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