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 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 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         atomic_inc(&pt->pending);
 202         smp_mb__after_atomic_inc();
 203         if (vcpu0 && waitqueue_active(&vcpu0->wq)) {
 204                 vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE;
 205                 wake_up_interruptible(&vcpu0->wq);
 206         }
 207
 208         pt->timer.expires = ktime_add_ns(pt->timer.expires, pt->period);
 209         pt->scheduled = ktime_to_ns(pt->timer.expires);
 210
 211         return (pt->period == 0 ? 0 : 1);
 212 }
 213
 214 int pit_has_pending_timer(struct kvm_vcpu *vcpu)
 215 {
 216         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 217
 218         if (pit && vcpu->vcpu_id == 0 && pit->pit_state.inject_pending)
 219                 return atomic_read(&pit->pit_state.pit_timer.pending);
 220
 221         return 0;
 222 }
 223
 224 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 225 {
 226         struct kvm_kpit_state *ps;
 227         int restart_timer = 0;
 228
 229         ps = container_of(data, struct kvm_kpit_state, pit_timer.timer);
 230
 231         restart_timer = __pit_timer_fn(ps);
 232
 233         if (restart_timer)
 234                 return HRTIMER_RESTART;
 235         else
 236                 return HRTIMER_NORESTART;
 237 }
 238
 239 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 240 {
 241         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 242         struct hrtimer *timer;
 243
 244         if (vcpu->vcpu_id != 0 || !pit)
 245                 return;
 246
 247         timer = &pit->pit_state.pit_timer.timer;
 248         if (hrtimer_cancel(timer))
 249                 hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS);
 250 }
 251
 252 static void destroy_pit_timer(struct kvm_kpit_timer *pt)
 253 {
 254         pr_debug("pit: execute del timer!\n");
 255         hrtimer_cancel(&pt->timer);
 256 }
 257
 258 static void create_pit_timer(struct kvm_kpit_timer *pt, u32 val, int is_period)
 259 {
 260         s64 interval;
 261
 262         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 263
 264         pr_debug("pit: create pit timer, interval is %llu nsec\n", interval);
 265
 266         /* TODO The new value only affected after the retriggered */
 267         hrtimer_cancel(&pt->timer);
 268         pt->period = (is_period == 0) ? 0 : interval;
 269         pt->timer.function = pit_timer_fn;
 270         atomic_set(&pt->pending, 0);
 271
 272         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
 273                       HRTIMER_MODE_ABS);
 274 }
 275
 276 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 277 {
 278         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 279
 280         WARN_ON(!mutex_is_locked(&ps->lock));
 281
 282         pr_debug("pit: load_count val is %d, channel is %d\n", val, channel);
 283
 284         /*
 285          * Though spec said the state of 8254 is undefined after power-up,
 286          * seems some tricky OS like Windows XP depends on IRQ0 interrupt
 287          * when booting up.
 288          * So here setting initialize rate for it, and not a specific number
 289          */
 290         if (val == 0)
 291                 val = 0x10000;
 292
 293         ps->channels[channel].count_load_time = ktime_get();
 294         ps->channels[channel].count = val;
 295
 296         if (channel != 0)
 297                 return;
 298
 299         /* Two types of timer
 300          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 301         switch (ps->channels[0].mode) {
 302         case 1:
 303         /* FIXME: enhance mode 4 precision */
 304         case 4:
 305                 create_pit_timer(&ps->pit_timer, val, 0);
 306                 break;
 307         case 2:
 308                 create_pit_timer(&ps->pit_timer, val, 1);
 309                 break;
 310         default:
 311                 destroy_pit_timer(&ps->pit_timer);
 312         }
 313 }
 314
 315 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val)
 316 {
 317         mutex_lock(&kvm->arch.vpit->pit_state.lock);
 318         pit_load_count(kvm, channel, val);
 319         mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 320 }
 321
 322 static void pit_ioport_write(struct kvm_io_device *this,
 323                              gpa_t addr, int len, const void *data)
 324 {
 325         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 326         struct kvm_kpit_state *pit_state = &pit->pit_state;
 327         struct kvm *kvm = pit->kvm;
 328         int channel, access;
 329         struct kvm_kpit_channel_state *s;
 330         u32 val = *(u32 *) data;
 331
 332         val  &= 0xff;
 333         addr &= KVM_PIT_CHANNEL_MASK;
 334
 335         mutex_lock(&pit_state->lock);
 336
 337         if (val != 0)
 338                 pr_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
 339                           (unsigned int)addr, len, val);
 340
 341         if (addr == 3) {
 342                 channel = val >> 6;
 343                 if (channel == 3) {
 344                         /* Read-Back Command. */
 345                         for (channel = 0; channel < 3; channel++) {
 346                                 s = &pit_state->channels[channel];
 347                                 if (val & (2 << channel)) {
 348                                         if (!(val & 0x20))
 349                                                 pit_latch_count(kvm, channel);
 350                                         if (!(val & 0x10))
 351                                                 pit_latch_status(kvm, channel);
 352                                 }
 353                         }
 354                 } else {
 355                         /* Select Counter <channel>. */
 356                         s = &pit_state->channels[channel];
 357                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 358                         if (access == 0) {
 359                                 pit_latch_count(kvm, channel);
 360                         } else {
 361                                 s->rw_mode = access;
 362                                 s->read_state = access;
 363                                 s->write_state = access;
 364                                 s->mode = (val >> 1) & 7;
 365                                 if (s->mode > 5)
 366                                         s->mode -= 4;
 367                                 s->bcd = val & 1;
 368                         }
 369                 }
 370         } else {
 371                 /* Write Count. */
 372                 s = &pit_state->channels[addr];
 373                 switch (s->write_state) {
 374                 default:
 375                 case RW_STATE_LSB:
 376                         pit_load_count(kvm, addr, val);
 377                         break;
 378                 case RW_STATE_MSB:
 379                         pit_load_count(kvm, addr, val << 8);
 380                         break;
 381                 case RW_STATE_WORD0:
 382                         s->write_latch = val;
 383                         s->write_state = RW_STATE_WORD1;
 384                         break;
 385                 case RW_STATE_WORD1:
 386                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 387                         s->write_state = RW_STATE_WORD0;
 388                         break;
 389                 }
 390         }
 391
 392         mutex_unlock(&pit_state->lock);
 393 }
 394
 395 static void pit_ioport_read(struct kvm_io_device *this,
 396                             gpa_t addr, int len, void *data)
 397 {
 398         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 399         struct kvm_kpit_state *pit_state = &pit->pit_state;
 400         struct kvm *kvm = pit->kvm;
 401         int ret, count;
 402         struct kvm_kpit_channel_state *s;
 403
 404         addr &= KVM_PIT_CHANNEL_MASK;
 405         s = &pit_state->channels[addr];
 406
 407         mutex_lock(&pit_state->lock);
 408
 409         if (s->status_latched) {
 410                 s->status_latched = 0;
 411                 ret = s->status;
 412         } else if (s->count_latched) {
 413                 switch (s->count_latched) {
 414                 default:
 415                 case RW_STATE_LSB:
 416                         ret = s->latched_count & 0xff;
 417                         s->count_latched = 0;
 418                         break;
 419                 case RW_STATE_MSB:
 420                         ret = s->latched_count >> 8;
 421                         s->count_latched = 0;
 422                         break;
 423                 case RW_STATE_WORD0:
 424                         ret = s->latched_count & 0xff;
 425                         s->count_latched = RW_STATE_MSB;
 426                         break;
 427                 }
 428         } else {
 429                 switch (s->read_state) {
 430                 default:
 431                 case RW_STATE_LSB:
 432                         count = pit_get_count(kvm, addr);
 433                         ret = count & 0xff;
 434                         break;
 435                 case RW_STATE_MSB:
 436                         count = pit_get_count(kvm, addr);
 437                         ret = (count >> 8) & 0xff;
 438                         break;
 439                 case RW_STATE_WORD0:
 440                         count = pit_get_count(kvm, addr);
 441                         ret = count & 0xff;
 442                         s->read_state = RW_STATE_WORD1;
 443                         break;
 444                 case RW_STATE_WORD1:
 445                         count = pit_get_count(kvm, addr);
 446                         ret = (count >> 8) & 0xff;
 447                         s->read_state = RW_STATE_WORD0;
 448                         break;
 449                 }
 450         }
 451
 452         if (len > sizeof(ret))
 453                 len = sizeof(ret);
 454         memcpy(data, (char *)&ret, len);
 455
 456         mutex_unlock(&pit_state->lock);
 457 }
 458
 459 static int pit_in_range(struct kvm_io_device *this, gpa_t addr)
 460 {
 461         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 462                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 463 }
 464
 465 static void speaker_ioport_write(struct kvm_io_device *this,
 466                                  gpa_t addr, int len, const void *data)
 467 {
 468         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 469         struct kvm_kpit_state *pit_state = &pit->pit_state;
 470         struct kvm *kvm = pit->kvm;
 471         u32 val = *(u32 *) data;
 472
 473         mutex_lock(&pit_state->lock);
 474         pit_state->speaker_data_on = (val >> 1) & 1;
 475         pit_set_gate(kvm, 2, val & 1);
 476         mutex_unlock(&pit_state->lock);
 477 }
 478
 479 static void speaker_ioport_read(struct kvm_io_device *this,
 480                                 gpa_t addr, int len, void *data)
 481 {
 482         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 483         struct kvm_kpit_state *pit_state = &pit->pit_state;
 484         struct kvm *kvm = pit->kvm;
 485         unsigned int refresh_clock;
 486         int ret;
 487
 488         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 489         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 490
 491         mutex_lock(&pit_state->lock);
 492         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 493                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 494         if (len > sizeof(ret))
 495                 len = sizeof(ret);
 496         memcpy(data, (char *)&ret, len);
 497         mutex_unlock(&pit_state->lock);
 498 }
 499
 500 static int speaker_in_range(struct kvm_io_device *this, gpa_t addr)
 501 {
 502         return (addr == KVM_SPEAKER_BASE_ADDRESS);
 503 }
 504
 505 void kvm_pit_reset(struct kvm_pit *pit)
 506 {
 507         int i;
 508         struct kvm_kpit_channel_state *c;
 509
 510         mutex_lock(&pit->pit_state.lock);
 511         for (i = 0; i < 3; i++) {
 512                 c = &pit->pit_state.channels[i];
 513                 c->mode = 0xff;
 514                 c->gate = (i != 2);
 515                 pit_load_count(pit->kvm, i, 0);
 516         }
 517         mutex_unlock(&pit->pit_state.lock);
 518
 519         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 520         pit->pit_state.inject_pending = 1;
 521 }
 522
 523 struct kvm_pit *kvm_create_pit(struct kvm *kvm)
 524 {
 525         struct kvm_pit *pit;
 526         struct kvm_kpit_state *pit_state;
 527
 528         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 529         if (!pit)
 530                 return NULL;
 531
 532         mutex_init(&pit->pit_state.lock);
 533         mutex_lock(&pit->pit_state.lock);
 534
 535         /* Initialize PIO device */
 536         pit->dev.read = pit_ioport_read;
 537         pit->dev.write = pit_ioport_write;
 538         pit->dev.in_range = pit_in_range;
 539         pit->dev.private = pit;
 540         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
 541
 542         pit->speaker_dev.read = speaker_ioport_read;
 543         pit->speaker_dev.write = speaker_ioport_write;
 544         pit->speaker_dev.in_range = speaker_in_range;
 545         pit->speaker_dev.private = pit;
 546         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->speaker_dev);
 547
 548         kvm->arch.vpit = pit;
 549         pit->kvm = kvm;
 550
 551         pit_state = &pit->pit_state;
 552         pit_state->pit = pit;
 553         hrtimer_init(&pit_state->pit_timer.timer,
 554                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 555         mutex_unlock(&pit->pit_state.lock);
 556
 557         kvm_pit_reset(pit);
 558
 559         return pit;
 560 }
 561
 562 void kvm_free_pit(struct kvm *kvm)
 563 {
 564         struct hrtimer *timer;
 565
 566         if (kvm->arch.vpit) {
 567                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 568                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
 569                 hrtimer_cancel(timer);
 570                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 571                 kfree(kvm->arch.vpit);
 572         }
 573 }
 574
 575 void __inject_pit_timer_intr(struct kvm *kvm)
 576 {
 577         mutex_lock(&kvm->lock);
 578         kvm_ioapic_set_irq(kvm->arch.vioapic, 0, 1);
 579         kvm_ioapic_set_irq(kvm->arch.vioapic, 0, 0);
 580         kvm_pic_set_irq(pic_irqchip(kvm), 0, 1);
 581         kvm_pic_set_irq(pic_irqchip(kvm), 0, 0);
 582         mutex_unlock(&kvm->lock);
 583 }
 584
 585 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
 586 {
 587         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 588         struct kvm *kvm = vcpu->kvm;
 589         struct kvm_kpit_state *ps;
 590
 591         if (vcpu && pit) {
 592                 ps = &pit->pit_state;
 593
 594                 /* Try to inject pending interrupts when:
 595                  * 1. Pending exists
 596                  * 2. Last interrupt was accepted or waited for too long time*/
 597                 if (atomic_read(&ps->pit_timer.pending) &&
 598                     (ps->inject_pending ||
 599                     (jiffies - ps->last_injected_time
 600                                 >= KVM_MAX_PIT_INTR_INTERVAL))) {
 601                         ps->inject_pending = 0;
 602                         __inject_pit_timer_intr(kvm);
 603                         ps->last_injected_time = jiffies;
 604                 }
 605         }
 606 }
 607
 608 void kvm_pit_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
 609 {
 610         struct kvm_arch *arch = &vcpu->kvm->arch;
 611         struct kvm_kpit_state *ps;
 612
 613         if (vcpu && arch->vpit) {
 614                 ps = &arch->vpit->pit_state;
 615                 if (atomic_read(&ps->pit_timer.pending) &&
 616                 (((arch->vpic->pics[0].imr & 1) == 0 &&
 617                   arch->vpic->pics[0].irq_base == vec) ||
 618                   (arch->vioapic->redirtbl[0].fields.vector == vec &&
 619                   arch->vioapic->redirtbl[0].fields.mask != 1))) {
 620                         ps->inject_pending = 1;
 621                         atomic_dec(&ps->pit_timer.pending);
 622                         ps->channels[0].count_load_time = ktime_get();
 623                 }
 624         }
 625 }