arch/x86/kvm/i8259.c

   1 /*
   2  * 8259 interrupt controller emulation
   3  *
   4  * Copyright (c) 2003-2004 Fabrice Bellard
   5  * Copyright (c) 2007 Intel Corporation
   6  * Copyright 2009 Red Hat, Inc. and/or its affiliates.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24  * THE SOFTWARE.
  25  * Authors:
  26  *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
  27  *   Port from Qemu.
  28  */
  29 #include <linux/mm.h>
  30 #include <linux/slab.h>
  31 #include <linux/bitops.h>
  32 #include "irq.h"
  33
  34 #include <linux/kvm_host.h>
  35 #include "trace.h"
  36
  37 #define pr_pic_unimpl(fmt, ...) \
  38         pr_err_ratelimited("kvm: pic: " fmt, ## __VA_ARGS__)
  39
  40 static void pic_irq_request(struct kvm *kvm, int level);
  41
  42 static void pic_lock(struct kvm_pic *s)
  43         __acquires(&s->lock)
  44 {
  45         spin_lock(&s->lock);
  46 }
  47
  48 static void pic_unlock(struct kvm_pic *s)
  49         __releases(&s->lock)
  50 {
  51         bool wakeup = s->wakeup_needed;
  52         struct kvm_vcpu *vcpu;
  53         int i;
  54
  55         s->wakeup_needed = false;
  56
  57         spin_unlock(&s->lock);
  58
  59         if (wakeup) {
  60                 kvm_for_each_vcpu(i, vcpu, s->kvm) {
  61                         if (kvm_apic_accept_pic_intr(vcpu)) {
  62                                 kvm_make_request(KVM_REQ_EVENT, vcpu);
  63                                 kvm_vcpu_kick(vcpu);
  64                                 return;
  65                         }
  66                 }
  67         }
  68 }
  69
  70 static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
  71 {
  72         s->isr &= ~(1 << irq);
  73         if (s != &s->pics_state->pics[0])
  74                 irq += 8;
  75         /*
  76          * We are dropping lock while calling ack notifiers since ack
  77          * notifier callbacks for assigned devices call into PIC recursively.
  78          * Other interrupt may be delivered to PIC while lock is dropped but
  79          * it should be safe since PIC state is already updated at this stage.
  80          */
  81         pic_unlock(s->pics_state);
  82         kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq);
  83         pic_lock(s->pics_state);
  84 }
  85
  86 /*
  87  * set irq level. If an edge is detected, then the IRR is set to 1
  88  */
  89 static inline int pic_set_irq1(struct kvm_kpic_state *s, int irq, int level)
  90 {
  91         int mask, ret = 1;
  92         mask = 1 << irq;
  93         if (s->elcr & mask)     /* level triggered */
  94                 if (level) {
  95                         ret = !(s->irr & mask);
  96                         s->irr |= mask;
  97                         s->last_irr |= mask;
  98                 } else {
  99                         s->irr &= ~mask;
 100                         s->last_irr &= ~mask;
 101                 }
 102         else    /* edge triggered */
 103                 if (level) {
 104                         if ((s->last_irr & mask) == 0) {
 105                                 ret = !(s->irr & mask);
 106                                 s->irr |= mask;
 107                         }
 108                         s->last_irr |= mask;
 109                 } else
 110                         s->last_irr &= ~mask;
 111
 112         return (s->imr & mask) ? -1 : ret;
 113 }
 114
 115 /*
 116  * return the highest priority found in mask (highest = smallest
 117  * number). Return 8 if no irq
 118  */
 119 static inline int get_priority(struct kvm_kpic_state *s, int mask)
 120 {
 121         int priority;
 122         if (mask == 0)
 123                 return 8;
 124         priority = 0;
 125         while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
 126                 priority++;
 127         return priority;
 128 }
 129
 130 /*
 131  * return the pic wanted interrupt. return -1 if none
 132  */
 133 static int pic_get_irq(struct kvm_kpic_state *s)
 134 {
 135         int mask, cur_priority, priority;
 136
 137         mask = s->irr & ~s->imr;
 138         priority = get_priority(s, mask);
 139         if (priority == 8)
 140                 return -1;
 141         /*
 142          * compute current priority. If special fully nested mode on the
 143          * master, the IRQ coming from the slave is not taken into account
 144          * for the priority computation.
 145          */
 146         mask = s->isr;
 147         if (s->special_fully_nested_mode && s == &s->pics_state->pics[0])
 148                 mask &= ~(1 << 2);
 149         cur_priority = get_priority(s, mask);
 150         if (priority < cur_priority)
 151                 /*
 152                  * higher priority found: an irq should be generated
 153                  */
 154                 return (priority + s->priority_add) & 7;
 155         else
 156                 return -1;
 157 }
 158
 159 /*
 160  * raise irq to CPU if necessary. must be called every time the active
 161  * irq may change
 162  */
 163 static void pic_update_irq(struct kvm_pic *s)
 164 {
 165         int irq2, irq;
 166
 167         irq2 = pic_get_irq(&s->pics[1]);
 168         if (irq2 >= 0) {
 169                 /*
 170                  * if irq request by slave pic, signal master PIC
 171                  */
 172                 pic_set_irq1(&s->pics[0], 2, 1);
 173                 pic_set_irq1(&s->pics[0], 2, 0);
 174         }
 175         irq = pic_get_irq(&s->pics[0]);
 176         pic_irq_request(s->kvm, irq >= 0);
 177 }
 178
 179 void kvm_pic_update_irq(struct kvm_pic *s)
 180 {
 181         pic_lock(s);
 182         pic_update_irq(s);
 183         pic_unlock(s);
 184 }
 185
 186 int kvm_pic_set_irq(struct kvm_pic *s, int irq, int irq_source_id, int level)
 187 {
 188         int ret, irq_level;
 189
 190         BUG_ON(irq < 0 || irq >= PIC_NUM_PINS);
 191
 192         pic_lock(s);
 193         irq_level = __kvm_irq_line_state(&s->irq_states[irq],
 194                                          irq_source_id, level);
 195         ret = pic_set_irq1(&s->pics[irq >> 3], irq & 7, irq_level);
 196         pic_update_irq(s);
 197         trace_kvm_pic_set_irq(irq >> 3, irq & 7, s->pics[irq >> 3].elcr,
 198                               s->pics[irq >> 3].imr, ret == 0);
 199         pic_unlock(s);
 200
 201         return ret;
 202 }
 203
 204 void kvm_pic_clear_all(struct kvm_pic *s, int irq_source_id)
 205 {
 206         int i;
 207
 208         pic_lock(s);
 209         for (i = 0; i < PIC_NUM_PINS; i++)
 210                 __clear_bit(irq_source_id, &s->irq_states[i]);
 211         pic_unlock(s);
 212 }
 213
 214 /*
 215  * acknowledge interrupt 'irq'
 216  */
 217 static inline void pic_intack(struct kvm_kpic_state *s, int irq)
 218 {
 219         s->isr |= 1 << irq;
 220         /*
 221          * We don't clear a level sensitive interrupt here
 222          */
 223         if (!(s->elcr & (1 << irq)))
 224                 s->irr &= ~(1 << irq);
 225
 226         if (s->auto_eoi) {
 227                 if (s->rotate_on_auto_eoi)
 228                         s->priority_add = (irq + 1) & 7;
 229                 pic_clear_isr(s, irq);
 230         }
 231
 232 }
 233
 234 int kvm_pic_read_irq(struct kvm *kvm)
 235 {
 236         int irq, irq2, intno;
 237         struct kvm_pic *s = kvm->arch.vpic;
 238
 239         s->output = 0;
 240
 241         pic_lock(s);
 242         irq = pic_get_irq(&s->pics[0]);
 243         if (irq >= 0) {
 244                 pic_intack(&s->pics[0], irq);
 245                 if (irq == 2) {
 246                         irq2 = pic_get_irq(&s->pics[1]);
 247                         if (irq2 >= 0)
 248                                 pic_intack(&s->pics[1], irq2);
 249                         else
 250                                 /*
 251                                  * spurious IRQ on slave controller
 252                                  */
 253                                 irq2 = 7;
 254                         intno = s->pics[1].irq_base + irq2;
 255                         irq = irq2 + 8;
 256                 } else
 257                         intno = s->pics[0].irq_base + irq;
 258         } else {
 259                 /*
 260                  * spurious IRQ on host controller
 261                  */
 262                 irq = 7;
 263                 intno = s->pics[0].irq_base + irq;
 264         }
 265         pic_update_irq(s);
 266         pic_unlock(s);
 267
 268         return intno;
 269 }
 270
 271 static void kvm_pic_reset(struct kvm_kpic_state *s)
 272 {
 273         int irq, i;
 274         struct kvm_vcpu *vcpu;
 275         u8 edge_irr = s->irr & ~s->elcr;
 276         bool found = false;
 277
 278         s->last_irr = 0;
 279         s->irr &= s->elcr;
 280         s->imr = 0;
 281         s->priority_add = 0;
 282         s->special_mask = 0;
 283         s->read_reg_select = 0;
 284         if (!s->init4) {
 285                 s->special_fully_nested_mode = 0;
 286                 s->auto_eoi = 0;
 287         }
 288         s->init_state = 1;
 289
 290         kvm_for_each_vcpu(i, vcpu, s->pics_state->kvm)
 291                 if (kvm_apic_accept_pic_intr(vcpu)) {
 292                         found = true;
 293                         break;
 294                 }
 295
 296
 297         if (!found)
 298                 return;
 299
 300         for (irq = 0; irq < PIC_NUM_PINS/2; irq++)
 301                 if (edge_irr & (1 << irq))
 302                         pic_clear_isr(s, irq);
 303 }
 304
 305 static void pic_ioport_write(void *opaque, u32 addr, u32 val)
 306 {
 307         struct kvm_kpic_state *s = opaque;
 308         int priority, cmd, irq;
 309
 310         addr &= 1;
 311         if (addr == 0) {
 312                 if (val & 0x10) {
 313                         s->init4 = val & 1;
 314                         if (val & 0x02)
 315                                 pr_pic_unimpl("single mode not supported");
 316                         if (val & 0x08)
 317                                 pr_pic_unimpl(
 318                                                 "level sensitive irq not supported");
 319                         kvm_pic_reset(s);
 320                 } else if (val & 0x08) {
 321                         if (val & 0x04)
 322                                 s->poll = 1;
 323                         if (val & 0x02)
 324                                 s->read_reg_select = val & 1;
 325                         if (val & 0x40)
 326                                 s->special_mask = (val >> 5) & 1;
 327                 } else {
 328                         cmd = val >> 5;
 329                         switch (cmd) {
 330                         case 0:
 331                         case 4:
 332                                 s->rotate_on_auto_eoi = cmd >> 2;
 333                                 break;
 334                         case 1: /* end of interrupt */
 335                         case 5:
 336                                 priority = get_priority(s, s->isr);
 337                                 if (priority != 8) {
 338                                         irq = (priority + s->priority_add) & 7;
 339                                         if (cmd == 5)
 340                                                 s->priority_add = (irq + 1) & 7;
 341                                         pic_clear_isr(s, irq);
 342                                         pic_update_irq(s->pics_state);
 343                                 }
 344                                 break;
 345                         case 3:
 346                                 irq = val & 7;
 347                                 pic_clear_isr(s, irq);
 348                                 pic_update_irq(s->pics_state);
 349                                 break;
 350                         case 6:
 351                                 s->priority_add = (val + 1) & 7;
 352                                 pic_update_irq(s->pics_state);
 353                                 break;
 354                         case 7:
 355                                 irq = val & 7;
 356                                 s->priority_add = (irq + 1) & 7;
 357                                 pic_clear_isr(s, irq);
 358                                 pic_update_irq(s->pics_state);
 359                                 break;
 360                         default:
 361                                 break;  /* no operation */
 362                         }
 363                 }
 364         } else
 365                 switch (s->init_state) {
 366                 case 0: { /* normal mode */
 367                         u8 imr_diff = s->imr ^ val,
 368                                 off = (s == &s->pics_state->pics[0]) ? 0 : 8;
 369                         s->imr = val;
 370                         for (irq = 0; irq < PIC_NUM_PINS/2; irq++)
 371                                 if (imr_diff & (1 << irq))
 372                                         kvm_fire_mask_notifiers(
 373                                                 s->pics_state->kvm,
 374                                                 SELECT_PIC(irq + off),
 375                                                 irq + off,
 376                                                 !!(s->imr & (1 << irq)));
 377                         pic_update_irq(s->pics_state);
 378                         break;
 379                 }
 380                 case 1:
 381                         s->irq_base = val & 0xf8;
 382                         s->init_state = 2;
 383                         break;
 384                 case 2:
 385                         if (s->init4)
 386                                 s->init_state = 3;
 387                         else
 388                                 s->init_state = 0;
 389                         break;
 390                 case 3:
 391                         s->special_fully_nested_mode = (val >> 4) & 1;
 392                         s->auto_eoi = (val >> 1) & 1;
 393                         s->init_state = 0;
 394                         break;
 395                 }
 396 }
 397
 398 static u32 pic_poll_read(struct kvm_kpic_state *s, u32 addr1)
 399 {
 400         int ret;
 401
 402         ret = pic_get_irq(s);
 403         if (ret >= 0) {
 404                 if (addr1 >> 7) {
 405                         s->pics_state->pics[0].isr &= ~(1 << 2);
 406                         s->pics_state->pics[0].irr &= ~(1 << 2);
 407                 }
 408                 s->irr &= ~(1 << ret);
 409                 pic_clear_isr(s, ret);
 410                 if (addr1 >> 7 || ret != 2)
 411                         pic_update_irq(s->pics_state);
 412         } else {
 413                 ret = 0x07;
 414                 pic_update_irq(s->pics_state);
 415         }
 416
 417         return ret;
 418 }
 419
 420 static u32 pic_ioport_read(void *opaque, u32 addr)
 421 {
 422         struct kvm_kpic_state *s = opaque;
 423         int ret;
 424
 425         if (s->poll) {
 426                 ret = pic_poll_read(s, addr);
 427                 s->poll = 0;
 428         } else
 429                 if ((addr & 1) == 0)
 430                         if (s->read_reg_select)
 431                                 ret = s->isr;
 432                         else
 433                                 ret = s->irr;
 434                 else
 435                         ret = s->imr;
 436         return ret;
 437 }
 438
 439 static void elcr_ioport_write(void *opaque, u32 addr, u32 val)
 440 {
 441         struct kvm_kpic_state *s = opaque;
 442         s->elcr = val & s->elcr_mask;
 443 }
 444
 445 static u32 elcr_ioport_read(void *opaque, u32 addr1)
 446 {
 447         struct kvm_kpic_state *s = opaque;
 448         return s->elcr;
 449 }
 450
 451 static int picdev_write(struct kvm_pic *s,
 452                          gpa_t addr, int len, const void *val)
 453 {
 454         unsigned char data = *(unsigned char *)val;
 455
 456         if (len != 1) {
 457                 pr_pic_unimpl("non byte write\n");
 458                 return 0;
 459         }
 460         switch (addr) {
 461         case 0x20:
 462         case 0x21:
 463         case 0xa0:
 464         case 0xa1:
 465                 pic_lock(s);
 466                 pic_ioport_write(&s->pics[addr >> 7], addr, data);
 467                 pic_unlock(s);
 468                 break;
 469         case 0x4d0:
 470         case 0x4d1:
 471                 pic_lock(s);
 472                 elcr_ioport_write(&s->pics[addr & 1], addr, data);
 473                 pic_unlock(s);
 474                 break;
 475         default:
 476                 return -EOPNOTSUPP;
 477         }
 478         return 0;
 479 }
 480
 481 static int picdev_read(struct kvm_pic *s,
 482                        gpa_t addr, int len, void *val)
 483 {
 484         unsigned char *data = (unsigned char *)val;
 485
 486         if (len != 1) {
 487                 memset(val, 0, len);
 488                 pr_pic_unimpl("non byte read\n");
 489                 return 0;
 490         }
 491         switch (addr) {
 492         case 0x20:
 493         case 0x21:
 494         case 0xa0:
 495         case 0xa1:
 496                 pic_lock(s);
 497                 *data = pic_ioport_read(&s->pics[addr >> 7], addr);
 498                 pic_unlock(s);
 499                 break;
 500         case 0x4d0:
 501         case 0x4d1:
 502                 pic_lock(s);
 503                 *data = elcr_ioport_read(&s->pics[addr & 1], addr);
 504                 pic_unlock(s);
 505                 break;
 506         default:
 507                 return -EOPNOTSUPP;
 508         }
 509         return 0;
 510 }
 511
 512 static int picdev_master_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 513                                gpa_t addr, int len, const void *val)
 514 {
 515         return picdev_write(container_of(dev, struct kvm_pic, dev_master),
 516                             addr, len, val);
 517 }
 518
 519 static int picdev_master_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 520                               gpa_t addr, int len, void *val)
 521 {
 522         return picdev_read(container_of(dev, struct kvm_pic, dev_master),
 523                             addr, len, val);
 524 }
 525
 526 static int picdev_slave_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 527                               gpa_t addr, int len, const void *val)
 528 {
 529         return picdev_write(container_of(dev, struct kvm_pic, dev_slave),
 530                             addr, len, val);
 531 }
 532
 533 static int picdev_slave_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 534                              gpa_t addr, int len, void *val)
 535 {
 536         return picdev_read(container_of(dev, struct kvm_pic, dev_slave),
 537                             addr, len, val);
 538 }
 539
 540 static int picdev_eclr_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 541                              gpa_t addr, int len, const void *val)
 542 {
 543         return picdev_write(container_of(dev, struct kvm_pic, dev_eclr),
 544                             addr, len, val);
 545 }
 546
 547 static int picdev_eclr_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 548                             gpa_t addr, int len, void *val)
 549 {
 550         return picdev_read(container_of(dev, struct kvm_pic, dev_eclr),
 551                             addr, len, val);
 552 }
 553
 554 /*
 555  * callback when PIC0 irq status changed
 556  */
 557 static void pic_irq_request(struct kvm *kvm, int level)
 558 {
 559         struct kvm_pic *s = kvm->arch.vpic;
 560
 561         if (!s->output)
 562                 s->wakeup_needed = true;
 563         s->output = level;
 564 }
 565
 566 static const struct kvm_io_device_ops picdev_master_ops = {
 567         .read     = picdev_master_read,
 568         .write    = picdev_master_write,
 569 };
 570
 571 static const struct kvm_io_device_ops picdev_slave_ops = {
 572         .read     = picdev_slave_read,
 573         .write    = picdev_slave_write,
 574 };
 575
 576 static const struct kvm_io_device_ops picdev_eclr_ops = {
 577         .read     = picdev_eclr_read,
 578         .write    = picdev_eclr_write,
 579 };
 580
 581 int kvm_pic_init(struct kvm *kvm)
 582 {
 583         struct kvm_pic *s;
 584         int ret;
 585
 586         s = kzalloc(sizeof(struct kvm_pic), GFP_KERNEL);
 587         if (!s)
 588                 return -ENOMEM;
 589         spin_lock_init(&s->lock);
 590         s->kvm = kvm;
 591         s->pics[0].elcr_mask = 0xf8;
 592         s->pics[1].elcr_mask = 0xde;
 593         s->pics[0].pics_state = s;
 594         s->pics[1].pics_state = s;
 595
 596         /*
 597          * Initialize PIO device
 598          */
 599         kvm_iodevice_init(&s->dev_master, &picdev_master_ops);
 600         kvm_iodevice_init(&s->dev_slave, &picdev_slave_ops);
 601         kvm_iodevice_init(&s->dev_eclr, &picdev_eclr_ops);
 602         mutex_lock(&kvm->slots_lock);
 603         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, 0x20, 2,
 604                                       &s->dev_master);
 605         if (ret < 0)
 606                 goto fail_unlock;
 607
 608         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, 0xa0, 2, &s->dev_slave);
 609         if (ret < 0)
 610                 goto fail_unreg_2;
 611
 612         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, 0x4d0, 2, &s->dev_eclr);
 613         if (ret < 0)
 614                 goto fail_unreg_1;
 615
 616         mutex_unlock(&kvm->slots_lock);
 617
 618         kvm->arch.vpic = s;
 619
 620         return 0;
 621
 622 fail_unreg_1:
 623         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &s->dev_slave);
 624
 625 fail_unreg_2:
 626         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &s->dev_master);
 627
 628 fail_unlock:
 629         mutex_unlock(&kvm->slots_lock);
 630
 631         kfree(s);
 632
 633         return ret;
 634 }
 635
 636 void kvm_pic_destroy(struct kvm *kvm)
 637 {
 638         struct kvm_pic *vpic = kvm->arch.vpic;
 639
 640         if (!vpic)
 641                 return;
 642
 643         mutex_lock(&kvm->slots_lock);
 644         kvm_io_bus_unregister_dev(vpic->kvm, KVM_PIO_BUS, &vpic->dev_master);
 645         kvm_io_bus_unregister_dev(vpic->kvm, KVM_PIO_BUS, &vpic->dev_slave);
 646         kvm_io_bus_unregister_dev(vpic->kvm, KVM_PIO_BUS, &vpic->dev_eclr);
 647         mutex_unlock(&kvm->slots_lock);
 648
 649         kvm->arch.vpic = NULL;
 650         kfree(vpic);
 651 }