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->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->timer);
 124         elapsed = ps->period - ktime_to_ns(remaining);
 125
 126         return elapsed;
 127 }
 128
 129 static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,
 130                         int channel)
 131 {
 132         if (channel == 0)
 133                 return __kpit_elapsed(kvm);
 134
 135         return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 136 }
 137
 138 static int pit_get_count(struct kvm *kvm, int channel)
 139 {
 140         struct kvm_kpit_channel_state *c =
 141                 &kvm->arch.vpit->pit_state.channels[channel];
 142         s64 d, t;
 143         int counter;
 144
 145         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 146
 147         t = kpit_elapsed(kvm, c, channel);
 148         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 149
 150         switch (c->mode) {
 151         case 0:
 152         case 1:
 153         case 4:
 154         case 5:
 155                 counter = (c->count - d) & 0xffff;
 156                 break;
 157         case 3:
 158                 /* XXX: may be incorrect for odd counts */
 159                 counter = c->count - (mod_64((2 * d), c->count));
 160                 break;
 161         default:
 162                 counter = c->count - mod_64(d, c->count);
 163                 break;
 164         }
 165         return counter;
 166 }
 167
 168 static int pit_get_out(struct kvm *kvm, int channel)
 169 {
 170         struct kvm_kpit_channel_state *c =
 171                 &kvm->arch.vpit->pit_state.channels[channel];
 172         s64 d, t;
 173         int out;
 174
 175         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 176
 177         t = kpit_elapsed(kvm, c, channel);
 178         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 179
 180         switch (c->mode) {
 181         default:
 182         case 0:
 183                 out = (d >= c->count);
 184                 break;
 185         case 1:
 186                 out = (d < c->count);
 187                 break;
 188         case 2:
 189                 out = ((mod_64(d, c->count) == 0) && (d != 0));
 190                 break;
 191         case 3:
 192                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
 193                 break;
 194         case 4:
 195         case 5:
 196                 out = (d == c->count);
 197                 break;
 198         }
 199
 200         return out;
 201 }
 202
 203 static void pit_latch_count(struct kvm *kvm, int channel)
 204 {
 205         struct kvm_kpit_channel_state *c =
 206                 &kvm->arch.vpit->pit_state.channels[channel];
 207
 208         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 209
 210         if (!c->count_latched) {
 211                 c->latched_count = pit_get_count(kvm, channel);
 212                 c->count_latched = c->rw_mode;
 213         }
 214 }
 215
 216 static void pit_latch_status(struct kvm *kvm, int channel)
 217 {
 218         struct kvm_kpit_channel_state *c =
 219                 &kvm->arch.vpit->pit_state.channels[channel];
 220
 221         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 222
 223         if (!c->status_latched) {
 224                 /* TODO: Return NULL COUNT (bit 6). */
 225                 c->status = ((pit_get_out(kvm, channel) << 7) |
 226                                 (c->rw_mode << 4) |
 227                                 (c->mode << 1) |
 228                                 c->bcd);
 229                 c->status_latched = 1;
 230         }
 231 }
 232
 233 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 234 {
 235         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 236                                                  irq_ack_notifier);
 237         int value;
 238
 239         spin_lock(&ps->inject_lock);
 240         value = atomic_dec_return(&ps->pending);
 241         if (value < 0)
 242                 /* spurious acks can be generated if, for example, the
 243                  * PIC is being reset.  Handle it gracefully here
 244                  */
 245                 atomic_inc(&ps->pending);
 246         else if (value > 0)
 247                 /* in this case, we had multiple outstanding pit interrupts
 248                  * that we needed to inject.  Reinject
 249                  */
 250                 queue_kthread_work(&ps->pit->worker, &ps->pit->expired);
 251         ps->irq_ack = 1;
 252         spin_unlock(&ps->inject_lock);
 253 }
 254
 255 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 256 {
 257         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 258         struct hrtimer *timer;
 259
 260         if (!kvm_vcpu_is_bsp(vcpu) || !pit)
 261                 return;
 262
 263         timer = &pit->pit_state.timer;
 264         if (hrtimer_cancel(timer))
 265                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 266 }
 267
 268 static void destroy_pit_timer(struct kvm_pit *pit)
 269 {
 270         hrtimer_cancel(&pit->pit_state.timer);
 271         flush_kthread_work(&pit->expired);
 272 }
 273
 274 static void pit_do_work(struct kthread_work *work)
 275 {
 276         struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
 277         struct kvm *kvm = pit->kvm;
 278         struct kvm_vcpu *vcpu;
 279         int i;
 280         struct kvm_kpit_state *ps = &pit->pit_state;
 281         int inject = 0;
 282
 283         /* Try to inject pending interrupts when
 284          * last one has been acked.
 285          */
 286         spin_lock(&ps->inject_lock);
 287         if (ps->irq_ack) {
 288                 ps->irq_ack = 0;
 289                 inject = 1;
 290         }
 291         spin_unlock(&ps->inject_lock);
 292         if (inject) {
 293                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1, false);
 294                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0, false);
 295
 296                 /*
 297                  * Provides NMI watchdog support via Virtual Wire mode.
 298                  * The route is: PIT -> PIC -> LVT0 in NMI mode.
 299                  *
 300                  * Note: Our Virtual Wire implementation is simplified, only
 301                  * propagating PIT interrupts to all VCPUs when they have set
 302                  * LVT0 to NMI delivery. Other PIC interrupts are just sent to
 303                  * VCPU0, and only if its LVT0 is in EXTINT mode.
 304                  */
 305                 if (kvm->arch.vapics_in_nmi_mode > 0)
 306                         kvm_for_each_vcpu(i, vcpu, kvm)
 307                                 kvm_apic_nmi_wd_deliver(vcpu);
 308         }
 309 }
 310
 311 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 312 {
 313         struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer);
 314         struct kvm_pit *pt = ps->kvm->arch.vpit;
 315
 316         if (ps->reinject || !atomic_read(&ps->pending)) {
 317                 atomic_inc(&ps->pending);
 318                 queue_kthread_work(&pt->worker, &pt->expired);
 319         }
 320
 321         if (ps->is_periodic) {
 322                 hrtimer_add_expires_ns(&ps->timer, ps->period);
 323                 return HRTIMER_RESTART;
 324         } else
 325                 return HRTIMER_NORESTART;
 326 }
 327
 328 static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
 329 {
 330         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 331         s64 interval;
 332
 333         if (!irqchip_in_kernel(kvm) || ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
 334                 return;
 335
 336         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 337
 338         pr_debug("create pit timer, interval is %llu nsec\n", interval);
 339
 340         /* TODO The new value only affected after the retriggered */
 341         hrtimer_cancel(&ps->timer);
 342         flush_kthread_work(&ps->pit->expired);
 343         ps->period = interval;
 344         ps->is_periodic = is_period;
 345
 346         ps->timer.function = pit_timer_fn;
 347         ps->kvm = ps->pit->kvm;
 348
 349         atomic_set(&ps->pending, 0);
 350         ps->irq_ack = 1;
 351
 352         hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
 353                       HRTIMER_MODE_ABS);
 354 }
 355
 356 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 357 {
 358         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 359
 360         WARN_ON(!mutex_is_locked(&ps->lock));
 361
 362         pr_debug("load_count val is %d, channel is %d\n", val, channel);
 363
 364         /*
 365          * The largest possible initial count is 0; this is equivalent
 366          * to 216 for binary counting and 104 for BCD counting.
 367          */
 368         if (val == 0)
 369                 val = 0x10000;
 370
 371         ps->channels[channel].count = val;
 372
 373         if (channel != 0) {
 374                 ps->channels[channel].count_load_time = ktime_get();
 375                 return;
 376         }
 377
 378         /* Two types of timer
 379          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 380         switch (ps->channels[0].mode) {
 381         case 0:
 382         case 1:
 383         /* FIXME: enhance mode 4 precision */
 384         case 4:
 385                 create_pit_timer(kvm, val, 0);
 386                 break;
 387         case 2:
 388         case 3:
 389                 create_pit_timer(kvm, val, 1);
 390                 break;
 391         default:
 392                 destroy_pit_timer(kvm->arch.vpit);
 393         }
 394 }
 395
 396 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
 397 {
 398         u8 saved_mode;
 399         if (hpet_legacy_start) {
 400                 /* save existing mode for later reenablement */
 401                 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
 402                 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
 403                 pit_load_count(kvm, channel, val);
 404                 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
 405         } else {
 406                 pit_load_count(kvm, channel, val);
 407         }
 408 }
 409
 410 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
 411 {
 412         return container_of(dev, struct kvm_pit, dev);
 413 }
 414
 415 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
 416 {
 417         return container_of(dev, struct kvm_pit, speaker_dev);
 418 }
 419
 420 static inline int pit_in_range(gpa_t addr)
 421 {
 422         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 423                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 424 }
 425
 426 static int pit_ioport_write(struct kvm_io_device *this,
 427                             gpa_t addr, int len, const void *data)
 428 {
 429         struct kvm_pit *pit = dev_to_pit(this);
 430         struct kvm_kpit_state *pit_state = &pit->pit_state;
 431         struct kvm *kvm = pit->kvm;
 432         int channel, access;
 433         struct kvm_kpit_channel_state *s;
 434         u32 val = *(u32 *) data;
 435         if (!pit_in_range(addr))
 436                 return -EOPNOTSUPP;
 437
 438         val  &= 0xff;
 439         addr &= KVM_PIT_CHANNEL_MASK;
 440
 441         mutex_lock(&pit_state->lock);
 442
 443         if (val != 0)
 444                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
 445                          (unsigned int)addr, len, val);
 446
 447         if (addr == 3) {
 448                 channel = val >> 6;
 449                 if (channel == 3) {
 450                         /* Read-Back Command. */
 451                         for (channel = 0; channel < 3; channel++) {
 452                                 s = &pit_state->channels[channel];
 453                                 if (val & (2 << channel)) {
 454                                         if (!(val & 0x20))
 455                                                 pit_latch_count(kvm, channel);
 456                                         if (!(val & 0x10))
 457                                                 pit_latch_status(kvm, channel);
 458                                 }
 459                         }
 460                 } else {
 461                         /* Select Counter <channel>. */
 462                         s = &pit_state->channels[channel];
 463                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 464                         if (access == 0) {
 465                                 pit_latch_count(kvm, channel);
 466                         } else {
 467                                 s->rw_mode = access;
 468                                 s->read_state = access;
 469                                 s->write_state = access;
 470                                 s->mode = (val >> 1) & 7;
 471                                 if (s->mode > 5)
 472                                         s->mode -= 4;
 473                                 s->bcd = val & 1;
 474                         }
 475                 }
 476         } else {
 477                 /* Write Count. */
 478                 s = &pit_state->channels[addr];
 479                 switch (s->write_state) {
 480                 default:
 481                 case RW_STATE_LSB:
 482                         pit_load_count(kvm, addr, val);
 483                         break;
 484                 case RW_STATE_MSB:
 485                         pit_load_count(kvm, addr, val << 8);
 486                         break;
 487                 case RW_STATE_WORD0:
 488                         s->write_latch = val;
 489                         s->write_state = RW_STATE_WORD1;
 490                         break;
 491                 case RW_STATE_WORD1:
 492                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 493                         s->write_state = RW_STATE_WORD0;
 494                         break;
 495                 }
 496         }
 497
 498         mutex_unlock(&pit_state->lock);
 499         return 0;
 500 }
 501
 502 static int pit_ioport_read(struct kvm_io_device *this,
 503                            gpa_t addr, int len, void *data)
 504 {
 505         struct kvm_pit *pit = dev_to_pit(this);
 506         struct kvm_kpit_state *pit_state = &pit->pit_state;
 507         struct kvm *kvm = pit->kvm;
 508         int ret, count;
 509         struct kvm_kpit_channel_state *s;
 510         if (!pit_in_range(addr))
 511                 return -EOPNOTSUPP;
 512
 513         addr &= KVM_PIT_CHANNEL_MASK;
 514         if (addr == 3)
 515                 return 0;
 516
 517         s = &pit_state->channels[addr];
 518
 519         mutex_lock(&pit_state->lock);
 520
 521         if (s->status_latched) {
 522                 s->status_latched = 0;
 523                 ret = s->status;
 524         } else if (s->count_latched) {
 525                 switch (s->count_latched) {
 526                 default:
 527                 case RW_STATE_LSB:
 528                         ret = s->latched_count & 0xff;
 529                         s->count_latched = 0;
 530                         break;
 531                 case RW_STATE_MSB:
 532                         ret = s->latched_count >> 8;
 533                         s->count_latched = 0;
 534                         break;
 535                 case RW_STATE_WORD0:
 536                         ret = s->latched_count & 0xff;
 537                         s->count_latched = RW_STATE_MSB;
 538                         break;
 539                 }
 540         } else {
 541                 switch (s->read_state) {
 542                 default:
 543                 case RW_STATE_LSB:
 544                         count = pit_get_count(kvm, addr);
 545                         ret = count & 0xff;
 546                         break;
 547                 case RW_STATE_MSB:
 548                         count = pit_get_count(kvm, addr);
 549                         ret = (count >> 8) & 0xff;
 550                         break;
 551                 case RW_STATE_WORD0:
 552                         count = pit_get_count(kvm, addr);
 553                         ret = count & 0xff;
 554                         s->read_state = RW_STATE_WORD1;
 555                         break;
 556                 case RW_STATE_WORD1:
 557                         count = pit_get_count(kvm, addr);
 558                         ret = (count >> 8) & 0xff;
 559                         s->read_state = RW_STATE_WORD0;
 560                         break;
 561                 }
 562         }
 563
 564         if (len > sizeof(ret))
 565                 len = sizeof(ret);
 566         memcpy(data, (char *)&ret, len);
 567
 568         mutex_unlock(&pit_state->lock);
 569         return 0;
 570 }
 571
 572 static int speaker_ioport_write(struct kvm_io_device *this,
 573                                 gpa_t addr, int len, const void *data)
 574 {
 575         struct kvm_pit *pit = speaker_to_pit(this);
 576         struct kvm_kpit_state *pit_state = &pit->pit_state;
 577         struct kvm *kvm = pit->kvm;
 578         u32 val = *(u32 *) data;
 579         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 580                 return -EOPNOTSUPP;
 581
 582         mutex_lock(&pit_state->lock);
 583         pit_state->speaker_data_on = (val >> 1) & 1;
 584         pit_set_gate(kvm, 2, val & 1);
 585         mutex_unlock(&pit_state->lock);
 586         return 0;
 587 }
 588
 589 static int speaker_ioport_read(struct kvm_io_device *this,
 590                                gpa_t addr, int len, void *data)
 591 {
 592         struct kvm_pit *pit = speaker_to_pit(this);
 593         struct kvm_kpit_state *pit_state = &pit->pit_state;
 594         struct kvm *kvm = pit->kvm;
 595         unsigned int refresh_clock;
 596         int ret;
 597         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 598                 return -EOPNOTSUPP;
 599
 600         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 601         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 602
 603         mutex_lock(&pit_state->lock);
 604         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 605                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 606         if (len > sizeof(ret))
 607                 len = sizeof(ret);
 608         memcpy(data, (char *)&ret, len);
 609         mutex_unlock(&pit_state->lock);
 610         return 0;
 611 }
 612
 613 void kvm_pit_reset(struct kvm_pit *pit)
 614 {
 615         int i;
 616         struct kvm_kpit_channel_state *c;
 617
 618         mutex_lock(&pit->pit_state.lock);
 619         pit->pit_state.flags = 0;
 620         for (i = 0; i < 3; i++) {
 621                 c = &pit->pit_state.channels[i];
 622                 c->mode = 0xff;
 623                 c->gate = (i != 2);
 624                 pit_load_count(pit->kvm, i, 0);
 625         }
 626         mutex_unlock(&pit->pit_state.lock);
 627
 628         atomic_set(&pit->pit_state.pending, 0);
 629         pit->pit_state.irq_ack = 1;
 630 }
 631
 632 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 633 {
 634         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 635
 636         if (!mask) {
 637                 atomic_set(&pit->pit_state.pending, 0);
 638                 pit->pit_state.irq_ack = 1;
 639         }
 640 }
 641
 642 static const struct kvm_io_device_ops pit_dev_ops = {
 643         .read     = pit_ioport_read,
 644         .write    = pit_ioport_write,
 645 };
 646
 647 static const struct kvm_io_device_ops speaker_dev_ops = {
 648         .read     = speaker_ioport_read,
 649         .write    = speaker_ioport_write,
 650 };
 651
 652 /* Caller must hold slots_lock */
 653 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 654 {
 655         struct kvm_pit *pit;
 656         struct kvm_kpit_state *pit_state;
 657         struct pid *pid;
 658         pid_t pid_nr;
 659         int ret;
 660
 661         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 662         if (!pit)
 663                 return NULL;
 664
 665         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 666         if (pit->irq_source_id < 0) {
 667                 kfree(pit);
 668                 return NULL;
 669         }
 670
 671         mutex_init(&pit->pit_state.lock);
 672         mutex_lock(&pit->pit_state.lock);
 673         spin_lock_init(&pit->pit_state.inject_lock);
 674
 675         pid = get_pid(task_tgid(current));
 676         pid_nr = pid_vnr(pid);
 677         put_pid(pid);
 678
 679         init_kthread_worker(&pit->worker);
 680         pit->worker_task = kthread_run(kthread_worker_fn, &pit->worker,
 681                                        "kvm-pit/%d", pid_nr);
 682         if (IS_ERR(pit->worker_task)) {
 683                 mutex_unlock(&pit->pit_state.lock);
 684                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
 685                 kfree(pit);
 686                 return NULL;
 687         }
 688         init_kthread_work(&pit->expired, pit_do_work);
 689
 690         kvm->arch.vpit = pit;
 691         pit->kvm = kvm;
 692
 693         pit_state = &pit->pit_state;
 694         pit_state->pit = pit;
 695         hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 696         pit_state->irq_ack_notifier.gsi = 0;
 697         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 698         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 699         pit_state->reinject = true;
 700         mutex_unlock(&pit->pit_state.lock);
 701
 702         kvm_pit_reset(pit);
 703
 704         pit->mask_notifier.func = pit_mask_notifer;
 705         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 706
 707         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
 708         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
 709                                       KVM_PIT_MEM_LENGTH, &pit->dev);
 710         if (ret < 0)
 711                 goto fail;
 712
 713         if (flags & KVM_PIT_SPEAKER_DUMMY) {
 714                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 715                 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
 716                                               KVM_SPEAKER_BASE_ADDRESS, 4,
 717                                               &pit->speaker_dev);
 718                 if (ret < 0)
 719                         goto fail_unregister;
 720         }
 721
 722         return pit;
 723
 724 fail_unregister:
 725         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
 726
 727 fail:
 728         kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 729         kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 730         kvm_free_irq_source_id(kvm, pit->irq_source_id);
 731         kthread_stop(pit->worker_task);
 732         kfree(pit);
 733         return NULL;
 734 }
 735
 736 void kvm_free_pit(struct kvm *kvm)
 737 {
 738         struct hrtimer *timer;
 739
 740         if (kvm->arch.vpit) {
 741                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
 742                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
 743                                               &kvm->arch.vpit->speaker_dev);
 744                 kvm_unregister_irq_mask_notifier(kvm, 0,
 745                                                &kvm->arch.vpit->mask_notifier);
 746                 kvm_unregister_irq_ack_notifier(kvm,
 747                                 &kvm->arch.vpit->pit_state.irq_ack_notifier);
 748                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 749                 timer = &kvm->arch.vpit->pit_state.timer;
 750                 hrtimer_cancel(timer);
 751                 flush_kthread_work(&kvm->arch.vpit->expired);
 752                 kthread_stop(kvm->arch.vpit->worker_task);
 753                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 754                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 755                 kfree(kvm->arch.vpit);
 756         }
 757 }