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 #include <linux/workqueue.h>
  38
  39 #include "irq.h"
  40 #include "i8254.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->pit_timer.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->pit_timer.timer);
 125         elapsed = ps->pit_timer.period - ktime_to_ns(remaining);
 126         elapsed = mod_64(elapsed, ps->pit_timer.period);
 127
 128         return elapsed;
 129 }
 130
 131 static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,
 132                         int channel)
 133 {
 134         if (channel == 0)
 135                 return __kpit_elapsed(kvm);
 136
 137         return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 138 }
 139
 140 static int pit_get_count(struct kvm *kvm, int channel)
 141 {
 142         struct kvm_kpit_channel_state *c =
 143                 &kvm->arch.vpit->pit_state.channels[channel];
 144         s64 d, t;
 145         int counter;
 146
 147         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 148
 149         t = kpit_elapsed(kvm, c, channel);
 150         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 151
 152         switch (c->mode) {
 153         case 0:
 154         case 1:
 155         case 4:
 156         case 5:
 157                 counter = (c->count - d) & 0xffff;
 158                 break;
 159         case 3:
 160                 /* XXX: may be incorrect for odd counts */
 161                 counter = c->count - (mod_64((2 * d), c->count));
 162                 break;
 163         default:
 164                 counter = c->count - mod_64(d, c->count);
 165                 break;
 166         }
 167         return counter;
 168 }
 169
 170 static int pit_get_out(struct kvm *kvm, int channel)
 171 {
 172         struct kvm_kpit_channel_state *c =
 173                 &kvm->arch.vpit->pit_state.channels[channel];
 174         s64 d, t;
 175         int out;
 176
 177         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 178
 179         t = kpit_elapsed(kvm, c, channel);
 180         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 181
 182         switch (c->mode) {
 183         default:
 184         case 0:
 185                 out = (d >= c->count);
 186                 break;
 187         case 1:
 188                 out = (d < c->count);
 189                 break;
 190         case 2:
 191                 out = ((mod_64(d, c->count) == 0) && (d != 0));
 192                 break;
 193         case 3:
 194                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
 195                 break;
 196         case 4:
 197         case 5:
 198                 out = (d == c->count);
 199                 break;
 200         }
 201
 202         return out;
 203 }
 204
 205 static void pit_latch_count(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->count_latched) {
 213                 c->latched_count = pit_get_count(kvm, channel);
 214                 c->count_latched = c->rw_mode;
 215         }
 216 }
 217
 218 static void pit_latch_status(struct kvm *kvm, int channel)
 219 {
 220         struct kvm_kpit_channel_state *c =
 221                 &kvm->arch.vpit->pit_state.channels[channel];
 222
 223         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 224
 225         if (!c->status_latched) {
 226                 /* TODO: Return NULL COUNT (bit 6). */
 227                 c->status = ((pit_get_out(kvm, channel) << 7) |
 228                                 (c->rw_mode << 4) |
 229                                 (c->mode << 1) |
 230                                 c->bcd);
 231                 c->status_latched = 1;
 232         }
 233 }
 234
 235 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 236 {
 237         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 238                                                  irq_ack_notifier);
 239         int value;
 240
 241         spin_lock(&ps->inject_lock);
 242         value = atomic_dec_return(&ps->pit_timer.pending);
 243         if (value < 0)
 244                 /* spurious acks can be generated if, for example, the
 245                  * PIC is being reset.  Handle it gracefully here
 246                  */
 247                 atomic_inc(&ps->pit_timer.pending);
 248         else if (value > 0)
 249                 /* in this case, we had multiple outstanding pit interrupts
 250                  * that we needed to inject.  Reinject
 251                  */
 252                 queue_work(ps->pit->wq, &ps->pit->expired);
 253         ps->irq_ack = 1;
 254         spin_unlock(&ps->inject_lock);
 255 }
 256
 257 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 258 {
 259         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 260         struct hrtimer *timer;
 261
 262         if (!kvm_vcpu_is_bsp(vcpu) || !pit)
 263                 return;
 264
 265         timer = &pit->pit_state.pit_timer.timer;
 266         if (hrtimer_cancel(timer))
 267                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 268 }
 269
 270 static void destroy_pit_timer(struct kvm_pit *pit)
 271 {
 272         hrtimer_cancel(&pit->pit_state.pit_timer.timer);
 273         cancel_work_sync(&pit->expired);
 274 }
 275
 276 static bool kpit_is_periodic(struct kvm_timer *ktimer)
 277 {
 278         struct kvm_kpit_state *ps = container_of(ktimer, struct kvm_kpit_state,
 279                                                  pit_timer);
 280         return ps->is_periodic;
 281 }
 282
 283 static struct kvm_timer_ops kpit_ops = {
 284         .is_periodic = kpit_is_periodic,
 285 };
 286
 287 static void pit_do_work(struct work_struct *work)
 288 {
 289         struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
 290         struct kvm *kvm = pit->kvm;
 291         struct kvm_vcpu *vcpu;
 292         int i;
 293         struct kvm_kpit_state *ps = &pit->pit_state;
 294         int inject = 0;
 295
 296         /* Try to inject pending interrupts when
 297          * last one has been acked.
 298          */
 299         spin_lock(&ps->inject_lock);
 300         if (ps->irq_ack) {
 301                 ps->irq_ack = 0;
 302                 inject = 1;
 303         }
 304         spin_unlock(&ps->inject_lock);
 305         if (inject) {
 306                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
 307                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
 308
 309                 /*
 310                  * Provides NMI watchdog support via Virtual Wire mode.
 311                  * The route is: PIT -> PIC -> LVT0 in NMI mode.
 312                  *
 313                  * Note: Our Virtual Wire implementation is simplified, only
 314                  * propagating PIT interrupts to all VCPUs when they have set
 315                  * LVT0 to NMI delivery. Other PIC interrupts are just sent to
 316                  * VCPU0, and only if its LVT0 is in EXTINT mode.
 317                  */
 318                 if (kvm->arch.vapics_in_nmi_mode > 0)
 319                         kvm_for_each_vcpu(i, vcpu, kvm)
 320                                 kvm_apic_nmi_wd_deliver(vcpu);
 321         }
 322 }
 323
 324 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 325 {
 326         struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
 327         struct kvm_pit *pt = ktimer->kvm->arch.vpit;
 328
 329         if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
 330                 atomic_inc(&ktimer->pending);
 331                 queue_work(pt->wq, &pt->expired);
 332         }
 333
 334         if (ktimer->t_ops->is_periodic(ktimer)) {
 335                 hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
 336                 return HRTIMER_RESTART;
 337         } else
 338                 return HRTIMER_NORESTART;
 339 }
 340
 341 static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
 342 {
 343         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 344         struct kvm_timer *pt = &ps->pit_timer;
 345         s64 interval;
 346
 347         if (!irqchip_in_kernel(kvm) || ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
 348                 return;
 349
 350         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 351
 352         pr_debug("create pit timer, interval is %llu nsec\n", interval);
 353
 354         /* TODO The new value only affected after the retriggered */
 355         hrtimer_cancel(&pt->timer);
 356         cancel_work_sync(&ps->pit->expired);
 357         pt->period = interval;
 358         ps->is_periodic = is_period;
 359
 360         pt->timer.function = pit_timer_fn;
 361         pt->t_ops = &kpit_ops;
 362         pt->kvm = ps->pit->kvm;
 363
 364         atomic_set(&pt->pending, 0);
 365         ps->irq_ack = 1;
 366
 367         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
 368                       HRTIMER_MODE_ABS);
 369 }
 370
 371 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 372 {
 373         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 374
 375         WARN_ON(!mutex_is_locked(&ps->lock));
 376
 377         pr_debug("load_count val is %d, channel is %d\n", val, channel);
 378
 379         /*
 380          * The largest possible initial count is 0; this is equivalent
 381          * to 216 for binary counting and 104 for BCD counting.
 382          */
 383         if (val == 0)
 384                 val = 0x10000;
 385
 386         ps->channels[channel].count = val;
 387
 388         if (channel != 0) {
 389                 ps->channels[channel].count_load_time = ktime_get();
 390                 return;
 391         }
 392
 393         /* Two types of timer
 394          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 395         switch (ps->channels[0].mode) {
 396         case 0:
 397         case 1:
 398         /* FIXME: enhance mode 4 precision */
 399         case 4:
 400                 create_pit_timer(kvm, val, 0);
 401                 break;
 402         case 2:
 403         case 3:
 404                 create_pit_timer(kvm, val, 1);
 405                 break;
 406         default:
 407                 destroy_pit_timer(kvm->arch.vpit);
 408         }
 409 }
 410
 411 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
 412 {
 413         u8 saved_mode;
 414         if (hpet_legacy_start) {
 415                 /* save existing mode for later reenablement */
 416                 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
 417                 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
 418                 pit_load_count(kvm, channel, val);
 419                 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
 420         } else {
 421                 pit_load_count(kvm, channel, val);
 422         }
 423 }
 424
 425 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
 426 {
 427         return container_of(dev, struct kvm_pit, dev);
 428 }
 429
 430 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
 431 {
 432         return container_of(dev, struct kvm_pit, speaker_dev);
 433 }
 434
 435 static inline int pit_in_range(gpa_t addr)
 436 {
 437         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 438                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 439 }
 440
 441 static int pit_ioport_write(struct kvm_io_device *this,
 442                             gpa_t addr, int len, const void *data)
 443 {
 444         struct kvm_pit *pit = dev_to_pit(this);
 445         struct kvm_kpit_state *pit_state = &pit->pit_state;
 446         struct kvm *kvm = pit->kvm;
 447         int channel, access;
 448         struct kvm_kpit_channel_state *s;
 449         u32 val = *(u32 *) data;
 450         if (!pit_in_range(addr))
 451                 return -EOPNOTSUPP;
 452
 453         val  &= 0xff;
 454         addr &= KVM_PIT_CHANNEL_MASK;
 455
 456         mutex_lock(&pit_state->lock);
 457
 458         if (val != 0)
 459                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
 460                          (unsigned int)addr, len, val);
 461
 462         if (addr == 3) {
 463                 channel = val >> 6;
 464                 if (channel == 3) {
 465                         /* Read-Back Command. */
 466                         for (channel = 0; channel < 3; channel++) {
 467                                 s = &pit_state->channels[channel];
 468                                 if (val & (2 << channel)) {
 469                                         if (!(val & 0x20))
 470                                                 pit_latch_count(kvm, channel);
 471                                         if (!(val & 0x10))
 472                                                 pit_latch_status(kvm, channel);
 473                                 }
 474                         }
 475                 } else {
 476                         /* Select Counter <channel>. */
 477                         s = &pit_state->channels[channel];
 478                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 479                         if (access == 0) {
 480                                 pit_latch_count(kvm, channel);
 481                         } else {
 482                                 s->rw_mode = access;
 483                                 s->read_state = access;
 484                                 s->write_state = access;
 485                                 s->mode = (val >> 1) & 7;
 486                                 if (s->mode > 5)
 487                                         s->mode -= 4;
 488                                 s->bcd = val & 1;
 489                         }
 490                 }
 491         } else {
 492                 /* Write Count. */
 493                 s = &pit_state->channels[addr];
 494                 switch (s->write_state) {
 495                 default:
 496                 case RW_STATE_LSB:
 497                         pit_load_count(kvm, addr, val);
 498                         break;
 499                 case RW_STATE_MSB:
 500                         pit_load_count(kvm, addr, val << 8);
 501                         break;
 502                 case RW_STATE_WORD0:
 503                         s->write_latch = val;
 504                         s->write_state = RW_STATE_WORD1;
 505                         break;
 506                 case RW_STATE_WORD1:
 507                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 508                         s->write_state = RW_STATE_WORD0;
 509                         break;
 510                 }
 511         }
 512
 513         mutex_unlock(&pit_state->lock);
 514         return 0;
 515 }
 516
 517 static int pit_ioport_read(struct kvm_io_device *this,
 518                            gpa_t addr, int len, void *data)
 519 {
 520         struct kvm_pit *pit = dev_to_pit(this);
 521         struct kvm_kpit_state *pit_state = &pit->pit_state;
 522         struct kvm *kvm = pit->kvm;
 523         int ret, count;
 524         struct kvm_kpit_channel_state *s;
 525         if (!pit_in_range(addr))
 526                 return -EOPNOTSUPP;
 527
 528         addr &= KVM_PIT_CHANNEL_MASK;
 529         if (addr == 3)
 530                 return 0;
 531
 532         s = &pit_state->channels[addr];
 533
 534         mutex_lock(&pit_state->lock);
 535
 536         if (s->status_latched) {
 537                 s->status_latched = 0;
 538                 ret = s->status;
 539         } else if (s->count_latched) {
 540                 switch (s->count_latched) {
 541                 default:
 542                 case RW_STATE_LSB:
 543                         ret = s->latched_count & 0xff;
 544                         s->count_latched = 0;
 545                         break;
 546                 case RW_STATE_MSB:
 547                         ret = s->latched_count >> 8;
 548                         s->count_latched = 0;
 549                         break;
 550                 case RW_STATE_WORD0:
 551                         ret = s->latched_count & 0xff;
 552                         s->count_latched = RW_STATE_MSB;
 553                         break;
 554                 }
 555         } else {
 556                 switch (s->read_state) {
 557                 default:
 558                 case RW_STATE_LSB:
 559                         count = pit_get_count(kvm, addr);
 560                         ret = count & 0xff;
 561                         break;
 562                 case RW_STATE_MSB:
 563                         count = pit_get_count(kvm, addr);
 564                         ret = (count >> 8) & 0xff;
 565                         break;
 566                 case RW_STATE_WORD0:
 567                         count = pit_get_count(kvm, addr);
 568                         ret = count & 0xff;
 569                         s->read_state = RW_STATE_WORD1;
 570                         break;
 571                 case RW_STATE_WORD1:
 572                         count = pit_get_count(kvm, addr);
 573                         ret = (count >> 8) & 0xff;
 574                         s->read_state = RW_STATE_WORD0;
 575                         break;
 576                 }
 577         }
 578
 579         if (len > sizeof(ret))
 580                 len = sizeof(ret);
 581         memcpy(data, (char *)&ret, len);
 582
 583         mutex_unlock(&pit_state->lock);
 584         return 0;
 585 }
 586
 587 static int speaker_ioport_write(struct kvm_io_device *this,
 588                                 gpa_t addr, int len, const void *data)
 589 {
 590         struct kvm_pit *pit = speaker_to_pit(this);
 591         struct kvm_kpit_state *pit_state = &pit->pit_state;
 592         struct kvm *kvm = pit->kvm;
 593         u32 val = *(u32 *) data;
 594         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 595                 return -EOPNOTSUPP;
 596
 597         mutex_lock(&pit_state->lock);
 598         pit_state->speaker_data_on = (val >> 1) & 1;
 599         pit_set_gate(kvm, 2, val & 1);
 600         mutex_unlock(&pit_state->lock);
 601         return 0;
 602 }
 603
 604 static int speaker_ioport_read(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         struct kvm *kvm = pit->kvm;
 610         unsigned int refresh_clock;
 611         int ret;
 612         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 613                 return -EOPNOTSUPP;
 614
 615         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 616         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 617
 618         mutex_lock(&pit_state->lock);
 619         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 620                 (pit_get_out(kvm, 2) << 5) | (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 void kvm_pit_reset(struct kvm_pit *pit)
 629 {
 630         int i;
 631         struct kvm_kpit_channel_state *c;
 632
 633         mutex_lock(&pit->pit_state.lock);
 634         pit->pit_state.flags = 0;
 635         for (i = 0; i < 3; i++) {
 636                 c = &pit->pit_state.channels[i];
 637                 c->mode = 0xff;
 638                 c->gate = (i != 2);
 639                 pit_load_count(pit->kvm, i, 0);
 640         }
 641         mutex_unlock(&pit->pit_state.lock);
 642
 643         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 644         pit->pit_state.irq_ack = 1;
 645 }
 646
 647 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 648 {
 649         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 650
 651         if (!mask) {
 652                 atomic_set(&pit->pit_state.pit_timer.pending, 0);
 653                 pit->pit_state.irq_ack = 1;
 654         }
 655 }
 656
 657 static const struct kvm_io_device_ops pit_dev_ops = {
 658         .read     = pit_ioport_read,
 659         .write    = pit_ioport_write,
 660 };
 661
 662 static const struct kvm_io_device_ops speaker_dev_ops = {
 663         .read     = speaker_ioport_read,
 664         .write    = speaker_ioport_write,
 665 };
 666
 667 /* Caller must hold slots_lock */
 668 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 669 {
 670         struct kvm_pit *pit;
 671         struct kvm_kpit_state *pit_state;
 672         int ret;
 673
 674         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 675         if (!pit)
 676                 return NULL;
 677
 678         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 679         if (pit->irq_source_id < 0) {
 680                 kfree(pit);
 681                 return NULL;
 682         }
 683
 684         mutex_init(&pit->pit_state.lock);
 685         mutex_lock(&pit->pit_state.lock);
 686         spin_lock_init(&pit->pit_state.inject_lock);
 687
 688         pit->wq = create_singlethread_workqueue("kvm-pit-wq");
 689         if (!pit->wq) {
 690                 mutex_unlock(&pit->pit_state.lock);
 691                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
 692                 kfree(pit);
 693                 return NULL;
 694         }
 695         INIT_WORK(&pit->expired, pit_do_work);
 696
 697         kvm->arch.vpit = pit;
 698         pit->kvm = kvm;
 699
 700         pit_state = &pit->pit_state;
 701         pit_state->pit = pit;
 702         hrtimer_init(&pit_state->pit_timer.timer,
 703                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 704         pit_state->irq_ack_notifier.gsi = 0;
 705         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 706         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 707         pit_state->pit_timer.reinject = true;
 708         mutex_unlock(&pit->pit_state.lock);
 709
 710         kvm_pit_reset(pit);
 711
 712         pit->mask_notifier.func = pit_mask_notifer;
 713         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 714
 715         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
 716         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
 717                                       KVM_PIT_MEM_LENGTH, &pit->dev);
 718         if (ret < 0)
 719                 goto fail;
 720
 721         if (flags & KVM_PIT_SPEAKER_DUMMY) {
 722                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 723                 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
 724                                               KVM_SPEAKER_BASE_ADDRESS, 4,
 725                                               &pit->speaker_dev);
 726                 if (ret < 0)
 727                         goto fail_unregister;
 728         }
 729
 730         return pit;
 731
 732 fail_unregister:
 733         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
 734
 735 fail:
 736         kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 737         kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 738         kvm_free_irq_source_id(kvm, pit->irq_source_id);
 739         destroy_workqueue(pit->wq);
 740         kfree(pit);
 741         return NULL;
 742 }
 743
 744 void kvm_free_pit(struct kvm *kvm)
 745 {
 746         struct hrtimer *timer;
 747
 748         if (kvm->arch.vpit) {
 749                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
 750                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
 751                                               &kvm->arch.vpit->speaker_dev);
 752                 kvm_unregister_irq_mask_notifier(kvm, 0,
 753                                                &kvm->arch.vpit->mask_notifier);
 754                 kvm_unregister_irq_ack_notifier(kvm,
 755                                 &kvm->arch.vpit->pit_state.irq_ack_notifier);
 756                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 757                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
 758                 hrtimer_cancel(timer);
 759                 cancel_work_sync(&kvm->arch.vpit->expired);
 760                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 761                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 762                 destroy_workqueue(kvm->arch.vpit->wq);
 763                 kfree(kvm->arch.vpit);
 764         }
 765 }