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
  41 #ifndef CONFIG_X86_64
  42 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
  43 #else
  44 #define mod_64(x, y) ((x) % (y))
  45 #endif
  46
  47 #define RW_STATE_LSB 1
  48 #define RW_STATE_MSB 2
  49 #define RW_STATE_WORD0 3
  50 #define RW_STATE_WORD1 4
  51
  52 /* Compute with 96 bit intermediate result: (a*b)/c */
  53 static u64 muldiv64(u64 a, u32 b, u32 c)
  54 {
  55         union {
  56                 u64 ll;
  57                 struct {
  58                         u32 low, high;
  59                 } l;
  60         } u, res;
  61         u64 rl, rh;
  62
  63         u.ll = a;
  64         rl = (u64)u.l.low * (u64)b;
  65         rh = (u64)u.l.high * (u64)b;
  66         rh += (rl >> 32);
  67         res.l.high = div64_u64(rh, c);
  68         res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
  69         return res.ll;
  70 }
  71
  72 static void pit_set_gate(struct kvm *kvm, int channel, u32 val)
  73 {
  74         struct kvm_kpit_channel_state *c =
  75                 &kvm->arch.vpit->pit_state.channels[channel];
  76
  77         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
  78
  79         switch (c->mode) {
  80         default:
  81         case 0:
  82         case 4:
  83                 /* XXX: just disable/enable counting */
  84                 break;
  85         case 1:
  86         case 2:
  87         case 3:
  88         case 5:
  89                 /* Restart counting on rising edge. */
  90                 if (c->gate < val)
  91                         c->count_load_time = ktime_get();
  92                 break;
  93         }
  94
  95         c->gate = val;
  96 }
  97
  98 static int pit_get_gate(struct kvm *kvm, int channel)
  99 {
 100         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 101
 102         return kvm->arch.vpit->pit_state.channels[channel].gate;
 103 }
 104
 105 static s64 __kpit_elapsed(struct kvm *kvm)
 106 {
 107         s64 elapsed;
 108         ktime_t remaining;
 109         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 110
 111         if (!ps->pit_timer.period)
 112                 return 0;
 113
 114         /*
 115          * The Counter does not stop when it reaches zero. In
 116          * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
 117          * the highest count, either FFFF hex for binary counting
 118          * or 9999 for BCD counting, and continues counting.
 119          * Modes 2 and 3 are periodic; the Counter reloads
 120          * itself with the initial count and continues counting
 121          * from there.
 122          */
 123         remaining = hrtimer_get_remaining(&ps->pit_timer.timer);
 124         elapsed = ps->pit_timer.period - ktime_to_ns(remaining);
 125         elapsed = mod_64(elapsed, ps->pit_timer.period);
 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->pit_timer.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->pit_timer.pending);
 247         else if (value > 0)
 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.pit_timer.timer;
 265         if (hrtimer_cancel(timer))
 266                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 267 }
 268
 269 static void destroy_pit_timer(struct kvm_pit *pit)
 270 {
 271         hrtimer_cancel(&pit->pit_state.pit_timer.timer);
 272         flush_kthread_work(&pit->expired);
 273 }
 274
 275 static bool kpit_is_periodic(struct kvm_pit_timer *ktimer)
 276 {
 277         struct kvm_kpit_state *ps = container_of(ktimer, struct kvm_kpit_state,
 278                                                  pit_timer);
 279         return ps->is_periodic;
 280 }
 281
 282 static struct kvm_pit_timer_ops kpit_ops = {
 283         .is_periodic = kpit_is_periodic,
 284 };
 285
 286 static void pit_do_work(struct kthread_work *work)
 287 {
 288         struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
 289         struct kvm *kvm = pit->kvm;
 290         struct kvm_vcpu *vcpu;
 291         int i;
 292         struct kvm_kpit_state *ps = &pit->pit_state;
 293         int inject = 0;
 294
 295         /* Try to inject pending interrupts when
 296          * last one has been acked.
 297          */
 298         spin_lock(&ps->inject_lock);
 299         if (ps->irq_ack) {
 300                 ps->irq_ack = 0;
 301                 inject = 1;
 302         }
 303         spin_unlock(&ps->inject_lock);
 304         if (inject) {
 305                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
 306                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
 307
 308                 /*
 309                  * Provides NMI watchdog support via Virtual Wire mode.
 310                  * The route is: PIT -> PIC -> LVT0 in NMI mode.
 311                  *
 312                  * Note: Our Virtual Wire implementation is simplified, only
 313                  * propagating PIT interrupts to all VCPUs when they have set
 314                  * LVT0 to NMI delivery. Other PIC interrupts are just sent to
 315                  * VCPU0, and only if its LVT0 is in EXTINT mode.
 316                  */
 317                 if (kvm->arch.vapics_in_nmi_mode > 0)
 318                         kvm_for_each_vcpu(i, vcpu, kvm)
 319                                 kvm_apic_nmi_wd_deliver(vcpu);
 320         }
 321 }
 322
 323 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 324 {
 325         struct kvm_pit_timer *ktimer = container_of(data, struct kvm_pit_timer, timer);
 326         struct kvm_pit *pt = ktimer->kvm->arch.vpit;
 327
 328         if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
 329                 atomic_inc(&ktimer->pending);
 330                 queue_kthread_work(&pt->worker, &pt->expired);
 331         }
 332
 333         if (ktimer->t_ops->is_periodic(ktimer)) {
 334                 hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
 335                 return HRTIMER_RESTART;
 336         } else
 337                 return HRTIMER_NORESTART;
 338 }
 339
 340 static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
 341 {
 342         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 343         struct kvm_pit_timer *pt = &ps->pit_timer;
 344         s64 interval;
 345
 346         if (!irqchip_in_kernel(kvm) || ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
 347                 return;
 348
 349         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 350
 351         pr_debug("create pit timer, interval is %llu nsec\n", interval);
 352
 353         /* TODO The new value only affected after the retriggered */
 354         hrtimer_cancel(&pt->timer);
 355         flush_kthread_work(&ps->pit->expired);
 356         pt->period = interval;
 357         ps->is_periodic = is_period;
 358
 359         pt->timer.function = pit_timer_fn;
 360         pt->t_ops = &kpit_ops;
 361         pt->kvm = ps->pit->kvm;
 362
 363         atomic_set(&pt->pending, 0);
 364         ps->irq_ack = 1;
 365
 366         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
 367                       HRTIMER_MODE_ABS);
 368 }
 369
 370 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 371 {
 372         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 373
 374         WARN_ON(!mutex_is_locked(&ps->lock));
 375
 376         pr_debug("load_count val is %d, channel is %d\n", val, channel);
 377
 378         /*
 379          * The largest possible initial count is 0; this is equivalent
 380          * to 216 for binary counting and 104 for BCD counting.
 381          */
 382         if (val == 0)
 383                 val = 0x10000;
 384
 385         ps->channels[channel].count = val;
 386
 387         if (channel != 0) {
 388                 ps->channels[channel].count_load_time = ktime_get();
 389                 return;
 390         }
 391
 392         /* Two types of timer
 393          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 394         switch (ps->channels[0].mode) {
 395         case 0:
 396         case 1:
 397         /* FIXME: enhance mode 4 precision */
 398         case 4:
 399                 create_pit_timer(kvm, val, 0);
 400                 break;
 401         case 2:
 402         case 3:
 403                 create_pit_timer(kvm, val, 1);
 404                 break;
 405         default:
 406                 destroy_pit_timer(kvm->arch.vpit);
 407         }
 408 }
 409
 410 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
 411 {
 412         u8 saved_mode;
 413         if (hpet_legacy_start) {
 414                 /* save existing mode for later reenablement */
 415                 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
 416                 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
 417                 pit_load_count(kvm, channel, val);
 418                 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
 419         } else {
 420                 pit_load_count(kvm, channel, val);
 421         }
 422 }
 423
 424 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
 425 {
 426         return container_of(dev, struct kvm_pit, dev);
 427 }
 428
 429 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
 430 {
 431         return container_of(dev, struct kvm_pit, speaker_dev);
 432 }
 433
 434 static inline int pit_in_range(gpa_t addr)
 435 {
 436         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 437                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 438 }
 439
 440 static int pit_ioport_write(struct kvm_io_device *this,
 441                             gpa_t addr, int len, const void *data)
 442 {
 443         struct kvm_pit *pit = dev_to_pit(this);
 444         struct kvm_kpit_state *pit_state = &pit->pit_state;
 445         struct kvm *kvm = pit->kvm;
 446         int channel, access;
 447         struct kvm_kpit_channel_state *s;
 448         u32 val = *(u32 *) data;
 449         if (!pit_in_range(addr))
 450                 return -EOPNOTSUPP;
 451
 452         val  &= 0xff;
 453         addr &= KVM_PIT_CHANNEL_MASK;
 454
 455         mutex_lock(&pit_state->lock);
 456
 457         if (val != 0)
 458                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
 459                          (unsigned int)addr, len, val);
 460
 461         if (addr == 3) {
 462                 channel = val >> 6;
 463                 if (channel == 3) {
 464                         /* Read-Back Command. */
 465                         for (channel = 0; channel < 3; channel++) {
 466                                 s = &pit_state->channels[channel];
 467                                 if (val & (2 << channel)) {
 468                                         if (!(val & 0x20))
 469                                                 pit_latch_count(kvm, channel);
 470                                         if (!(val & 0x10))
 471                                                 pit_latch_status(kvm, channel);
 472                                 }
 473                         }
 474                 } else {
 475                         /* Select Counter <channel>. */
 476                         s = &pit_state->channels[channel];
 477                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 478                         if (access == 0) {
 479                                 pit_latch_count(kvm, channel);
 480                         } else {
 481                                 s->rw_mode = access;
 482                                 s->read_state = access;
 483                                 s->write_state = access;
 484                                 s->mode = (val >> 1) & 7;
 485                                 if (s->mode > 5)
 486                                         s->mode -= 4;
 487                                 s->bcd = val & 1;
 488                         }
 489                 }
 490         } else {
 491                 /* Write Count. */
 492                 s = &pit_state->channels[addr];
 493                 switch (s->write_state) {
 494                 default:
 495                 case RW_STATE_LSB:
 496                         pit_load_count(kvm, addr, val);
 497                         break;
 498                 case RW_STATE_MSB:
 499                         pit_load_count(kvm, addr, val << 8);
 500                         break;
 501                 case RW_STATE_WORD0:
 502                         s->write_latch = val;
 503                         s->write_state = RW_STATE_WORD1;
 504                         break;
 505                 case RW_STATE_WORD1:
 506                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 507                         s->write_state = RW_STATE_WORD0;
 508                         break;
 509                 }
 510         }
 511
 512         mutex_unlock(&pit_state->lock);
 513         return 0;
 514 }
 515
 516 static int pit_ioport_read(struct kvm_io_device *this,
 517                            gpa_t addr, int len, void *data)
 518 {
 519         struct kvm_pit *pit = dev_to_pit(this);
 520         struct kvm_kpit_state *pit_state = &pit->pit_state;
 521         struct kvm *kvm = pit->kvm;
 522         int ret, count;
 523         struct kvm_kpit_channel_state *s;
 524         if (!pit_in_range(addr))
 525                 return -EOPNOTSUPP;
 526
 527         addr &= KVM_PIT_CHANNEL_MASK;
 528         if (addr == 3)
 529                 return 0;
 530
 531         s = &pit_state->channels[addr];
 532
 533         mutex_lock(&pit_state->lock);
 534
 535         if (s->status_latched) {
 536                 s->status_latched = 0;
 537                 ret = s->status;
 538         } else if (s->count_latched) {
 539                 switch (s->count_latched) {
 540                 default:
 541                 case RW_STATE_LSB:
 542                         ret = s->latched_count & 0xff;
 543                         s->count_latched = 0;
 544                         break;
 545                 case RW_STATE_MSB:
 546                         ret = s->latched_count >> 8;
 547                         s->count_latched = 0;
 548                         break;
 549                 case RW_STATE_WORD0:
 550                         ret = s->latched_count & 0xff;
 551                         s->count_latched = RW_STATE_MSB;
 552                         break;
 553                 }
 554         } else {
 555                 switch (s->read_state) {
 556                 default:
 557                 case RW_STATE_LSB:
 558                         count = pit_get_count(kvm, addr);
 559                         ret = count & 0xff;
 560                         break;
 561                 case RW_STATE_MSB:
 562                         count = pit_get_count(kvm, addr);
 563                         ret = (count >> 8) & 0xff;
 564                         break;
 565                 case RW_STATE_WORD0:
 566                         count = pit_get_count(kvm, addr);
 567                         ret = count & 0xff;
 568                         s->read_state = RW_STATE_WORD1;
 569                         break;
 570                 case RW_STATE_WORD1:
 571                         count = pit_get_count(kvm, addr);
 572                         ret = (count >> 8) & 0xff;
 573                         s->read_state = RW_STATE_WORD0;
 574                         break;
 575                 }
 576         }
 577
 578         if (len > sizeof(ret))
 579                 len = sizeof(ret);
 580         memcpy(data, (char *)&ret, len);
 581
 582         mutex_unlock(&pit_state->lock);
 583         return 0;
 584 }
 585
 586 static int speaker_ioport_write(struct kvm_io_device *this,
 587                                 gpa_t addr, int len, const void *data)
 588 {
 589         struct kvm_pit *pit = speaker_to_pit(this);
 590         struct kvm_kpit_state *pit_state = &pit->pit_state;
 591         struct kvm *kvm = pit->kvm;
 592         u32 val = *(u32 *) data;
 593         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 594                 return -EOPNOTSUPP;
 595
 596         mutex_lock(&pit_state->lock);
 597         pit_state->speaker_data_on = (val >> 1) & 1;
 598         pit_set_gate(kvm, 2, val & 1);
 599         mutex_unlock(&pit_state->lock);
 600         return 0;
 601 }
 602
 603 static int speaker_ioport_read(struct kvm_io_device *this,
 604                                gpa_t addr, int len, void *data)
 605 {
 606         struct kvm_pit *pit = speaker_to_pit(this);
 607         struct kvm_kpit_state *pit_state = &pit->pit_state;
 608         struct kvm *kvm = pit->kvm;
 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->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 619                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 620         if (len > sizeof(ret))
 621                 len = sizeof(ret);
 622         memcpy(data, (char *)&ret, len);
 623         mutex_unlock(&pit_state->lock);
 624         return 0;
 625 }
 626
 627 void kvm_pit_reset(struct kvm_pit *pit)
 628 {
 629         int i;
 630         struct kvm_kpit_channel_state *c;
 631
 632         mutex_lock(&pit->pit_state.lock);
 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->kvm, i, 0);
 639         }
 640         mutex_unlock(&pit->pit_state.lock);
 641
 642         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 643         pit->pit_state.irq_ack = 1;
 644 }
 645
 646 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 647 {
 648         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 649
 650         if (!mask) {
 651                 atomic_set(&pit->pit_state.pit_timer.pending, 0);
 652                 pit->pit_state.irq_ack = 1;
 653         }
 654 }
 655
 656 static const struct kvm_io_device_ops pit_dev_ops = {
 657         .read     = pit_ioport_read,
 658         .write    = pit_ioport_write,
 659 };
 660
 661 static const struct kvm_io_device_ops speaker_dev_ops = {
 662         .read     = speaker_ioport_read,
 663         .write    = speaker_ioport_write,
 664 };
 665
 666 /* Caller must hold slots_lock */
 667 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 668 {
 669         struct kvm_pit *pit;
 670         struct kvm_kpit_state *pit_state;
 671         struct pid *pid;
 672         pid_t pid_nr;
 673         int ret;
 674
 675         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 676         if (!pit)
 677                 return NULL;
 678
 679         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 680         if (pit->irq_source_id < 0) {
 681                 kfree(pit);
 682                 return NULL;
 683         }
 684
 685         mutex_init(&pit->pit_state.lock);
 686         mutex_lock(&pit->pit_state.lock);
 687         spin_lock_init(&pit->pit_state.inject_lock);
 688
 689         pid = get_pid(task_tgid(current));
 690         pid_nr = pid_vnr(pid);
 691         put_pid(pid);
 692
 693         init_kthread_worker(&pit->worker);
 694         pit->worker_task = kthread_run(kthread_worker_fn, &pit->worker,
 695                                        "kvm-pit/%d", pid_nr);
 696         if (IS_ERR(pit->worker_task)) {
 697                 mutex_unlock(&pit->pit_state.lock);
 698                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
 699                 kfree(pit);
 700                 return NULL;
 701         }
 702         init_kthread_work(&pit->expired, pit_do_work);
 703
 704         kvm->arch.vpit = pit;
 705         pit->kvm = kvm;
 706
 707         pit_state = &pit->pit_state;
 708         pit_state->pit = pit;
 709         hrtimer_init(&pit_state->pit_timer.timer,
 710                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 711         pit_state->irq_ack_notifier.gsi = 0;
 712         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 713         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 714         pit_state->pit_timer.reinject = true;
 715         mutex_unlock(&pit->pit_state.lock);
 716
 717         kvm_pit_reset(pit);
 718
 719         pit->mask_notifier.func = pit_mask_notifer;
 720         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 721
 722         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
 723         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
 724                                       KVM_PIT_MEM_LENGTH, &pit->dev);
 725         if (ret < 0)
 726                 goto fail;
 727
 728         if (flags & KVM_PIT_SPEAKER_DUMMY) {
 729                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 730                 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
 731                                               KVM_SPEAKER_BASE_ADDRESS, 4,
 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         kthread_stop(pit->worker_task);
 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                 flush_kthread_work(&kvm->arch.vpit->expired);
 767                 kthread_stop(kvm->arch.vpit->worker_task);
 768                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 769                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 770                 kfree(kvm->arch.vpit);
 771         }
 772 }