drivers/iommu/intr_remapping.c

   1 #include <linux/interrupt.h>
   2 #include <linux/dmar.h>
   3 #include <linux/spinlock.h>
   4 #include <linux/slab.h>
   5 #include <linux/jiffies.h>
   6 #include <linux/hpet.h>
   7 #include <linux/pci.h>
   8 #include <linux/irq.h>
   9 #include <asm/io_apic.h>
  10 #include <asm/smp.h>
  11 #include <asm/cpu.h>
  12 #include <linux/intel-iommu.h>
  13 #include "intr_remapping.h"
  14 #include <acpi/acpi.h>
  15 #include <asm/pci-direct.h>
  16
  17 static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
  18 static struct hpet_scope ir_hpet[MAX_HPET_TBS];
  19 static int ir_ioapic_num, ir_hpet_num;
  20 int intr_remapping_enabled;
  21
  22 static int disable_intremap;
  23 static int disable_sourceid_checking;
  24 static int no_x2apic_optout;
  25
  26 static __init int setup_nointremap(char *str)
  27 {
  28         disable_intremap = 1;
  29         return 0;
  30 }
  31 early_param("nointremap", setup_nointremap);
  32
  33 static __init int setup_intremap(char *str)
  34 {
  35         if (!str)
  36                 return -EINVAL;
  37
  38         while (*str) {
  39                 if (!strncmp(str, "on", 2))
  40                         disable_intremap = 0;
  41                 else if (!strncmp(str, "off", 3))
  42                         disable_intremap = 1;
  43                 else if (!strncmp(str, "nosid", 5))
  44                         disable_sourceid_checking = 1;
  45                 else if (!strncmp(str, "no_x2apic_optout", 16))
  46                         no_x2apic_optout = 1;
  47
  48                 str += strcspn(str, ",");
  49                 while (*str == ',')
  50                         str++;
  51         }
  52
  53         return 0;
  54 }
  55 early_param("intremap", setup_intremap);
  56
  57 static DEFINE_RAW_SPINLOCK(irq_2_ir_lock);
  58
  59 static struct irq_2_iommu *irq_2_iommu(unsigned int irq)
  60 {
  61         struct irq_cfg *cfg = irq_get_chip_data(irq);
  62         return cfg ? &cfg->irq_2_iommu : NULL;
  63 }
  64
  65 int get_irte(int irq, struct irte *entry)
  66 {
  67         struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
  68         unsigned long flags;
  69         int index;
  70
  71         if (!entry || !irq_iommu)
  72                 return -1;
  73
  74         raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
  75
  76         index = irq_iommu->irte_index + irq_iommu->sub_handle;
  77         *entry = *(irq_iommu->iommu->ir_table->base + index);
  78
  79         raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
  80         return 0;
  81 }
  82
  83 int alloc_irte(struct intel_iommu *iommu, int irq, u16 count)
  84 {
  85         struct ir_table *table = iommu->ir_table;
  86         struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
  87         u16 index, start_index;
  88         unsigned int mask = 0;
  89         unsigned long flags;
  90         int i;
  91
  92         if (!count || !irq_iommu)
  93                 return -1;
  94
  95         /*
  96          * start the IRTE search from index 0.
  97          */
  98         index = start_index = 0;
  99
 100         if (count > 1) {
 101                 count = __roundup_pow_of_two(count);
 102                 mask = ilog2(count);
 103         }
 104
 105         if (mask > ecap_max_handle_mask(iommu->ecap)) {
 106                 printk(KERN_ERR
 107                        "Requested mask %x exceeds the max invalidation handle"
 108                        " mask value %Lx\n", mask,
 109                        ecap_max_handle_mask(iommu->ecap));
 110                 return -1;
 111         }
 112
 113         raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
 114         do {
 115                 for (i = index; i < index + count; i++)
 116                         if  (table->base[i].present)
 117                                 break;
 118                 /* empty index found */
 119                 if (i == index + count)
 120                         break;
 121
 122                 index = (index + count) % INTR_REMAP_TABLE_ENTRIES;
 123
 124                 if (index == start_index) {
 125                         raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 126                         printk(KERN_ERR "can't allocate an IRTE\n");
 127                         return -1;
 128                 }
 129         } while (1);
 130
 131         for (i = index; i < index + count; i++)
 132                 table->base[i].present = 1;
 133
 134         irq_iommu->iommu = iommu;
 135         irq_iommu->irte_index =  index;
 136         irq_iommu->sub_handle = 0;
 137         irq_iommu->irte_mask = mask;
 138
 139         raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 140
 141         return index;
 142 }
 143
 144 static int qi_flush_iec(struct intel_iommu *iommu, int index, int mask)
 145 {
 146         struct qi_desc desc;
 147
 148         desc.low = QI_IEC_IIDEX(index) | QI_IEC_TYPE | QI_IEC_IM(mask)
 149                    | QI_IEC_SELECTIVE;
 150         desc.high = 0;
 151
 152         return qi_submit_sync(&desc, iommu);
 153 }
 154
 155 int map_irq_to_irte_handle(int irq, u16 *sub_handle)
 156 {
 157         struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
 158         unsigned long flags;
 159         int index;
 160
 161         if (!irq_iommu)
 162                 return -1;
 163
 164         raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
 165         *sub_handle = irq_iommu->sub_handle;
 166         index = irq_iommu->irte_index;
 167         raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 168         return index;
 169 }
 170
 171 int set_irte_irq(int irq, struct intel_iommu *iommu, u16 index, u16 subhandle)
 172 {
 173         struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
 174         unsigned long flags;
 175
 176         if (!irq_iommu)
 177                 return -1;
 178
 179         raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
 180
 181         irq_iommu->iommu = iommu;
 182         irq_iommu->irte_index = index;
 183         irq_iommu->sub_handle = subhandle;
 184         irq_iommu->irte_mask = 0;
 185
 186         raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 187
 188         return 0;
 189 }
 190
 191 int modify_irte(int irq, struct irte *irte_modified)
 192 {
 193         struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
 194         struct intel_iommu *iommu;
 195         unsigned long flags;
 196         struct irte *irte;
 197         int rc, index;
 198
 199         if (!irq_iommu)
 200                 return -1;
 201
 202         raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
 203
 204         iommu = irq_iommu->iommu;
 205
 206         index = irq_iommu->irte_index + irq_iommu->sub_handle;
 207         irte = &iommu->ir_table->base[index];
 208
 209         set_64bit(&irte->low, irte_modified->low);
 210         set_64bit(&irte->high, irte_modified->high);
 211         __iommu_flush_cache(iommu, irte, sizeof(*irte));
 212
 213         rc = qi_flush_iec(iommu, index, 0);
 214         raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 215
 216         return rc;
 217 }
 218
 219 struct intel_iommu *map_hpet_to_ir(u8 hpet_id)
 220 {
 221         int i;
 222
 223         for (i = 0; i < MAX_HPET_TBS; i++)
 224                 if (ir_hpet[i].id == hpet_id)
 225                         return ir_hpet[i].iommu;
 226         return NULL;
 227 }
 228
 229 struct intel_iommu *map_ioapic_to_ir(int apic)
 230 {
 231         int i;
 232
 233         for (i = 0; i < MAX_IO_APICS; i++)
 234                 if (ir_ioapic[i].id == apic)
 235                         return ir_ioapic[i].iommu;
 236         return NULL;
 237 }
 238
 239 struct intel_iommu *map_dev_to_ir(struct pci_dev *dev)
 240 {
 241         struct dmar_drhd_unit *drhd;
 242
 243         drhd = dmar_find_matched_drhd_unit(dev);
 244         if (!drhd)
 245                 return NULL;
 246
 247         return drhd->iommu;
 248 }
 249
 250 static int clear_entries(struct irq_2_iommu *irq_iommu)
 251 {
 252         struct irte *start, *entry, *end;
 253         struct intel_iommu *iommu;
 254         int index;
 255
 256         if (irq_iommu->sub_handle)
 257                 return 0;
 258
 259         iommu = irq_iommu->iommu;
 260         index = irq_iommu->irte_index + irq_iommu->sub_handle;
 261
 262         start = iommu->ir_table->base + index;
 263         end = start + (1 << irq_iommu->irte_mask);
 264
 265         for (entry = start; entry < end; entry++) {
 266                 set_64bit(&entry->low, 0);
 267                 set_64bit(&entry->high, 0);
 268         }
 269
 270         return qi_flush_iec(iommu, index, irq_iommu->irte_mask);
 271 }
 272
 273 int free_irte(int irq)
 274 {
 275         struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
 276         unsigned long flags;
 277         int rc;
 278
 279         if (!irq_iommu)
 280                 return -1;
 281
 282         raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
 283
 284         rc = clear_entries(irq_iommu);
 285
 286         irq_iommu->iommu = NULL;
 287         irq_iommu->irte_index = 0;
 288         irq_iommu->sub_handle = 0;
 289         irq_iommu->irte_mask = 0;
 290
 291         raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 292
 293         return rc;
 294 }
 295
 296 /*
 297  * source validation type
 298  */
 299 #define SVT_NO_VERIFY           0x0  /* no verification is required */
 300 #define SVT_VERIFY_SID_SQ       0x1  /* verify using SID and SQ fields */
 301 #define SVT_VERIFY_BUS          0x2  /* verify bus of request-id */
 302
 303 /*
 304  * source-id qualifier
 305  */
 306 #define SQ_ALL_16       0x0  /* verify all 16 bits of request-id */
 307 #define SQ_13_IGNORE_1  0x1  /* verify most significant 13 bits, ignore
 308                               * the third least significant bit
 309                               */
 310 #define SQ_13_IGNORE_2  0x2  /* verify most significant 13 bits, ignore
 311                               * the second and third least significant bits
 312                               */
 313 #define SQ_13_IGNORE_3  0x3  /* verify most significant 13 bits, ignore
 314                               * the least three significant bits
 315                               */
 316
 317 /*
 318  * set SVT, SQ and SID fields of irte to verify
 319  * source ids of interrupt requests
 320  */
 321 static void set_irte_sid(struct irte *irte, unsigned int svt,
 322                          unsigned int sq, unsigned int sid)
 323 {
 324         if (disable_sourceid_checking)
 325                 svt = SVT_NO_VERIFY;
 326         irte->svt = svt;
 327         irte->sq = sq;
 328         irte->sid = sid;
 329 }
 330
 331 int set_ioapic_sid(struct irte *irte, int apic)
 332 {
 333         int i;
 334         u16 sid = 0;
 335
 336         if (!irte)
 337                 return -1;
 338
 339         for (i = 0; i < MAX_IO_APICS; i++) {
 340                 if (ir_ioapic[i].id == apic) {
 341                         sid = (ir_ioapic[i].bus << 8) | ir_ioapic[i].devfn;
 342                         break;
 343                 }
 344         }
 345
 346         if (sid == 0) {
 347                 pr_warning("Failed to set source-id of IOAPIC (%d)\n", apic);
 348                 return -1;
 349         }
 350
 351         set_irte_sid(irte, 1, 0, sid);
 352
 353         return 0;
 354 }
 355
 356 int set_hpet_sid(struct irte *irte, u8 id)
 357 {
 358         int i;
 359         u16 sid = 0;
 360
 361         if (!irte)
 362                 return -1;
 363
 364         for (i = 0; i < MAX_HPET_TBS; i++) {
 365                 if (ir_hpet[i].id == id) {
 366                         sid = (ir_hpet[i].bus << 8) | ir_hpet[i].devfn;
 367                         break;
 368                 }
 369         }
 370
 371         if (sid == 0) {
 372                 pr_warning("Failed to set source-id of HPET block (%d)\n", id);
 373                 return -1;
 374         }
 375
 376         /*
 377          * Should really use SQ_ALL_16. Some platforms are broken.
 378          * While we figure out the right quirks for these broken platforms, use
 379          * SQ_13_IGNORE_3 for now.
 380          */
 381         set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_13_IGNORE_3, sid);
 382
 383         return 0;
 384 }
 385
 386 int set_msi_sid(struct irte *irte, struct pci_dev *dev)
 387 {
 388         struct pci_dev *bridge;
 389
 390         if (!irte || !dev)
 391                 return -1;
 392
 393         /* PCIe device or Root Complex integrated PCI device */
 394         if (pci_is_pcie(dev) || !dev->bus->parent) {
 395                 set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16,
 396                              (dev->bus->number << 8) | dev->devfn);
 397                 return 0;
 398         }
 399
 400         bridge = pci_find_upstream_pcie_bridge(dev);
 401         if (bridge) {
 402                 if (pci_is_pcie(bridge))/* this is a PCIe-to-PCI/PCIX bridge */
 403                         set_irte_sid(irte, SVT_VERIFY_BUS, SQ_ALL_16,
 404                                 (bridge->bus->number << 8) | dev->bus->number);
 405                 else /* this is a legacy PCI bridge */
 406                         set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16,
 407                                 (bridge->bus->number << 8) | bridge->devfn);
 408         }
 409
 410         return 0;
 411 }
 412
 413 static void iommu_set_intr_remapping(struct intel_iommu *iommu, int mode)
 414 {
 415         u64 addr;
 416         u32 sts;
 417         unsigned long flags;
 418
 419         addr = virt_to_phys((void *)iommu->ir_table->base);
 420
 421         raw_spin_lock_irqsave(&iommu->register_lock, flags);
 422
 423         dmar_writeq(iommu->reg + DMAR_IRTA_REG,
 424                     (addr) | IR_X2APIC_MODE(mode) | INTR_REMAP_TABLE_REG_SIZE);
 425
 426         /* Set interrupt-remapping table pointer */
 427         iommu->gcmd |= DMA_GCMD_SIRTP;
 428         writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
 429
 430         IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
 431                       readl, (sts & DMA_GSTS_IRTPS), sts);
 432         raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
 433
 434         /*
 435          * global invalidation of interrupt entry cache before enabling
 436          * interrupt-remapping.
 437          */
 438         qi_global_iec(iommu);
 439
 440         raw_spin_lock_irqsave(&iommu->register_lock, flags);
 441
 442         /* Enable interrupt-remapping */
 443         iommu->gcmd |= DMA_GCMD_IRE;
 444         writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
 445
 446         IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
 447                       readl, (sts & DMA_GSTS_IRES), sts);
 448
 449         raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
 450 }
 451
 452
 453 static int setup_intr_remapping(struct intel_iommu *iommu, int mode)
 454 {
 455         struct ir_table *ir_table;
 456         struct page *pages;
 457
 458         ir_table = iommu->ir_table = kzalloc(sizeof(struct ir_table),
 459                                              GFP_ATOMIC);
 460
 461         if (!iommu->ir_table)
 462                 return -ENOMEM;
 463
 464         pages = alloc_pages_node(iommu->node, GFP_ATOMIC | __GFP_ZERO,
 465                                  INTR_REMAP_PAGE_ORDER);
 466
 467         if (!pages) {
 468                 printk(KERN_ERR "failed to allocate pages of order %d\n",
 469                        INTR_REMAP_PAGE_ORDER);
 470                 kfree(iommu->ir_table);
 471                 return -ENOMEM;
 472         }
 473
 474         ir_table->base = page_address(pages);
 475
 476         iommu_set_intr_remapping(iommu, mode);
 477         return 0;
 478 }
 479
 480 /*
 481  * Disable Interrupt Remapping.
 482  */
 483 static void iommu_disable_intr_remapping(struct intel_iommu *iommu)
 484 {
 485         unsigned long flags;
 486         u32 sts;
 487
 488         if (!ecap_ir_support(iommu->ecap))
 489                 return;
 490
 491         /*
 492          * global invalidation of interrupt entry cache before disabling
 493          * interrupt-remapping.
 494          */
 495         qi_global_iec(iommu);
 496
 497         raw_spin_lock_irqsave(&iommu->register_lock, flags);
 498
 499         sts = dmar_readq(iommu->reg + DMAR_GSTS_REG);
 500         if (!(sts & DMA_GSTS_IRES))
 501                 goto end;
 502
 503         iommu->gcmd &= ~DMA_GCMD_IRE;
 504         writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
 505
 506         IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
 507                       readl, !(sts & DMA_GSTS_IRES), sts);
 508
 509 end:
 510         raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
 511 }
 512
 513 static int __init dmar_x2apic_optout(void)
 514 {
 515         struct acpi_table_dmar *dmar;
 516         dmar = (struct acpi_table_dmar *)dmar_tbl;
 517         if (!dmar || no_x2apic_optout)
 518                 return 0;
 519         return dmar->flags & DMAR_X2APIC_OPT_OUT;
 520 }
 521
 522 int __init intr_remapping_supported(void)
 523 {
 524         struct dmar_drhd_unit *drhd;
 525
 526         if (disable_intremap)
 527                 return 0;
 528
 529         if (!dmar_ir_support())
 530                 return 0;
 531
 532         for_each_drhd_unit(drhd) {
 533                 struct intel_iommu *iommu = drhd->iommu;
 534
 535                 if (!ecap_ir_support(iommu->ecap))
 536                         return 0;
 537         }
 538
 539         return 1;
 540 }
 541
 542 int __init enable_intr_remapping(void)
 543 {
 544         struct dmar_drhd_unit *drhd;
 545         int setup = 0;
 546         int eim = 0;
 547
 548         if (parse_ioapics_under_ir() != 1) {
 549                 printk(KERN_INFO "Not enable interrupt remapping\n");
 550                 return -1;
 551         }
 552
 553         if (x2apic_supported()) {
 554                 eim = !dmar_x2apic_optout();
 555                 WARN(!eim, KERN_WARNING
 556                            "Your BIOS is broken and requested that x2apic be disabled\n"
 557                            "This will leave your machine vulnerable to irq-injection attacks\n"
 558                            "Use 'intremap=no_x2apic_optout' to override BIOS request\n");
 559         }
 560
 561         for_each_drhd_unit(drhd) {
 562                 struct intel_iommu *iommu = drhd->iommu;
 563
 564                 /*
 565                  * If the queued invalidation is already initialized,
 566                  * shouldn't disable it.
 567                  */
 568                 if (iommu->qi)
 569                         continue;
 570
 571                 /*
 572                  * Clear previous faults.
 573                  */
 574                 dmar_fault(-1, iommu);
 575
 576                 /*
 577                  * Disable intr remapping and queued invalidation, if already
 578                  * enabled prior to OS handover.
 579                  */
 580                 iommu_disable_intr_remapping(iommu);
 581
 582                 dmar_disable_qi(iommu);
 583         }
 584
 585         /*
 586          * check for the Interrupt-remapping support
 587          */
 588         for_each_drhd_unit(drhd) {
 589                 struct intel_iommu *iommu = drhd->iommu;
 590
 591                 if (!ecap_ir_support(iommu->ecap))
 592                         continue;
 593
 594                 if (eim && !ecap_eim_support(iommu->ecap)) {
 595                         printk(KERN_INFO "DRHD %Lx: EIM not supported by DRHD, "
 596                                " ecap %Lx\n", drhd->reg_base_addr, iommu->ecap);
 597                         return -1;
 598                 }
 599         }
 600
 601         /*
 602          * Enable queued invalidation for all the DRHD's.
 603          */
 604         for_each_drhd_unit(drhd) {
 605                 int ret;
 606                 struct intel_iommu *iommu = drhd->iommu;
 607                 ret = dmar_enable_qi(iommu);
 608
 609                 if (ret) {
 610                         printk(KERN_ERR "DRHD %Lx: failed to enable queued, "
 611                                " invalidation, ecap %Lx, ret %d\n",
 612                                drhd->reg_base_addr, iommu->ecap, ret);
 613                         return -1;
 614                 }
 615         }
 616
 617         /*
 618          * Setup Interrupt-remapping for all the DRHD's now.
 619          */
 620         for_each_drhd_unit(drhd) {
 621                 struct intel_iommu *iommu = drhd->iommu;
 622
 623                 if (!ecap_ir_support(iommu->ecap))
 624                         continue;
 625
 626                 if (setup_intr_remapping(iommu, eim))
 627                         goto error;
 628
 629                 setup = 1;
 630         }
 631
 632         if (!setup)
 633                 goto error;
 634
 635         intr_remapping_enabled = 1;
 636         pr_info("Enabled IRQ remapping in %s mode\n", eim ? "x2apic" : "xapic");
 637
 638         return eim ? IRQ_REMAP_X2APIC_MODE : IRQ_REMAP_XAPIC_MODE;
 639
 640 error:
 641         /*
 642          * handle error condition gracefully here!
 643          */
 644         return -1;
 645 }
 646
 647 static void ir_parse_one_hpet_scope(struct acpi_dmar_device_scope *scope,
 648                                       struct intel_iommu *iommu)
 649 {
 650         struct acpi_dmar_pci_path *path;
 651         u8 bus;
 652         int count;
 653
 654         bus = scope->bus;
 655         path = (struct acpi_dmar_pci_path *)(scope + 1);
 656         count = (scope->length - sizeof(struct acpi_dmar_device_scope))
 657                 / sizeof(struct acpi_dmar_pci_path);
 658
 659         while (--count > 0) {
 660                 /*
 661                  * Access PCI directly due to the PCI
 662                  * subsystem isn't initialized yet.
 663                  */
 664                 bus = read_pci_config_byte(bus, path->dev, path->fn,
 665                                            PCI_SECONDARY_BUS);
 666                 path++;
 667         }
 668         ir_hpet[ir_hpet_num].bus   = bus;
 669         ir_hpet[ir_hpet_num].devfn = PCI_DEVFN(path->dev, path->fn);
 670         ir_hpet[ir_hpet_num].iommu = iommu;
 671         ir_hpet[ir_hpet_num].id    = scope->enumeration_id;
 672         ir_hpet_num++;
 673 }
 674
 675 static void ir_parse_one_ioapic_scope(struct acpi_dmar_device_scope *scope,
 676                                       struct intel_iommu *iommu)
 677 {
 678         struct acpi_dmar_pci_path *path;
 679         u8 bus;
 680         int count;
 681
 682         bus = scope->bus;
 683         path = (struct acpi_dmar_pci_path *)(scope + 1);
 684         count = (scope->length - sizeof(struct acpi_dmar_device_scope))
 685                 / sizeof(struct acpi_dmar_pci_path);
 686
 687         while (--count > 0) {
 688                 /*
 689                  * Access PCI directly due to the PCI
 690                  * subsystem isn't initialized yet.
 691                  */
 692                 bus = read_pci_config_byte(bus, path->dev, path->fn,
 693                                            PCI_SECONDARY_BUS);
 694                 path++;
 695         }
 696
 697         ir_ioapic[ir_ioapic_num].bus   = bus;
 698         ir_ioapic[ir_ioapic_num].devfn = PCI_DEVFN(path->dev, path->fn);
 699         ir_ioapic[ir_ioapic_num].iommu = iommu;
 700         ir_ioapic[ir_ioapic_num].id    = scope->enumeration_id;
 701         ir_ioapic_num++;
 702 }
 703
 704 static int ir_parse_ioapic_hpet_scope(struct acpi_dmar_header *header,
 705                                       struct intel_iommu *iommu)
 706 {
 707         struct acpi_dmar_hardware_unit *drhd;
 708         struct acpi_dmar_device_scope *scope;
 709         void *start, *end;
 710
 711         drhd = (struct acpi_dmar_hardware_unit *)header;
 712
 713         start = (void *)(drhd + 1);
 714         end = ((void *)drhd) + header->length;
 715
 716         while (start < end) {
 717                 scope = start;
 718                 if (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_IOAPIC) {
 719                         if (ir_ioapic_num == MAX_IO_APICS) {
 720                                 printk(KERN_WARNING "Exceeded Max IO APICS\n");
 721                                 return -1;
 722                         }
 723
 724                         printk(KERN_INFO "IOAPIC id %d under DRHD base "
 725                                " 0x%Lx IOMMU %d\n", scope->enumeration_id,
 726                                drhd->address, iommu->seq_id);
 727
 728                         ir_parse_one_ioapic_scope(scope, iommu);
 729                 } else if (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_HPET) {
 730                         if (ir_hpet_num == MAX_HPET_TBS) {
 731                                 printk(KERN_WARNING "Exceeded Max HPET blocks\n");
 732                                 return -1;
 733                         }
 734
 735                         printk(KERN_INFO "HPET id %d under DRHD base"
 736                                " 0x%Lx\n", scope->enumeration_id,
 737                                drhd->address);
 738
 739                         ir_parse_one_hpet_scope(scope, iommu);
 740                 }
 741                 start += scope->length;
 742         }
 743
 744         return 0;
 745 }
 746
 747 /*
 748  * Finds the assocaition between IOAPIC's and its Interrupt-remapping
 749  * hardware unit.
 750  */
 751 int __init parse_ioapics_under_ir(void)
 752 {
 753         struct dmar_drhd_unit *drhd;
 754         int ir_supported = 0;
 755
 756         for_each_drhd_unit(drhd) {
 757                 struct intel_iommu *iommu = drhd->iommu;
 758
 759                 if (ecap_ir_support(iommu->ecap)) {
 760                         if (ir_parse_ioapic_hpet_scope(drhd->hdr, iommu))
 761                                 return -1;
 762
 763                         ir_supported = 1;
 764                 }
 765         }
 766
 767         if (ir_supported && ir_ioapic_num != nr_ioapics) {
 768                 printk(KERN_WARNING
 769                        "Not all IO-APIC's listed under remapping hardware\n");
 770                 return -1;
 771         }
 772
 773         return ir_supported;
 774 }
 775
 776 int ir_dev_scope_init(void)
 777 {
 778         if (!intr_remapping_enabled)
 779                 return 0;
 780
 781         return dmar_dev_scope_init();
 782 }
 783 rootfs_initcall(ir_dev_scope_init);
 784
 785 void disable_intr_remapping(void)
 786 {
 787         struct dmar_drhd_unit *drhd;
 788         struct intel_iommu *iommu = NULL;
 789
 790         /*
 791          * Disable Interrupt-remapping for all the DRHD's now.
 792          */
 793         for_each_iommu(iommu, drhd) {
 794                 if (!ecap_ir_support(iommu->ecap))
 795                         continue;
 796
 797                 iommu_disable_intr_remapping(iommu);
 798         }
 799 }
 800
 801 int reenable_intr_remapping(int eim)
 802 {
 803         struct dmar_drhd_unit *drhd;
 804         int setup = 0;
 805         struct intel_iommu *iommu = NULL;
 806
 807         for_each_iommu(iommu, drhd)
 808                 if (iommu->qi)
 809                         dmar_reenable_qi(iommu);
 810
 811         /*
 812          * Setup Interrupt-remapping for all the DRHD's now.
 813          */
 814         for_each_iommu(iommu, drhd) {
 815                 if (!ecap_ir_support(iommu->ecap))
 816                         continue;
 817
 818                 /* Set up interrupt remapping for iommu.*/
 819                 iommu_set_intr_remapping(iommu, eim);
 820                 setup = 1;
 821         }
 822
 823         if (!setup)
 824                 goto error;
 825
 826         return 0;
 827
 828 error:
 829         /*
 830          * handle error condition gracefully here!
 831          */
 832         return -1;
 833 }
 834