drivers/iommu/intel-svm.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright © 2015 Intel Corporation.
   4  *
   5  * Authors: David Woodhouse <[email protected]>
   6  */
   7
   8 #include <linux/intel-iommu.h>
   9 #include <linux/mmu_notifier.h>
  10 #include <linux/sched.h>
  11 #include <linux/sched/mm.h>
  12 #include <linux/slab.h>
  13 #include <linux/intel-svm.h>
  14 #include <linux/rculist.h>
  15 #include <linux/pci.h>
  16 #include <linux/pci-ats.h>
  17 #include <linux/dmar.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/mm_types.h>
  20 #include <asm/page.h>
  21
  22 #include "intel-pasid.h"
  23
  24 static irqreturn_t prq_event_thread(int irq, void *d);
  25
  26 int intel_svm_init(struct intel_iommu *iommu)
  27 {
  28         if (cpu_feature_enabled(X86_FEATURE_GBPAGES) &&
  29                         !cap_fl1gp_support(iommu->cap))
  30                 return -EINVAL;
  31
  32         if (cpu_feature_enabled(X86_FEATURE_LA57) &&
  33                         !cap_5lp_support(iommu->cap))
  34                 return -EINVAL;
  35
  36         return 0;
  37 }
  38
  39 #define PRQ_ORDER 0
  40
  41 int intel_svm_enable_prq(struct intel_iommu *iommu)
  42 {
  43         struct page *pages;
  44         int irq, ret;
  45
  46         pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, PRQ_ORDER);
  47         if (!pages) {
  48                 pr_warn("IOMMU: %s: Failed to allocate page request queue\n",
  49                         iommu->name);
  50                 return -ENOMEM;
  51         }
  52         iommu->prq = page_address(pages);
  53
  54         irq = dmar_alloc_hwirq(DMAR_UNITS_SUPPORTED + iommu->seq_id, iommu->node, iommu);
  55         if (irq <= 0) {
  56                 pr_err("IOMMU: %s: Failed to create IRQ vector for page request queue\n",
  57                        iommu->name);
  58                 ret = -EINVAL;
  59         err:
  60                 free_pages((unsigned long)iommu->prq, PRQ_ORDER);
  61                 iommu->prq = NULL;
  62                 return ret;
  63         }
  64         iommu->pr_irq = irq;
  65
  66         snprintf(iommu->prq_name, sizeof(iommu->prq_name), "dmar%d-prq", iommu->seq_id);
  67
  68         ret = request_threaded_irq(irq, NULL, prq_event_thread, IRQF_ONESHOT,
  69                                    iommu->prq_name, iommu);
  70         if (ret) {
  71                 pr_err("IOMMU: %s: Failed to request IRQ for page request queue\n",
  72                        iommu->name);
  73                 dmar_free_hwirq(irq);
  74                 iommu->pr_irq = 0;
  75                 goto err;
  76         }
  77         dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
  78         dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
  79         dmar_writeq(iommu->reg + DMAR_PQA_REG, virt_to_phys(iommu->prq) | PRQ_ORDER);
  80
  81         return 0;
  82 }
  83
  84 int intel_svm_finish_prq(struct intel_iommu *iommu)
  85 {
  86         dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
  87         dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
  88         dmar_writeq(iommu->reg + DMAR_PQA_REG, 0ULL);
  89
  90         if (iommu->pr_irq) {
  91                 free_irq(iommu->pr_irq, iommu);
  92                 dmar_free_hwirq(iommu->pr_irq);
  93                 iommu->pr_irq = 0;
  94         }
  95
  96         free_pages((unsigned long)iommu->prq, PRQ_ORDER);
  97         iommu->prq = NULL;
  98
  99         return 0;
 100 }
 101
 102 static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_dev *sdev,
 103                                 unsigned long address, unsigned long pages, int ih)
 104 {
 105         struct qi_desc desc;
 106
 107         /*
 108          * Do PASID granu IOTLB invalidation if page selective capability is
 109          * not available.
 110          */
 111         if (pages == -1 || !cap_pgsel_inv(svm->iommu->cap)) {
 112                 desc.qw0 = QI_EIOTLB_PASID(svm->pasid) |
 113                         QI_EIOTLB_DID(sdev->did) |
 114                         QI_EIOTLB_GRAN(QI_GRAN_NONG_PASID) |
 115                         QI_EIOTLB_TYPE;
 116                 desc.qw1 = 0;
 117         } else {
 118                 int mask = ilog2(__roundup_pow_of_two(pages));
 119
 120                 desc.qw0 = QI_EIOTLB_PASID(svm->pasid) |
 121                                 QI_EIOTLB_DID(sdev->did) |
 122                                 QI_EIOTLB_GRAN(QI_GRAN_PSI_PASID) |
 123                                 QI_EIOTLB_TYPE;
 124                 desc.qw1 = QI_EIOTLB_ADDR(address) |
 125                                 QI_EIOTLB_IH(ih) |
 126                                 QI_EIOTLB_AM(mask);
 127         }
 128         desc.qw2 = 0;
 129         desc.qw3 = 0;
 130         qi_submit_sync(&desc, svm->iommu);
 131
 132         if (sdev->dev_iotlb) {
 133                 desc.qw0 = QI_DEV_EIOTLB_PASID(svm->pasid) |
 134                                 QI_DEV_EIOTLB_SID(sdev->sid) |
 135                                 QI_DEV_EIOTLB_QDEP(sdev->qdep) |
 136                                 QI_DEIOTLB_TYPE;
 137                 if (pages == -1) {
 138                         desc.qw1 = QI_DEV_EIOTLB_ADDR(-1ULL >> 1) |
 139                                         QI_DEV_EIOTLB_SIZE;
 140                 } else if (pages > 1) {
 141                         /* The least significant zero bit indicates the size. So,
 142                          * for example, an "address" value of 0x12345f000 will
 143                          * flush from 0x123440000 to 0x12347ffff (256KiB). */
 144                         unsigned long last = address + ((unsigned long)(pages - 1) << VTD_PAGE_SHIFT);
 145                         unsigned long mask = __rounddown_pow_of_two(address ^ last);
 146
 147                         desc.qw1 = QI_DEV_EIOTLB_ADDR((address & ~mask) |
 148                                         (mask - 1)) | QI_DEV_EIOTLB_SIZE;
 149                 } else {
 150                         desc.qw1 = QI_DEV_EIOTLB_ADDR(address);
 151                 }
 152                 desc.qw2 = 0;
 153                 desc.qw3 = 0;
 154                 qi_submit_sync(&desc, svm->iommu);
 155         }
 156 }
 157
 158 static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address,
 159                                 unsigned long pages, int ih)
 160 {
 161         struct intel_svm_dev *sdev;
 162
 163         rcu_read_lock();
 164         list_for_each_entry_rcu(sdev, &svm->devs, list)
 165                 intel_flush_svm_range_dev(svm, sdev, address, pages, ih);
 166         rcu_read_unlock();
 167 }
 168
 169 /* Pages have been freed at this point */
 170 static void intel_invalidate_range(struct mmu_notifier *mn,
 171                                    struct mm_struct *mm,
 172                                    unsigned long start, unsigned long end)
 173 {
 174         struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
 175
 176         intel_flush_svm_range(svm, start,
 177                               (end - start + PAGE_SIZE - 1) >> VTD_PAGE_SHIFT, 0);
 178 }
 179
 180 static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 181 {
 182         struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
 183         struct intel_svm_dev *sdev;
 184
 185         /* This might end up being called from exit_mmap(), *before* the page
 186          * tables are cleared. And __mmu_notifier_release() will delete us from
 187          * the list of notifiers so that our invalidate_range() callback doesn't
 188          * get called when the page tables are cleared. So we need to protect
 189          * against hardware accessing those page tables.
 190          *
 191          * We do it by clearing the entry in the PASID table and then flushing
 192          * the IOTLB and the PASID table caches. This might upset hardware;
 193          * perhaps we'll want to point the PASID to a dummy PGD (like the zero
 194          * page) so that we end up taking a fault that the hardware really
 195          * *has* to handle gracefully without affecting other processes.
 196          */
 197         rcu_read_lock();
 198         list_for_each_entry_rcu(sdev, &svm->devs, list) {
 199                 intel_pasid_tear_down_entry(svm->iommu, sdev->dev, svm->pasid);
 200                 intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
 201         }
 202         rcu_read_unlock();
 203
 204 }
 205
 206 static const struct mmu_notifier_ops intel_mmuops = {
 207         .release = intel_mm_release,
 208         .invalidate_range = intel_invalidate_range,
 209 };
 210
 211 static DEFINE_MUTEX(pasid_mutex);
 212 static LIST_HEAD(global_svm_list);
 213
 214 int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ops *ops)
 215 {
 216         struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
 217         struct device_domain_info *info;
 218         struct intel_svm_dev *sdev;
 219         struct intel_svm *svm = NULL;
 220         struct mm_struct *mm = NULL;
 221         int pasid_max;
 222         int ret;
 223
 224         if (!iommu || dmar_disabled)
 225                 return -EINVAL;
 226
 227         if (dev_is_pci(dev)) {
 228                 pasid_max = pci_max_pasids(to_pci_dev(dev));
 229                 if (pasid_max < 0)
 230                         return -EINVAL;
 231         } else
 232                 pasid_max = 1 << 20;
 233
 234         if (flags & SVM_FLAG_SUPERVISOR_MODE) {
 235                 if (!ecap_srs(iommu->ecap))
 236                         return -EINVAL;
 237         } else if (pasid) {
 238                 mm = get_task_mm(current);
 239                 BUG_ON(!mm);
 240         }
 241
 242         mutex_lock(&pasid_mutex);
 243         if (pasid && !(flags & SVM_FLAG_PRIVATE_PASID)) {
 244                 struct intel_svm *t;
 245
 246                 list_for_each_entry(t, &global_svm_list, list) {
 247                         if (t->mm != mm || (t->flags & SVM_FLAG_PRIVATE_PASID))
 248                                 continue;
 249
 250                         svm = t;
 251                         if (svm->pasid >= pasid_max) {
 252                                 dev_warn(dev,
 253                                          "Limited PASID width. Cannot use existing PASID %d\n",
 254                                          svm->pasid);
 255                                 ret = -ENOSPC;
 256                                 goto out;
 257                         }
 258
 259                         list_for_each_entry(sdev, &svm->devs, list) {
 260                                 if (dev == sdev->dev) {
 261                                         if (sdev->ops != ops) {
 262                                                 ret = -EBUSY;
 263                                                 goto out;
 264                                         }
 265                                         sdev->users++;
 266                                         goto success;
 267                                 }
 268                         }
 269
 270                         break;
 271                 }
 272         }
 273
 274         sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
 275         if (!sdev) {
 276                 ret = -ENOMEM;
 277                 goto out;
 278         }
 279         sdev->dev = dev;
 280
 281         ret = intel_iommu_enable_pasid(iommu, dev);
 282         if (ret || !pasid) {
 283                 /* If they don't actually want to assign a PASID, this is
 284                  * just an enabling check/preparation. */
 285                 kfree(sdev);
 286                 goto out;
 287         }
 288
 289         info = dev->archdata.iommu;
 290         if (!info || !info->pasid_supported) {
 291                 kfree(sdev);
 292                 goto out;
 293         }
 294
 295         sdev->did = FLPT_DEFAULT_DID;
 296         sdev->sid = PCI_DEVID(info->bus, info->devfn);
 297         if (info->ats_enabled) {
 298                 sdev->dev_iotlb = 1;
 299                 sdev->qdep = info->ats_qdep;
 300                 if (sdev->qdep >= QI_DEV_EIOTLB_MAX_INVS)
 301                         sdev->qdep = 0;
 302         }
 303
 304         /* Finish the setup now we know we're keeping it */
 305         sdev->users = 1;
 306         sdev->ops = ops;
 307         init_rcu_head(&sdev->rcu);
 308
 309         if (!svm) {
 310                 svm = kzalloc(sizeof(*svm), GFP_KERNEL);
 311                 if (!svm) {
 312                         ret = -ENOMEM;
 313                         kfree(sdev);
 314                         goto out;
 315                 }
 316                 svm->iommu = iommu;
 317
 318                 if (pasid_max > intel_pasid_max_id)
 319                         pasid_max = intel_pasid_max_id;
 320
 321                 /* Do not use PASID 0 in caching mode (virtualised IOMMU) */
 322                 ret = intel_pasid_alloc_id(svm,
 323                                            !!cap_caching_mode(iommu->cap),
 324                                            pasid_max - 1, GFP_KERNEL);
 325                 if (ret < 0) {
 326                         kfree(svm);
 327                         kfree(sdev);
 328                         goto out;
 329                 }
 330                 svm->pasid = ret;
 331                 svm->notifier.ops = &intel_mmuops;
 332                 svm->mm = mm;
 333                 svm->flags = flags;
 334                 INIT_LIST_HEAD_RCU(&svm->devs);
 335                 INIT_LIST_HEAD(&svm->list);
 336                 ret = -ENOMEM;
 337                 if (mm) {
 338                         ret = mmu_notifier_register(&svm->notifier, mm);
 339                         if (ret) {
 340                                 intel_pasid_free_id(svm->pasid);
 341                                 kfree(svm);
 342                                 kfree(sdev);
 343                                 goto out;
 344                         }
 345                 }
 346
 347                 spin_lock(&iommu->lock);
 348                 ret = intel_pasid_setup_first_level(iommu, dev,
 349                                 mm ? mm->pgd : init_mm.pgd,
 350                                 svm->pasid, FLPT_DEFAULT_DID,
 351                                 mm ? 0 : PASID_FLAG_SUPERVISOR_MODE);
 352                 spin_unlock(&iommu->lock);
 353                 if (ret) {
 354                         if (mm)
 355                                 mmu_notifier_unregister(&svm->notifier, mm);
 356                         intel_pasid_free_id(svm->pasid);
 357                         kfree(svm);
 358                         kfree(sdev);
 359                         goto out;
 360                 }
 361
 362                 list_add_tail(&svm->list, &global_svm_list);
 363         } else {
 364                 /*
 365                  * Binding a new device with existing PASID, need to setup
 366                  * the PASID entry.
 367                  */
 368                 spin_lock(&iommu->lock);
 369                 ret = intel_pasid_setup_first_level(iommu, dev,
 370                                                 mm ? mm->pgd : init_mm.pgd,
 371                                                 svm->pasid, FLPT_DEFAULT_DID,
 372                                                 mm ? 0 : PASID_FLAG_SUPERVISOR_MODE);
 373                 spin_unlock(&iommu->lock);
 374                 if (ret) {
 375                         kfree(sdev);
 376                         goto out;
 377                 }
 378         }
 379         list_add_rcu(&sdev->list, &svm->devs);
 380
 381  success:
 382         *pasid = svm->pasid;
 383         ret = 0;
 384  out:
 385         mutex_unlock(&pasid_mutex);
 386         if (mm)
 387                 mmput(mm);
 388         return ret;
 389 }
 390 EXPORT_SYMBOL_GPL(intel_svm_bind_mm);
 391
 392 int intel_svm_unbind_mm(struct device *dev, int pasid)
 393 {
 394         struct intel_svm_dev *sdev;
 395         struct intel_iommu *iommu;
 396         struct intel_svm *svm;
 397         int ret = -EINVAL;
 398
 399         mutex_lock(&pasid_mutex);
 400         iommu = intel_svm_device_to_iommu(dev);
 401         if (!iommu)
 402                 goto out;
 403
 404         svm = intel_pasid_lookup_id(pasid);
 405         if (!svm)
 406                 goto out;
 407
 408         list_for_each_entry(sdev, &svm->devs, list) {
 409                 if (dev == sdev->dev) {
 410                         ret = 0;
 411                         sdev->users--;
 412                         if (!sdev->users) {
 413                                 list_del_rcu(&sdev->list);
 414                                 /* Flush the PASID cache and IOTLB for this device.
 415                                  * Note that we do depend on the hardware *not* using
 416                                  * the PASID any more. Just as we depend on other
 417                                  * devices never using PASIDs that they have no right
 418                                  * to use. We have a *shared* PASID table, because it's
 419                                  * large and has to be physically contiguous. So it's
 420                                  * hard to be as defensive as we might like. */
 421                                 intel_pasid_tear_down_entry(iommu, dev, svm->pasid);
 422                                 intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
 423                                 kfree_rcu(sdev, rcu);
 424
 425                                 if (list_empty(&svm->devs)) {
 426                                         intel_pasid_free_id(svm->pasid);
 427                                         if (svm->mm)
 428                                                 mmu_notifier_unregister(&svm->notifier, svm->mm);
 429
 430                                         list_del(&svm->list);
 431
 432                                         /* We mandate that no page faults may be outstanding
 433                                          * for the PASID when intel_svm_unbind_mm() is called.
 434                                          * If that is not obeyed, subtle errors will happen.
 435                                          * Let's make them less subtle... */
 436                                         memset(svm, 0x6b, sizeof(*svm));
 437                                         kfree(svm);
 438                                 }
 439                         }
 440                         break;
 441                 }
 442         }
 443  out:
 444         mutex_unlock(&pasid_mutex);
 445
 446         return ret;
 447 }
 448 EXPORT_SYMBOL_GPL(intel_svm_unbind_mm);
 449
 450 int intel_svm_is_pasid_valid(struct device *dev, int pasid)
 451 {
 452         struct intel_iommu *iommu;
 453         struct intel_svm *svm;
 454         int ret = -EINVAL;
 455
 456         mutex_lock(&pasid_mutex);
 457         iommu = intel_svm_device_to_iommu(dev);
 458         if (!iommu)
 459                 goto out;
 460
 461         svm = intel_pasid_lookup_id(pasid);
 462         if (!svm)
 463                 goto out;
 464
 465         /* init_mm is used in this case */
 466         if (!svm->mm)
 467                 ret = 1;
 468         else if (atomic_read(&svm->mm->mm_users) > 0)
 469                 ret = 1;
 470         else
 471                 ret = 0;
 472
 473  out:
 474         mutex_unlock(&pasid_mutex);
 475
 476         return ret;
 477 }
 478 EXPORT_SYMBOL_GPL(intel_svm_is_pasid_valid);
 479
 480 /* Page request queue descriptor */
 481 struct page_req_dsc {
 482         union {
 483                 struct {
 484                         u64 type:8;
 485                         u64 pasid_present:1;
 486                         u64 priv_data_present:1;
 487                         u64 rsvd:6;
 488                         u64 rid:16;
 489                         u64 pasid:20;
 490                         u64 exe_req:1;
 491                         u64 pm_req:1;
 492                         u64 rsvd2:10;
 493                 };
 494                 u64 qw_0;
 495         };
 496         union {
 497                 struct {
 498                         u64 rd_req:1;
 499                         u64 wr_req:1;
 500                         u64 lpig:1;
 501                         u64 prg_index:9;
 502                         u64 addr:52;
 503                 };
 504                 u64 qw_1;
 505         };
 506         u64 priv_data[2];
 507 };
 508
 509 #define PRQ_RING_MASK ((0x1000 << PRQ_ORDER) - 0x10)
 510
 511 static bool access_error(struct vm_area_struct *vma, struct page_req_dsc *req)
 512 {
 513         unsigned long requested = 0;
 514
 515         if (req->exe_req)
 516                 requested |= VM_EXEC;
 517
 518         if (req->rd_req)
 519                 requested |= VM_READ;
 520
 521         if (req->wr_req)
 522                 requested |= VM_WRITE;
 523
 524         return (requested & ~vma->vm_flags) != 0;
 525 }
 526
 527 static bool is_canonical_address(u64 addr)
 528 {
 529         int shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
 530         long saddr = (long) addr;
 531
 532         return (((saddr << shift) >> shift) == saddr);
 533 }
 534
 535 static irqreturn_t prq_event_thread(int irq, void *d)
 536 {
 537         struct intel_iommu *iommu = d;
 538         struct intel_svm *svm = NULL;
 539         int head, tail, handled = 0;
 540
 541         /* Clear PPR bit before reading head/tail registers, to
 542          * ensure that we get a new interrupt if needed. */
 543         writel(DMA_PRS_PPR, iommu->reg + DMAR_PRS_REG);
 544
 545         tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
 546         head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
 547         while (head != tail) {
 548                 struct intel_svm_dev *sdev;
 549                 struct vm_area_struct *vma;
 550                 struct page_req_dsc *req;
 551                 struct qi_desc resp;
 552                 int result;
 553                 vm_fault_t ret;
 554                 u64 address;
 555
 556                 handled = 1;
 557
 558                 req = &iommu->prq[head / sizeof(*req)];
 559
 560                 result = QI_RESP_FAILURE;
 561                 address = (u64)req->addr << VTD_PAGE_SHIFT;
 562                 if (!req->pasid_present) {
 563                         pr_err("%s: Page request without PASID: %08llx %08llx\n",
 564                                iommu->name, ((unsigned long long *)req)[0],
 565                                ((unsigned long long *)req)[1]);
 566                         goto no_pasid;
 567                 }
 568
 569                 if (!svm || svm->pasid != req->pasid) {
 570                         rcu_read_lock();
 571                         svm = intel_pasid_lookup_id(req->pasid);
 572                         /* It *can't* go away, because the driver is not permitted
 573                          * to unbind the mm while any page faults are outstanding.
 574                          * So we only need RCU to protect the internal idr code. */
 575                         rcu_read_unlock();
 576
 577                         if (!svm) {
 578                                 pr_err("%s: Page request for invalid PASID %d: %08llx %08llx\n",
 579                                        iommu->name, req->pasid, ((unsigned long long *)req)[0],
 580                                        ((unsigned long long *)req)[1]);
 581                                 goto no_pasid;
 582                         }
 583                 }
 584
 585                 result = QI_RESP_INVALID;
 586                 /* Since we're using init_mm.pgd directly, we should never take
 587                  * any faults on kernel addresses. */
 588                 if (!svm->mm)
 589                         goto bad_req;
 590                 /* If the mm is already defunct, don't handle faults. */
 591                 if (!mmget_not_zero(svm->mm))
 592                         goto bad_req;
 593
 594                 /* If address is not canonical, return invalid response */
 595                 if (!is_canonical_address(address))
 596                         goto bad_req;
 597
 598                 down_read(&svm->mm->mmap_sem);
 599                 vma = find_extend_vma(svm->mm, address);
 600                 if (!vma || address < vma->vm_start)
 601                         goto invalid;
 602
 603                 if (access_error(vma, req))
 604                         goto invalid;
 605
 606                 ret = handle_mm_fault(vma, address,
 607                                       req->wr_req ? FAULT_FLAG_WRITE : 0);
 608                 if (ret & VM_FAULT_ERROR)
 609                         goto invalid;
 610
 611                 result = QI_RESP_SUCCESS;
 612         invalid:
 613                 up_read(&svm->mm->mmap_sem);
 614                 mmput(svm->mm);
 615         bad_req:
 616                 /* Accounting for major/minor faults? */
 617                 rcu_read_lock();
 618                 list_for_each_entry_rcu(sdev, &svm->devs, list) {
 619                         if (sdev->sid == req->rid)
 620                                 break;
 621                 }
 622                 /* Other devices can go away, but the drivers are not permitted
 623                  * to unbind while any page faults might be in flight. So it's
 624                  * OK to drop the 'lock' here now we have it. */
 625                 rcu_read_unlock();
 626
 627                 if (WARN_ON(&sdev->list == &svm->devs))
 628                         sdev = NULL;
 629
 630                 if (sdev && sdev->ops && sdev->ops->fault_cb) {
 631                         int rwxp = (req->rd_req << 3) | (req->wr_req << 2) |
 632                                 (req->exe_req << 1) | (req->pm_req);
 633                         sdev->ops->fault_cb(sdev->dev, req->pasid, req->addr,
 634                                             req->priv_data, rwxp, result);
 635                 }
 636                 /* We get here in the error case where the PASID lookup failed,
 637                    and these can be NULL. Do not use them below this point! */
 638                 sdev = NULL;
 639                 svm = NULL;
 640         no_pasid:
 641                 if (req->lpig || req->priv_data_present) {
 642                         /*
 643                          * Per VT-d spec. v3.0 ch7.7, system software must
 644                          * respond with page group response if private data
 645                          * is present (PDP) or last page in group (LPIG) bit
 646                          * is set. This is an additional VT-d feature beyond
 647                          * PCI ATS spec.
 648                          */
 649                         resp.qw0 = QI_PGRP_PASID(req->pasid) |
 650                                 QI_PGRP_DID(req->rid) |
 651                                 QI_PGRP_PASID_P(req->pasid_present) |
 652                                 QI_PGRP_PDP(req->pasid_present) |
 653                                 QI_PGRP_RESP_CODE(result) |
 654                                 QI_PGRP_RESP_TYPE;
 655                         resp.qw1 = QI_PGRP_IDX(req->prg_index) |
 656                                 QI_PGRP_LPIG(req->lpig);
 657
 658                         if (req->priv_data_present)
 659                                 memcpy(&resp.qw2, req->priv_data,
 660                                        sizeof(req->priv_data));
 661                 }
 662                 resp.qw2 = 0;
 663                 resp.qw3 = 0;
 664                 qi_submit_sync(&resp, iommu);
 665
 666                 head = (head + sizeof(*req)) & PRQ_RING_MASK;
 667         }
 668
 669         dmar_writeq(iommu->reg + DMAR_PQH_REG, tail);
 670
 671         return IRQ_RETVAL(handled);
 672 }