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 "irq.h"
  30
  31 #include <linux/kvm_host.h>
  32
  33 static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
  34 {
  35         s->isr &= ~(1 << irq);
  36         s->isr_ack |= (1 << irq);
  37 }
  38
  39 void kvm_pic_clear_isr_ack(struct kvm *kvm)
  40 {
  41         struct kvm_pic *s = pic_irqchip(kvm);
  42         s->pics[0].isr_ack = 0xff;
  43         s->pics[1].isr_ack = 0xff;
  44 }
  45
  46 /*
  47  * set irq level. If an edge is detected, then the IRR is set to 1
  48  */
  49 static inline void pic_set_irq1(struct kvm_kpic_state *s, int irq, int level)
  50 {
  51         int mask;
  52         mask = 1 << irq;
  53         if (s->elcr & mask)     /* level triggered */
  54                 if (level) {
  55                         s->irr |= mask;
  56                         s->last_irr |= mask;
  57                 } else {
  58                         s->irr &= ~mask;
  59                         s->last_irr &= ~mask;
  60                 }
  61         else    /* edge triggered */
  62                 if (level) {
  63                         if ((s->last_irr & mask) == 0)
  64                                 s->irr |= mask;
  65                         s->last_irr |= mask;
  66                 } else
  67                         s->last_irr &= ~mask;
  68 }
  69
  70 /*
  71  * return the highest priority found in mask (highest = smallest
  72  * number). Return 8 if no irq
  73  */
  74 static inline int get_priority(struct kvm_kpic_state *s, int mask)
  75 {
  76         int priority;
  77         if (mask == 0)
  78                 return 8;
  79         priority = 0;
  80         while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
  81                 priority++;
  82         return priority;
  83 }
  84
  85 /*
  86  * return the pic wanted interrupt. return -1 if none
  87  */
  88 static int pic_get_irq(struct kvm_kpic_state *s)
  89 {
  90         int mask, cur_priority, priority;
  91
  92         mask = s->irr & ~s->imr;
  93         priority = get_priority(s, mask);
  94         if (priority == 8)
  95                 return -1;
  96         /*
  97          * compute current priority. If special fully nested mode on the
  98          * master, the IRQ coming from the slave is not taken into account
  99          * for the priority computation.
 100          */
 101         mask = s->isr;
 102         if (s->special_fully_nested_mode && s == &s->pics_state->pics[0])
 103                 mask &= ~(1 << 2);
 104         cur_priority = get_priority(s, mask);
 105         if (priority < cur_priority)
 106                 /*
 107                  * higher priority found: an irq should be generated
 108                  */
 109                 return (priority + s->priority_add) & 7;
 110         else
 111                 return -1;
 112 }
 113
 114 /*
 115  * raise irq to CPU if necessary. must be called every time the active
 116  * irq may change
 117  */
 118 static void pic_update_irq(struct kvm_pic *s)
 119 {
 120         int irq2, irq;
 121
 122         irq2 = pic_get_irq(&s->pics[1]);
 123         if (irq2 >= 0) {
 124                 /*
 125                  * if irq request by slave pic, signal master PIC
 126                  */
 127                 pic_set_irq1(&s->pics[0], 2, 1);
 128                 pic_set_irq1(&s->pics[0], 2, 0);
 129         }
 130         irq = pic_get_irq(&s->pics[0]);
 131         if (irq >= 0)
 132                 s->irq_request(s->irq_request_opaque, 1);
 133         else
 134                 s->irq_request(s->irq_request_opaque, 0);
 135 }
 136
 137 void kvm_pic_update_irq(struct kvm_pic *s)
 138 {
 139         pic_update_irq(s);
 140 }
 141
 142 void kvm_pic_set_irq(void *opaque, int irq, int level)
 143 {
 144         struct kvm_pic *s = opaque;
 145
 146         if (irq >= 0 && irq < PIC_NUM_PINS) {
 147                 pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
 148                 pic_update_irq(s);
 149         }
 150 }
 151
 152 /*
 153  * acknowledge interrupt 'irq'
 154  */
 155 static inline void pic_intack(struct kvm_kpic_state *s, int irq)
 156 {
 157         s->isr |= 1 << irq;
 158         if (s->auto_eoi) {
 159                 if (s->rotate_on_auto_eoi)
 160                         s->priority_add = (irq + 1) & 7;
 161                 pic_clear_isr(s, irq);
 162         }
 163         /*
 164          * We don't clear a level sensitive interrupt here
 165          */
 166         if (!(s->elcr & (1 << irq)))
 167                 s->irr &= ~(1 << irq);
 168 }
 169
 170 int kvm_pic_read_irq(struct kvm *kvm)
 171 {
 172         int irq, irq2, intno;
 173         struct kvm_pic *s = pic_irqchip(kvm);
 174
 175         irq = pic_get_irq(&s->pics[0]);
 176         if (irq >= 0) {
 177                 pic_intack(&s->pics[0], irq);
 178                 if (irq == 2) {
 179                         irq2 = pic_get_irq(&s->pics[1]);
 180                         if (irq2 >= 0)
 181                                 pic_intack(&s->pics[1], irq2);
 182                         else
 183                                 /*
 184                                  * spurious IRQ on slave controller
 185                                  */
 186                                 irq2 = 7;
 187                         intno = s->pics[1].irq_base + irq2;
 188                         irq = irq2 + 8;
 189                 } else
 190                         intno = s->pics[0].irq_base + irq;
 191         } else {
 192                 /*
 193                  * spurious IRQ on host controller
 194                  */
 195                 irq = 7;
 196                 intno = s->pics[0].irq_base + irq;
 197         }
 198         pic_update_irq(s);
 199         kvm_notify_acked_irq(kvm, irq);
 200
 201         return intno;
 202 }
 203
 204 void kvm_pic_reset(struct kvm_kpic_state *s)
 205 {
 206         int irq, irqbase;
 207         struct kvm *kvm = s->pics_state->irq_request_opaque;
 208         struct kvm_vcpu *vcpu0 = kvm->vcpus[0];
 209
 210         if (s == &s->pics_state->pics[0])
 211                 irqbase = 0;
 212         else
 213                 irqbase = 8;
 214
 215         for (irq = 0; irq < PIC_NUM_PINS/2; irq++) {
 216                 if (vcpu0 && kvm_apic_accept_pic_intr(vcpu0))
 217                         if (s->irr & (1 << irq) || s->isr & (1 << irq))
 218                                 kvm_notify_acked_irq(kvm, irq+irqbase);
 219         }
 220         s->last_irr = 0;
 221         s->irr = 0;
 222         s->imr = 0;
 223         s->isr = 0;
 224         s->isr_ack = 0xff;
 225         s->priority_add = 0;
 226         s->irq_base = 0;
 227         s->read_reg_select = 0;
 228         s->poll = 0;
 229         s->special_mask = 0;
 230         s->init_state = 0;
 231         s->auto_eoi = 0;
 232         s->rotate_on_auto_eoi = 0;
 233         s->special_fully_nested_mode = 0;
 234         s->init4 = 0;
 235 }
 236
 237 static void pic_ioport_write(void *opaque, u32 addr, u32 val)
 238 {
 239         struct kvm_kpic_state *s = opaque;
 240         int priority, cmd, irq;
 241
 242         addr &= 1;
 243         if (addr == 0) {
 244                 if (val & 0x10) {
 245                         kvm_pic_reset(s);       /* init */
 246                         /*
 247                          * deassert a pending interrupt
 248                          */
 249                         s->pics_state->irq_request(s->pics_state->
 250                                                    irq_request_opaque, 0);
 251                         s->init_state = 1;
 252                         s->init4 = val & 1;
 253                         if (val & 0x02)
 254                                 printk(KERN_ERR "single mode not supported");
 255                         if (val & 0x08)
 256                                 printk(KERN_ERR
 257                                        "level sensitive irq not supported");
 258                 } else if (val & 0x08) {
 259                         if (val & 0x04)
 260                                 s->poll = 1;
 261                         if (val & 0x02)
 262                                 s->read_reg_select = val & 1;
 263                         if (val & 0x40)
 264                                 s->special_mask = (val >> 5) & 1;
 265                 } else {
 266                         cmd = val >> 5;
 267                         switch (cmd) {
 268                         case 0:
 269                         case 4:
 270                                 s->rotate_on_auto_eoi = cmd >> 2;
 271                                 break;
 272                         case 1: /* end of interrupt */
 273                         case 5:
 274                                 priority = get_priority(s, s->isr);
 275                                 if (priority != 8) {
 276                                         irq = (priority + s->priority_add) & 7;
 277                                         pic_clear_isr(s, irq);
 278                                         if (cmd == 5)
 279                                                 s->priority_add = (irq + 1) & 7;
 280                                         pic_update_irq(s->pics_state);
 281                                 }
 282                                 break;
 283                         case 3:
 284                                 irq = val & 7;
 285                                 pic_clear_isr(s, irq);
 286                                 pic_update_irq(s->pics_state);
 287                                 break;
 288                         case 6:
 289                                 s->priority_add = (val + 1) & 7;
 290                                 pic_update_irq(s->pics_state);
 291                                 break;
 292                         case 7:
 293                                 irq = val & 7;
 294                                 s->priority_add = (irq + 1) & 7;
 295                                 pic_clear_isr(s, irq);
 296                                 pic_update_irq(s->pics_state);
 297                                 break;
 298                         default:
 299                                 break;  /* no operation */
 300                         }
 301                 }
 302         } else
 303                 switch (s->init_state) {
 304                 case 0:         /* normal mode */
 305                         s->imr = val;
 306                         pic_update_irq(s->pics_state);
 307                         break;
 308                 case 1:
 309                         s->irq_base = val & 0xf8;
 310                         s->init_state = 2;
 311                         break;
 312                 case 2:
 313                         if (s->init4)
 314                                 s->init_state = 3;
 315                         else
 316                                 s->init_state = 0;
 317                         break;
 318                 case 3:
 319                         s->special_fully_nested_mode = (val >> 4) & 1;
 320                         s->auto_eoi = (val >> 1) & 1;
 321                         s->init_state = 0;
 322                         break;
 323                 }
 324 }
 325
 326 static u32 pic_poll_read(struct kvm_kpic_state *s, u32 addr1)
 327 {
 328         int ret;
 329
 330         ret = pic_get_irq(s);
 331         if (ret >= 0) {
 332                 if (addr1 >> 7) {
 333                         s->pics_state->pics[0].isr &= ~(1 << 2);
 334                         s->pics_state->pics[0].irr &= ~(1 << 2);
 335                 }
 336                 s->irr &= ~(1 << ret);
 337                 pic_clear_isr(s, ret);
 338                 if (addr1 >> 7 || ret != 2)
 339                         pic_update_irq(s->pics_state);
 340         } else {
 341                 ret = 0x07;
 342                 pic_update_irq(s->pics_state);
 343         }
 344
 345         return ret;
 346 }
 347
 348 static u32 pic_ioport_read(void *opaque, u32 addr1)
 349 {
 350         struct kvm_kpic_state *s = opaque;
 351         unsigned int addr;
 352         int ret;
 353
 354         addr = addr1;
 355         addr &= 1;
 356         if (s->poll) {
 357                 ret = pic_poll_read(s, addr1);
 358                 s->poll = 0;
 359         } else
 360                 if (addr == 0)
 361                         if (s->read_reg_select)
 362                                 ret = s->isr;
 363                         else
 364                                 ret = s->irr;
 365                 else
 366                         ret = s->imr;
 367         return ret;
 368 }
 369
 370 static void elcr_ioport_write(void *opaque, u32 addr, u32 val)
 371 {
 372         struct kvm_kpic_state *s = opaque;
 373         s->elcr = val & s->elcr_mask;
 374 }
 375
 376 static u32 elcr_ioport_read(void *opaque, u32 addr1)
 377 {
 378         struct kvm_kpic_state *s = opaque;
 379         return s->elcr;
 380 }
 381
 382 static int picdev_in_range(struct kvm_io_device *this, gpa_t addr,
 383                            int len, int is_write)
 384 {
 385         switch (addr) {
 386         case 0x20:
 387         case 0x21:
 388         case 0xa0:
 389         case 0xa1:
 390         case 0x4d0:
 391         case 0x4d1:
 392                 return 1;
 393         default:
 394                 return 0;
 395         }
 396 }
 397
 398 static void picdev_write(struct kvm_io_device *this,
 399                          gpa_t addr, int len, const void *val)
 400 {
 401         struct kvm_pic *s = this->private;
 402         unsigned char data = *(unsigned char *)val;
 403
 404         if (len != 1) {
 405                 if (printk_ratelimit())
 406                         printk(KERN_ERR "PIC: non byte write\n");
 407                 return;
 408         }
 409         switch (addr) {
 410         case 0x20:
 411         case 0x21:
 412         case 0xa0:
 413         case 0xa1:
 414                 pic_ioport_write(&s->pics[addr >> 7], addr, data);
 415                 break;
 416         case 0x4d0:
 417         case 0x4d1:
 418                 elcr_ioport_write(&s->pics[addr & 1], addr, data);
 419                 break;
 420         }
 421 }
 422
 423 static void picdev_read(struct kvm_io_device *this,
 424                         gpa_t addr, int len, void *val)
 425 {
 426         struct kvm_pic *s = this->private;
 427         unsigned char data = 0;
 428
 429         if (len != 1) {
 430                 if (printk_ratelimit())
 431                         printk(KERN_ERR "PIC: non byte read\n");
 432                 return;
 433         }
 434         switch (addr) {
 435         case 0x20:
 436         case 0x21:
 437         case 0xa0:
 438         case 0xa1:
 439                 data = pic_ioport_read(&s->pics[addr >> 7], addr);
 440                 break;
 441         case 0x4d0:
 442         case 0x4d1:
 443                 data = elcr_ioport_read(&s->pics[addr & 1], addr);
 444                 break;
 445         }
 446         *(unsigned char *)val = data;
 447 }
 448
 449 /*
 450  * callback when PIC0 irq status changed
 451  */
 452 static void pic_irq_request(void *opaque, int level)
 453 {
 454         struct kvm *kvm = opaque;
 455         struct kvm_vcpu *vcpu = kvm->vcpus[0];
 456         struct kvm_pic *s = pic_irqchip(kvm);
 457         int irq = pic_get_irq(&s->pics[0]);
 458
 459         s->output = level;
 460         if (vcpu && level && (s->pics[0].isr_ack & (1 << irq))) {
 461                 s->pics[0].isr_ack &= ~(1 << irq);
 462                 kvm_vcpu_kick(vcpu);
 463         }
 464 }
 465
 466 struct kvm_pic *kvm_create_pic(struct kvm *kvm)
 467 {
 468         struct kvm_pic *s;
 469         s = kzalloc(sizeof(struct kvm_pic), GFP_KERNEL);
 470         if (!s)
 471                 return NULL;
 472         s->pics[0].elcr_mask = 0xf8;
 473         s->pics[1].elcr_mask = 0xde;
 474         s->irq_request = pic_irq_request;
 475         s->irq_request_opaque = kvm;
 476         s->pics[0].pics_state = s;
 477         s->pics[1].pics_state = s;
 478
 479         /*
 480          * Initialize PIO device
 481          */
 482         s->dev.read = picdev_read;
 483         s->dev.write = picdev_write;
 484         s->dev.in_range = picdev_in_range;
 485         s->dev.private = s;
 486         kvm_io_bus_register_dev(&kvm->pio_bus, &s->dev);
 487         return s;
 488 }