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  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a copy
  10  * of this software and associated documentation files (the "Software"), to deal
  11  * in the Software without restriction, including without limitation the rights
  12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13  * copies of the Software, and to permit persons to whom the Software is
  14  * furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25  * THE SOFTWARE.
  26  *
  27  * Authors:
  28  *   Sheng Yang <sheng.yang@intel.com>
  29  *   Based on QEMU and Xen.
  30  */
  31
  32 #include <linux/kvm_host.h>
  33
  34 #include "irq.h"
  35 #include "i8254.h"
  36
  37 #ifndef CONFIG_X86_64
  38 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
  39 #else
  40 #define mod_64(x, y) ((x) % (y))
  41 #endif
  42
  43 #define RW_STATE_LSB 1
  44 #define RW_STATE_MSB 2
  45 #define RW_STATE_WORD0 3
  46 #define RW_STATE_WORD1 4
  47
  48 /* Compute with 96 bit intermediate result: (a*b)/c */
  49 static u64 muldiv64(u64 a, u32 b, u32 c)
  50 {
  51         union {
  52                 u64 ll;
  53                 struct {
  54                         u32 low, high;
  55                 } l;
  56         } u, res;
  57         u64 rl, rh;
  58
  59         u.ll = a;
  60         rl = (u64)u.l.low * (u64)b;
  61         rh = (u64)u.l.high * (u64)b;
  62         rh += (rl >> 32);
  63         res.l.high = div64_u64(rh, c);
  64         res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
  65         return res.ll;
  66 }
  67
  68 static void pit_set_gate(struct kvm *kvm, int channel, u32 val)
  69 {
  70         struct kvm_kpit_channel_state *c =
  71                 &kvm->arch.vpit->pit_state.channels[channel];
  72
  73         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
  74
  75         switch (c->mode) {
  76         default:
  77         case 0:
  78         case 4:
  79                 /* XXX: just disable/enable counting */
  80                 break;
  81         case 1:
  82         case 2:
  83         case 3:
  84         case 5:
  85                 /* Restart counting on rising edge. */
  86                 if (c->gate < val)
  87                         c->count_load_time = ktime_get();
  88                 break;
  89         }
  90
  91         c->gate = val;
  92 }
  93
  94 static int pit_get_gate(struct kvm *kvm, int channel)
  95 {
  96         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
  97
  98         return kvm->arch.vpit->pit_state.channels[channel].gate;
  99 }
 100
 101 static int pit_get_count(struct kvm *kvm, int channel)
 102 {
 103         struct kvm_kpit_channel_state *c =
 104                 &kvm->arch.vpit->pit_state.channels[channel];
 105         s64 d, t;
 106         int counter;
 107
 108         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 109
 110         t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 111         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 112
 113         switch (c->mode) {
 114         case 0:
 115         case 1:
 116         case 4:
 117         case 5:
 118                 counter = (c->count - d) & 0xffff;
 119                 break;
 120         case 3:
 121                 /* XXX: may be incorrect for odd counts */
 122                 counter = c->count - (mod_64((2 * d), c->count));
 123                 break;
 124         default:
 125                 counter = c->count - mod_64(d, c->count);
 126                 break;
 127         }
 128         return counter;
 129 }
 130
 131 static int pit_get_out(struct kvm *kvm, int channel)
 132 {
 133         struct kvm_kpit_channel_state *c =
 134                 &kvm->arch.vpit->pit_state.channels[channel];
 135         s64 d, t;
 136         int out;
 137
 138         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 139
 140         t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
 141         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
 142
 143         switch (c->mode) {
 144         default:
 145         case 0:
 146                 out = (d >= c->count);
 147                 break;
 148         case 1:
 149                 out = (d < c->count);
 150                 break;
 151         case 2:
 152                 out = ((mod_64(d, c->count) == 0) && (d != 0));
 153                 break;
 154         case 3:
 155                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
 156                 break;
 157         case 4:
 158         case 5:
 159                 out = (d == c->count);
 160                 break;
 161         }
 162
 163         return out;
 164 }
 165
 166 static void pit_latch_count(struct kvm *kvm, int channel)
 167 {
 168         struct kvm_kpit_channel_state *c =
 169                 &kvm->arch.vpit->pit_state.channels[channel];
 170
 171         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 172
 173         if (!c->count_latched) {
 174                 c->latched_count = pit_get_count(kvm, channel);
 175                 c->count_latched = c->rw_mode;
 176         }
 177 }
 178
 179 static void pit_latch_status(struct kvm *kvm, int channel)
 180 {
 181         struct kvm_kpit_channel_state *c =
 182                 &kvm->arch.vpit->pit_state.channels[channel];
 183
 184         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
 185
 186         if (!c->status_latched) {
 187                 /* TODO: Return NULL COUNT (bit 6). */
 188                 c->status = ((pit_get_out(kvm, channel) << 7) |
 189                                 (c->rw_mode << 4) |
 190                                 (c->mode << 1) |
 191                                 c->bcd);
 192                 c->status_latched = 1;
 193         }
 194 }
 195
 196 static int __pit_timer_fn(struct kvm_kpit_state *ps)
 197 {
 198         struct kvm_vcpu *vcpu0 = ps->pit->kvm->vcpus[0];
 199         struct kvm_kpit_timer *pt = &ps->pit_timer;
 200
 201         if (!atomic_inc_and_test(&pt->pending))
 202                 set_bit(KVM_REQ_PENDING_TIMER, &vcpu0->requests);
 203
 204         if (vcpu0 && waitqueue_active(&vcpu0->wq))
 205                 wake_up_interruptible(&vcpu0->wq);
 206
 207         hrtimer_add_expires_ns(&pt->timer, pt->period);
 208         pt->scheduled = hrtimer_get_expires_ns(&pt->timer);
 209         if (pt->period)
 210                 ps->channels[0].count_load_time = hrtimer_get_expires(&pt->timer);
 211
 212         return (pt->period == 0 ? 0 : 1);
 213 }
 214
 215 int pit_has_pending_timer(struct kvm_vcpu *vcpu)
 216 {
 217         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 218
 219         if (pit && vcpu->vcpu_id == 0 && pit->pit_state.irq_ack)
 220                 return atomic_read(&pit->pit_state.pit_timer.pending);
 221         return 0;
 222 }
 223
 224 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 225 {
 226         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 227                                                  irq_ack_notifier);
 228         spin_lock(&ps->inject_lock);
 229         if (atomic_dec_return(&ps->pit_timer.pending) < 0)
 230                 atomic_inc(&ps->pit_timer.pending);
 231         ps->irq_ack = 1;
 232         spin_unlock(&ps->inject_lock);
 233 }
 234
 235 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 236 {
 237         struct kvm_kpit_state *ps;
 238         int restart_timer = 0;
 239
 240         ps = container_of(data, struct kvm_kpit_state, pit_timer.timer);
 241
 242         restart_timer = __pit_timer_fn(ps);
 243
 244         if (restart_timer)
 245                 return HRTIMER_RESTART;
 246         else
 247                 return HRTIMER_NORESTART;
 248 }
 249
 250 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 251 {
 252         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 253         struct hrtimer *timer;
 254
 255         if (vcpu->vcpu_id != 0 || !pit)
 256                 return;
 257
 258         timer = &pit->pit_state.pit_timer.timer;
 259         if (hrtimer_cancel(timer))
 260                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 261 }
 262
 263 static void destroy_pit_timer(struct kvm_kpit_timer *pt)
 264 {
 265         pr_debug("pit: execute del timer!\n");
 266         hrtimer_cancel(&pt->timer);
 267 }
 268
 269 static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
 270 {
 271         struct kvm_kpit_timer *pt = &ps->pit_timer;
 272         s64 interval;
 273
 274         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 275
 276         pr_debug("pit: create pit timer, interval is %llu nsec\n", interval);
 277
 278         /* TODO The new value only affected after the retriggered */
 279         hrtimer_cancel(&pt->timer);
 280         pt->period = (is_period == 0) ? 0 : interval;
 281         pt->timer.function = pit_timer_fn;
 282         atomic_set(&pt->pending, 0);
 283         ps->irq_ack = 1;
 284
 285         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
 286                       HRTIMER_MODE_ABS);
 287 }
 288
 289 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 290 {
 291         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 292
 293         WARN_ON(!mutex_is_locked(&ps->lock));
 294
 295         pr_debug("pit: load_count val is %d, channel is %d\n", val, channel);
 296
 297         /*
 298          * Though spec said the state of 8254 is undefined after power-up,
 299          * seems some tricky OS like Windows XP depends on IRQ0 interrupt
 300          * when booting up.
 301          * So here setting initialize rate for it, and not a specific number
 302          */
 303         if (val == 0)
 304                 val = 0x10000;
 305
 306         ps->channels[channel].count_load_time = ktime_get();
 307         ps->channels[channel].count = val;
 308
 309         if (channel != 0)
 310                 return;
 311
 312         /* Two types of timer
 313          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 314         switch (ps->channels[0].mode) {
 315         case 1:
 316         /* FIXME: enhance mode 4 precision */
 317         case 4:
 318                 create_pit_timer(ps, val, 0);
 319                 break;
 320         case 2:
 321         case 3:
 322                 create_pit_timer(ps, val, 1);
 323                 break;
 324         default:
 325                 destroy_pit_timer(&ps->pit_timer);
 326         }
 327 }
 328
 329 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val)
 330 {
 331         mutex_lock(&kvm->arch.vpit->pit_state.lock);
 332         pit_load_count(kvm, channel, val);
 333         mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 334 }
 335
 336 static void pit_ioport_write(struct kvm_io_device *this,
 337                              gpa_t addr, int len, const void *data)
 338 {
 339         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 340         struct kvm_kpit_state *pit_state = &pit->pit_state;
 341         struct kvm *kvm = pit->kvm;
 342         int channel, access;
 343         struct kvm_kpit_channel_state *s;
 344         u32 val = *(u32 *) data;
 345
 346         val  &= 0xff;
 347         addr &= KVM_PIT_CHANNEL_MASK;
 348
 349         mutex_lock(&pit_state->lock);
 350
 351         if (val != 0)
 352                 pr_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
 353                           (unsigned int)addr, len, val);
 354
 355         if (addr == 3) {
 356                 channel = val >> 6;
 357                 if (channel == 3) {
 358                         /* Read-Back Command. */
 359                         for (channel = 0; channel < 3; channel++) {
 360                                 s = &pit_state->channels[channel];
 361                                 if (val & (2 << channel)) {
 362                                         if (!(val & 0x20))
 363                                                 pit_latch_count(kvm, channel);
 364                                         if (!(val & 0x10))
 365                                                 pit_latch_status(kvm, channel);
 366                                 }
 367                         }
 368                 } else {
 369                         /* Select Counter <channel>. */
 370                         s = &pit_state->channels[channel];
 371                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 372                         if (access == 0) {
 373                                 pit_latch_count(kvm, channel);
 374                         } else {
 375                                 s->rw_mode = access;
 376                                 s->read_state = access;
 377                                 s->write_state = access;
 378                                 s->mode = (val >> 1) & 7;
 379                                 if (s->mode > 5)
 380                                         s->mode -= 4;
 381                                 s->bcd = val & 1;
 382                         }
 383                 }
 384         } else {
 385                 /* Write Count. */
 386                 s = &pit_state->channels[addr];
 387                 switch (s->write_state) {
 388                 default:
 389                 case RW_STATE_LSB:
 390                         pit_load_count(kvm, addr, val);
 391                         break;
 392                 case RW_STATE_MSB:
 393                         pit_load_count(kvm, addr, val << 8);
 394                         break;
 395                 case RW_STATE_WORD0:
 396                         s->write_latch = val;
 397                         s->write_state = RW_STATE_WORD1;
 398                         break;
 399                 case RW_STATE_WORD1:
 400                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 401                         s->write_state = RW_STATE_WORD0;
 402                         break;
 403                 }
 404         }
 405
 406         mutex_unlock(&pit_state->lock);
 407 }
 408
 409 static void pit_ioport_read(struct kvm_io_device *this,
 410                             gpa_t addr, int len, void *data)
 411 {
 412         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 413         struct kvm_kpit_state *pit_state = &pit->pit_state;
 414         struct kvm *kvm = pit->kvm;
 415         int ret, count;
 416         struct kvm_kpit_channel_state *s;
 417
 418         addr &= KVM_PIT_CHANNEL_MASK;
 419         s = &pit_state->channels[addr];
 420
 421         mutex_lock(&pit_state->lock);
 422
 423         if (s->status_latched) {
 424                 s->status_latched = 0;
 425                 ret = s->status;
 426         } else if (s->count_latched) {
 427                 switch (s->count_latched) {
 428                 default:
 429                 case RW_STATE_LSB:
 430                         ret = s->latched_count & 0xff;
 431                         s->count_latched = 0;
 432                         break;
 433                 case RW_STATE_MSB:
 434                         ret = s->latched_count >> 8;
 435                         s->count_latched = 0;
 436                         break;
 437                 case RW_STATE_WORD0:
 438                         ret = s->latched_count & 0xff;
 439                         s->count_latched = RW_STATE_MSB;
 440                         break;
 441                 }
 442         } else {
 443                 switch (s->read_state) {
 444                 default:
 445                 case RW_STATE_LSB:
 446                         count = pit_get_count(kvm, addr);
 447                         ret = count & 0xff;
 448                         break;
 449                 case RW_STATE_MSB:
 450                         count = pit_get_count(kvm, addr);
 451                         ret = (count >> 8) & 0xff;
 452                         break;
 453                 case RW_STATE_WORD0:
 454                         count = pit_get_count(kvm, addr);
 455                         ret = count & 0xff;
 456                         s->read_state = RW_STATE_WORD1;
 457                         break;
 458                 case RW_STATE_WORD1:
 459                         count = pit_get_count(kvm, addr);
 460                         ret = (count >> 8) & 0xff;
 461                         s->read_state = RW_STATE_WORD0;
 462                         break;
 463                 }
 464         }
 465
 466         if (len > sizeof(ret))
 467                 len = sizeof(ret);
 468         memcpy(data, (char *)&ret, len);
 469
 470         mutex_unlock(&pit_state->lock);
 471 }
 472
 473 static int pit_in_range(struct kvm_io_device *this, gpa_t addr,
 474                         int len, int is_write)
 475 {
 476         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 477                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 478 }
 479
 480 static void speaker_ioport_write(struct kvm_io_device *this,
 481                                  gpa_t addr, int len, const void *data)
 482 {
 483         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 484         struct kvm_kpit_state *pit_state = &pit->pit_state;
 485         struct kvm *kvm = pit->kvm;
 486         u32 val = *(u32 *) data;
 487
 488         mutex_lock(&pit_state->lock);
 489         pit_state->speaker_data_on = (val >> 1) & 1;
 490         pit_set_gate(kvm, 2, val & 1);
 491         mutex_unlock(&pit_state->lock);
 492 }
 493
 494 static void speaker_ioport_read(struct kvm_io_device *this,
 495                                 gpa_t addr, int len, void *data)
 496 {
 497         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 498         struct kvm_kpit_state *pit_state = &pit->pit_state;
 499         struct kvm *kvm = pit->kvm;
 500         unsigned int refresh_clock;
 501         int ret;
 502
 503         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 504         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 505
 506         mutex_lock(&pit_state->lock);
 507         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 508                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 509         if (len > sizeof(ret))
 510                 len = sizeof(ret);
 511         memcpy(data, (char *)&ret, len);
 512         mutex_unlock(&pit_state->lock);
 513 }
 514
 515 static int speaker_in_range(struct kvm_io_device *this, gpa_t addr,
 516                             int len, int is_write)
 517 {
 518         return (addr == KVM_SPEAKER_BASE_ADDRESS);
 519 }
 520
 521 void kvm_pit_reset(struct kvm_pit *pit)
 522 {
 523         int i;
 524         struct kvm_kpit_channel_state *c;
 525
 526         mutex_lock(&pit->pit_state.lock);
 527         for (i = 0; i < 3; i++) {
 528                 c = &pit->pit_state.channels[i];
 529                 c->mode = 0xff;
 530                 c->gate = (i != 2);
 531                 pit_load_count(pit->kvm, i, 0);
 532         }
 533         mutex_unlock(&pit->pit_state.lock);
 534
 535         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 536         pit->pit_state.irq_ack = 1;
 537 }
 538
 539 struct kvm_pit *kvm_create_pit(struct kvm *kvm)
 540 {
 541         struct kvm_pit *pit;
 542         struct kvm_kpit_state *pit_state;
 543
 544         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 545         if (!pit)
 546                 return NULL;
 547
 548         mutex_init(&pit->pit_state.lock);
 549         mutex_lock(&pit->pit_state.lock);
 550         spin_lock_init(&pit->pit_state.inject_lock);
 551
 552         /* Initialize PIO device */
 553         pit->dev.read = pit_ioport_read;
 554         pit->dev.write = pit_ioport_write;
 555         pit->dev.in_range = pit_in_range;
 556         pit->dev.private = pit;
 557         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
 558
 559         pit->speaker_dev.read = speaker_ioport_read;
 560         pit->speaker_dev.write = speaker_ioport_write;
 561         pit->speaker_dev.in_range = speaker_in_range;
 562         pit->speaker_dev.private = pit;
 563         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->speaker_dev);
 564
 565         kvm->arch.vpit = pit;
 566         pit->kvm = kvm;
 567
 568         pit_state = &pit->pit_state;
 569         pit_state->pit = pit;
 570         hrtimer_init(&pit_state->pit_timer.timer,
 571                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 572         pit_state->irq_ack_notifier.gsi = 0;
 573         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 574         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 575         mutex_unlock(&pit->pit_state.lock);
 576
 577         kvm_pit_reset(pit);
 578
 579         return pit;
 580 }
 581
 582 void kvm_free_pit(struct kvm *kvm)
 583 {
 584         struct hrtimer *timer;
 585
 586         if (kvm->arch.vpit) {
 587                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 588                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
 589                 hrtimer_cancel(timer);
 590                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 591                 kfree(kvm->arch.vpit);
 592         }
 593 }
 594
 595 static void __inject_pit_timer_intr(struct kvm *kvm)
 596 {
 597         mutex_lock(&kvm->lock);
 598         kvm_set_irq(kvm, 0, 1);
 599         kvm_set_irq(kvm, 0, 0);
 600         mutex_unlock(&kvm->lock);
 601 }
 602
 603 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
 604 {
 605         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 606         struct kvm *kvm = vcpu->kvm;
 607         struct kvm_kpit_state *ps;
 608
 609         if (vcpu && pit) {
 610                 int inject = 0;
 611                 ps = &pit->pit_state;
 612
 613                 /* Try to inject pending interrupts when
 614                  * last one has been acked.
 615                  */
 616                 spin_lock(&ps->inject_lock);
 617                 if (atomic_read(&ps->pit_timer.pending) && ps->irq_ack) {
 618                         ps->irq_ack = 0;
 619                         inject = 1;
 620                 }
 621                 spin_unlock(&ps->inject_lock);
 622                 if (inject)
 623                         __inject_pit_timer_intr(kvm);
 624         }
 625 }