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))
 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                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) {
 401                         create_pit_timer(kvm, val, 0);
 402                 }
 403                 break;
 404         case 2:
 405         case 3:
 406                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){
 407                         create_pit_timer(kvm, val, 1);
 408                 }
 409                 break;
 410         default:
 411                 destroy_pit_timer(kvm->arch.vpit);
 412         }
 413 }
 414
 415 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
 416 {
 417         u8 saved_mode;
 418         if (hpet_legacy_start) {
 419                 /* save existing mode for later reenablement */
 420                 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
 421                 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
 422                 pit_load_count(kvm, channel, val);
 423                 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
 424         } else {
 425                 pit_load_count(kvm, channel, val);
 426         }
 427 }
 428
 429 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
 430 {
 431         return container_of(dev, struct kvm_pit, dev);
 432 }
 433
 434 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
 435 {
 436         return container_of(dev, struct kvm_pit, speaker_dev);
 437 }
 438
 439 static inline int pit_in_range(gpa_t addr)
 440 {
 441         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 442                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 443 }
 444
 445 static int pit_ioport_write(struct kvm_io_device *this,
 446                             gpa_t addr, int len, const void *data)
 447 {
 448         struct kvm_pit *pit = dev_to_pit(this);
 449         struct kvm_kpit_state *pit_state = &pit->pit_state;
 450         struct kvm *kvm = pit->kvm;
 451         int channel, access;
 452         struct kvm_kpit_channel_state *s;
 453         u32 val = *(u32 *) data;
 454         if (!pit_in_range(addr))
 455                 return -EOPNOTSUPP;
 456
 457         val  &= 0xff;
 458         addr &= KVM_PIT_CHANNEL_MASK;
 459
 460         mutex_lock(&pit_state->lock);
 461
 462         if (val != 0)
 463                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
 464                          (unsigned int)addr, len, val);
 465
 466         if (addr == 3) {
 467                 channel = val >> 6;
 468                 if (channel == 3) {
 469                         /* Read-Back Command. */
 470                         for (channel = 0; channel < 3; channel++) {
 471                                 s = &pit_state->channels[channel];
 472                                 if (val & (2 << channel)) {
 473                                         if (!(val & 0x20))
 474                                                 pit_latch_count(kvm, channel);
 475                                         if (!(val & 0x10))
 476                                                 pit_latch_status(kvm, channel);
 477                                 }
 478                         }
 479                 } else {
 480                         /* Select Counter <channel>. */
 481                         s = &pit_state->channels[channel];
 482                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 483                         if (access == 0) {
 484                                 pit_latch_count(kvm, channel);
 485                         } else {
 486                                 s->rw_mode = access;
 487                                 s->read_state = access;
 488                                 s->write_state = access;
 489                                 s->mode = (val >> 1) & 7;
 490                                 if (s->mode > 5)
 491                                         s->mode -= 4;
 492                                 s->bcd = val & 1;
 493                         }
 494                 }
 495         } else {
 496                 /* Write Count. */
 497                 s = &pit_state->channels[addr];
 498                 switch (s->write_state) {
 499                 default:
 500                 case RW_STATE_LSB:
 501                         pit_load_count(kvm, addr, val);
 502                         break;
 503                 case RW_STATE_MSB:
 504                         pit_load_count(kvm, addr, val << 8);
 505                         break;
 506                 case RW_STATE_WORD0:
 507                         s->write_latch = val;
 508                         s->write_state = RW_STATE_WORD1;
 509                         break;
 510                 case RW_STATE_WORD1:
 511                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 512                         s->write_state = RW_STATE_WORD0;
 513                         break;
 514                 }
 515         }
 516
 517         mutex_unlock(&pit_state->lock);
 518         return 0;
 519 }
 520
 521 static int pit_ioport_read(struct kvm_io_device *this,
 522                            gpa_t addr, int len, void *data)
 523 {
 524         struct kvm_pit *pit = dev_to_pit(this);
 525         struct kvm_kpit_state *pit_state = &pit->pit_state;
 526         struct kvm *kvm = pit->kvm;
 527         int ret, count;
 528         struct kvm_kpit_channel_state *s;
 529         if (!pit_in_range(addr))
 530                 return -EOPNOTSUPP;
 531
 532         addr &= KVM_PIT_CHANNEL_MASK;
 533         if (addr == 3)
 534                 return 0;
 535
 536         s = &pit_state->channels[addr];
 537
 538         mutex_lock(&pit_state->lock);
 539
 540         if (s->status_latched) {
 541                 s->status_latched = 0;
 542                 ret = s->status;
 543         } else if (s->count_latched) {
 544                 switch (s->count_latched) {
 545                 default:
 546                 case RW_STATE_LSB:
 547                         ret = s->latched_count & 0xff;
 548                         s->count_latched = 0;
 549                         break;
 550                 case RW_STATE_MSB:
 551                         ret = s->latched_count >> 8;
 552                         s->count_latched = 0;
 553                         break;
 554                 case RW_STATE_WORD0:
 555                         ret = s->latched_count & 0xff;
 556                         s->count_latched = RW_STATE_MSB;
 557                         break;
 558                 }
 559         } else {
 560                 switch (s->read_state) {
 561                 default:
 562                 case RW_STATE_LSB:
 563                         count = pit_get_count(kvm, addr);
 564                         ret = count & 0xff;
 565                         break;
 566                 case RW_STATE_MSB:
 567                         count = pit_get_count(kvm, addr);
 568                         ret = (count >> 8) & 0xff;
 569                         break;
 570                 case RW_STATE_WORD0:
 571                         count = pit_get_count(kvm, addr);
 572                         ret = count & 0xff;
 573                         s->read_state = RW_STATE_WORD1;
 574                         break;
 575                 case RW_STATE_WORD1:
 576                         count = pit_get_count(kvm, addr);
 577                         ret = (count >> 8) & 0xff;
 578                         s->read_state = RW_STATE_WORD0;
 579                         break;
 580                 }
 581         }
 582
 583         if (len > sizeof(ret))
 584                 len = sizeof(ret);
 585         memcpy(data, (char *)&ret, len);
 586
 587         mutex_unlock(&pit_state->lock);
 588         return 0;
 589 }
 590
 591 static int speaker_ioport_write(struct kvm_io_device *this,
 592                                 gpa_t addr, int len, const void *data)
 593 {
 594         struct kvm_pit *pit = speaker_to_pit(this);
 595         struct kvm_kpit_state *pit_state = &pit->pit_state;
 596         struct kvm *kvm = pit->kvm;
 597         u32 val = *(u32 *) data;
 598         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 599                 return -EOPNOTSUPP;
 600
 601         mutex_lock(&pit_state->lock);
 602         pit_state->speaker_data_on = (val >> 1) & 1;
 603         pit_set_gate(kvm, 2, val & 1);
 604         mutex_unlock(&pit_state->lock);
 605         return 0;
 606 }
 607
 608 static int speaker_ioport_read(struct kvm_io_device *this,
 609                                gpa_t addr, int len, void *data)
 610 {
 611         struct kvm_pit *pit = speaker_to_pit(this);
 612         struct kvm_kpit_state *pit_state = &pit->pit_state;
 613         struct kvm *kvm = pit->kvm;
 614         unsigned int refresh_clock;
 615         int ret;
 616         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 617                 return -EOPNOTSUPP;
 618
 619         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 620         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 621
 622         mutex_lock(&pit_state->lock);
 623         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 624                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 625         if (len > sizeof(ret))
 626                 len = sizeof(ret);
 627         memcpy(data, (char *)&ret, len);
 628         mutex_unlock(&pit_state->lock);
 629         return 0;
 630 }
 631
 632 void kvm_pit_reset(struct kvm_pit *pit)
 633 {
 634         int i;
 635         struct kvm_kpit_channel_state *c;
 636
 637         mutex_lock(&pit->pit_state.lock);
 638         pit->pit_state.flags = 0;
 639         for (i = 0; i < 3; i++) {
 640                 c = &pit->pit_state.channels[i];
 641                 c->mode = 0xff;
 642                 c->gate = (i != 2);
 643                 pit_load_count(pit->kvm, i, 0);
 644         }
 645         mutex_unlock(&pit->pit_state.lock);
 646
 647         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 648         pit->pit_state.irq_ack = 1;
 649 }
 650
 651 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 652 {
 653         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 654
 655         if (!mask) {
 656                 atomic_set(&pit->pit_state.pit_timer.pending, 0);
 657                 pit->pit_state.irq_ack = 1;
 658         }
 659 }
 660
 661 static const struct kvm_io_device_ops pit_dev_ops = {
 662         .read     = pit_ioport_read,
 663         .write    = pit_ioport_write,
 664 };
 665
 666 static const struct kvm_io_device_ops speaker_dev_ops = {
 667         .read     = speaker_ioport_read,
 668         .write    = speaker_ioport_write,
 669 };
 670
 671 /* Caller must hold slots_lock */
 672 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 673 {
 674         struct kvm_pit *pit;
 675         struct kvm_kpit_state *pit_state;
 676         int ret;
 677
 678         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 679         if (!pit)
 680                 return NULL;
 681
 682         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 683         if (pit->irq_source_id < 0) {
 684                 kfree(pit);
 685                 return NULL;
 686         }
 687
 688         mutex_init(&pit->pit_state.lock);
 689         mutex_lock(&pit->pit_state.lock);
 690         spin_lock_init(&pit->pit_state.inject_lock);
 691
 692         pit->wq = create_singlethread_workqueue("kvm-pit-wq");
 693         if (!pit->wq) {
 694                 mutex_unlock(&pit->pit_state.lock);
 695                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
 696                 kfree(pit);
 697                 return NULL;
 698         }
 699         INIT_WORK(&pit->expired, pit_do_work);
 700
 701         kvm->arch.vpit = pit;
 702         pit->kvm = kvm;
 703
 704         pit_state = &pit->pit_state;
 705         pit_state->pit = pit;
 706         hrtimer_init(&pit_state->pit_timer.timer,
 707                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 708         pit_state->irq_ack_notifier.gsi = 0;
 709         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 710         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 711         pit_state->pit_timer.reinject = true;
 712         mutex_unlock(&pit->pit_state.lock);
 713
 714         kvm_pit_reset(pit);
 715
 716         pit->mask_notifier.func = pit_mask_notifer;
 717         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 718
 719         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
 720         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
 721                                       KVM_PIT_MEM_LENGTH, &pit->dev);
 722         if (ret < 0)
 723                 goto fail;
 724
 725         if (flags & KVM_PIT_SPEAKER_DUMMY) {
 726                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 727                 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
 728                                               KVM_SPEAKER_BASE_ADDRESS, 4,
 729                                               &pit->speaker_dev);
 730                 if (ret < 0)
 731                         goto fail_unregister;
 732         }
 733
 734         return pit;
 735
 736 fail_unregister:
 737         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
 738
 739 fail:
 740         kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 741         kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 742         kvm_free_irq_source_id(kvm, pit->irq_source_id);
 743         destroy_workqueue(pit->wq);
 744         kfree(pit);
 745         return NULL;
 746 }
 747
 748 void kvm_free_pit(struct kvm *kvm)
 749 {
 750         struct hrtimer *timer;
 751
 752         if (kvm->arch.vpit) {
 753                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
 754                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
 755                                               &kvm->arch.vpit->speaker_dev);
 756                 kvm_unregister_irq_mask_notifier(kvm, 0,
 757                                                &kvm->arch.vpit->mask_notifier);
 758                 kvm_unregister_irq_ack_notifier(kvm,
 759                                 &kvm->arch.vpit->pit_state.irq_ack_notifier);
 760                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 761                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
 762                 hrtimer_cancel(timer);
 763                 cancel_work_sync(&kvm->arch.vpit->expired);
 764                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 765                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 766                 destroy_workqueue(kvm->arch.vpit->wq);
 767                 kfree(kvm->arch.vpit);
 768         }
 769 }