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