These changes are the raw update to linux-4.4.6-rt14. Kernel sources
[kvmfornfv.git] / kernel / drivers / iommu / intel-svm.c
diff --git a/kernel/drivers/iommu/intel-svm.c b/kernel/drivers/iommu/intel-svm.c
new file mode 100644 (file)
index 0000000..d9939fa
--- /dev/null
@@ -0,0 +1,647 @@
+/*
+ * Copyright © 2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * Authors: David Woodhouse <dwmw2@infradead.org>
+ */
+
+#include <linux/intel-iommu.h>
+#include <linux/mmu_notifier.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/intel-svm.h>
+#include <linux/rculist.h>
+#include <linux/pci.h>
+#include <linux/pci-ats.h>
+#include <linux/dmar.h>
+#include <linux/interrupt.h>
+
+static irqreturn_t prq_event_thread(int irq, void *d);
+
+struct pasid_entry {
+       u64 val;
+};
+
+struct pasid_state_entry {
+       u64 val;
+};
+
+int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
+{
+       struct page *pages;
+       int order;
+
+       order = ecap_pss(iommu->ecap) + 7 - PAGE_SHIFT;
+       if (order < 0)
+               order = 0;
+
+       pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
+       if (!pages) {
+               pr_warn("IOMMU: %s: Failed to allocate PASID table\n",
+                       iommu->name);
+               return -ENOMEM;
+       }
+       iommu->pasid_table = page_address(pages);
+       pr_info("%s: Allocated order %d PASID table.\n", iommu->name, order);
+
+       if (ecap_dis(iommu->ecap)) {
+               pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
+               if (pages)
+                       iommu->pasid_state_table = page_address(pages);
+               else
+                       pr_warn("IOMMU: %s: Failed to allocate PASID state table\n",
+                               iommu->name);
+       }
+
+       idr_init(&iommu->pasid_idr);
+
+       return 0;
+}
+
+int intel_svm_free_pasid_tables(struct intel_iommu *iommu)
+{
+       int order;
+
+       order = ecap_pss(iommu->ecap) + 7 - PAGE_SHIFT;
+       if (order < 0)
+               order = 0;
+
+       if (iommu->pasid_table) {
+               free_pages((unsigned long)iommu->pasid_table, order);
+               iommu->pasid_table = NULL;
+       }
+       if (iommu->pasid_state_table) {
+               free_pages((unsigned long)iommu->pasid_state_table, order);
+               iommu->pasid_state_table = NULL;
+       }
+       idr_destroy(&iommu->pasid_idr);
+       return 0;
+}
+
+#define PRQ_ORDER 0
+
+int intel_svm_enable_prq(struct intel_iommu *iommu)
+{
+       struct page *pages;
+       int irq, ret;
+
+       pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, PRQ_ORDER);
+       if (!pages) {
+               pr_warn("IOMMU: %s: Failed to allocate page request queue\n",
+                       iommu->name);
+               return -ENOMEM;
+       }
+       iommu->prq = page_address(pages);
+
+       irq = dmar_alloc_hwirq(DMAR_UNITS_SUPPORTED + iommu->seq_id, iommu->node, iommu);
+       if (irq <= 0) {
+               pr_err("IOMMU: %s: Failed to create IRQ vector for page request queue\n",
+                      iommu->name);
+               ret = -EINVAL;
+       err:
+               free_pages((unsigned long)iommu->prq, PRQ_ORDER);
+               iommu->prq = NULL;
+               return ret;
+       }
+       iommu->pr_irq = irq;
+
+       snprintf(iommu->prq_name, sizeof(iommu->prq_name), "dmar%d-prq", iommu->seq_id);
+
+       ret = request_threaded_irq(irq, NULL, prq_event_thread, IRQF_ONESHOT,
+                                  iommu->prq_name, iommu);
+       if (ret) {
+               pr_err("IOMMU: %s: Failed to request IRQ for page request queue\n",
+                      iommu->name);
+               dmar_free_hwirq(irq);
+               goto err;
+       }
+       dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
+       dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
+       dmar_writeq(iommu->reg + DMAR_PQA_REG, virt_to_phys(iommu->prq) | PRQ_ORDER);
+
+       return 0;
+}
+
+int intel_svm_finish_prq(struct intel_iommu *iommu)
+{
+       dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
+       dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
+       dmar_writeq(iommu->reg + DMAR_PQA_REG, 0ULL);
+
+       free_irq(iommu->pr_irq, iommu);
+       dmar_free_hwirq(iommu->pr_irq);
+       iommu->pr_irq = 0;
+
+       free_pages((unsigned long)iommu->prq, PRQ_ORDER);
+       iommu->prq = NULL;
+
+       return 0;
+}
+
+static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_dev *sdev,
+                                      unsigned long address, unsigned long pages, int ih, int gl)
+{
+       struct qi_desc desc;
+
+       if (pages == -1) {
+               /* For global kernel pages we have to flush them in *all* PASIDs
+                * because that's the only option the hardware gives us. Despite
+                * the fact that they are actually only accessible through one. */
+               if (gl)
+                       desc.low = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(sdev->did) |
+                               QI_EIOTLB_GRAN(QI_GRAN_ALL_ALL) | QI_EIOTLB_TYPE;
+               else
+                       desc.low = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(sdev->did) |
+                               QI_EIOTLB_GRAN(QI_GRAN_NONG_PASID) | QI_EIOTLB_TYPE;
+               desc.high = 0;
+       } else {
+               int mask = ilog2(__roundup_pow_of_two(pages));
+
+               desc.low = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(sdev->did) |
+                       QI_EIOTLB_GRAN(QI_GRAN_PSI_PASID) | QI_EIOTLB_TYPE;
+               desc.high = QI_EIOTLB_ADDR(address) | QI_EIOTLB_GL(gl) |
+                       QI_EIOTLB_IH(ih) | QI_EIOTLB_AM(mask);
+       }
+       qi_submit_sync(&desc, svm->iommu);
+
+       if (sdev->dev_iotlb) {
+               desc.low = QI_DEV_EIOTLB_PASID(svm->pasid) | QI_DEV_EIOTLB_SID(sdev->sid) |
+                       QI_DEV_EIOTLB_QDEP(sdev->qdep) | QI_DEIOTLB_TYPE;
+               if (pages == -1) {
+                       desc.high = QI_DEV_EIOTLB_ADDR(-1ULL >> 1) | QI_DEV_EIOTLB_SIZE;
+               } else if (pages > 1) {
+                       /* The least significant zero bit indicates the size. So,
+                        * for example, an "address" value of 0x12345f000 will
+                        * flush from 0x123440000 to 0x12347ffff (256KiB). */
+                       unsigned long last = address + ((unsigned long)(pages - 1) << VTD_PAGE_SHIFT);
+                       unsigned long mask = __rounddown_pow_of_two(address ^ last);;
+
+                       desc.high = QI_DEV_EIOTLB_ADDR((address & ~mask) | (mask - 1)) | QI_DEV_EIOTLB_SIZE;
+               } else {
+                       desc.high = QI_DEV_EIOTLB_ADDR(address);
+               }
+               qi_submit_sync(&desc, svm->iommu);
+       }
+}
+
+static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address,
+                                 unsigned long pages, int ih, int gl)
+{
+       struct intel_svm_dev *sdev;
+
+       /* Try deferred invalidate if available */
+       if (svm->iommu->pasid_state_table &&
+           !cmpxchg64(&svm->iommu->pasid_state_table[svm->pasid].val, 0, 1ULL << 63))
+               return;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(sdev, &svm->devs, list)
+               intel_flush_svm_range_dev(svm, sdev, address, pages, ih, gl);
+       rcu_read_unlock();
+}
+
+static void intel_change_pte(struct mmu_notifier *mn, struct mm_struct *mm,
+                            unsigned long address, pte_t pte)
+{
+       struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+       intel_flush_svm_range(svm, address, 1, 1, 0);
+}
+
+static void intel_invalidate_page(struct mmu_notifier *mn, struct mm_struct *mm,
+                                 unsigned long address)
+{
+       struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+       intel_flush_svm_range(svm, address, 1, 1, 0);
+}
+
+/* Pages have been freed at this point */
+static void intel_invalidate_range(struct mmu_notifier *mn,
+                                  struct mm_struct *mm,
+                                  unsigned long start, unsigned long end)
+{
+       struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+       intel_flush_svm_range(svm, start,
+                             (end - start + PAGE_SIZE - 1) >> VTD_PAGE_SHIFT, 0, 0);
+}
+
+
+static void intel_flush_pasid_dev(struct intel_svm *svm, struct intel_svm_dev *sdev, int pasid)
+{
+       struct qi_desc desc;
+
+       desc.high = 0;
+       desc.low = QI_PC_TYPE | QI_PC_DID(sdev->did) | QI_PC_PASID_SEL | QI_PC_PASID(pasid);
+
+       qi_submit_sync(&desc, svm->iommu);
+}
+
+static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
+{
+       struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+       struct intel_svm_dev *sdev;
+
+       /* This might end up being called from exit_mmap(), *before* the page
+        * tables are cleared. And __mmu_notifier_release() will delete us from
+        * the list of notifiers so that our invalidate_range() callback doesn't
+        * get called when the page tables are cleared. So we need to protect
+        * against hardware accessing those page tables.
+        *
+        * We do it by clearing the entry in the PASID table and then flushing
+        * the IOTLB and the PASID table caches. This might upset hardware;
+        * perhaps we'll want to point the PASID to a dummy PGD (like the zero
+        * page) so that we end up taking a fault that the hardware really
+        * *has* to handle gracefully without affecting other processes.
+        */
+       svm->iommu->pasid_table[svm->pasid].val = 0;
+       wmb();
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(sdev, &svm->devs, list) {
+               intel_flush_pasid_dev(svm, sdev, svm->pasid);
+               intel_flush_svm_range_dev(svm, sdev, 0, -1, 0, !svm->mm);
+       }
+       rcu_read_unlock();
+
+}
+
+static const struct mmu_notifier_ops intel_mmuops = {
+       .release = intel_mm_release,
+       .change_pte = intel_change_pte,
+       .invalidate_page = intel_invalidate_page,
+       .invalidate_range = intel_invalidate_range,
+};
+
+static DEFINE_MUTEX(pasid_mutex);
+
+int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ops *ops)
+{
+       struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
+       struct intel_svm_dev *sdev;
+       struct intel_svm *svm = NULL;
+       struct mm_struct *mm = NULL;
+       int pasid_max;
+       int ret;
+
+       if (WARN_ON(!iommu))
+               return -EINVAL;
+
+       if (dev_is_pci(dev)) {
+               pasid_max = pci_max_pasids(to_pci_dev(dev));
+               if (pasid_max < 0)
+                       return -EINVAL;
+       } else
+               pasid_max = 1 << 20;
+
+       if ((flags & SVM_FLAG_SUPERVISOR_MODE)) {
+               if (!ecap_srs(iommu->ecap))
+                       return -EINVAL;
+       } else if (pasid) {
+               mm = get_task_mm(current);
+               BUG_ON(!mm);
+       }
+
+       mutex_lock(&pasid_mutex);
+       if (pasid && !(flags & SVM_FLAG_PRIVATE_PASID)) {
+               int i;
+
+               idr_for_each_entry(&iommu->pasid_idr, svm, i) {
+                       if (svm->mm != mm ||
+                           (svm->flags & SVM_FLAG_PRIVATE_PASID))
+                               continue;
+
+                       if (svm->pasid >= pasid_max) {
+                               dev_warn(dev,
+                                        "Limited PASID width. Cannot use existing PASID %d\n",
+                                        svm->pasid);
+                               ret = -ENOSPC;
+                               goto out;
+                       }
+
+                       list_for_each_entry(sdev, &svm->devs, list) {
+                               if (dev == sdev->dev) {
+                                       if (sdev->ops != ops) {
+                                               ret = -EBUSY;
+                                               goto out;
+                                       }
+                                       sdev->users++;
+                                       goto success;
+                               }
+                       }
+
+                       break;
+               }
+       }
+
+       sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
+       if (!sdev) {
+               ret = -ENOMEM;
+               goto out;
+       }
+       sdev->dev = dev;
+
+       ret = intel_iommu_enable_pasid(iommu, sdev);
+       if (ret || !pasid) {
+               /* If they don't actually want to assign a PASID, this is
+                * just an enabling check/preparation. */
+               kfree(sdev);
+               goto out;
+       }
+       /* Finish the setup now we know we're keeping it */
+       sdev->users = 1;
+       sdev->ops = ops;
+       init_rcu_head(&sdev->rcu);
+
+       if (!svm) {
+               svm = kzalloc(sizeof(*svm), GFP_KERNEL);
+               if (!svm) {
+                       ret = -ENOMEM;
+                       kfree(sdev);
+                       goto out;
+               }
+               svm->iommu = iommu;
+
+               if (pasid_max > 2 << ecap_pss(iommu->ecap))
+                       pasid_max = 2 << ecap_pss(iommu->ecap);
+
+               /* Do not use PASID 0 in caching mode (virtualised IOMMU) */
+               ret = idr_alloc(&iommu->pasid_idr, svm,
+                               !!cap_caching_mode(iommu->cap),
+                               pasid_max - 1, GFP_KERNEL);
+               if (ret < 0) {
+                       kfree(svm);
+                       goto out;
+               }
+               svm->pasid = ret;
+               svm->notifier.ops = &intel_mmuops;
+               svm->mm = mm;
+               svm->flags = flags;
+               INIT_LIST_HEAD_RCU(&svm->devs);
+               ret = -ENOMEM;
+               if (mm) {
+                       ret = mmu_notifier_register(&svm->notifier, mm);
+                       if (ret) {
+                               idr_remove(&svm->iommu->pasid_idr, svm->pasid);
+                               kfree(svm);
+                               kfree(sdev);
+                               goto out;
+                       }
+                       iommu->pasid_table[svm->pasid].val = (u64)__pa(mm->pgd) | 1;
+               } else
+                       iommu->pasid_table[svm->pasid].val = (u64)__pa(init_mm.pgd) | 1 | (1ULL << 11);
+               wmb();
+               /* In caching mode, we still have to flush with PASID 0 when
+                * a PASID table entry becomes present. Not entirely clear
+                * *why* that would be the case — surely we could just issue
+                * a flush with the PASID value that we've changed? The PASID
+                * is the index into the table, after all. It's not like domain
+                * IDs in the case of the equivalent context-entry change in
+                * caching mode. And for that matter it's not entirely clear why
+                * a VMM would be in the business of caching the PASID table
+                * anyway. Surely that can be left entirely to the guest? */
+               if (cap_caching_mode(iommu->cap))
+                       intel_flush_pasid_dev(svm, sdev, 0);
+       }
+       list_add_rcu(&sdev->list, &svm->devs);
+
+ success:
+       *pasid = svm->pasid;
+       ret = 0;
+ out:
+       mutex_unlock(&pasid_mutex);
+       if (mm)
+               mmput(mm);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(intel_svm_bind_mm);
+
+int intel_svm_unbind_mm(struct device *dev, int pasid)
+{
+       struct intel_svm_dev *sdev;
+       struct intel_iommu *iommu;
+       struct intel_svm *svm;
+       int ret = -EINVAL;
+
+       mutex_lock(&pasid_mutex);
+       iommu = intel_svm_device_to_iommu(dev);
+       if (!iommu || !iommu->pasid_table)
+               goto out;
+
+       svm = idr_find(&iommu->pasid_idr, pasid);
+       if (!svm)
+               goto out;
+
+       list_for_each_entry(sdev, &svm->devs, list) {
+               if (dev == sdev->dev) {
+                       ret = 0;
+                       sdev->users--;
+                       if (!sdev->users) {
+                               list_del_rcu(&sdev->list);
+                               /* Flush the PASID cache and IOTLB for this device.
+                                * Note that we do depend on the hardware *not* using
+                                * the PASID any more. Just as we depend on other
+                                * devices never using PASIDs that they have no right
+                                * to use. We have a *shared* PASID table, because it's
+                                * large and has to be physically contiguous. So it's
+                                * hard to be as defensive as we might like. */
+                               intel_flush_pasid_dev(svm, sdev, svm->pasid);
+                               intel_flush_svm_range_dev(svm, sdev, 0, -1, 0, !svm->mm);
+                               kfree_rcu(sdev, rcu);
+
+                               if (list_empty(&svm->devs)) {
+
+                                       idr_remove(&svm->iommu->pasid_idr, svm->pasid);
+                                       if (svm->mm)
+                                               mmu_notifier_unregister(&svm->notifier, svm->mm);
+
+                                       /* We mandate that no page faults may be outstanding
+                                        * for the PASID when intel_svm_unbind_mm() is called.
+                                        * If that is not obeyed, subtle errors will happen.
+                                        * Let's make them less subtle... */
+                                       memset(svm, 0x6b, sizeof(*svm));
+                                       kfree(svm);
+                               }
+                       }
+                       break;
+               }
+       }
+ out:
+       mutex_unlock(&pasid_mutex);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(intel_svm_unbind_mm);
+
+/* Page request queue descriptor */
+struct page_req_dsc {
+       u64 srr:1;
+       u64 bof:1;
+       u64 pasid_present:1;
+       u64 lpig:1;
+       u64 pasid:20;
+       u64 bus:8;
+       u64 private:23;
+       u64 prg_index:9;
+       u64 rd_req:1;
+       u64 wr_req:1;
+       u64 exe_req:1;
+       u64 priv_req:1;
+       u64 devfn:8;
+       u64 addr:52;
+};
+
+#define PRQ_RING_MASK ((0x1000 << PRQ_ORDER) - 0x10)
+
+static bool access_error(struct vm_area_struct *vma, struct page_req_dsc *req)
+{
+       unsigned long requested = 0;
+
+       if (req->exe_req)
+               requested |= VM_EXEC;
+
+       if (req->rd_req)
+               requested |= VM_READ;
+
+       if (req->wr_req)
+               requested |= VM_WRITE;
+
+       return (requested & ~vma->vm_flags) != 0;
+}
+
+static irqreturn_t prq_event_thread(int irq, void *d)
+{
+       struct intel_iommu *iommu = d;
+       struct intel_svm *svm = NULL;
+       int head, tail, handled = 0;
+
+       /* Clear PPR bit before reading head/tail registers, to
+        * ensure that we get a new interrupt if needed. */
+       writel(DMA_PRS_PPR, iommu->reg + DMAR_PRS_REG);
+
+       tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
+       head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
+       while (head != tail) {
+               struct intel_svm_dev *sdev;
+               struct vm_area_struct *vma;
+               struct page_req_dsc *req;
+               struct qi_desc resp;
+               int ret, result;
+               u64 address;
+
+               handled = 1;
+
+               req = &iommu->prq[head / sizeof(*req)];
+
+               result = QI_RESP_FAILURE;
+               address = (u64)req->addr << VTD_PAGE_SHIFT;
+               if (!req->pasid_present) {
+                       pr_err("%s: Page request without PASID: %08llx %08llx\n",
+                              iommu->name, ((unsigned long long *)req)[0],
+                              ((unsigned long long *)req)[1]);
+                       goto bad_req;
+               }
+
+               if (!svm || svm->pasid != req->pasid) {
+                       rcu_read_lock();
+                       svm = idr_find(&iommu->pasid_idr, req->pasid);
+                       /* It *can't* go away, because the driver is not permitted
+                        * to unbind the mm while any page faults are outstanding.
+                        * So we only need RCU to protect the internal idr code. */
+                       rcu_read_unlock();
+
+                       if (!svm) {
+                               pr_err("%s: Page request for invalid PASID %d: %08llx %08llx\n",
+                                      iommu->name, req->pasid, ((unsigned long long *)req)[0],
+                                      ((unsigned long long *)req)[1]);
+                               goto no_pasid;
+                       }
+               }
+
+               result = QI_RESP_INVALID;
+               /* Since we're using init_mm.pgd directly, we should never take
+                * any faults on kernel addresses. */
+               if (!svm->mm)
+                       goto bad_req;
+               /* If the mm is already defunct, don't handle faults. */
+               if (!atomic_inc_not_zero(&svm->mm->mm_users))
+                       goto bad_req;
+               down_read(&svm->mm->mmap_sem);
+               vma = find_extend_vma(svm->mm, address);
+               if (!vma || address < vma->vm_start)
+                       goto invalid;
+
+               if (access_error(vma, req))
+                       goto invalid;
+
+               ret = handle_mm_fault(svm->mm, vma, address,
+                                     req->wr_req ? FAULT_FLAG_WRITE : 0);
+               if (ret & VM_FAULT_ERROR)
+                       goto invalid;
+
+               result = QI_RESP_SUCCESS;
+       invalid:
+               up_read(&svm->mm->mmap_sem);
+               mmput(svm->mm);
+       bad_req:
+               /* Accounting for major/minor faults? */
+               rcu_read_lock();
+               list_for_each_entry_rcu(sdev, &svm->devs, list) {
+                       if (sdev->sid == PCI_DEVID(req->bus, req->devfn))
+                               break;
+               }
+               /* Other devices can go away, but the drivers are not permitted
+                * to unbind while any page faults might be in flight. So it's
+                * OK to drop the 'lock' here now we have it. */
+               rcu_read_unlock();
+
+               if (WARN_ON(&sdev->list == &svm->devs))
+                       sdev = NULL;
+
+               if (sdev && sdev->ops && sdev->ops->fault_cb) {
+                       int rwxp = (req->rd_req << 3) | (req->wr_req << 2) |
+                               (req->exe_req << 1) | (req->priv_req);
+                       sdev->ops->fault_cb(sdev->dev, req->pasid, req->addr, req->private, rwxp, result);
+               }
+               /* We get here in the error case where the PASID lookup failed,
+                  and these can be NULL. Do not use them below this point! */
+               sdev = NULL;
+               svm = NULL;
+       no_pasid:
+               if (req->lpig) {
+                       /* Page Group Response */
+                       resp.low = QI_PGRP_PASID(req->pasid) |
+                               QI_PGRP_DID((req->bus << 8) | req->devfn) |
+                               QI_PGRP_PASID_P(req->pasid_present) |
+                               QI_PGRP_RESP_TYPE;
+                       resp.high = QI_PGRP_IDX(req->prg_index) |
+                               QI_PGRP_PRIV(req->private) | QI_PGRP_RESP_CODE(result);
+
+                       qi_submit_sync(&resp, iommu);
+               } else if (req->srr) {
+                       /* Page Stream Response */
+                       resp.low = QI_PSTRM_IDX(req->prg_index) |
+                               QI_PSTRM_PRIV(req->private) | QI_PSTRM_BUS(req->bus) |
+                               QI_PSTRM_PASID(req->pasid) | QI_PSTRM_RESP_TYPE;
+                       resp.high = QI_PSTRM_ADDR(address) | QI_PSTRM_DEVFN(req->devfn) |
+                               QI_PSTRM_RESP_CODE(result);
+
+                       qi_submit_sync(&resp, iommu);
+               }
+
+               head = (head + sizeof(*req)) & PRQ_RING_MASK;
+       }
+
+       dmar_writeq(iommu->reg + DMAR_PQH_REG, tail);
+
+       return IRQ_RETVAL(handled);
+}