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 <[email protected]>
  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 "ioapic.h"
  39 #include "irq.h"
  40 #include "i8254.h"
  41 #include "x86.h"
  42
  43 #ifndef CONFIG_X86_64
  44 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
  45 #else
  46 #define mod_64(x, y) ((x) % (y))
  47 #endif
  48
  49 #define RW_STATE_LSB 1
  50 #define RW_STATE_MSB 2
  51 #define RW_STATE_WORD0 3
  52 #define RW_STATE_WORD1 4
  53
  54 static void pit_set_gate(struct kvm_pit *pit, int channel, u32 val)
  55 {
  56         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
  57
  58         switch (c->mode) {
  59         default:
  60         case 0:
  61         case 4:
  62                 /* XXX: just disable/enable counting */
  63                 break;
  64         case 1:
  65         case 2:
  66         case 3:
  67         case 5:
  68                 /* Restart counting on rising edge. */
  69                 if (c->gate < val)
  70                         c->count_load_time = ktime_get();
  71                 break;
  72         }
  73
  74         c->gate = val;
  75 }
  76
  77 static int pit_get_gate(struct kvm_pit *pit, int channel)
  78 {
  79         return pit->pit_state.channels[channel].gate;
  80 }
  81
  82 static s64 __kpit_elapsed(struct kvm_pit *pit)
  83 {
  84         s64 elapsed;
  85         ktime_t remaining;
  86         struct kvm_kpit_state *ps = &pit->pit_state;
  87
  88         if (!ps->period)
  89                 return 0;
  90
  91         /*
  92          * The Counter does not stop when it reaches zero. In
  93          * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
  94          * the highest count, either FFFF hex for binary counting
  95          * or 9999 for BCD counting, and continues counting.
  96          * Modes 2 and 3 are periodic; the Counter reloads
  97          * itself with the initial count and continues counting
  98          * from there.
  99          */
 100         remaining = hrtimer_get_remaining(&ps->timer);
 101         elapsed = ps->period - ktime_to_ns(remaining);
 102
 103         return elapsed;
 104 }
 105
 106 static s64 kpit_elapsed(struct kvm_pit *pit, struct kvm_kpit_channel_state *c,
 107                         int channel)
 108 {
 109         if (channel == 0)
 110                 return __kpit_elapsed(pit);
 111
 112         return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 113 }
 114
 115 static int pit_get_count(struct kvm_pit *pit, int channel)
 116 {
 117         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
 118         s64 d, t;
 119         int counter;
 120
 121         t = kpit_elapsed(pit, c, channel);
 122         d = mul_u64_u32_div(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 123
 124         switch (c->mode) {
 125         case 0:
 126         case 1:
 127         case 4:
 128         case 5:
 129                 counter = (c->count - d) & 0xffff;
 130                 break;
 131         case 3:
 132                 /* XXX: may be incorrect for odd counts */
 133                 counter = c->count - (mod_64((2 * d), c->count));
 134                 break;
 135         default:
 136                 counter = c->count - mod_64(d, c->count);
 137                 break;
 138         }
 139         return counter;
 140 }
 141
 142 static int pit_get_out(struct kvm_pit *pit, int channel)
 143 {
 144         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
 145         s64 d, t;
 146         int out;
 147
 148         t = kpit_elapsed(pit, c, channel);
 149         d = mul_u64_u32_div(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 150
 151         switch (c->mode) {
 152         default:
 153         case 0:
 154                 out = (d >= c->count);
 155                 break;
 156         case 1:
 157                 out = (d < c->count);
 158                 break;
 159         case 2:
 160                 out = ((mod_64(d, c->count) == 0) && (d != 0));
 161                 break;
 162         case 3:
 163                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
 164                 break;
 165         case 4:
 166         case 5:
 167                 out = (d == c->count);
 168                 break;
 169         }
 170
 171         return out;
 172 }
 173
 174 static void pit_latch_count(struct kvm_pit *pit, int channel)
 175 {
 176         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
 177
 178         if (!c->count_latched) {
 179                 c->latched_count = pit_get_count(pit, channel);
 180                 c->count_latched = c->rw_mode;
 181         }
 182 }
 183
 184 static void pit_latch_status(struct kvm_pit *pit, int channel)
 185 {
 186         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
 187
 188         if (!c->status_latched) {
 189                 /* TODO: Return NULL COUNT (bit 6). */
 190                 c->status = ((pit_get_out(pit, channel) << 7) |
 191                                 (c->rw_mode << 4) |
 192                                 (c->mode << 1) |
 193                                 c->bcd);
 194                 c->status_latched = 1;
 195         }
 196 }
 197
 198 static inline struct kvm_pit *pit_state_to_pit(struct kvm_kpit_state *ps)
 199 {
 200         return container_of(ps, struct kvm_pit, pit_state);
 201 }
 202
 203 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 204 {
 205         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 206                                                  irq_ack_notifier);
 207         struct kvm_pit *pit = pit_state_to_pit(ps);
 208
 209         atomic_set(&ps->irq_ack, 1);
 210         /* irq_ack should be set before pending is read.  Order accesses with
 211          * inc(pending) in pit_timer_fn and xchg(irq_ack, 0) in pit_do_work.
 212          */
 213         smp_mb();
 214         if (atomic_dec_if_positive(&ps->pending) > 0)
 215                 kthread_queue_work(pit->worker, &pit->expired);
 216 }
 217
 218 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 219 {
 220         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 221         struct hrtimer *timer;
 222
 223         /* Somewhat arbitrarily make vcpu0 the owner of the PIT. */
 224         if (vcpu->vcpu_id || !pit)
 225                 return;
 226
 227         timer = &pit->pit_state.timer;
 228         mutex_lock(&pit->pit_state.lock);
 229         if (hrtimer_cancel(timer))
 230                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 231         mutex_unlock(&pit->pit_state.lock);
 232 }
 233
 234 static void destroy_pit_timer(struct kvm_pit *pit)
 235 {
 236         hrtimer_cancel(&pit->pit_state.timer);
 237         kthread_flush_work(&pit->expired);
 238 }
 239
 240 static void pit_do_work(struct kthread_work *work)
 241 {
 242         struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
 243         struct kvm *kvm = pit->kvm;
 244         struct kvm_vcpu *vcpu;
 245         unsigned long i;
 246         struct kvm_kpit_state *ps = &pit->pit_state;
 247
 248         if (atomic_read(&ps->reinject) && !atomic_xchg(&ps->irq_ack, 0))
 249                 return;
 250
 251         kvm_set_irq(kvm, pit->irq_source_id, 0, 1, false);
 252         kvm_set_irq(kvm, pit->irq_source_id, 0, 0, false);
 253
 254         /*
 255          * Provides NMI watchdog support via Virtual Wire mode.
 256          * The route is: PIT -> LVT0 in NMI mode.
 257          *
 258          * Note: Our Virtual Wire implementation does not follow
 259          * the MP specification.  We propagate a PIT interrupt to all
 260          * VCPUs and only when LVT0 is in NMI mode.  The interrupt can
 261          * also be simultaneously delivered through PIC and IOAPIC.
 262          */
 263         if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0)
 264                 kvm_for_each_vcpu(i, vcpu, kvm)
 265                         kvm_apic_nmi_wd_deliver(vcpu);
 266 }
 267
 268 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 269 {
 270         struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer);
 271         struct kvm_pit *pt = pit_state_to_pit(ps);
 272
 273         if (atomic_read(&ps->reinject))
 274                 atomic_inc(&ps->pending);
 275
 276         kthread_queue_work(pt->worker, &pt->expired);
 277
 278         if (ps->is_periodic) {
 279                 hrtimer_add_expires_ns(&ps->timer, ps->period);
 280                 return HRTIMER_RESTART;
 281         } else
 282                 return HRTIMER_NORESTART;
 283 }
 284
 285 static inline void kvm_pit_reset_reinject(struct kvm_pit *pit)
 286 {
 287         atomic_set(&pit->pit_state.pending, 0);
 288         atomic_set(&pit->pit_state.irq_ack, 1);
 289 }
 290
 291 void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject)
 292 {
 293         struct kvm_kpit_state *ps = &pit->pit_state;
 294         struct kvm *kvm = pit->kvm;
 295
 296         if (atomic_read(&ps->reinject) == reinject)
 297                 return;
 298
 299         /*
 300          * AMD SVM AVIC accelerates EOI write and does not trap.
 301          * This cause in-kernel PIT re-inject mode to fail
 302          * since it checks ps->irq_ack before kvm_set_irq()
 303          * and relies on the ack notifier to timely queue
 304          * the pt->worker work iterm and reinject the missed tick.
 305          * So, deactivate APICv when PIT is in reinject mode.
 306          */
 307         if (reinject) {
 308                 kvm_set_apicv_inhibit(kvm, APICV_INHIBIT_REASON_PIT_REINJ);
 309                 /* The initial state is preserved while ps->reinject == 0. */
 310                 kvm_pit_reset_reinject(pit);
 311                 kvm_register_irq_ack_notifier(kvm, &ps->irq_ack_notifier);
 312                 kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 313         } else {
 314                 kvm_clear_apicv_inhibit(kvm, APICV_INHIBIT_REASON_PIT_REINJ);
 315                 kvm_unregister_irq_ack_notifier(kvm, &ps->irq_ack_notifier);
 316                 kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 317         }
 318
 319         atomic_set(&ps->reinject, reinject);
 320 }
 321
 322 static void create_pit_timer(struct kvm_pit *pit, u32 val, int is_period)
 323 {
 324         struct kvm_kpit_state *ps = &pit->pit_state;
 325         struct kvm *kvm = pit->kvm;
 326         s64 interval;
 327
 328         if (!ioapic_in_kernel(kvm) ||
 329             ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
 330                 return;
 331
 332         interval = mul_u64_u32_div(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 333
 334         pr_debug("create pit timer, interval is %llu nsec\n", interval);
 335
 336         /* TODO The new value only affected after the retriggered */
 337         hrtimer_cancel(&ps->timer);
 338         kthread_flush_work(&pit->expired);
 339         ps->period = interval;
 340         ps->is_periodic = is_period;
 341
 342         kvm_pit_reset_reinject(pit);
 343
 344         /*
 345          * Do not allow the guest to program periodic timers with small
 346          * interval, since the hrtimers are not throttled by the host
 347          * scheduler.
 348          */
 349         if (ps->is_periodic) {
 350                 s64 min_period = min_timer_period_us * 1000LL;
 351
 352                 if (ps->period < min_period) {
 353                         pr_info_ratelimited(
 354                             "kvm: requested %lld ns "
 355                             "i8254 timer period limited to %lld ns\n",
 356                             ps->period, min_period);
 357                         ps->period = min_period;
 358                 }
 359         }
 360
 361         hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
 362                       HRTIMER_MODE_ABS);
 363 }
 364
 365 static void pit_load_count(struct kvm_pit *pit, int channel, u32 val)
 366 {
 367         struct kvm_kpit_state *ps = &pit->pit_state;
 368
 369         pr_debug("load_count val is %u, channel is %d\n", val, channel);
 370
 371         /*
 372          * The largest possible initial count is 0; this is equivalent
 373          * to 216 for binary counting and 104 for BCD counting.
 374          */
 375         if (val == 0)
 376                 val = 0x10000;
 377
 378         ps->channels[channel].count = val;
 379
 380         if (channel != 0) {
 381                 ps->channels[channel].count_load_time = ktime_get();
 382                 return;
 383         }
 384
 385         /* Two types of timer
 386          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 387         switch (ps->channels[0].mode) {
 388         case 0:
 389         case 1:
 390         /* FIXME: enhance mode 4 precision */
 391         case 4:
 392                 create_pit_timer(pit, val, 0);
 393                 break;
 394         case 2:
 395         case 3:
 396                 create_pit_timer(pit, val, 1);
 397                 break;
 398         default:
 399                 destroy_pit_timer(pit);
 400         }
 401 }
 402
 403 void kvm_pit_load_count(struct kvm_pit *pit, int channel, u32 val,
 404                 int hpet_legacy_start)
 405 {
 406         u8 saved_mode;
 407
 408         WARN_ON_ONCE(!mutex_is_locked(&pit->pit_state.lock));
 409
 410         if (hpet_legacy_start) {
 411                 /* save existing mode for later reenablement */
 412                 WARN_ON(channel != 0);
 413                 saved_mode = pit->pit_state.channels[0].mode;
 414                 pit->pit_state.channels[0].mode = 0xff; /* disable timer */
 415                 pit_load_count(pit, channel, val);
 416                 pit->pit_state.channels[0].mode = saved_mode;
 417         } else {
 418                 pit_load_count(pit, channel, val);
 419         }
 420 }
 421
 422 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
 423 {
 424         return container_of(dev, struct kvm_pit, dev);
 425 }
 426
 427 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
 428 {
 429         return container_of(dev, struct kvm_pit, speaker_dev);
 430 }
 431
 432 static inline int pit_in_range(gpa_t addr)
 433 {
 434         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 435                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 436 }
 437
 438 static int pit_ioport_write(struct kvm_vcpu *vcpu,
 439                                 struct kvm_io_device *this,
 440                             gpa_t addr, int len, const void *data)
 441 {
 442         struct kvm_pit *pit = dev_to_pit(this);
 443         struct kvm_kpit_state *pit_state = &pit->pit_state;
 444         int channel, access;
 445         struct kvm_kpit_channel_state *s;
 446         u32 val = *(u32 *) data;
 447         if (!pit_in_range(addr))
 448                 return -EOPNOTSUPP;
 449
 450         val  &= 0xff;
 451         addr &= KVM_PIT_CHANNEL_MASK;
 452
 453         mutex_lock(&pit_state->lock);
 454
 455         if (val != 0)
 456                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
 457                          (unsigned int)addr, len, val);
 458
 459         if (addr == 3) {
 460                 channel = val >> 6;
 461                 if (channel == 3) {
 462                         /* Read-Back Command. */
 463                         for (channel = 0; channel < 3; channel++) {
 464                                 if (val & (2 << channel)) {
 465                                         if (!(val & 0x20))
 466                                                 pit_latch_count(pit, channel);
 467                                         if (!(val & 0x10))
 468                                                 pit_latch_status(pit, channel);
 469                                 }
 470                         }
 471                 } else {
 472                         /* Select Counter <channel>. */
 473                         s = &pit_state->channels[channel];
 474                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 475                         if (access == 0) {
 476                                 pit_latch_count(pit, channel);
 477                         } else {
 478                                 s->rw_mode = access;
 479                                 s->read_state = access;
 480                                 s->write_state = access;
 481                                 s->mode = (val >> 1) & 7;
 482                                 if (s->mode > 5)
 483                                         s->mode -= 4;
 484                                 s->bcd = val & 1;
 485                         }
 486                 }
 487         } else {
 488                 /* Write Count. */
 489                 s = &pit_state->channels[addr];
 490                 switch (s->write_state) {
 491                 default:
 492                 case RW_STATE_LSB:
 493                         pit_load_count(pit, addr, val);
 494                         break;
 495                 case RW_STATE_MSB:
 496                         pit_load_count(pit, addr, val << 8);
 497                         break;
 498                 case RW_STATE_WORD0:
 499                         s->write_latch = val;
 500                         s->write_state = RW_STATE_WORD1;
 501                         break;
 502                 case RW_STATE_WORD1:
 503                         pit_load_count(pit, addr, s->write_latch | (val << 8));
 504                         s->write_state = RW_STATE_WORD0;
 505                         break;
 506                 }
 507         }
 508
 509         mutex_unlock(&pit_state->lock);
 510         return 0;
 511 }
 512
 513 static int pit_ioport_read(struct kvm_vcpu *vcpu,
 514                            struct kvm_io_device *this,
 515                            gpa_t addr, int len, void *data)
 516 {
 517         struct kvm_pit *pit = dev_to_pit(this);
 518         struct kvm_kpit_state *pit_state = &pit->pit_state;
 519         int ret, count;
 520         struct kvm_kpit_channel_state *s;
 521         if (!pit_in_range(addr))
 522                 return -EOPNOTSUPP;
 523
 524         addr &= KVM_PIT_CHANNEL_MASK;
 525         if (addr == 3)
 526                 return 0;
 527
 528         s = &pit_state->channels[addr];
 529
 530         mutex_lock(&pit_state->lock);
 531
 532         if (s->status_latched) {
 533                 s->status_latched = 0;
 534                 ret = s->status;
 535         } else if (s->count_latched) {
 536                 switch (s->count_latched) {
 537                 default:
 538                 case RW_STATE_LSB:
 539                         ret = s->latched_count & 0xff;
 540                         s->count_latched = 0;
 541                         break;
 542                 case RW_STATE_MSB:
 543                         ret = s->latched_count >> 8;
 544                         s->count_latched = 0;
 545                         break;
 546                 case RW_STATE_WORD0:
 547                         ret = s->latched_count & 0xff;
 548                         s->count_latched = RW_STATE_MSB;
 549                         break;
 550                 }
 551         } else {
 552                 switch (s->read_state) {
 553                 default:
 554                 case RW_STATE_LSB:
 555                         count = pit_get_count(pit, addr);
 556                         ret = count & 0xff;
 557                         break;
 558                 case RW_STATE_MSB:
 559                         count = pit_get_count(pit, addr);
 560                         ret = (count >> 8) & 0xff;
 561                         break;
 562                 case RW_STATE_WORD0:
 563                         count = pit_get_count(pit, addr);
 564                         ret = count & 0xff;
 565                         s->read_state = RW_STATE_WORD1;
 566                         break;
 567                 case RW_STATE_WORD1:
 568                         count = pit_get_count(pit, addr);
 569                         ret = (count >> 8) & 0xff;
 570                         s->read_state = RW_STATE_WORD0;
 571                         break;
 572                 }
 573         }
 574
 575         if (len > sizeof(ret))
 576                 len = sizeof(ret);
 577         memcpy(data, (char *)&ret, len);
 578
 579         mutex_unlock(&pit_state->lock);
 580         return 0;
 581 }
 582
 583 static int speaker_ioport_write(struct kvm_vcpu *vcpu,
 584                                 struct kvm_io_device *this,
 585                                 gpa_t addr, int len, const void *data)
 586 {
 587         struct kvm_pit *pit = speaker_to_pit(this);
 588         struct kvm_kpit_state *pit_state = &pit->pit_state;
 589         u32 val = *(u32 *) data;
 590         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 591                 return -EOPNOTSUPP;
 592
 593         mutex_lock(&pit_state->lock);
 594         if (val & (1 << 1))
 595                 pit_state->flags |= KVM_PIT_FLAGS_SPEAKER_DATA_ON;
 596         else
 597                 pit_state->flags &= ~KVM_PIT_FLAGS_SPEAKER_DATA_ON;
 598         pit_set_gate(pit, 2, val & 1);
 599         mutex_unlock(&pit_state->lock);
 600         return 0;
 601 }
 602
 603 static int speaker_ioport_read(struct kvm_vcpu *vcpu,
 604                                    struct kvm_io_device *this,
 605                                    gpa_t addr, int len, void *data)
 606 {
 607         struct kvm_pit *pit = speaker_to_pit(this);
 608         struct kvm_kpit_state *pit_state = &pit->pit_state;
 609         unsigned int refresh_clock;
 610         int ret;
 611         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 612                 return -EOPNOTSUPP;
 613
 614         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 615         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 616
 617         mutex_lock(&pit_state->lock);
 618         ret = (!!(pit_state->flags & KVM_PIT_FLAGS_SPEAKER_DATA_ON) << 1) |
 619                 pit_get_gate(pit, 2) | (pit_get_out(pit, 2) << 5) |
 620                 (refresh_clock << 4);
 621         if (len > sizeof(ret))
 622                 len = sizeof(ret);
 623         memcpy(data, (char *)&ret, len);
 624         mutex_unlock(&pit_state->lock);
 625         return 0;
 626 }
 627
 628 static void kvm_pit_reset(struct kvm_pit *pit)
 629 {
 630         int i;
 631         struct kvm_kpit_channel_state *c;
 632
 633         pit->pit_state.flags = 0;
 634         for (i = 0; i < 3; i++) {
 635                 c = &pit->pit_state.channels[i];
 636                 c->mode = 0xff;
 637                 c->gate = (i != 2);
 638                 pit_load_count(pit, i, 0);
 639         }
 640
 641         kvm_pit_reset_reinject(pit);
 642 }
 643
 644 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 645 {
 646         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 647
 648         if (!mask)
 649                 kvm_pit_reset_reinject(pit);
 650 }
 651
 652 static const struct kvm_io_device_ops pit_dev_ops = {
 653         .read     = pit_ioport_read,
 654         .write    = pit_ioport_write,
 655 };
 656
 657 static const struct kvm_io_device_ops speaker_dev_ops = {
 658         .read     = speaker_ioport_read,
 659         .write    = speaker_ioport_write,
 660 };
 661
 662 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 663 {
 664         struct kvm_pit *pit;
 665         struct kvm_kpit_state *pit_state;
 666         struct pid *pid;
 667         pid_t pid_nr;
 668         int ret;
 669
 670         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL_ACCOUNT);
 671         if (!pit)
 672                 return NULL;
 673
 674         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 675         if (pit->irq_source_id < 0)
 676                 goto fail_request;
 677
 678         mutex_init(&pit->pit_state.lock);
 679
 680         pid = get_pid(task_tgid(current));
 681         pid_nr = pid_vnr(pid);
 682         put_pid(pid);
 683
 684         pit->worker = kthread_create_worker(0, "kvm-pit/%d", pid_nr);
 685         if (IS_ERR(pit->worker))
 686                 goto fail_kthread;
 687
 688         kthread_init_work(&pit->expired, pit_do_work);
 689
 690         pit->kvm = kvm;
 691
 692         pit_state = &pit->pit_state;
 693         hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 694         pit_state->timer.function = pit_timer_fn;
 695
 696         pit_state->irq_ack_notifier.gsi = 0;
 697         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 698         pit->mask_notifier.func = pit_mask_notifer;
 699
 700         kvm_pit_reset(pit);
 701
 702         kvm_pit_set_reinject(pit, true);
 703
 704         mutex_lock(&kvm->slots_lock);
 705         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
 706         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
 707                                       KVM_PIT_MEM_LENGTH, &pit->dev);
 708         if (ret < 0)
 709                 goto fail_register_pit;
 710
 711         if (flags & KVM_PIT_SPEAKER_DUMMY) {
 712                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 713                 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
 714                                               KVM_SPEAKER_BASE_ADDRESS, 4,
 715                                               &pit->speaker_dev);
 716                 if (ret < 0)
 717                         goto fail_register_speaker;
 718         }
 719         mutex_unlock(&kvm->slots_lock);
 720
 721         return pit;
 722
 723 fail_register_speaker:
 724         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
 725 fail_register_pit:
 726         mutex_unlock(&kvm->slots_lock);
 727         kvm_pit_set_reinject(pit, false);
 728         kthread_destroy_worker(pit->worker);
 729 fail_kthread:
 730         kvm_free_irq_source_id(kvm, pit->irq_source_id);
 731 fail_request:
 732         kfree(pit);
 733         return NULL;
 734 }
 735
 736 void kvm_free_pit(struct kvm *kvm)
 737 {
 738         struct kvm_pit *pit = kvm->arch.vpit;
 739
 740         if (pit) {
 741                 mutex_lock(&kvm->slots_lock);
 742                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
 743                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->speaker_dev);
 744                 mutex_unlock(&kvm->slots_lock);
 745                 kvm_pit_set_reinject(pit, false);
 746                 hrtimer_cancel(&pit->pit_state.timer);
 747                 kthread_destroy_worker(pit->worker);
 748                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
 749                 kfree(pit);
 750         }
 751 }