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->bsp_vcpu;
  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         pic_lock(s);
  76         s->pics[0].isr_ack = 0xff;
  77         s->pics[1].isr_ack = 0xff;
  78         pic_unlock(s);
  79 }
  80
  81 /*
  82  * set irq level. If an edge is detected, then the IRR is set to 1
  83  */
  84 static inline int pic_set_irq1(struct kvm_kpic_state *s, int irq, int level)
  85 {
  86         int mask, ret = 1;
  87         mask = 1 << irq;
  88         if (s->elcr & mask)     /* level triggered */
  89                 if (level) {
  90                         ret = !(s->irr & mask);
  91                         s->irr |= mask;
  92                         s->last_irr |= mask;
  93                 } else {
  94                         s->irr &= ~mask;
  95                         s->last_irr &= ~mask;
  96                 }
  97         else    /* edge triggered */
  98                 if (level) {
  99                         if ((s->last_irr & mask) == 0) {
 100                                 ret = !(s->irr & mask);
 101                                 s->irr |= mask;
 102                         }
 103                         s->last_irr |= mask;
 104                 } else
 105                         s->last_irr &= ~mask;
 106
 107         return (s->imr & mask) ? -1 : ret;
 108 }
 109
 110 /*
 111  * return the highest priority found in mask (highest = smallest
 112  * number). Return 8 if no irq
 113  */
 114 static inline int get_priority(struct kvm_kpic_state *s, int mask)
 115 {
 116         int priority;
 117         if (mask == 0)
 118                 return 8;
 119         priority = 0;
 120         while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
 121                 priority++;
 122         return priority;
 123 }
 124
 125 /*
 126  * return the pic wanted interrupt. return -1 if none
 127  */
 128 static int pic_get_irq(struct kvm_kpic_state *s)
 129 {
 130         int mask, cur_priority, priority;
 131
 132         mask = s->irr & ~s->imr;
 133         priority = get_priority(s, mask);
 134         if (priority == 8)
 135                 return -1;
 136         /*
 137          * compute current priority. If special fully nested mode on the
 138          * master, the IRQ coming from the slave is not taken into account
 139          * for the priority computation.
 140          */
 141         mask = s->isr;
 142         if (s->special_fully_nested_mode && s == &s->pics_state->pics[0])
 143                 mask &= ~(1 << 2);
 144         cur_priority = get_priority(s, mask);
 145         if (priority < cur_priority)
 146                 /*
 147                  * higher priority found: an irq should be generated
 148                  */
 149                 return (priority + s->priority_add) & 7;
 150         else
 151                 return -1;
 152 }
 153
 154 /*
 155  * raise irq to CPU if necessary. must be called every time the active
 156  * irq may change
 157  */
 158 static void pic_update_irq(struct kvm_pic *s)
 159 {
 160         int irq2, irq;
 161
 162         irq2 = pic_get_irq(&s->pics[1]);
 163         if (irq2 >= 0) {
 164                 /*
 165                  * if irq request by slave pic, signal master PIC
 166                  */
 167                 pic_set_irq1(&s->pics[0], 2, 1);
 168                 pic_set_irq1(&s->pics[0], 2, 0);
 169         }
 170         irq = pic_get_irq(&s->pics[0]);
 171         if (irq >= 0)
 172                 s->irq_request(s->irq_request_opaque, 1);
 173         else
 174                 s->irq_request(s->irq_request_opaque, 0);
 175 }
 176
 177 void kvm_pic_update_irq(struct kvm_pic *s)
 178 {
 179         pic_lock(s);
 180         pic_update_irq(s);
 181         pic_unlock(s);
 182 }
 183
 184 int kvm_pic_set_irq(void *opaque, int irq, int level)
 185 {
 186         struct kvm_pic *s = opaque;
 187         int ret = -1;
 188
 189         pic_lock(s);
 190         if (irq >= 0 && irq < PIC_NUM_PINS) {
 191                 ret = pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
 192                 pic_update_irq(s);
 193         }
 194         pic_unlock(s);
 195
 196         return ret;
 197 }
 198
 199 /*
 200  * acknowledge interrupt 'irq'
 201  */
 202 static inline void pic_intack(struct kvm_kpic_state *s, int irq)
 203 {
 204         s->isr |= 1 << irq;
 205         if (s->auto_eoi) {
 206                 if (s->rotate_on_auto_eoi)
 207                         s->priority_add = (irq + 1) & 7;
 208                 pic_clear_isr(s, irq);
 209         }
 210         /*
 211          * We don't clear a level sensitive interrupt here
 212          */
 213         if (!(s->elcr & (1 << irq)))
 214                 s->irr &= ~(1 << irq);
 215 }
 216
 217 int kvm_pic_read_irq(struct kvm *kvm)
 218 {
 219         int irq, irq2, intno;
 220         struct kvm_pic *s = pic_irqchip(kvm);
 221
 222         pic_lock(s);
 223         irq = pic_get_irq(&s->pics[0]);
 224         if (irq >= 0) {
 225                 pic_intack(&s->pics[0], irq);
 226                 if (irq == 2) {
 227                         irq2 = pic_get_irq(&s->pics[1]);
 228                         if (irq2 >= 0)
 229                                 pic_intack(&s->pics[1], irq2);
 230                         else
 231                                 /*
 232                                  * spurious IRQ on slave controller
 233                                  */
 234                                 irq2 = 7;
 235                         intno = s->pics[1].irq_base + irq2;
 236                         irq = irq2 + 8;
 237                 } else
 238                         intno = s->pics[0].irq_base + irq;
 239         } else {
 240                 /*
 241                  * spurious IRQ on host controller
 242                  */
 243                 irq = 7;
 244                 intno = s->pics[0].irq_base + irq;
 245         }
 246         pic_update_irq(s);
 247         pic_unlock(s);
 248         kvm_notify_acked_irq(kvm, SELECT_PIC(irq), irq);
 249
 250         return intno;
 251 }
 252
 253 void kvm_pic_reset(struct kvm_kpic_state *s)
 254 {
 255         int irq, irqbase, n;
 256         struct kvm *kvm = s->pics_state->irq_request_opaque;
 257         struct kvm_vcpu *vcpu0 = kvm->bsp_vcpu;
 258
 259         if (s == &s->pics_state->pics[0])
 260                 irqbase = 0;
 261         else
 262                 irqbase = 8;
 263
 264         for (irq = 0; irq < PIC_NUM_PINS/2; irq++) {
 265                 if (vcpu0 && kvm_apic_accept_pic_intr(vcpu0))
 266                         if (s->irr & (1 << irq) || s->isr & (1 << irq)) {
 267                                 n = irq + irqbase;
 268                                 s->pics_state->pending_acks |= 1 << n;
 269                         }
 270         }
 271         s->last_irr = 0;
 272         s->irr = 0;
 273         s->imr = 0;
 274         s->isr = 0;
 275         s->isr_ack = 0xff;
 276         s->priority_add = 0;
 277         s->irq_base = 0;
 278         s->read_reg_select = 0;
 279         s->poll = 0;
 280         s->special_mask = 0;
 281         s->init_state = 0;
 282         s->auto_eoi = 0;
 283         s->rotate_on_auto_eoi = 0;
 284         s->special_fully_nested_mode = 0;
 285         s->init4 = 0;
 286 }
 287
 288 static void pic_ioport_write(void *opaque, u32 addr, u32 val)
 289 {
 290         struct kvm_kpic_state *s = opaque;
 291         int priority, cmd, irq;
 292
 293         addr &= 1;
 294         if (addr == 0) {
 295                 if (val & 0x10) {
 296                         kvm_pic_reset(s);       /* init */
 297                         /*
 298                          * deassert a pending interrupt
 299                          */
 300                         s->pics_state->irq_request(s->pics_state->
 301                                                    irq_request_opaque, 0);
 302                         s->init_state = 1;
 303                         s->init4 = val & 1;
 304                         if (val & 0x02)
 305                                 printk(KERN_ERR "single mode not supported");
 306                         if (val & 0x08)
 307                                 printk(KERN_ERR
 308                                        "level sensitive irq not supported");
 309                 } else if (val & 0x08) {
 310                         if (val & 0x04)
 311                                 s->poll = 1;
 312                         if (val & 0x02)
 313                                 s->read_reg_select = val & 1;
 314                         if (val & 0x40)
 315                                 s->special_mask = (val >> 5) & 1;
 316                 } else {
 317                         cmd = val >> 5;
 318                         switch (cmd) {
 319                         case 0:
 320                         case 4:
 321                                 s->rotate_on_auto_eoi = cmd >> 2;
 322                                 break;
 323                         case 1: /* end of interrupt */
 324                         case 5:
 325                                 priority = get_priority(s, s->isr);
 326                                 if (priority != 8) {
 327                                         irq = (priority + s->priority_add) & 7;
 328                                         pic_clear_isr(s, irq);
 329                                         if (cmd == 5)
 330                                                 s->priority_add = (irq + 1) & 7;
 331                                         pic_update_irq(s->pics_state);
 332                                 }
 333                                 break;
 334                         case 3:
 335                                 irq = val & 7;
 336                                 pic_clear_isr(s, irq);
 337                                 pic_update_irq(s->pics_state);
 338                                 break;
 339                         case 6:
 340                                 s->priority_add = (val + 1) & 7;
 341                                 pic_update_irq(s->pics_state);
 342                                 break;
 343                         case 7:
 344                                 irq = val & 7;
 345                                 s->priority_add = (irq + 1) & 7;
 346                                 pic_clear_isr(s, irq);
 347                                 pic_update_irq(s->pics_state);
 348                                 break;
 349                         default:
 350                                 break;  /* no operation */
 351                         }
 352                 }
 353         } else
 354                 switch (s->init_state) {
 355                 case 0:         /* normal mode */
 356                         s->imr = val;
 357                         pic_update_irq(s->pics_state);
 358                         break;
 359                 case 1:
 360                         s->irq_base = val & 0xf8;
 361                         s->init_state = 2;
 362                         break;
 363                 case 2:
 364                         if (s->init4)
 365                                 s->init_state = 3;
 366                         else
 367                                 s->init_state = 0;
 368                         break;
 369                 case 3:
 370                         s->special_fully_nested_mode = (val >> 4) & 1;
 371                         s->auto_eoi = (val >> 1) & 1;
 372                         s->init_state = 0;
 373                         break;
 374                 }
 375 }
 376
 377 static u32 pic_poll_read(struct kvm_kpic_state *s, u32 addr1)
 378 {
 379         int ret;
 380
 381         ret = pic_get_irq(s);
 382         if (ret >= 0) {
 383                 if (addr1 >> 7) {
 384                         s->pics_state->pics[0].isr &= ~(1 << 2);
 385                         s->pics_state->pics[0].irr &= ~(1 << 2);
 386                 }
 387                 s->irr &= ~(1 << ret);
 388                 pic_clear_isr(s, ret);
 389                 if (addr1 >> 7 || ret != 2)
 390                         pic_update_irq(s->pics_state);
 391         } else {
 392                 ret = 0x07;
 393                 pic_update_irq(s->pics_state);
 394         }
 395
 396         return ret;
 397 }
 398
 399 static u32 pic_ioport_read(void *opaque, u32 addr1)
 400 {
 401         struct kvm_kpic_state *s = opaque;
 402         unsigned int addr;
 403         int ret;
 404
 405         addr = addr1;
 406         addr &= 1;
 407         if (s->poll) {
 408                 ret = pic_poll_read(s, addr1);
 409                 s->poll = 0;
 410         } else
 411                 if (addr == 0)
 412                         if (s->read_reg_select)
 413                                 ret = s->isr;
 414                         else
 415                                 ret = s->irr;
 416                 else
 417                         ret = s->imr;
 418         return ret;
 419 }
 420
 421 static void elcr_ioport_write(void *opaque, u32 addr, u32 val)
 422 {
 423         struct kvm_kpic_state *s = opaque;
 424         s->elcr = val & s->elcr_mask;
 425 }
 426
 427 static u32 elcr_ioport_read(void *opaque, u32 addr1)
 428 {
 429         struct kvm_kpic_state *s = opaque;
 430         return s->elcr;
 431 }
 432
 433 static int picdev_in_range(gpa_t addr)
 434 {
 435         switch (addr) {
 436         case 0x20:
 437         case 0x21:
 438         case 0xa0:
 439         case 0xa1:
 440         case 0x4d0:
 441         case 0x4d1:
 442                 return 1;
 443         default:
 444                 return 0;
 445         }
 446 }
 447
 448 static inline struct kvm_pic *to_pic(struct kvm_io_device *dev)
 449 {
 450         return container_of(dev, struct kvm_pic, dev);
 451 }
 452
 453 static int picdev_write(struct kvm_io_device *this,
 454                          gpa_t addr, int len, const void *val)
 455 {
 456         struct kvm_pic *s = to_pic(this);
 457         unsigned char data = *(unsigned char *)val;
 458         if (!picdev_in_range(addr))
 459                 return -EOPNOTSUPP;
 460
 461         if (len != 1) {
 462                 if (printk_ratelimit())
 463                         printk(KERN_ERR "PIC: non byte write\n");
 464                 return 0;
 465         }
 466         pic_lock(s);
 467         switch (addr) {
 468         case 0x20:
 469         case 0x21:
 470         case 0xa0:
 471         case 0xa1:
 472                 pic_ioport_write(&s->pics[addr >> 7], addr, data);
 473                 break;
 474         case 0x4d0:
 475         case 0x4d1:
 476                 elcr_ioport_write(&s->pics[addr & 1], addr, data);
 477                 break;
 478         }
 479         pic_unlock(s);
 480         return 0;
 481 }
 482
 483 static int picdev_read(struct kvm_io_device *this,
 484                        gpa_t addr, int len, void *val)
 485 {
 486         struct kvm_pic *s = to_pic(this);
 487         unsigned char data = 0;
 488         if (!picdev_in_range(addr))
 489                 return -EOPNOTSUPP;
 490
 491         if (len != 1) {
 492                 if (printk_ratelimit())
 493                         printk(KERN_ERR "PIC: non byte read\n");
 494                 return 0;
 495         }
 496         pic_lock(s);
 497         switch (addr) {
 498         case 0x20:
 499         case 0x21:
 500         case 0xa0:
 501         case 0xa1:
 502                 data = pic_ioport_read(&s->pics[addr >> 7], addr);
 503                 break;
 504         case 0x4d0:
 505         case 0x4d1:
 506                 data = elcr_ioport_read(&s->pics[addr & 1], addr);
 507                 break;
 508         }
 509         *(unsigned char *)val = data;
 510         pic_unlock(s);
 511         return 0;
 512 }
 513
 514 /*
 515  * callback when PIC0 irq status changed
 516  */
 517 static void pic_irq_request(void *opaque, int level)
 518 {
 519         struct kvm *kvm = opaque;
 520         struct kvm_vcpu *vcpu = kvm->bsp_vcpu;
 521         struct kvm_pic *s = pic_irqchip(kvm);
 522         int irq = pic_get_irq(&s->pics[0]);
 523
 524         s->output = level;
 525         if (vcpu && level && (s->pics[0].isr_ack & (1 << irq))) {
 526                 s->pics[0].isr_ack &= ~(1 << irq);
 527                 s->wakeup_needed = true;
 528         }
 529 }
 530
 531 static const struct kvm_io_device_ops picdev_ops = {
 532         .read     = picdev_read,
 533         .write    = picdev_write,
 534 };
 535
 536 struct kvm_pic *kvm_create_pic(struct kvm *kvm)
 537 {
 538         struct kvm_pic *s;
 539         s = kzalloc(sizeof(struct kvm_pic), GFP_KERNEL);
 540         if (!s)
 541                 return NULL;
 542         spin_lock_init(&s->lock);
 543         s->kvm = kvm;
 544         s->pics[0].elcr_mask = 0xf8;
 545         s->pics[1].elcr_mask = 0xde;
 546         s->irq_request = pic_irq_request;
 547         s->irq_request_opaque = kvm;
 548         s->pics[0].pics_state = s;
 549         s->pics[1].pics_state = s;
 550
 551         /*
 552          * Initialize PIO device
 553          */
 554         kvm_iodevice_init(&s->dev, &picdev_ops);
 555         kvm_io_bus_register_dev(kvm, &kvm->pio_bus, &s->dev);
 556         return s;
 557 }