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 affilates.
   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 int pit_has_pending_timer(struct kvm_vcpu *vcpu)
 236 {
 237         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 238
 239         if (pit && kvm_vcpu_is_bsp(vcpu) && pit->pit_state.irq_ack)
 240                 return atomic_read(&pit->pit_state.pit_timer.pending);
 241         return 0;
 242 }
 243
 244 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 245 {
 246         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 247                                                  irq_ack_notifier);
 248         int value;
 249
 250         spin_lock(&ps->inject_lock);
 251         value = atomic_dec_return(&ps->pit_timer.pending);
 252         if (value < 0)
 253                 /* spurious acks can be generated if, for example, the
 254                  * PIC is being reset.  Handle it gracefully here
 255                  */
 256                 atomic_inc(&ps->pit_timer.pending);
 257         else if (value > 0)
 258                 /* in this case, we had multiple outstanding pit interrupts
 259                  * that we needed to inject.  Reinject
 260                  */
 261                 queue_work(ps->pit->wq, &ps->pit->expired);
 262         ps->irq_ack = 1;
 263         spin_unlock(&ps->inject_lock);
 264 }
 265
 266 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 267 {
 268         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 269         struct hrtimer *timer;
 270
 271         if (!kvm_vcpu_is_bsp(vcpu) || !pit)
 272                 return;
 273
 274         timer = &pit->pit_state.pit_timer.timer;
 275         if (hrtimer_cancel(timer))
 276                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 277 }
 278
 279 static void destroy_pit_timer(struct kvm_pit *pit)
 280 {
 281         hrtimer_cancel(&pit->pit_state.pit_timer.timer);
 282         cancel_work_sync(&pit->expired);
 283 }
 284
 285 static bool kpit_is_periodic(struct kvm_timer *ktimer)
 286 {
 287         struct kvm_kpit_state *ps = container_of(ktimer, struct kvm_kpit_state,
 288                                                  pit_timer);
 289         return ps->is_periodic;
 290 }
 291
 292 static struct kvm_timer_ops kpit_ops = {
 293         .is_periodic = kpit_is_periodic,
 294 };
 295
 296 static void pit_do_work(struct work_struct *work)
 297 {
 298         struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
 299         struct kvm *kvm = pit->kvm;
 300         struct kvm_vcpu *vcpu;
 301         int i;
 302         struct kvm_kpit_state *ps = &pit->pit_state;
 303         int inject = 0;
 304
 305         /* Try to inject pending interrupts when
 306          * last one has been acked.
 307          */
 308         spin_lock(&ps->inject_lock);
 309         if (ps->irq_ack) {
 310                 ps->irq_ack = 0;
 311                 inject = 1;
 312         }
 313         spin_unlock(&ps->inject_lock);
 314         if (inject) {
 315                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
 316                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
 317
 318                 /*
 319                  * Provides NMI watchdog support via Virtual Wire mode.
 320                  * The route is: PIT -> PIC -> LVT0 in NMI mode.
 321                  *
 322                  * Note: Our Virtual Wire implementation is simplified, only
 323                  * propagating PIT interrupts to all VCPUs when they have set
 324                  * LVT0 to NMI delivery. Other PIC interrupts are just sent to
 325                  * VCPU0, and only if its LVT0 is in EXTINT mode.
 326                  */
 327                 if (kvm->arch.vapics_in_nmi_mode > 0)
 328                         kvm_for_each_vcpu(i, vcpu, kvm)
 329                                 kvm_apic_nmi_wd_deliver(vcpu);
 330         }
 331 }
 332
 333 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 334 {
 335         struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
 336         struct kvm_pit *pt = ktimer->kvm->arch.vpit;
 337
 338         if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
 339                 atomic_inc(&ktimer->pending);
 340                 queue_work(pt->wq, &pt->expired);
 341         }
 342
 343         if (ktimer->t_ops->is_periodic(ktimer)) {
 344                 hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
 345                 return HRTIMER_RESTART;
 346         } else
 347                 return HRTIMER_NORESTART;
 348 }
 349
 350 static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
 351 {
 352         struct kvm_timer *pt = &ps->pit_timer;
 353         s64 interval;
 354
 355         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 356
 357         pr_debug("create pit timer, interval is %llu nsec\n", interval);
 358
 359         /* TODO The new value only affected after the retriggered */
 360         hrtimer_cancel(&pt->timer);
 361         cancel_work_sync(&ps->pit->expired);
 362         pt->period = interval;
 363         ps->is_periodic = is_period;
 364
 365         pt->timer.function = pit_timer_fn;
 366         pt->t_ops = &kpit_ops;
 367         pt->kvm = ps->pit->kvm;
 368
 369         atomic_set(&pt->pending, 0);
 370         ps->irq_ack = 1;
 371
 372         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
 373                       HRTIMER_MODE_ABS);
 374 }
 375
 376 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 377 {
 378         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 379
 380         WARN_ON(!mutex_is_locked(&ps->lock));
 381
 382         pr_debug("load_count val is %d, channel is %d\n", val, channel);
 383
 384         /*
 385          * The largest possible initial count is 0; this is equivalent
 386          * to 216 for binary counting and 104 for BCD counting.
 387          */
 388         if (val == 0)
 389                 val = 0x10000;
 390
 391         ps->channels[channel].count = val;
 392
 393         if (channel != 0) {
 394                 ps->channels[channel].count_load_time = ktime_get();
 395                 return;
 396         }
 397
 398         /* Two types of timer
 399          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 400         switch (ps->channels[0].mode) {
 401         case 0:
 402         case 1:
 403         /* FIXME: enhance mode 4 precision */
 404         case 4:
 405                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) {
 406                         create_pit_timer(ps, val, 0);
 407                 }
 408                 break;
 409         case 2:
 410         case 3:
 411                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){
 412                         create_pit_timer(ps, val, 1);
 413                 }
 414                 break;
 415         default:
 416                 destroy_pit_timer(kvm->arch.vpit);
 417         }
 418 }
 419
 420 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
 421 {
 422         u8 saved_mode;
 423         if (hpet_legacy_start) {
 424                 /* save existing mode for later reenablement */
 425                 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
 426                 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
 427                 pit_load_count(kvm, channel, val);
 428                 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
 429         } else {
 430                 pit_load_count(kvm, channel, val);
 431         }
 432 }
 433
 434 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
 435 {
 436         return container_of(dev, struct kvm_pit, dev);
 437 }
 438
 439 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
 440 {
 441         return container_of(dev, struct kvm_pit, speaker_dev);
 442 }
 443
 444 static inline int pit_in_range(gpa_t addr)
 445 {
 446         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 447                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 448 }
 449
 450 static int pit_ioport_write(struct kvm_io_device *this,
 451                             gpa_t addr, int len, const void *data)
 452 {
 453         struct kvm_pit *pit = dev_to_pit(this);
 454         struct kvm_kpit_state *pit_state = &pit->pit_state;
 455         struct kvm *kvm = pit->kvm;
 456         int channel, access;
 457         struct kvm_kpit_channel_state *s;
 458         u32 val = *(u32 *) data;
 459         if (!pit_in_range(addr))
 460                 return -EOPNOTSUPP;
 461
 462         val  &= 0xff;
 463         addr &= KVM_PIT_CHANNEL_MASK;
 464
 465         mutex_lock(&pit_state->lock);
 466
 467         if (val != 0)
 468                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
 469                          (unsigned int)addr, len, val);
 470
 471         if (addr == 3) {
 472                 channel = val >> 6;
 473                 if (channel == 3) {
 474                         /* Read-Back Command. */
 475                         for (channel = 0; channel < 3; channel++) {
 476                                 s = &pit_state->channels[channel];
 477                                 if (val & (2 << channel)) {
 478                                         if (!(val & 0x20))
 479                                                 pit_latch_count(kvm, channel);
 480                                         if (!(val & 0x10))
 481                                                 pit_latch_status(kvm, channel);
 482                                 }
 483                         }
 484                 } else {
 485                         /* Select Counter <channel>. */
 486                         s = &pit_state->channels[channel];
 487                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 488                         if (access == 0) {
 489                                 pit_latch_count(kvm, channel);
 490                         } else {
 491                                 s->rw_mode = access;
 492                                 s->read_state = access;
 493                                 s->write_state = access;
 494                                 s->mode = (val >> 1) & 7;
 495                                 if (s->mode > 5)
 496                                         s->mode -= 4;
 497                                 s->bcd = val & 1;
 498                         }
 499                 }
 500         } else {
 501                 /* Write Count. */
 502                 s = &pit_state->channels[addr];
 503                 switch (s->write_state) {
 504                 default:
 505                 case RW_STATE_LSB:
 506                         pit_load_count(kvm, addr, val);
 507                         break;
 508                 case RW_STATE_MSB:
 509                         pit_load_count(kvm, addr, val << 8);
 510                         break;
 511                 case RW_STATE_WORD0:
 512                         s->write_latch = val;
 513                         s->write_state = RW_STATE_WORD1;
 514                         break;
 515                 case RW_STATE_WORD1:
 516                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 517                         s->write_state = RW_STATE_WORD0;
 518                         break;
 519                 }
 520         }
 521
 522         mutex_unlock(&pit_state->lock);
 523         return 0;
 524 }
 525
 526 static int pit_ioport_read(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_io_device *this,
 597                                 gpa_t addr, int len, const void *data)
 598 {
 599         struct kvm_pit *pit = speaker_to_pit(this);
 600         struct kvm_kpit_state *pit_state = &pit->pit_state;
 601         struct kvm *kvm = pit->kvm;
 602         u32 val = *(u32 *) data;
 603         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 604                 return -EOPNOTSUPP;
 605
 606         mutex_lock(&pit_state->lock);
 607         pit_state->speaker_data_on = (val >> 1) & 1;
 608         pit_set_gate(kvm, 2, val & 1);
 609         mutex_unlock(&pit_state->lock);
 610         return 0;
 611 }
 612
 613 static int speaker_ioport_read(struct kvm_io_device *this,
 614                                gpa_t addr, int len, void *data)
 615 {
 616         struct kvm_pit *pit = speaker_to_pit(this);
 617         struct kvm_kpit_state *pit_state = &pit->pit_state;
 618         struct kvm *kvm = pit->kvm;
 619         unsigned int refresh_clock;
 620         int ret;
 621         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 622                 return -EOPNOTSUPP;
 623
 624         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 625         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 626
 627         mutex_lock(&pit_state->lock);
 628         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 629                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 630         if (len > sizeof(ret))
 631                 len = sizeof(ret);
 632         memcpy(data, (char *)&ret, len);
 633         mutex_unlock(&pit_state->lock);
 634         return 0;
 635 }
 636
 637 void kvm_pit_reset(struct kvm_pit *pit)
 638 {
 639         int i;
 640         struct kvm_kpit_channel_state *c;
 641
 642         mutex_lock(&pit->pit_state.lock);
 643         pit->pit_state.flags = 0;
 644         for (i = 0; i < 3; i++) {
 645                 c = &pit->pit_state.channels[i];
 646                 c->mode = 0xff;
 647                 c->gate = (i != 2);
 648                 pit_load_count(pit->kvm, i, 0);
 649         }
 650         mutex_unlock(&pit->pit_state.lock);
 651
 652         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 653         pit->pit_state.irq_ack = 1;
 654 }
 655
 656 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 657 {
 658         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 659
 660         if (!mask) {
 661                 atomic_set(&pit->pit_state.pit_timer.pending, 0);
 662                 pit->pit_state.irq_ack = 1;
 663         }
 664 }
 665
 666 static const struct kvm_io_device_ops pit_dev_ops = {
 667         .read     = pit_ioport_read,
 668         .write    = pit_ioport_write,
 669 };
 670
 671 static const struct kvm_io_device_ops speaker_dev_ops = {
 672         .read     = speaker_ioport_read,
 673         .write    = speaker_ioport_write,
 674 };
 675
 676 /* Caller must hold slots_lock */
 677 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 678 {
 679         struct kvm_pit *pit;
 680         struct kvm_kpit_state *pit_state;
 681         int ret;
 682
 683         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 684         if (!pit)
 685                 return NULL;
 686
 687         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 688         if (pit->irq_source_id < 0) {
 689                 kfree(pit);
 690                 return NULL;
 691         }
 692
 693         mutex_init(&pit->pit_state.lock);
 694         mutex_lock(&pit->pit_state.lock);
 695         spin_lock_init(&pit->pit_state.inject_lock);
 696
 697         pit->wq = create_singlethread_workqueue("kvm-pit-wq");
 698         if (!pit->wq) {
 699                 mutex_unlock(&pit->pit_state.lock);
 700                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
 701                 kfree(pit);
 702                 return NULL;
 703         }
 704         INIT_WORK(&pit->expired, pit_do_work);
 705
 706         kvm->arch.vpit = pit;
 707         pit->kvm = kvm;
 708
 709         pit_state = &pit->pit_state;
 710         pit_state->pit = pit;
 711         hrtimer_init(&pit_state->pit_timer.timer,
 712                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 713         pit_state->irq_ack_notifier.gsi = 0;
 714         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 715         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 716         pit_state->pit_timer.reinject = true;
 717         mutex_unlock(&pit->pit_state.lock);
 718
 719         kvm_pit_reset(pit);
 720
 721         pit->mask_notifier.func = pit_mask_notifer;
 722         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 723
 724         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
 725         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, &pit->dev);
 726         if (ret < 0)
 727                 goto fail;
 728
 729         if (flags & KVM_PIT_SPEAKER_DUMMY) {
 730                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 731                 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
 732                                                 &pit->speaker_dev);
 733                 if (ret < 0)
 734                         goto fail_unregister;
 735         }
 736
 737         return pit;
 738
 739 fail_unregister:
 740         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
 741
 742 fail:
 743         kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 744         kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 745         kvm_free_irq_source_id(kvm, pit->irq_source_id);
 746         destroy_workqueue(pit->wq);
 747         kfree(pit);
 748         return NULL;
 749 }
 750
 751 void kvm_free_pit(struct kvm *kvm)
 752 {
 753         struct hrtimer *timer;
 754
 755         if (kvm->arch.vpit) {
 756                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
 757                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
 758                                               &kvm->arch.vpit->speaker_dev);
 759                 kvm_unregister_irq_mask_notifier(kvm, 0,
 760                                                &kvm->arch.vpit->mask_notifier);
 761                 kvm_unregister_irq_ack_notifier(kvm,
 762                                 &kvm->arch.vpit->pit_state.irq_ack_notifier);
 763                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 764                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
 765                 hrtimer_cancel(timer);
 766                 cancel_work_sync(&kvm->arch.vpit->expired);
 767                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 768                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 769                 destroy_workqueue(kvm->arch.vpit->wq);
 770                 kfree(kvm->arch.vpit);
 771         }
 772 }