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 "ioapic.h"
  39 #include "irq.h"
  40 #include "i8254.h"
  41 #include "x86.h"
  42
  43 #ifndef CONFIG_X86_64
  44 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
  45 #else
  46 #define mod_64(x, y) ((x) % (y))
  47 #endif
  48
  49 #define RW_STATE_LSB 1
  50 #define RW_STATE_MSB 2
  51 #define RW_STATE_WORD0 3
  52 #define RW_STATE_WORD1 4
  53
  54 /* Compute with 96 bit intermediate result: (a*b)/c */
  55 static u64 muldiv64(u64 a, u32 b, u32 c)
  56 {
  57         union {
  58                 u64 ll;
  59                 struct {
  60                         u32 low, high;
  61                 } l;
  62         } u, res;
  63         u64 rl, rh;
  64
  65         u.ll = a;
  66         rl = (u64)u.l.low * (u64)b;
  67         rh = (u64)u.l.high * (u64)b;
  68         rh += (rl >> 32);
  69         res.l.high = div64_u64(rh, c);
  70         res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
  71         return res.ll;
  72 }
  73
  74 static void pit_set_gate(struct kvm *kvm, int channel, u32 val)
  75 {
  76         struct kvm_kpit_channel_state *c =
  77                 &kvm->arch.vpit->pit_state.channels[channel];
  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         return kvm->arch.vpit->pit_state.channels[channel].gate;
 101 }
 102
 103 static s64 __kpit_elapsed(struct kvm *kvm)
 104 {
 105         s64 elapsed;
 106         ktime_t remaining;
 107         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 108
 109         if (!ps->period)
 110                 return 0;
 111
 112         /*
 113          * The Counter does not stop when it reaches zero. In
 114          * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
 115          * the highest count, either FFFF hex for binary counting
 116          * or 9999 for BCD counting, and continues counting.
 117          * Modes 2 and 3 are periodic; the Counter reloads
 118          * itself with the initial count and continues counting
 119          * from there.
 120          */
 121         remaining = hrtimer_get_remaining(&ps->timer);
 122         elapsed = ps->period - ktime_to_ns(remaining);
 123
 124         return elapsed;
 125 }
 126
 127 static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,
 128                         int channel)
 129 {
 130         if (channel == 0)
 131                 return __kpit_elapsed(kvm);
 132
 133         return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 134 }
 135
 136 static int pit_get_count(struct kvm *kvm, int channel)
 137 {
 138         struct kvm_kpit_channel_state *c =
 139                 &kvm->arch.vpit->pit_state.channels[channel];
 140         s64 d, t;
 141         int counter;
 142
 143         t = kpit_elapsed(kvm, c, channel);
 144         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 145
 146         switch (c->mode) {
 147         case 0:
 148         case 1:
 149         case 4:
 150         case 5:
 151                 counter = (c->count - d) & 0xffff;
 152                 break;
 153         case 3:
 154                 /* XXX: may be incorrect for odd counts */
 155                 counter = c->count - (mod_64((2 * d), c->count));
 156                 break;
 157         default:
 158                 counter = c->count - mod_64(d, c->count);
 159                 break;
 160         }
 161         return counter;
 162 }
 163
 164 static int pit_get_out(struct kvm *kvm, int channel)
 165 {
 166         struct kvm_kpit_channel_state *c =
 167                 &kvm->arch.vpit->pit_state.channels[channel];
 168         s64 d, t;
 169         int out;
 170
 171         t = kpit_elapsed(kvm, c, channel);
 172         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 173
 174         switch (c->mode) {
 175         default:
 176         case 0:
 177                 out = (d >= c->count);
 178                 break;
 179         case 1:
 180                 out = (d < c->count);
 181                 break;
 182         case 2:
 183                 out = ((mod_64(d, c->count) == 0) && (d != 0));
 184                 break;
 185         case 3:
 186                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
 187                 break;
 188         case 4:
 189         case 5:
 190                 out = (d == c->count);
 191                 break;
 192         }
 193
 194         return out;
 195 }
 196
 197 static void pit_latch_count(struct kvm *kvm, int channel)
 198 {
 199         struct kvm_kpit_channel_state *c =
 200                 &kvm->arch.vpit->pit_state.channels[channel];
 201
 202         if (!c->count_latched) {
 203                 c->latched_count = pit_get_count(kvm, channel);
 204                 c->count_latched = c->rw_mode;
 205         }
 206 }
 207
 208 static void pit_latch_status(struct kvm *kvm, int channel)
 209 {
 210         struct kvm_kpit_channel_state *c =
 211                 &kvm->arch.vpit->pit_state.channels[channel];
 212
 213         if (!c->status_latched) {
 214                 /* TODO: Return NULL COUNT (bit 6). */
 215                 c->status = ((pit_get_out(kvm, channel) << 7) |
 216                                 (c->rw_mode << 4) |
 217                                 (c->mode << 1) |
 218                                 c->bcd);
 219                 c->status_latched = 1;
 220         }
 221 }
 222
 223 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 224 {
 225         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 226                                                  irq_ack_notifier);
 227
 228         atomic_set(&ps->irq_ack, 1);
 229         /* irq_ack should be set before pending is read.  Order accesses with
 230          * inc(pending) in pit_timer_fn and xchg(irq_ack, 0) in pit_do_work.
 231          */
 232         smp_mb();
 233         if (atomic_dec_if_positive(&ps->pending) > 0 && ps->reinject)
 234                 queue_kthread_work(&ps->pit->worker, &ps->pit->expired);
 235 }
 236
 237 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 238 {
 239         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 240         struct hrtimer *timer;
 241
 242         if (!kvm_vcpu_is_bsp(vcpu) || !pit)
 243                 return;
 244
 245         timer = &pit->pit_state.timer;
 246         mutex_lock(&pit->pit_state.lock);
 247         if (hrtimer_cancel(timer))
 248                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 249         mutex_unlock(&pit->pit_state.lock);
 250 }
 251
 252 static void destroy_pit_timer(struct kvm_pit *pit)
 253 {
 254         hrtimer_cancel(&pit->pit_state.timer);
 255         flush_kthread_work(&pit->expired);
 256 }
 257
 258 static void pit_do_work(struct kthread_work *work)
 259 {
 260         struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
 261         struct kvm *kvm = pit->kvm;
 262         struct kvm_vcpu *vcpu;
 263         int i;
 264         struct kvm_kpit_state *ps = &pit->pit_state;
 265
 266         if (ps->reinject && !atomic_xchg(&ps->irq_ack, 0))
 267                 return;
 268
 269         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1, false);
 270         kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0, false);
 271
 272         /*
 273          * Provides NMI watchdog support via Virtual Wire mode.
 274          * The route is: PIT -> LVT0 in NMI mode.
 275          *
 276          * Note: Our Virtual Wire implementation does not follow
 277          * the MP specification.  We propagate a PIT interrupt to all
 278          * VCPUs and only when LVT0 is in NMI mode.  The interrupt can
 279          * also be simultaneously delivered through PIC and IOAPIC.
 280          */
 281         if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0)
 282                 kvm_for_each_vcpu(i, vcpu, kvm)
 283                         kvm_apic_nmi_wd_deliver(vcpu);
 284 }
 285
 286 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 287 {
 288         struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer);
 289         struct kvm_pit *pt = ps->kvm->arch.vpit;
 290
 291         if (ps->reinject)
 292                 atomic_inc(&ps->pending);
 293
 294         queue_kthread_work(&pt->worker, &pt->expired);
 295
 296         if (ps->is_periodic) {
 297                 hrtimer_add_expires_ns(&ps->timer, ps->period);
 298                 return HRTIMER_RESTART;
 299         } else
 300                 return HRTIMER_NORESTART;
 301 }
 302
 303 static inline void kvm_pit_reset_reinject(struct kvm_pit *pit)
 304 {
 305         atomic_set(&pit->pit_state.pending, 0);
 306         atomic_set(&pit->pit_state.irq_ack, 1);
 307 }
 308
 309 static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
 310 {
 311         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 312         s64 interval;
 313
 314         if (!ioapic_in_kernel(kvm) ||
 315             ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
 316                 return;
 317
 318         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 319
 320         pr_debug("create pit timer, interval is %llu nsec\n", interval);
 321
 322         /* TODO The new value only affected after the retriggered */
 323         hrtimer_cancel(&ps->timer);
 324         flush_kthread_work(&ps->pit->expired);
 325         ps->period = interval;
 326         ps->is_periodic = is_period;
 327
 328         ps->timer.function = pit_timer_fn;
 329         ps->kvm = ps->pit->kvm;
 330
 331         kvm_pit_reset_reinject(ps->pit);
 332
 333         /*
 334          * Do not allow the guest to program periodic timers with small
 335          * interval, since the hrtimers are not throttled by the host
 336          * scheduler.
 337          */
 338         if (ps->is_periodic) {
 339                 s64 min_period = min_timer_period_us * 1000LL;
 340
 341                 if (ps->period < min_period) {
 342                         pr_info_ratelimited(
 343                             "kvm: requested %lld ns "
 344                             "i8254 timer period limited to %lld ns\n",
 345                             ps->period, min_period);
 346                         ps->period = min_period;
 347                 }
 348         }
 349
 350         hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
 351                       HRTIMER_MODE_ABS);
 352 }
 353
 354 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 355 {
 356         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 357
 358         pr_debug("load_count val is %d, channel is %d\n", val, channel);
 359
 360         /*
 361          * The largest possible initial count is 0; this is equivalent
 362          * to 216 for binary counting and 104 for BCD counting.
 363          */
 364         if (val == 0)
 365                 val = 0x10000;
 366
 367         ps->channels[channel].count = val;
 368
 369         if (channel != 0) {
 370                 ps->channels[channel].count_load_time = ktime_get();
 371                 return;
 372         }
 373
 374         /* Two types of timer
 375          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 376         switch (ps->channels[0].mode) {
 377         case 0:
 378         case 1:
 379         /* FIXME: enhance mode 4 precision */
 380         case 4:
 381                 create_pit_timer(kvm, val, 0);
 382                 break;
 383         case 2:
 384         case 3:
 385                 create_pit_timer(kvm, val, 1);
 386                 break;
 387         default:
 388                 destroy_pit_timer(kvm->arch.vpit);
 389         }
 390 }
 391
 392 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
 393 {
 394         u8 saved_mode;
 395
 396         WARN_ON_ONCE(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 397
 398         if (hpet_legacy_start) {
 399                 /* save existing mode for later reenablement */
 400                 WARN_ON(channel != 0);
 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_vcpu *vcpu,
 427                                 struct kvm_io_device *this,
 428                             gpa_t addr, int len, const void *data)
 429 {
 430         struct kvm_pit *pit = dev_to_pit(this);
 431         struct kvm_kpit_state *pit_state = &pit->pit_state;
 432         struct kvm *kvm = pit->kvm;
 433         int channel, access;
 434         struct kvm_kpit_channel_state *s;
 435         u32 val = *(u32 *) data;
 436         if (!pit_in_range(addr))
 437                 return -EOPNOTSUPP;
 438
 439         val  &= 0xff;
 440         addr &= KVM_PIT_CHANNEL_MASK;
 441
 442         mutex_lock(&pit_state->lock);
 443
 444         if (val != 0)
 445                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
 446                          (unsigned int)addr, len, val);
 447
 448         if (addr == 3) {
 449                 channel = val >> 6;
 450                 if (channel == 3) {
 451                         /* Read-Back Command. */
 452                         for (channel = 0; channel < 3; channel++) {
 453                                 s = &pit_state->channels[channel];
 454                                 if (val & (2 << channel)) {
 455                                         if (!(val & 0x20))
 456                                                 pit_latch_count(kvm, channel);
 457                                         if (!(val & 0x10))
 458                                                 pit_latch_status(kvm, channel);
 459                                 }
 460                         }
 461                 } else {
 462                         /* Select Counter <channel>. */
 463                         s = &pit_state->channels[channel];
 464                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 465                         if (access == 0) {
 466                                 pit_latch_count(kvm, channel);
 467                         } else {
 468                                 s->rw_mode = access;
 469                                 s->read_state = access;
 470                                 s->write_state = access;
 471                                 s->mode = (val >> 1) & 7;
 472                                 if (s->mode > 5)
 473                                         s->mode -= 4;
 474                                 s->bcd = val & 1;
 475                         }
 476                 }
 477         } else {
 478                 /* Write Count. */
 479                 s = &pit_state->channels[addr];
 480                 switch (s->write_state) {
 481                 default:
 482                 case RW_STATE_LSB:
 483                         pit_load_count(kvm, addr, val);
 484                         break;
 485                 case RW_STATE_MSB:
 486                         pit_load_count(kvm, addr, val << 8);
 487                         break;
 488                 case RW_STATE_WORD0:
 489                         s->write_latch = val;
 490                         s->write_state = RW_STATE_WORD1;
 491                         break;
 492                 case RW_STATE_WORD1:
 493                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 494                         s->write_state = RW_STATE_WORD0;
 495                         break;
 496                 }
 497         }
 498
 499         mutex_unlock(&pit_state->lock);
 500         return 0;
 501 }
 502
 503 static int pit_ioport_read(struct kvm_vcpu *vcpu,
 504                            struct kvm_io_device *this,
 505                            gpa_t addr, int len, void *data)
 506 {
 507         struct kvm_pit *pit = dev_to_pit(this);
 508         struct kvm_kpit_state *pit_state = &pit->pit_state;
 509         struct kvm *kvm = pit->kvm;
 510         int ret, count;
 511         struct kvm_kpit_channel_state *s;
 512         if (!pit_in_range(addr))
 513                 return -EOPNOTSUPP;
 514
 515         addr &= KVM_PIT_CHANNEL_MASK;
 516         if (addr == 3)
 517                 return 0;
 518
 519         s = &pit_state->channels[addr];
 520
 521         mutex_lock(&pit_state->lock);
 522
 523         if (s->status_latched) {
 524                 s->status_latched = 0;
 525                 ret = s->status;
 526         } else if (s->count_latched) {
 527                 switch (s->count_latched) {
 528                 default:
 529                 case RW_STATE_LSB:
 530                         ret = s->latched_count & 0xff;
 531                         s->count_latched = 0;
 532                         break;
 533                 case RW_STATE_MSB:
 534                         ret = s->latched_count >> 8;
 535                         s->count_latched = 0;
 536                         break;
 537                 case RW_STATE_WORD0:
 538                         ret = s->latched_count & 0xff;
 539                         s->count_latched = RW_STATE_MSB;
 540                         break;
 541                 }
 542         } else {
 543                 switch (s->read_state) {
 544                 default:
 545                 case RW_STATE_LSB:
 546                         count = pit_get_count(kvm, addr);
 547                         ret = count & 0xff;
 548                         break;
 549                 case RW_STATE_MSB:
 550                         count = pit_get_count(kvm, addr);
 551                         ret = (count >> 8) & 0xff;
 552                         break;
 553                 case RW_STATE_WORD0:
 554                         count = pit_get_count(kvm, addr);
 555                         ret = count & 0xff;
 556                         s->read_state = RW_STATE_WORD1;
 557                         break;
 558                 case RW_STATE_WORD1:
 559                         count = pit_get_count(kvm, addr);
 560                         ret = (count >> 8) & 0xff;
 561                         s->read_state = RW_STATE_WORD0;
 562                         break;
 563                 }
 564         }
 565
 566         if (len > sizeof(ret))
 567                 len = sizeof(ret);
 568         memcpy(data, (char *)&ret, len);
 569
 570         mutex_unlock(&pit_state->lock);
 571         return 0;
 572 }
 573
 574 static int speaker_ioport_write(struct kvm_vcpu *vcpu,
 575                                 struct kvm_io_device *this,
 576                                 gpa_t addr, int len, const void *data)
 577 {
 578         struct kvm_pit *pit = speaker_to_pit(this);
 579         struct kvm_kpit_state *pit_state = &pit->pit_state;
 580         struct kvm *kvm = pit->kvm;
 581         u32 val = *(u32 *) data;
 582         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 583                 return -EOPNOTSUPP;
 584
 585         mutex_lock(&pit_state->lock);
 586         pit_state->speaker_data_on = (val >> 1) & 1;
 587         pit_set_gate(kvm, 2, val & 1);
 588         mutex_unlock(&pit_state->lock);
 589         return 0;
 590 }
 591
 592 static int speaker_ioport_read(struct kvm_vcpu *vcpu,
 593                                    struct kvm_io_device *this,
 594                                    gpa_t addr, int len, void *data)
 595 {
 596         struct kvm_pit *pit = speaker_to_pit(this);
 597         struct kvm_kpit_state *pit_state = &pit->pit_state;
 598         struct kvm *kvm = pit->kvm;
 599         unsigned int refresh_clock;
 600         int ret;
 601         if (addr != KVM_SPEAKER_BASE_ADDRESS)
 602                 return -EOPNOTSUPP;
 603
 604         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 605         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 606
 607         mutex_lock(&pit_state->lock);
 608         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 609                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 610         if (len > sizeof(ret))
 611                 len = sizeof(ret);
 612         memcpy(data, (char *)&ret, len);
 613         mutex_unlock(&pit_state->lock);
 614         return 0;
 615 }
 616
 617 void kvm_pit_reset(struct kvm_pit *pit)
 618 {
 619         int i;
 620         struct kvm_kpit_channel_state *c;
 621
 622         mutex_lock(&pit->pit_state.lock);
 623         pit->pit_state.flags = 0;
 624         for (i = 0; i < 3; i++) {
 625                 c = &pit->pit_state.channels[i];
 626                 c->mode = 0xff;
 627                 c->gate = (i != 2);
 628                 pit_load_count(pit->kvm, i, 0);
 629         }
 630         mutex_unlock(&pit->pit_state.lock);
 631
 632         kvm_pit_reset_reinject(pit);
 633 }
 634
 635 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 636 {
 637         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 638
 639         if (!mask)
 640                 kvm_pit_reset_reinject(pit);
 641 }
 642
 643 static const struct kvm_io_device_ops pit_dev_ops = {
 644         .read     = pit_ioport_read,
 645         .write    = pit_ioport_write,
 646 };
 647
 648 static const struct kvm_io_device_ops speaker_dev_ops = {
 649         .read     = speaker_ioport_read,
 650         .write    = speaker_ioport_write,
 651 };
 652
 653 /* Caller must hold slots_lock */
 654 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 655 {
 656         struct kvm_pit *pit;
 657         struct kvm_kpit_state *pit_state;
 658         struct pid *pid;
 659         pid_t pid_nr;
 660         int ret;
 661
 662         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 663         if (!pit)
 664                 return NULL;
 665
 666         pit->irq_source_id = kvm_request_irq_source_id(kvm);
 667         if (pit->irq_source_id < 0) {
 668                 kfree(pit);
 669                 return NULL;
 670         }
 671
 672         mutex_init(&pit->pit_state.lock);
 673         mutex_lock(&pit->pit_state.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 }