git.oblomov.eu Git - linux-2.6/blob - 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         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         if (pt->period)
 211                 ps->channels[0].count_load_time = pt->timer.expires;
 212
 213         return (pt->period == 0 ? 0 : 1);
 214 }
 215
 216 int pit_has_pending_timer(struct kvm_vcpu *vcpu)
 217 {
 218         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 219
 220         if (pit && vcpu->vcpu_id == 0 && pit->pit_state.irq_ack)
 221                 return atomic_read(&pit->pit_state.pit_timer.pending);
 222         return 0;
 223 }
 224
 225 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 226 {
 227         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 228                                                  irq_ack_notifier);
 229         spin_lock(&ps->inject_lock);
 230         if (atomic_dec_return(&ps->pit_timer.pending) < 0)
 231                 atomic_inc(&ps->pit_timer.pending);
 232         ps->irq_ack = 1;
 233         spin_unlock(&ps->inject_lock);
 234 }
 235
 236 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 237 {
 238         struct kvm_kpit_state *ps;
 239         int restart_timer = 0;
 240
 241         ps = container_of(data, struct kvm_kpit_state, pit_timer.timer);
 242
 243         restart_timer = __pit_timer_fn(ps);
 244
 245         if (restart_timer)
 246                 return HRTIMER_RESTART;
 247         else
 248                 return HRTIMER_NORESTART;
 249 }
 250
 251 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 252 {
 253         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 254         struct hrtimer *timer;
 255
 256         if (vcpu->vcpu_id != 0 || !pit)
 257                 return;
 258
 259         timer = &pit->pit_state.pit_timer.timer;
 260         if (hrtimer_cancel(timer))
 261                 hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS);
 262 }
 263
 264 static void destroy_pit_timer(struct kvm_kpit_timer *pt)
 265 {
 266         pr_debug("pit: execute del timer!\n");
 267         hrtimer_cancel(&pt->timer);
 268 }
 269
 270 static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
 271 {
 272         struct kvm_kpit_timer *pt = &ps->pit_timer;
 273         s64 interval;
 274
 275         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 276
 277         pr_debug("pit: create pit timer, interval is %llu nsec\n", interval);
 278
 279         /* TODO The new value only affected after the retriggered */
 280         hrtimer_cancel(&pt->timer);
 281         pt->period = (is_period == 0) ? 0 : interval;
 282         pt->timer.function = pit_timer_fn;
 283         atomic_set(&pt->pending, 0);
 284         ps->irq_ack = 1;
 285
 286         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
 287                       HRTIMER_MODE_ABS);
 288 }
 289
 290 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 291 {
 292         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 293
 294         WARN_ON(!mutex_is_locked(&ps->lock));
 295
 296         pr_debug("pit: load_count val is %d, channel is %d\n", val, channel);
 297
 298         /*
 299          * Though spec said the state of 8254 is undefined after power-up,
 300          * seems some tricky OS like Windows XP depends on IRQ0 interrupt
 301          * when booting up.
 302          * So here setting initialize rate for it, and not a specific number
 303          */
 304         if (val == 0)
 305                 val = 0x10000;
 306
 307         ps->channels[channel].count_load_time = ktime_get();
 308         ps->channels[channel].count = val;
 309
 310         if (channel != 0)
 311                 return;
 312
 313         /* Two types of timer
 314          * mode 1 is one shot, mode 2 is period, otherwise del timer */
 315         switch (ps->channels[0].mode) {
 316         case 1:
 317         /* FIXME: enhance mode 4 precision */
 318         case 4:
 319                 create_pit_timer(ps, val, 0);
 320                 break;
 321         case 2:
 322         case 3:
 323                 create_pit_timer(ps, val, 1);
 324                 break;
 325         default:
 326                 destroy_pit_timer(&ps->pit_timer);
 327         }
 328 }
 329
 330 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val)
 331 {
 332         mutex_lock(&kvm->arch.vpit->pit_state.lock);
 333         pit_load_count(kvm, channel, val);
 334         mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 335 }
 336
 337 static void pit_ioport_write(struct kvm_io_device *this,
 338                              gpa_t addr, int len, const void *data)
 339 {
 340         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 341         struct kvm_kpit_state *pit_state = &pit->pit_state;
 342         struct kvm *kvm = pit->kvm;
 343         int channel, access;
 344         struct kvm_kpit_channel_state *s;
 345         u32 val = *(u32 *) data;
 346
 347         val  &= 0xff;
 348         addr &= KVM_PIT_CHANNEL_MASK;
 349
 350         mutex_lock(&pit_state->lock);
 351
 352         if (val != 0)
 353                 pr_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
 354                           (unsigned int)addr, len, val);
 355
 356         if (addr == 3) {
 357                 channel = val >> 6;
 358                 if (channel == 3) {
 359                         /* Read-Back Command. */
 360                         for (channel = 0; channel < 3; channel++) {
 361                                 s = &pit_state->channels[channel];
 362                                 if (val & (2 << channel)) {
 363                                         if (!(val & 0x20))
 364                                                 pit_latch_count(kvm, channel);
 365                                         if (!(val & 0x10))
 366                                                 pit_latch_status(kvm, channel);
 367                                 }
 368                         }
 369                 } else {
 370                         /* Select Counter <channel>. */
 371                         s = &pit_state->channels[channel];
 372                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
 373                         if (access == 0) {
 374                                 pit_latch_count(kvm, channel);
 375                         } else {
 376                                 s->rw_mode = access;
 377                                 s->read_state = access;
 378                                 s->write_state = access;
 379                                 s->mode = (val >> 1) & 7;
 380                                 if (s->mode > 5)
 381                                         s->mode -= 4;
 382                                 s->bcd = val & 1;
 383                         }
 384                 }
 385         } else {
 386                 /* Write Count. */
 387                 s = &pit_state->channels[addr];
 388                 switch (s->write_state) {
 389                 default:
 390                 case RW_STATE_LSB:
 391                         pit_load_count(kvm, addr, val);
 392                         break;
 393                 case RW_STATE_MSB:
 394                         pit_load_count(kvm, addr, val << 8);
 395                         break;
 396                 case RW_STATE_WORD0:
 397                         s->write_latch = val;
 398                         s->write_state = RW_STATE_WORD1;
 399                         break;
 400                 case RW_STATE_WORD1:
 401                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
 402                         s->write_state = RW_STATE_WORD0;
 403                         break;
 404                 }
 405         }
 406
 407         mutex_unlock(&pit_state->lock);
 408 }
 409
 410 static void pit_ioport_read(struct kvm_io_device *this,
 411                             gpa_t addr, int len, void *data)
 412 {
 413         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 414         struct kvm_kpit_state *pit_state = &pit->pit_state;
 415         struct kvm *kvm = pit->kvm;
 416         int ret, count;
 417         struct kvm_kpit_channel_state *s;
 418
 419         addr &= KVM_PIT_CHANNEL_MASK;
 420         s = &pit_state->channels[addr];
 421
 422         mutex_lock(&pit_state->lock);
 423
 424         if (s->status_latched) {
 425                 s->status_latched = 0;
 426                 ret = s->status;
 427         } else if (s->count_latched) {
 428                 switch (s->count_latched) {
 429                 default:
 430                 case RW_STATE_LSB:
 431                         ret = s->latched_count & 0xff;
 432                         s->count_latched = 0;
 433                         break;
 434                 case RW_STATE_MSB:
 435                         ret = s->latched_count >> 8;
 436                         s->count_latched = 0;
 437                         break;
 438                 case RW_STATE_WORD0:
 439                         ret = s->latched_count & 0xff;
 440                         s->count_latched = RW_STATE_MSB;
 441                         break;
 442                 }
 443         } else {
 444                 switch (s->read_state) {
 445                 default:
 446                 case RW_STATE_LSB:
 447                         count = pit_get_count(kvm, addr);
 448                         ret = count & 0xff;
 449                         break;
 450                 case RW_STATE_MSB:
 451                         count = pit_get_count(kvm, addr);
 452                         ret = (count >> 8) & 0xff;
 453                         break;
 454                 case RW_STATE_WORD0:
 455                         count = pit_get_count(kvm, addr);
 456                         ret = count & 0xff;
 457                         s->read_state = RW_STATE_WORD1;
 458                         break;
 459                 case RW_STATE_WORD1:
 460                         count = pit_get_count(kvm, addr);
 461                         ret = (count >> 8) & 0xff;
 462                         s->read_state = RW_STATE_WORD0;
 463                         break;
 464                 }
 465         }
 466
 467         if (len > sizeof(ret))
 468                 len = sizeof(ret);
 469         memcpy(data, (char *)&ret, len);
 470
 471         mutex_unlock(&pit_state->lock);
 472 }
 473
 474 static int pit_in_range(struct kvm_io_device *this, gpa_t addr,
 475                         int len, int is_write)
 476 {
 477         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
 478                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
 479 }
 480
 481 static void speaker_ioport_write(struct kvm_io_device *this,
 482                                  gpa_t addr, int len, const void *data)
 483 {
 484         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 485         struct kvm_kpit_state *pit_state = &pit->pit_state;
 486         struct kvm *kvm = pit->kvm;
 487         u32 val = *(u32 *) data;
 488
 489         mutex_lock(&pit_state->lock);
 490         pit_state->speaker_data_on = (val >> 1) & 1;
 491         pit_set_gate(kvm, 2, val & 1);
 492         mutex_unlock(&pit_state->lock);
 493 }
 494
 495 static void speaker_ioport_read(struct kvm_io_device *this,
 496                                 gpa_t addr, int len, void *data)
 497 {
 498         struct kvm_pit *pit = (struct kvm_pit *)this->private;
 499         struct kvm_kpit_state *pit_state = &pit->pit_state;
 500         struct kvm *kvm = pit->kvm;
 501         unsigned int refresh_clock;
 502         int ret;
 503
 504         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
 505         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
 506
 507         mutex_lock(&pit_state->lock);
 508         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
 509                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
 510         if (len > sizeof(ret))
 511                 len = sizeof(ret);
 512         memcpy(data, (char *)&ret, len);
 513         mutex_unlock(&pit_state->lock);
 514 }
 515
 516 static int speaker_in_range(struct kvm_io_device *this, gpa_t addr,
 517                             int len, int is_write)
 518 {
 519         return (addr == KVM_SPEAKER_BASE_ADDRESS);
 520 }
 521
 522 void kvm_pit_reset(struct kvm_pit *pit)
 523 {
 524         int i;
 525         struct kvm_kpit_channel_state *c;
 526
 527         mutex_lock(&pit->pit_state.lock);
 528         for (i = 0; i < 3; i++) {
 529                 c = &pit->pit_state.channels[i];
 530                 c->mode = 0xff;
 531                 c->gate = (i != 2);
 532                 pit_load_count(pit->kvm, i, 0);
 533         }
 534         mutex_unlock(&pit->pit_state.lock);
 535
 536         atomic_set(&pit->pit_state.pit_timer.pending, 0);
 537         pit->pit_state.irq_ack = 1;
 538 }
 539
 540 struct kvm_pit *kvm_create_pit(struct kvm *kvm)
 541 {
 542         struct kvm_pit *pit;
 543         struct kvm_kpit_state *pit_state;
 544
 545         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
 546         if (!pit)
 547                 return NULL;
 548
 549         mutex_init(&pit->pit_state.lock);
 550         mutex_lock(&pit->pit_state.lock);
 551         spin_lock_init(&pit->pit_state.inject_lock);
 552
 553         /* Initialize PIO device */
 554         pit->dev.read = pit_ioport_read;
 555         pit->dev.write = pit_ioport_write;
 556         pit->dev.in_range = pit_in_range;
 557         pit->dev.private = pit;
 558         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
 559
 560         pit->speaker_dev.read = speaker_ioport_read;
 561         pit->speaker_dev.write = speaker_ioport_write;
 562         pit->speaker_dev.in_range = speaker_in_range;
 563         pit->speaker_dev.private = pit;
 564         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->speaker_dev);
 565
 566         kvm->arch.vpit = pit;
 567         pit->kvm = kvm;
 568
 569         pit_state = &pit->pit_state;
 570         pit_state->pit = pit;
 571         hrtimer_init(&pit_state->pit_timer.timer,
 572                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 573         pit_state->irq_ack_notifier.gsi = 0;
 574         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 575         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 576         mutex_unlock(&pit->pit_state.lock);
 577
 578         kvm_pit_reset(pit);
 579
 580         return pit;
 581 }
 582
 583 void kvm_free_pit(struct kvm *kvm)
 584 {
 585         struct hrtimer *timer;
 586
 587         if (kvm->arch.vpit) {
 588                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
 589                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
 590                 hrtimer_cancel(timer);
 591                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 592                 kfree(kvm->arch.vpit);
 593         }
 594 }
 595
 596 static void __inject_pit_timer_intr(struct kvm *kvm)
 597 {
 598         mutex_lock(&kvm->lock);
 599         kvm_set_irq(kvm, 0, 1);
 600         kvm_set_irq(kvm, 0, 0);
 601         mutex_unlock(&kvm->lock);
 602 }
 603
 604 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
 605 {
 606         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 607         struct kvm *kvm = vcpu->kvm;
 608         struct kvm_kpit_state *ps;
 609
 610         if (vcpu && pit) {
 611                 int inject = 0;
 612                 ps = &pit->pit_state;
 613
 614                 /* Try to inject pending interrupts when
 615                  * last one has been acked.
 616                  */
 617                 spin_lock(&ps->inject_lock);
 618                 if (atomic_read(&ps->pit_timer.pending) && ps->irq_ack) {
 619                         ps->irq_ack = 0;
 620                         inject = 1;
 621                 }
 622                 spin_unlock(&ps->inject_lock);
 623                 if (inject)
 624                         __inject_pit_timer_intr(kvm);
 625         }
 626 }