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