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  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  * Authors:
  25  *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
  26  *   Port from Qemu.
  27  */
  28 #include <linux/mm.h>
  29 #include <linux/bitops.h>
  30 #include "irq.h"
  31
  32 #include <linux/kvm_host.h>
  33
  34 static void pic_lock(struct kvm_pic *s)
  35         __acquires(&s->lock)
  36 {
  37         spin_lock(&s->lock);
  38 }
  39
  40 static void pic_unlock(struct kvm_pic *s)
  41         __releases(&s->lock)
  42 {
  43         struct kvm *kvm = s->kvm;
  44         unsigned acks = s->pending_acks;
  45         bool wakeup = s->wakeup_needed;
  46         struct kvm_vcpu *vcpu;
  47
  48         s->pending_acks = 0;
  49         s->wakeup_needed = false;
  50
  51         spin_unlock(&s->lock);
  52
  53         while (acks) {
  54                 kvm_notify_acked_irq(kvm, SELECT_PIC(__ffs(acks)),
  55                                      __ffs(acks));
  56                 acks &= acks - 1;
  57         }
  58
  59         if (wakeup) {
  60                 vcpu = s->kvm->vcpus[0];
  61                 if (vcpu)
  62                         kvm_vcpu_kick(vcpu);
  63         }
  64 }
  65
  66 static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
  67 {
  68         s->isr &= ~(1 << irq);
  69         s->isr_ack |= (1 << irq);
  70 }
  71
  72 void kvm_pic_clear_isr_ack(struct kvm *kvm)
  73 {
  74         struct kvm_pic *s = pic_irqchip(kvm);
  75         s->pics[0].isr_ack = 0xff;
  76         s->pics[1].isr_ack = 0xff;
  77 }
  78
  79 /*
  80  * set irq level. If an edge is detected, then the IRR is set to 1
  81  */
  82 static inline int pic_set_irq1(struct kvm_kpic_state *s, int irq, int level)
  83 {
  84         int mask, ret = 1;
  85         mask = 1 << irq;
  86         if (s->elcr & mask)     /* level triggered */
  87                 if (level) {
  88                         ret = !(s->irr & mask);
  89                         s->irr |= mask;
  90                         s->last_irr |= mask;
  91                 } else {
  92                         s->irr &= ~mask;
  93                         s->last_irr &= ~mask;
  94                 }
  95         else    /* edge triggered */
  96                 if (level) {
  97                         if ((s->last_irr & mask) == 0) {
  98                                 ret = !(s->irr & mask);
  99                                 s->irr |= mask;
 100                         }
 101                         s->last_irr |= mask;
 102                 } else
 103                         s->last_irr &= ~mask;
 104
 105         return (s->imr & mask) ? -1 : ret;
 106 }
 107
 108 /*
 109  * return the highest priority found in mask (highest = smallest
 110  * number). Return 8 if no irq
 111  */
 112 static inline int get_priority(struct kvm_kpic_state *s, int mask)
 113 {
 114         int priority;
 115         if (mask == 0)
 116                 return 8;
 117         priority = 0;
 118         while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
 119                 priority++;
 120         return priority;
 121 }
 122
 123 /*
 124  * return the pic wanted interrupt. return -1 if none
 125  */
 126 static int pic_get_irq(struct kvm_kpic_state *s)
 127 {
 128         int mask, cur_priority, priority;
 129
 130         mask = s->irr & ~s->imr;
 131         priority = get_priority(s, mask);
 132         if (priority == 8)
 133                 return -1;
 134         /*
 135          * compute current priority. If special fully nested mode on the
 136          * master, the IRQ coming from the slave is not taken into account
 137          * for the priority computation.
 138          */
 139         mask = s->isr;
 140         if (s->special_fully_nested_mode && s == &s->pics_state->pics[0])
 141                 mask &= ~(1 << 2);
 142         cur_priority = get_priority(s, mask);
 143         if (priority < cur_priority)
 144                 /*
 145                  * higher priority found: an irq should be generated
 146                  */
 147                 return (priority + s->priority_add) & 7;
 148         else
 149                 return -1;
 150 }
 151
 152 /*
 153  * raise irq to CPU if necessary. must be called every time the active
 154  * irq may change
 155  */
 156 static void pic_update_irq(struct kvm_pic *s)
 157 {
 158         int irq2, irq;
 159
 160         irq2 = pic_get_irq(&s->pics[1]);
 161         if (irq2 >= 0) {
 162                 /*
 163                  * if irq request by slave pic, signal master PIC
 164                  */
 165                 pic_set_irq1(&s->pics[0], 2, 1);
 166                 pic_set_irq1(&s->pics[0], 2, 0);
 167         }
 168         irq = pic_get_irq(&s->pics[0]);
 169         if (irq >= 0)
 170                 s->irq_request(s->irq_request_opaque, 1);
 171         else
 172                 s->irq_request(s->irq_request_opaque, 0);
 173 }
 174
 175 void kvm_pic_update_irq(struct kvm_pic *s)
 176 {
 177         pic_lock(s);
 178         pic_update_irq(s);
 179         pic_unlock(s);
 180 }
 181
 182 int kvm_pic_set_irq(void *opaque, int irq, int level)
 183 {
 184         struct kvm_pic *s = opaque;
 185         int ret = -1;
 186
 187         pic_lock(s);
 188         if (irq >= 0 && irq < PIC_NUM_PINS) {
 189                 ret = pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
 190                 pic_update_irq(s);
 191         }
 192         pic_unlock(s);
 193
 194         return ret;
 195 }
 196
 197 /*
 198  * acknowledge interrupt 'irq'
 199  */
 200 static inline void pic_intack(struct kvm_kpic_state *s, int irq)
 201 {
 202         s->isr |= 1 << irq;
 203         if (s->auto_eoi) {
 204                 if (s->rotate_on_auto_eoi)
 205                         s->priority_add = (irq + 1) & 7;
 206                 pic_clear_isr(s, irq);
 207         }
 208         /*
 209          * We don't clear a level sensitive interrupt here
 210          */
 211         if (!(s->elcr & (1 << irq)))
 212                 s->irr &= ~(1 << irq);
 213 }
 214
 215 int kvm_pic_read_irq(struct kvm *kvm)
 216 {
 217         int irq, irq2, intno;
 218         struct kvm_pic *s = pic_irqchip(kvm);
 219
 220         pic_lock(s);
 221         irq = pic_get_irq(&s->pics[0]);
 222         if (irq >= 0) {
 223                 pic_intack(&s->pics[0], irq);
 224                 if (irq == 2) {
 225                         irq2 = pic_get_irq(&s->pics[1]);
 226                         if (irq2 >= 0)
 227                                 pic_intack(&s->pics[1], irq2);
 228                         else
 229                                 /*
 230                                  * spurious IRQ on slave controller
 231                                  */
 232                                 irq2 = 7;
 233                         intno = s->pics[1].irq_base + irq2;
 234                         irq = irq2 + 8;
 235                 } else
 236                         intno = s->pics[0].irq_base + irq;
 237         } else {
 238                 /*
 239                  * spurious IRQ on host controller
 240                  */
 241                 irq = 7;
 242                 intno = s->pics[0].irq_base + irq;
 243         }
 244         pic_update_irq(s);
 245         pic_unlock(s);
 246         kvm_notify_acked_irq(kvm, SELECT_PIC(irq), irq);
 247
 248         return intno;
 249 }
 250
 251 void kvm_pic_reset(struct kvm_kpic_state *s)
 252 {
 253         int irq, irqbase, n;
 254         struct kvm *kvm = s->pics_state->irq_request_opaque;
 255         struct kvm_vcpu *vcpu0 = kvm->vcpus[0];
 256
 257         if (s == &s->pics_state->pics[0])
 258                 irqbase = 0;
 259         else
 260                 irqbase = 8;
 261
 262         for (irq = 0; irq < PIC_NUM_PINS/2; irq++) {
 263                 if (vcpu0 && kvm_apic_accept_pic_intr(vcpu0))
 264                         if (s->irr & (1 << irq) || s->isr & (1 << irq)) {
 265                                 n = irq + irqbase;
 266                                 s->pics_state->pending_acks |= 1 << n;
 267                         }
 268         }
 269         s->last_irr = 0;
 270         s->irr = 0;
 271         s->imr = 0;
 272         s->isr = 0;
 273         s->isr_ack = 0xff;
 274         s->priority_add = 0;
 275         s->irq_base = 0;
 276         s->read_reg_select = 0;
 277         s->poll = 0;
 278         s->special_mask = 0;
 279         s->init_state = 0;
 280         s->auto_eoi = 0;
 281         s->rotate_on_auto_eoi = 0;
 282         s->special_fully_nested_mode = 0;
 283         s->init4 = 0;
 284 }
 285
 286 static void pic_ioport_write(void *opaque, u32 addr, u32 val)
 287 {
 288         struct kvm_kpic_state *s = opaque;
 289         int priority, cmd, irq;
 290
 291         addr &= 1;
 292         if (addr == 0) {
 293                 if (val & 0x10) {
 294                         kvm_pic_reset(s);       /* init */
 295                         /*
 296                          * deassert a pending interrupt
 297                          */
 298                         s->pics_state->irq_request(s->pics_state->
 299                                                    irq_request_opaque, 0);
 300                         s->init_state = 1;
 301                         s->init4 = val & 1;
 302                         if (val & 0x02)
 303                                 printk(KERN_ERR "single mode not supported");
 304                         if (val & 0x08)
 305                                 printk(KERN_ERR
 306                                        "level sensitive irq not supported");
 307                 } else if (val & 0x08) {
 308                         if (val & 0x04)
 309                                 s->poll = 1;
 310                         if (val & 0x02)
 311                                 s->read_reg_select = val & 1;
 312                         if (val & 0x40)
 313                                 s->special_mask = (val >> 5) & 1;
 314                 } else {
 315                         cmd = val >> 5;
 316                         switch (cmd) {
 317                         case 0:
 318                         case 4:
 319                                 s->rotate_on_auto_eoi = cmd >> 2;
 320                                 break;
 321                         case 1: /* end of interrupt */
 322                         case 5:
 323                                 priority = get_priority(s, s->isr);
 324                                 if (priority != 8) {
 325                                         irq = (priority + s->priority_add) & 7;
 326                                         pic_clear_isr(s, irq);
 327                                         if (cmd == 5)
 328                                                 s->priority_add = (irq + 1) & 7;
 329                                         pic_update_irq(s->pics_state);
 330                                 }
 331                                 break;
 332                         case 3:
 333                                 irq = val & 7;
 334                                 pic_clear_isr(s, irq);
 335                                 pic_update_irq(s->pics_state);
 336                                 break;
 337                         case 6:
 338                                 s->priority_add = (val + 1) & 7;
 339                                 pic_update_irq(s->pics_state);
 340                                 break;
 341                         case 7:
 342                                 irq = val & 7;
 343                                 s->priority_add = (irq + 1) & 7;
 344                                 pic_clear_isr(s, irq);
 345                                 pic_update_irq(s->pics_state);
 346                                 break;
 347                         default:
 348                                 break;  /* no operation */
 349                         }
 350                 }
 351         } else
 352                 switch (s->init_state) {
 353                 case 0:         /* normal mode */
 354                         s->imr = val;
 355                         pic_update_irq(s->pics_state);
 356                         break;
 357                 case 1:
 358                         s->irq_base = val & 0xf8;
 359                         s->init_state = 2;
 360                         break;
 361                 case 2:
 362                         if (s->init4)
 363                                 s->init_state = 3;
 364                         else
 365                                 s->init_state = 0;
 366                         break;
 367                 case 3:
 368                         s->special_fully_nested_mode = (val >> 4) & 1;
 369                         s->auto_eoi = (val >> 1) & 1;
 370                         s->init_state = 0;
 371                         break;
 372                 }
 373 }
 374
 375 static u32 pic_poll_read(struct kvm_kpic_state *s, u32 addr1)
 376 {
 377         int ret;
 378
 379         ret = pic_get_irq(s);
 380         if (ret >= 0) {
 381                 if (addr1 >> 7) {
 382                         s->pics_state->pics[0].isr &= ~(1 << 2);
 383                         s->pics_state->pics[0].irr &= ~(1 << 2);
 384                 }
 385                 s->irr &= ~(1 << ret);
 386                 pic_clear_isr(s, ret);
 387                 if (addr1 >> 7 || ret != 2)
 388                         pic_update_irq(s->pics_state);
 389         } else {
 390                 ret = 0x07;
 391                 pic_update_irq(s->pics_state);
 392         }
 393
 394         return ret;
 395 }
 396
 397 static u32 pic_ioport_read(void *opaque, u32 addr1)
 398 {
 399         struct kvm_kpic_state *s = opaque;
 400         unsigned int addr;
 401         int ret;
 402
 403         addr = addr1;
 404         addr &= 1;
 405         if (s->poll) {
 406                 ret = pic_poll_read(s, addr1);
 407                 s->poll = 0;
 408         } else
 409                 if (addr == 0)
 410                         if (s->read_reg_select)
 411                                 ret = s->isr;
 412                         else
 413                                 ret = s->irr;
 414                 else
 415                         ret = s->imr;
 416         return ret;
 417 }
 418
 419 static void elcr_ioport_write(void *opaque, u32 addr, u32 val)
 420 {
 421         struct kvm_kpic_state *s = opaque;
 422         s->elcr = val & s->elcr_mask;
 423 }
 424
 425 static u32 elcr_ioport_read(void *opaque, u32 addr1)
 426 {
 427         struct kvm_kpic_state *s = opaque;
 428         return s->elcr;
 429 }
 430
 431 static int picdev_in_range(struct kvm_io_device *this, gpa_t addr,
 432                            int len, int is_write)
 433 {
 434         switch (addr) {
 435         case 0x20:
 436         case 0x21:
 437         case 0xa0:
 438         case 0xa1:
 439         case 0x4d0:
 440         case 0x4d1:
 441                 return 1;
 442         default:
 443                 return 0;
 444         }
 445 }
 446
 447 static void picdev_write(struct kvm_io_device *this,
 448                          gpa_t addr, int len, const void *val)
 449 {
 450         struct kvm_pic *s = this->private;
 451         unsigned char data = *(unsigned char *)val;
 452
 453         if (len != 1) {
 454                 if (printk_ratelimit())
 455                         printk(KERN_ERR "PIC: non byte write\n");
 456                 return;
 457         }
 458         pic_lock(s);
 459         switch (addr) {
 460         case 0x20:
 461         case 0x21:
 462         case 0xa0:
 463         case 0xa1:
 464                 pic_ioport_write(&s->pics[addr >> 7], addr, data);
 465                 break;
 466         case 0x4d0:
 467         case 0x4d1:
 468                 elcr_ioport_write(&s->pics[addr & 1], addr, data);
 469                 break;
 470         }
 471         pic_unlock(s);
 472 }
 473
 474 static void picdev_read(struct kvm_io_device *this,
 475                         gpa_t addr, int len, void *val)
 476 {
 477         struct kvm_pic *s = this->private;
 478         unsigned char data = 0;
 479
 480         if (len != 1) {
 481                 if (printk_ratelimit())
 482                         printk(KERN_ERR "PIC: non byte read\n");
 483                 return;
 484         }
 485         pic_lock(s);
 486         switch (addr) {
 487         case 0x20:
 488         case 0x21:
 489         case 0xa0:
 490         case 0xa1:
 491                 data = pic_ioport_read(&s->pics[addr >> 7], addr);
 492                 break;
 493         case 0x4d0:
 494         case 0x4d1:
 495                 data = elcr_ioport_read(&s->pics[addr & 1], addr);
 496                 break;
 497         }
 498         *(unsigned char *)val = data;
 499         pic_unlock(s);
 500 }
 501
 502 /*
 503  * callback when PIC0 irq status changed
 504  */
 505 static void pic_irq_request(void *opaque, int level)
 506 {
 507         struct kvm *kvm = opaque;
 508         struct kvm_vcpu *vcpu = kvm->vcpus[0];
 509         struct kvm_pic *s = pic_irqchip(kvm);
 510         int irq = pic_get_irq(&s->pics[0]);
 511
 512         s->output = level;
 513         if (vcpu && level && (s->pics[0].isr_ack & (1 << irq))) {
 514                 s->pics[0].isr_ack &= ~(1 << irq);
 515                 s->wakeup_needed = true;
 516         }
 517 }
 518
 519 struct kvm_pic *kvm_create_pic(struct kvm *kvm)
 520 {
 521         struct kvm_pic *s;
 522         s = kzalloc(sizeof(struct kvm_pic), GFP_KERNEL);
 523         if (!s)
 524                 return NULL;
 525         spin_lock_init(&s->lock);
 526         s->kvm = kvm;
 527         s->pics[0].elcr_mask = 0xf8;
 528         s->pics[1].elcr_mask = 0xde;
 529         s->irq_request = pic_irq_request;
 530         s->irq_request_opaque = kvm;
 531         s->pics[0].pics_state = s;
 532         s->pics[1].pics_state = s;
 533
 534         /*
 535          * Initialize PIO device
 536          */
 537         s->dev.read = picdev_read;
 538         s->dev.write = picdev_write;
 539         s->dev.in_range = picdev_in_range;
 540         s->dev.private = s;
 541         kvm_io_bus_register_dev(&kvm->pio_bus, &s->dev);
 542         return s;
 543 }