474                         for (channel = 0; channel < 3; channel++) {
 475                                 s = &pit_state->channels[channel];
 476                                 if (val & (2 << channel)) {
 477                                         if (!(val & 0x20))
 478                                                 pit_latch_count(kvm, channel);
 479                                         if (!(val & 0x10))
 480                                                 pit_latch_status(kvm, channel);
 481                                 }
 482                         }
 483                 } else {
 484                         /* Select Counter <channel>. */
 485                         s = &pit_state->channels[channel];
 486                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 487                         if (access == 0) {
 488                                 pit_latch_count(kvm, channel);
 489                         } else {
 490                                 s->rw_mode = access;
 491                                 s->read_state = access;
 492                                 s->write_state = access;
 493                                 s->mode = (val >> 1) & 7;
 494                                 if (s->mode > 5)
 495                                         s->mode -= 4;
 496                                 s->bcd = val & 1;
 497                         }
 498                 }
 499         } else {
 500                 /* Write Count. */
 501                 s = &pit_state->channels[addr];
 502                 switch (s->write_state) {
 503                 default:
 504                 case RW_STATE_LSB:
 505                         pit_load_count(kvm, addr, val);
 506                         break;
 507                 case RW_STATE_MSB:
 508                         pit_load_count(kvm, addr, val << 8);
 509                         break;
 510                 case RW_STATE_WORD0:
 511                         s->write_latch = val;
 512                         s->write_state = RW_STATE_WORD1;
 513                         break;
 514                 case RW_STATE_WORD1:
 515                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 516                         s->write_state = RW_STATE_WORD0;
 517                         break;
 518                 }
 519         }
 520
 521         mutex_unlock(&pit_state->lock);
 522         return 0;
 523 }
 524
 525 static int pit_ioport_read(struct kvm_vcpu *vcpu,
 526                            struct kvm_io_device *this,
 527                            gpa_t addr, int len, void *data)
 528 {
 529         struct kvm_pit *pit = dev_to_pit(this);
 530         struct kvm_kpit_state *pit_state = &pit->pit_state;
 531         struct kvm *kvm = pit->kvm;
 532         int ret, count;
 533         struct kvm_kpit_channel_state *s;
 534         if (!pit_in_range(addr))
 535                 return -EOPNOTSUPP;
 536
 537         addr &= KVM_PIT_CHANNEL_MASK;
 538         if (addr == 3)
 539                 return 0;
 540
 541         s = &pit_state->channels[addr];
 542
 543         mutex_lock(&pit_state->lock);
 544
 545         if (s->status_latched) {
 546                 s->status_latched = 0;
 547                 ret = s->status;
 548         } else if (s->count_latched) {
 549                 switch (s->count_latched) {
 550                 default:
 551                 case RW_STATE_LSB:
 552                         ret = s->latched_count & 0xff;
 553                         s->count_latched = 0;
 554                         break;
 555                 case RW_STATE_MSB:
 556                         ret = s->latched_count >> 8;
 557                         s->count_latched = 0;
 558                         break;
 559                 case RW_STATE_WORD0:
 560                         ret = s->latched_count & 0xff;
 561                         s->count_latched = RW_STATE_MSB;
 562                         break;
 563                 }
 564         } else {
 565                 switch (s->read_state) {
 566                 default:
 567                 case RW_STATE_LSB:
 568                         count = pit_get_count(kvm, addr);
 569                         ret = count & 0xff;
 570                         break;
 571                 case RW_STATE_MSB:
 572                         count = pit_get_count(kvm, addr);
 573                         ret = (count >> 8) & 0xff;
 574                         break;
 575                 case RW_STATE_WORD0:
 576                         count = pit_get_count(kvm, addr);
 577                         ret = count & 0xff;
 578                         s->read_state = RW_STATE_WORD1;
 579                         break;
 580                 case RW_STATE_WORD1:
 581                         count = pit_get_count(kvm, addr);
 582                         ret = (count >> 8) & 0xff;
 583                         s->read_state = RW_STATE_WORD0;
 584                         break;
 585                 }
 586         }
 587
 588         if (len > sizeof(ret))
 589                 len = sizeof(ret);
 590         memcpy(data, (char *)&ret, len);
 591
 592         mutex_unlock(&pit_state->lock);
 593         return 0;
 594 }
 595
 596 static int speaker_ioport_write(struct kvm_vcpu *vcpu,
 597                                 struct kvm_io_device *this,
 598                                 gpa_t addr, int len, const void *data)
 599 {
 600         struct kvm_pit *pit = speaker_to_pit(this);
 601         struct kvm_kpit_state *pit_state = &pit->pit_state;
 602         struct kvm *kvm = pit->kvm;
 603         u32 val = *(u32 *) data;
 604         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 605                 return -EOPNOTSUPP;
 606
 607         mutex_lock(&pit_state->lock);
 608         pit_state->speaker_data_on = (val >> 1) & 1;
 609         pit_set_gate(kvm, 2, val & 1);
 610         mutex_unlock(&pit_state->lock);
 611         return 0;
 612 }
 613
 614 static int speaker_ioport_read(struct kvm_vcpu *vcpu,
 615                                    struct kvm_io_device *this,
 616                                    gpa_t addr, int len, void *data)
 617 {
 618         struct kvm_pit *pit = speaker_to_pit(this);
 619         struct kvm_kpit_state *pit_state = &pit->pit_state;
 620         struct kvm *kvm = pit->kvm;
 621         unsigned int refresh_clock;
 622         int ret;
 623         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 624                 return -EOPNOTSUPP;
 625
 626         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 627         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 628
 629         mutex_lock(&pit_state->lock);
 630         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 631                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 632         if (len > sizeof(ret))
 633                 len = sizeof(ret);
 634         memcpy(data, (char *)&ret, len);
 635         mutex_unlock(&pit_state->lock);
 636         return 0;
 637 }
 638
 639 void kvm_pit_reset(struct kvm_pit *pit)
 640 {
 641         int i;
 642         struct kvm_kpit_channel_state *c;
 643
 644         mutex_lock(&pit->pit_state.lock);
 645         pit->pit_state.flags = 0;
 646         for (i = 0; i < 3; i++) {
 647                 c = &pit->pit_state.channels[i];
 648                 c->mode = 0xff;
 649                 c->gate = (i != 2);
 650                 pit_load_count(pit->kvm, i, 0);
 651         }
 652         mutex_unlock(&pit->pit_state.lock);
 653
 654         atomic_set(&pit->pit_state.pending, 0);
 655         pit->pit_state.irq_ack = 1;
 656 }
 657
 658 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 659 {
 660         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 661
 662         if (!mask) {
 663                 atomic_set(&pit->pit_state.pending, 0);
 664                 pit->pit_state.irq_ack = 1;
 665         }
 666 }
 667
 668 static const struct kvm_io_device_ops pit_dev_ops = {
 669         .read     = pit_ioport_read,
 670         .write    = pit_ioport_write,
 671 };
 672
 673 static const struct kvm_io_device_ops speaker_dev_ops = {
 674         .read     = speaker_ioport_read,
 675         .write    = speaker_ioport_write,
 676 };
 677
 678 /* Caller must hold slots_lock */
 679 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 680 {
 681         struct kvm_pit *pit;
 682         struct kvm_kpit_state *pit_state;
 683         struct pid *pid;
 684         pid_t pid_nr;
 685         int ret;
 686
 687         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 688         if (!pit)
 689                 return NULL;
 690
 691         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 692         if (pit->irq_source_id < 0) {
 693                 kfree(pit);
 694                 return NULL;
 695         }
 696
 697         mutex_init(&pit->pit_state.lock);
 698         mutex_lock(&pit->pit_state.lock);
 699         spin_lock_init(&pit->pit_state.inject_lock);
 700
 701         pid = get_pid(task_tgid(current));
 702         pid_nr = pid_vnr(pid);
 703         put_pid(pid);
 704
 705         init_kthread_worker(&pit->worker);
 706         pit->worker_task = kthread_run(kthread_worker_fn, &pit->worker,
 707                                        "kvm-pit/%d", pid_nr);
 708         if (IS_ERR(pit->worker_task)) {
 709                 mutex_unlock(&pit->pit_state.lock);
 710                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
 711                 kfree(pit);
 712                 return NULL;
 713         }
 714         init_kthread_work(&pit->expired, pit_do_work);
 715
 716         kvm->arch.vpit = pit;
 717         pit->kvm = kvm;
 718
 719         pit_state = &pit->pit_state;
 720         pit_state->pit = pit;
 721         hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 722         pit_state->irq_ack_notifier.gsi = 0;
 723         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 724         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 725         pit_state->reinject = true;
 726         mutex_unlock(&pit->pit_state.lock);
 727
 728         kvm_pit_reset(pit);
 729
 730         pit->mask_notifier.func = pit_mask_notifer;
 731         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 732
 733         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
 734         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
 735                                       KVM_PIT_MEM_LENGTH, &pit->dev);
 736         if (ret < 0)
 737                 goto fail;
 738
 739         if (flags & KVM_PIT_SPEAKER_DUMMY) {
 740                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 741                 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
 742                                               KVM_SPEAKER_BASE_ADDRESS, 4,
 743                                               &pit->speaker_dev);
 744                 if (ret < 0)
 745                         goto fail_unregister;
 746         }
 747
 748         return pit;
 749
 750 fail_unregister:
 751         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
 752
 753 fail:
 754         kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 755         kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 756         kvm_free_irq_source_id(kvm, pit->irq_source_id);
 757         kthread_stop(pit->worker_task);
 758         kfree(pit);
 759         return NULL;
 760 }
 761
 762 void kvm_free_pit(struct kvm *kvm)
 763 {
 764         struct hrtimer *timer;
 765
 766         if (kvm->arch.vpit) {
 767                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
 768                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
 769                                               &kvm->arch.vpit->speaker_dev);
 770                 kvm_unregister_irq_mask_notifier(kvm, 0,
 771                                                &kvm->arch.vpit->mask_notifier);
 772                 kvm_unregister_irq_ack_notifier(kvm,
 773                                 &kvm->arch.vpit->pit_state.irq_ack_notifier);
 774                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 775                 timer = &kvm->arch.vpit->pit_state.timer;
 776                 hrtimer_cancel(timer);
 777                 flush_kthread_work(&kvm->arch.vpit->expired);
 778                 kthread_stop(kvm->arch.vpit->worker_task);
 779                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 780                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 781                 kfree(kvm->arch.vpit);
 782         }
 783 }