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 unsigned long 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; 274 unsigned long i; 275 struct kvm_vcpu *vcpu; 276 u8 edge_irr = s->irr & ~s->elcr; 277 bool found = false; 278 279 s->last_irr = 0; 280 s->irr &= s->elcr; 281 s->imr = 0; 282 s->priority_add = 0; 283 s->special_mask = 0; 284 s->read_reg_select = 0; 285 if (!s->init4) { 286 s->special_fully_nested_mode = 0; 287 s->auto_eoi = 0; 288 } 289 s->init_state = 1; 290 291 kvm_for_each_vcpu(i, vcpu, s->pics_state->kvm) 292 if (kvm_apic_accept_pic_intr(vcpu)) { 293 found = true; 294 break; 295 } 296 297 298 if (!found) 299 return; 300 301 for (irq = 0; irq < PIC_NUM_PINS/2; irq++) 302 if (edge_irr & (1 << irq)) 303 pic_clear_isr(s, irq); 304 } 305 306 static void pic_ioport_write(void *opaque, u32 addr, u32 val) 307 { 308 struct kvm_kpic_state *s = opaque; 309 int priority, cmd, irq; 310 311 addr &= 1; 312 if (addr == 0) { 313 if (val & 0x10) { 314 s->init4 = val & 1; 315 if (val & 0x02) 316 pr_pic_unimpl("single mode not supported"); 317 if (val & 0x08) 318 pr_pic_unimpl( 319 "level sensitive irq not supported"); 320 kvm_pic_reset(s); 321 } else if (val & 0x08) { 322 if (val & 0x04) 323 s->poll = 1; 324 if (val & 0x02) 325 s->read_reg_select = val & 1; 326 if (val & 0x40) 327 s->special_mask = (val >> 5) & 1; 328 } else { 329 cmd = val >> 5; 330 switch (cmd) { 331 case 0: 332 case 4: 333 s->rotate_on_auto_eoi = cmd >> 2; 334 break; 335 case 1: /* end of interrupt */ 336 case 5: 337 priority = get_priority(s, s->isr); 338 if (priority != 8) { 339 irq = (priority + s->priority_add) & 7; 340 if (cmd == 5) 341 s->priority_add = (irq + 1) & 7; 342 pic_clear_isr(s, irq); 343 pic_update_irq(s->pics_state); 344 } 345 break; 346 case 3: 347 irq = val & 7; 348 pic_clear_isr(s, irq); 349 pic_update_irq(s->pics_state); 350 break; 351 case 6: 352 s->priority_add = (val + 1) & 7; 353 pic_update_irq(s->pics_state); 354 break; 355 case 7: 356 irq = val & 7; 357 s->priority_add = (irq + 1) & 7; 358 pic_clear_isr(s, irq); 359 pic_update_irq(s->pics_state); 360 break; 361 default: 362 break; /* no operation */ 363 } 364 } 365 } else 366 switch (s->init_state) { 367 case 0: { /* normal mode */ 368 u8 imr_diff = s->imr ^ val, 369 off = (s == &s->pics_state->pics[0]) ? 0 : 8; 370 s->imr = val; 371 for (irq = 0; irq < PIC_NUM_PINS/2; irq++) 372 if (imr_diff & (1 << irq)) 373 kvm_fire_mask_notifiers( 374 s->pics_state->kvm, 375 SELECT_PIC(irq + off), 376 irq + off, 377 !!(s->imr & (1 << irq))); 378 pic_update_irq(s->pics_state); 379 break; 380 } 381 case 1: 382 s->irq_base = val & 0xf8; 383 s->init_state = 2; 384 break; 385 case 2: 386 if (s->init4) 387 s->init_state = 3; 388 else 389 s->init_state = 0; 390 break; 391 case 3: 392 s->special_fully_nested_mode = (val >> 4) & 1; 393 s->auto_eoi = (val >> 1) & 1; 394 s->init_state = 0; 395 break; 396 } 397 } 398 399 static u32 pic_poll_read(struct kvm_kpic_state *s, u32 addr1) 400 { 401 int ret; 402 403 ret = pic_get_irq(s); 404 if (ret >= 0) { 405 if (addr1 >> 7) { 406 s->pics_state->pics[0].isr &= ~(1 << 2); 407 s->pics_state->pics[0].irr &= ~(1 << 2); 408 } 409 s->irr &= ~(1 << ret); 410 pic_clear_isr(s, ret); 411 if (addr1 >> 7 || ret != 2) 412 pic_update_irq(s->pics_state); 413 } else { 414 ret = 0x07; 415 pic_update_irq(s->pics_state); 416 } 417 418 return ret; 419 } 420 421 static u32 pic_ioport_read(void *opaque, u32 addr) 422 { 423 struct kvm_kpic_state *s = opaque; 424 int ret; 425 426 if (s->poll) { 427 ret = pic_poll_read(s, addr); 428 s->poll = 0; 429 } else 430 if ((addr & 1) == 0) 431 if (s->read_reg_select) 432 ret = s->isr; 433 else 434 ret = s->irr; 435 else 436 ret = s->imr; 437 return ret; 438 } 439 440 static void elcr_ioport_write(void *opaque, u32 addr, u32 val) 441 { 442 struct kvm_kpic_state *s = opaque; 443 s->elcr = val & s->elcr_mask; 444 } 445 446 static u32 elcr_ioport_read(void *opaque, u32 addr1) 447 { 448 struct kvm_kpic_state *s = opaque; 449 return s->elcr; 450 } 451 452 static int picdev_write(struct kvm_pic *s, 453 gpa_t addr, int len, const void *val) 454 { 455 unsigned char data = *(unsigned char *)val; 456 457 if (len != 1) { 458 pr_pic_unimpl("non byte write\n"); 459 return 0; 460 } 461 switch (addr) { 462 case 0x20: 463 case 0x21: 464 pic_lock(s); 465 pic_ioport_write(&s->pics[0], addr, data); 466 pic_unlock(s); 467 break; 468 case 0xa0: 469 case 0xa1: 470 pic_lock(s); 471 pic_ioport_write(&s->pics[1], addr, data); 472 pic_unlock(s); 473 break; 474 case 0x4d0: 475 case 0x4d1: 476 pic_lock(s); 477 elcr_ioport_write(&s->pics[addr & 1], addr, data); 478 pic_unlock(s); 479 break; 480 default: 481 return -EOPNOTSUPP; 482 } 483 return 0; 484 } 485 486 static int picdev_read(struct kvm_pic *s, 487 gpa_t addr, int len, void *val) 488 { 489 unsigned char *data = (unsigned char *)val; 490 491 if (len != 1) { 492 memset(val, 0, len); 493 pr_pic_unimpl("non byte read\n"); 494 return 0; 495 } 496 switch (addr) { 497 case 0x20: 498 case 0x21: 499 case 0xa0: 500 case 0xa1: 501 pic_lock(s); 502 *data = pic_ioport_read(&s->pics[addr >> 7], addr); 503 pic_unlock(s); 504 break; 505 case 0x4d0: 506 case 0x4d1: 507 pic_lock(s); 508 *data = elcr_ioport_read(&s->pics[addr & 1], addr); 509 pic_unlock(s); 510 break; 511 default: 512 return -EOPNOTSUPP; 513 } 514 return 0; 515 } 516 517 static int picdev_master_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, 518 gpa_t addr, int len, const void *val) 519 { 520 return picdev_write(container_of(dev, struct kvm_pic, dev_master), 521 addr, len, val); 522 } 523 524 static int picdev_master_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, 525 gpa_t addr, int len, void *val) 526 { 527 return picdev_read(container_of(dev, struct kvm_pic, dev_master), 528 addr, len, val); 529 } 530 531 static int picdev_slave_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, 532 gpa_t addr, int len, const void *val) 533 { 534 return picdev_write(container_of(dev, struct kvm_pic, dev_slave), 535 addr, len, val); 536 } 537 538 static int picdev_slave_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, 539 gpa_t addr, int len, void *val) 540 { 541 return picdev_read(container_of(dev, struct kvm_pic, dev_slave), 542 addr, len, val); 543 } 544 545 static int picdev_elcr_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, 546 gpa_t addr, int len, const void *val) 547 { 548 return picdev_write(container_of(dev, struct kvm_pic, dev_elcr), 549 addr, len, val); 550 } 551 552 static int picdev_elcr_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, 553 gpa_t addr, int len, void *val) 554 { 555 return picdev_read(container_of(dev, struct kvm_pic, dev_elcr), 556 addr, len, val); 557 } 558 559 /* 560 * callback when PIC0 irq status changed 561 */ 562 static void pic_irq_request(struct kvm *kvm, int level) 563 { 564 struct kvm_pic *s = kvm->arch.vpic; 565 566 if (!s->output) 567 s->wakeup_needed = true; 568 s->output = level; 569 } 570 571 static const struct kvm_io_device_ops picdev_master_ops = { 572 .read = picdev_master_read, 573 .write = picdev_master_write, 574 }; 575 576 static const struct kvm_io_device_ops picdev_slave_ops = { 577 .read = picdev_slave_read, 578 .write = picdev_slave_write, 579 }; 580 581 static const struct kvm_io_device_ops picdev_elcr_ops = { 582 .read = picdev_elcr_read, 583 .write = picdev_elcr_write, 584 }; 585 586 int kvm_pic_init(struct kvm *kvm) 587 { 588 struct kvm_pic *s; 589 int ret; 590 591 s = kzalloc(sizeof(struct kvm_pic), GFP_KERNEL_ACCOUNT); 592 if (!s) 593 return -ENOMEM; 594 spin_lock_init(&s->lock); 595 s->kvm = kvm; 596 s->pics[0].elcr_mask = 0xf8; 597 s->pics[1].elcr_mask = 0xde; 598 s->pics[0].pics_state = s; 599 s->pics[1].pics_state = s; 600 601 /* 602 * Initialize PIO device 603 */ 604 kvm_iodevice_init(&s->dev_master, &picdev_master_ops); 605 kvm_iodevice_init(&s->dev_slave, &picdev_slave_ops); 606 kvm_iodevice_init(&s->dev_elcr, &picdev_elcr_ops); 607 mutex_lock(&kvm->slots_lock); 608 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, 0x20, 2, 609 &s->dev_master); 610 if (ret < 0) 611 goto fail_unlock; 612 613 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, 0xa0, 2, &s->dev_slave); 614 if (ret < 0) 615 goto fail_unreg_2; 616 617 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, 0x4d0, 2, &s->dev_elcr); 618 if (ret < 0) 619 goto fail_unreg_1; 620 621 mutex_unlock(&kvm->slots_lock); 622 623 kvm->arch.vpic = s; 624 625 return 0; 626 627 fail_unreg_1: 628 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &s->dev_slave); 629 630 fail_unreg_2: 631 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &s->dev_master); 632 633 fail_unlock: 634 mutex_unlock(&kvm->slots_lock); 635 636 kfree(s); 637 638 return ret; 639 } 640 641 void kvm_pic_destroy(struct kvm *kvm) 642 { 643 struct kvm_pic *vpic = kvm->arch.vpic; 644 645 if (!vpic) 646 return; 647 648 mutex_lock(&kvm->slots_lock); 649 kvm_io_bus_unregister_dev(vpic->kvm, KVM_PIO_BUS, &vpic->dev_master); 650 kvm_io_bus_unregister_dev(vpic->kvm, KVM_PIO_BUS, &vpic->dev_slave); 651 kvm_io_bus_unregister_dev(vpic->kvm, KVM_PIO_BUS, &vpic->dev_elcr); 652 mutex_unlock(&kvm->slots_lock); 653 654 kvm->arch.vpic = NULL; 655 kfree(vpic); 656 } 657