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 #include "trace.h"
  34
  35 static void pic_lock(struct kvm_pic *s)
  36         __acquires(&s->lock)
  37 {
  38         spin_lock(&s->lock);
  39 }
  40
  41 static void pic_unlock(struct kvm_pic *s)
  42         __releases(&s->lock)
  43 {
  44         spin_unlock(&s->lock);
  45 }
  46
  47 static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
  48 {
  49         s->isr &= ~(1 << irq);
  50         s->isr_ack |= (1 << irq);
  51         if (s != &s->pics_state->pics[0])
  52                 irq += 8;
  53         kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq);
  54 }
  55
  56 void kvm_pic_clear_isr_ack(struct kvm *kvm)
  57 {
  58         struct kvm_pic *s = pic_irqchip(kvm);
  59         pic_lock(s);
  60         s->pics[0].isr_ack = 0xff;
  61         s->pics[1].isr_ack = 0xff;
  62         pic_unlock(s);
  63 }
  64
  65 /*
  66  * set irq level. If an edge is detected, then the IRR is set to 1
  67  */
  68 static inline int pic_set_irq1(struct kvm_kpic_state *s, int irq, int level)
  69 {
  70         int mask, ret = 1;
  71         mask = 1 << irq;
  72         if (s->elcr & mask)     /* level triggered */
  73                 if (level) {
  74                         ret = !(s->irr & mask);
  75                         s->irr |= mask;
  76                         s->last_irr |= mask;
  77                 } else {
  78                         s->irr &= ~mask;
  79                         s->last_irr &= ~mask;
  80                 }
  81         else    /* edge triggered */
  82                 if (level) {
  83                         if ((s->last_irr & mask) == 0) {
  84                                 ret = !(s->irr & mask);
  85                                 s->irr |= mask;
  86                         }
  87                         s->last_irr |= mask;
  88                 } else
  89                         s->last_irr &= ~mask;
  90
  91         return (s->imr & mask) ? -1 : ret;
  92 }
  93
  94 /*
  95  * return the highest priority found in mask (highest = smallest
  96  * number). Return 8 if no irq
  97  */
  98 static inline int get_priority(struct kvm_kpic_state *s, int mask)
  99 {
 100         int priority;
 101         if (mask == 0)
 102                 return 8;
 103         priority = 0;
 104         while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
 105                 priority++;
 106         return priority;
 107 }
 108
 109 /*
 110  * return the pic wanted interrupt. return -1 if none
 111  */
 112 static int pic_get_irq(struct kvm_kpic_state *s)
 113 {
 114         int mask, cur_priority, priority;
 115
 116         mask = s->irr & ~s->imr;
 117         priority = get_priority(s, mask);
 118         if (priority == 8)
 119                 return -1;
 120         /*
 121          * compute current priority. If special fully nested mode on the
 122          * master, the IRQ coming from the slave is not taken into account
 123          * for the priority computation.
 124          */
 125         mask = s->isr;
 126         if (s->special_fully_nested_mode && s == &s->pics_state->pics[0])
 127                 mask &= ~(1 << 2);
 128         cur_priority = get_priority(s, mask);
 129         if (priority < cur_priority)
 130                 /*
 131                  * higher priority found: an irq should be generated
 132                  */
 133                 return (priority + s->priority_add) & 7;
 134         else
 135                 return -1;
 136 }
 137
 138 /*
 139  * raise irq to CPU if necessary. must be called every time the active
 140  * irq may change
 141  */
 142 static void pic_update_irq(struct kvm_pic *s)
 143 {
 144         int irq2, irq;
 145
 146         irq2 = pic_get_irq(&s->pics[1]);
 147         if (irq2 >= 0) {
 148                 /*
 149                  * if irq request by slave pic, signal master PIC
 150                  */
 151                 pic_set_irq1(&s->pics[0], 2, 1);
 152                 pic_set_irq1(&s->pics[0], 2, 0);
 153         }
 154         irq = pic_get_irq(&s->pics[0]);
 155         if (irq >= 0)
 156                 s->irq_request(s->irq_request_opaque, 1);
 157         else
 158                 s->irq_request(s->irq_request_opaque, 0);
 159 }
 160
 161 void kvm_pic_update_irq(struct kvm_pic *s)
 162 {
 163         pic_lock(s);
 164         pic_update_irq(s);
 165         pic_unlock(s);
 166 }
 167
 168 int kvm_pic_set_irq(void *opaque, int irq, int level)
 169 {
 170         struct kvm_pic *s = opaque;
 171         int ret = -1;
 172
 173         pic_lock(s);
 174         if (irq >= 0 && irq < PIC_NUM_PINS) {
 175                 ret = pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
 176                 pic_update_irq(s);
 177                 trace_kvm_pic_set_irq(irq >> 3, irq & 7, s->pics[irq >> 3].elcr,
 178                                       s->pics[irq >> 3].imr, ret == 0);
 179         }
 180         pic_unlock(s);
 181
 182         return ret;
 183 }
 184
 185 /*
 186  * acknowledge interrupt 'irq'
 187  */
 188 static inline void pic_intack(struct kvm_kpic_state *s, int irq)
 189 {
 190         s->isr |= 1 << irq;
 191         if (s->auto_eoi) {
 192                 if (s->rotate_on_auto_eoi)
 193                         s->priority_add = (irq + 1) & 7;
 194                 pic_clear_isr(s, irq);
 195         }
 196         /*
 197          * We don't clear a level sensitive interrupt here
 198          */
 199         if (!(s->elcr & (1 << irq)))
 200                 s->irr &= ~(1 << irq);
 201 }
 202
 203 int kvm_pic_read_irq(struct kvm *kvm)
 204 {
 205         int irq, irq2, intno;
 206         struct kvm_pic *s = pic_irqchip(kvm);
 207
 208         pic_lock(s);
 209         irq = pic_get_irq(&s->pics[0]);
 210         if (irq >= 0) {
 211                 pic_intack(&s->pics[0], irq);
 212                 if (irq == 2) {
 213                         irq2 = pic_get_irq(&s->pics[1]);
 214                         if (irq2 >= 0)
 215                                 pic_intack(&s->pics[1], irq2);
 216                         else
 217                                 /*
 218                                  * spurious IRQ on slave controller
 219                                  */
 220                                 irq2 = 7;
 221                         intno = s->pics[1].irq_base + irq2;
 222                         irq = irq2 + 8;
 223                 } else
 224                         intno = s->pics[0].irq_base + irq;
 225         } else {
 226                 /*
 227                  * spurious IRQ on host controller
 228                  */
 229                 irq = 7;
 230                 intno = s->pics[0].irq_base + irq;
 231         }
 232         pic_update_irq(s);
 233         pic_unlock(s);
 234
 235         return intno;
 236 }
 237
 238 void kvm_pic_reset(struct kvm_kpic_state *s)
 239 {
 240         int irq, irqbase, n;
 241         struct kvm *kvm = s->pics_state->irq_request_opaque;
 242         struct kvm_vcpu *vcpu0 = kvm->bsp_vcpu;
 243
 244         if (s == &s->pics_state->pics[0])
 245                 irqbase = 0;
 246         else
 247                 irqbase = 8;
 248
 249         for (irq = 0; irq < PIC_NUM_PINS/2; irq++) {
 250                 if (vcpu0 && kvm_apic_accept_pic_intr(vcpu0))
 251                         if (s->irr & (1 << irq) || s->isr & (1 << irq)) {
 252                                 n = irq + irqbase;
 253                                 kvm_notify_acked_irq(kvm, SELECT_PIC(n), n);
 254                         }
 255         }
 256         s->last_irr = 0;
 257         s->irr = 0;
 258         s->imr = 0;
 259         s->isr = 0;
 260         s->isr_ack = 0xff;
 261         s->priority_add = 0;
 262         s->irq_base = 0;
 263         s->read_reg_select = 0;
 264         s->poll = 0;
 265         s->special_mask = 0;
 266         s->init_state = 0;
 267         s->auto_eoi = 0;
 268         s->rotate_on_auto_eoi = 0;
 269         s->special_fully_nested_mode = 0;
 270         s->init4 = 0;
 271 }
 272
 273 static void pic_ioport_write(void *opaque, u32 addr, u32 val)
 274 {
 275         struct kvm_kpic_state *s = opaque;
 276         int priority, cmd, irq;
 277
 278         addr &= 1;
 279         if (addr == 0) {
 280                 if (val & 0x10) {
 281                         kvm_pic_reset(s);       /* init */
 282                         /*
 283                          * deassert a pending interrupt
 284                          */
 285                         s->pics_state->irq_request(s->pics_state->
 286                                                    irq_request_opaque, 0);
 287                         s->init_state = 1;
 288                         s->init4 = val & 1;
 289                         if (val & 0x02)
 290                                 printk(KERN_ERR "single mode not supported");
 291                         if (val & 0x08)
 292                                 printk(KERN_ERR
 293                                        "level sensitive irq not supported");
 294                 } else if (val & 0x08) {
 295                         if (val & 0x04)
 296                                 s->poll = 1;
 297                         if (val & 0x02)
 298                                 s->read_reg_select = val & 1;
 299                         if (val & 0x40)
 300                                 s->special_mask = (val >> 5) & 1;
 301                 } else {
 302                         cmd = val >> 5;
 303                         switch (cmd) {
 304                         case 0:
 305                         case 4:
 306                                 s->rotate_on_auto_eoi = cmd >> 2;
 307                                 break;
 308                         case 1: /* end of interrupt */
 309                         case 5:
 310                                 priority = get_priority(s, s->isr);
 311                                 if (priority != 8) {
 312                                         irq = (priority + s->priority_add) & 7;
 313                                         pic_clear_isr(s, irq);
 314                                         if (cmd == 5)
 315                                                 s->priority_add = (irq + 1) & 7;
 316                                         pic_update_irq(s->pics_state);
 317                                 }
 318                                 break;
 319                         case 3:
 320                                 irq = val & 7;
 321                                 pic_clear_isr(s, irq);
 322                                 pic_update_irq(s->pics_state);
 323                                 break;
 324                         case 6:
 325                                 s->priority_add = (val + 1) & 7;
 326                                 pic_update_irq(s->pics_state);
 327                                 break;
 328                         case 7:
 329                                 irq = val & 7;
 330                                 s->priority_add = (irq + 1) & 7;
 331                                 pic_clear_isr(s, irq);
 332                                 pic_update_irq(s->pics_state);
 333                                 break;
 334                         default:
 335                                 break;  /* no operation */
 336                         }
 337                 }
 338         } else
 339                 switch (s->init_state) {
 340                 case 0:         /* normal mode */
 341                         s->imr = val;
 342                         pic_update_irq(s->pics_state);
 343                         break;
 344                 case 1:
 345                         s->irq_base = val & 0xf8;
 346                         s->init_state = 2;
 347                         break;
 348                 case 2:
 349                         if (s->init4)
 350                                 s->init_state = 3;
 351                         else
 352                                 s->init_state = 0;
 353                         break;
 354                 case 3:
 355                         s->special_fully_nested_mode = (val >> 4) & 1;
 356                         s->auto_eoi = (val >> 1) & 1;
 357                         s->init_state = 0;
 358                         break;
 359                 }
 360 }
 361
 362 static u32 pic_poll_read(struct kvm_kpic_state *s, u32 addr1)
 363 {
 364         int ret;
 365
 366         ret = pic_get_irq(s);
 367         if (ret >= 0) {
 368                 if (addr1 >> 7) {
 369                         s->pics_state->pics[0].isr &= ~(1 << 2);
 370                         s->pics_state->pics[0].irr &= ~(1 << 2);
 371                 }
 372                 s->irr &= ~(1 << ret);
 373                 pic_clear_isr(s, ret);
 374                 if (addr1 >> 7 || ret != 2)
 375                         pic_update_irq(s->pics_state);
 376         } else {
 377                 ret = 0x07;
 378                 pic_update_irq(s->pics_state);
 379         }
 380
 381         return ret;
 382 }
 383
 384 static u32 pic_ioport_read(void *opaque, u32 addr1)
 385 {
 386         struct kvm_kpic_state *s = opaque;
 387         unsigned int addr;
 388         int ret;
 389
 390         addr = addr1;
 391         addr &= 1;
 392         if (s->poll) {
 393                 ret = pic_poll_read(s, addr1);
 394                 s->poll = 0;
 395         } else
 396                 if (addr == 0)
 397                         if (s->read_reg_select)
 398                                 ret = s->isr;
 399                         else
 400                                 ret = s->irr;
 401                 else
 402                         ret = s->imr;
 403         return ret;
 404 }
 405
 406 static void elcr_ioport_write(void *opaque, u32 addr, u32 val)
 407 {
 408         struct kvm_kpic_state *s = opaque;
 409         s->elcr = val & s->elcr_mask;
 410 }
 411
 412 static u32 elcr_ioport_read(void *opaque, u32 addr1)
 413 {
 414         struct kvm_kpic_state *s = opaque;
 415         return s->elcr;
 416 }
 417
 418 static int picdev_in_range(gpa_t addr)
 419 {
 420         switch (addr) {
 421         case 0x20:
 422         case 0x21:
 423         case 0xa0:
 424         case 0xa1:
 425         case 0x4d0:
 426         case 0x4d1:
 427                 return 1;
 428         default:
 429                 return 0;
 430         }
 431 }
 432
 433 static inline struct kvm_pic *to_pic(struct kvm_io_device *dev)
 434 {
 435         return container_of(dev, struct kvm_pic, dev);
 436 }
 437
 438 static int picdev_write(struct kvm_io_device *this,
 439                          gpa_t addr, int len, const void *val)
 440 {
 441         struct kvm_pic *s = to_pic(this);
 442         unsigned char data = *(unsigned char *)val;
 443         if (!picdev_in_range(addr))
 444                 return -EOPNOTSUPP;
 445
 446         if (len != 1) {
 447                 if (printk_ratelimit())
 448                         printk(KERN_ERR "PIC: non byte write\n");
 449                 return 0;
 450         }
 451         pic_lock(s);
 452         switch (addr) {
 453         case 0x20:
 454         case 0x21:
 455         case 0xa0:
 456         case 0xa1:
 457                 pic_ioport_write(&s->pics[addr >> 7], addr, data);
 458                 break;
 459         case 0x4d0:
 460         case 0x4d1:
 461                 elcr_ioport_write(&s->pics[addr & 1], addr, data);
 462                 break;
 463         }
 464         pic_unlock(s);
 465         return 0;
 466 }
 467
 468 static int picdev_read(struct kvm_io_device *this,
 469                        gpa_t addr, int len, void *val)
 470 {
 471         struct kvm_pic *s = to_pic(this);
 472         unsigned char data = 0;
 473         if (!picdev_in_range(addr))
 474                 return -EOPNOTSUPP;
 475
 476         if (len != 1) {
 477                 if (printk_ratelimit())
 478                         printk(KERN_ERR "PIC: non byte read\n");
 479                 return 0;
 480         }
 481         pic_lock(s);
 482         switch (addr) {
 483         case 0x20:
 484         case 0x21:
 485         case 0xa0:
 486         case 0xa1:
 487                 data = pic_ioport_read(&s->pics[addr >> 7], addr);
 488                 break;
 489         case 0x4d0:
 490         case 0x4d1:
 491                 data = elcr_ioport_read(&s->pics[addr & 1], addr);
 492                 break;
 493         }
 494         *(unsigned char *)val = data;
 495         pic_unlock(s);
 496         return 0;
 497 }
 498
 499 /*
 500  * callback when PIC0 irq status changed
 501  */
 502 static void pic_irq_request(void *opaque, int level)
 503 {
 504         struct kvm *kvm = opaque;
 505         struct kvm_vcpu *vcpu = kvm->bsp_vcpu;
 506         struct kvm_pic *s = pic_irqchip(kvm);
 507         int irq = pic_get_irq(&s->pics[0]);
 508
 509         s->output = level;
 510         if (vcpu && level && (s->pics[0].isr_ack & (1 << irq))) {
 511                 s->pics[0].isr_ack &= ~(1 << irq);
 512                 kvm_vcpu_kick(vcpu);
 513         }
 514 }
 515
 516 static const struct kvm_io_device_ops picdev_ops = {
 517         .read     = picdev_read,
 518         .write    = picdev_write,
 519 };
 520
 521 struct kvm_pic *kvm_create_pic(struct kvm *kvm)
 522 {
 523         struct kvm_pic *s;
 524         int ret;
 525
 526         s = kzalloc(sizeof(struct kvm_pic), GFP_KERNEL);
 527         if (!s)
 528                 return NULL;
 529         spin_lock_init(&s->lock);
 530         s->kvm = kvm;
 531         s->pics[0].elcr_mask = 0xf8;
 532         s->pics[1].elcr_mask = 0xde;
 533         s->irq_request = pic_irq_request;
 534         s->irq_request_opaque = kvm;
 535         s->pics[0].pics_state = s;
 536         s->pics[1].pics_state = s;
 537
 538         /*
 539          * Initialize PIO device
 540          */
 541         kvm_iodevice_init(&s->dev, &picdev_ops);
 542         ret = kvm_io_bus_register_dev(kvm, &kvm->pio_bus, &s->dev);
 543         if (ret < 0) {
 544                 kfree(s);
 545                 return NULL;
 546         }
 547
 548         return s;
 549 }