Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 701 insertions, 0 deletions

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
new file mode 100644
index 000000000..ef3aadec9
--- /dev/null
+++ b/drivers/iommu/intel-svm.c
@@ -0,0 +1,701 @@
+/*
+ * 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/sched/mm.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>
+#include <linux/mm_types.h>
+#include <asm/page.h>
+
+#include "intel-pasid.h"
+
+#define PASID_ENTRY_P		BIT_ULL(0)
+#define PASID_ENTRY_FLPM_5LP	BIT_ULL(9)
+#define PASID_ENTRY_SRE		BIT_ULL(11)
+
+static irqreturn_t prq_event_thread(int irq, void *d);
+
+struct pasid_state_entry {
+	u64 val;
+};
+
+int intel_svm_init(struct intel_iommu *iommu)
+{
+	struct page *pages;
+	int order;
+
+	if (cpu_feature_enabled(X86_FEATURE_GBPAGES) &&
+			!cap_fl1gp_support(iommu->cap))
+		return -EINVAL;
+
+	if (cpu_feature_enabled(X86_FEATURE_LA57) &&
+			!cap_5lp_support(iommu->cap))
+		return -EINVAL;
+
+	/* Start at 2 because it's defined as 2^(1+PSS) */
+	iommu->pasid_max = 2 << ecap_pss(iommu->ecap);
+
+	/* Eventually I'm promised we will get a multi-level PASID table
+	 * and it won't have to be physically contiguous. Until then,
+	 * limit the size because 8MiB contiguous allocations can be hard
+	 * to come by. The limit of 0x20000, which is 1MiB for each of
+	 * the PASID and PASID-state tables, is somewhat arbitrary. */
+	if (iommu->pasid_max > 0x20000)
+		iommu->pasid_max = 0x20000;
+
+	order = get_order(sizeof(struct pasid_entry) * iommu->pasid_max);
+	if (ecap_dis(iommu->ecap)) {
+		/* Just making it explicit... */
+		BUILD_BUG_ON(sizeof(struct pasid_entry) != sizeof(struct pasid_state_entry));
+		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);
+	}
+
+	return 0;
+}
+
+int intel_svm_exit(struct intel_iommu *iommu)
+{
+	int order = get_order(sizeof(struct pasid_entry) * iommu->pasid_max);
+
+	if (iommu->pasid_state_table) {
+		free_pages((unsigned long)iommu->pasid_state_table, order);
+		iommu->pasid_state_table = NULL;
+	}
+
+	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);
+		iommu->pr_irq = 0;
+		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);
+
+	if (iommu->pr_irq) {
+		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);
+}
+
+/* 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.
+	 */
+	rcu_read_lock();
+	list_for_each_entry_rcu(sdev, &svm->devs, list) {
+		intel_pasid_clear_entry(sdev->dev, svm->pasid);
+		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 = {
+	.flags = MMU_INVALIDATE_DOES_NOT_BLOCK,
+	.release = intel_mm_release,
+	.change_pte = intel_change_pte,
+	.invalidate_range = intel_invalidate_range,
+};
+
+static DEFINE_MUTEX(pasid_mutex);
+static LIST_HEAD(global_svm_list);
+
+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 pasid_entry *entry;
+	struct intel_svm_dev *sdev;
+	struct intel_svm *svm = NULL;
+	struct mm_struct *mm = NULL;
+	u64 pasid_entry_val;
+	int pasid_max;
+	int ret;
+
+	if (!iommu || dmar_disabled)
+		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)) {
+		struct intel_svm *t;
+
+		list_for_each_entry(t, &global_svm_list, list) {
+			if (t->mm != mm || (t->flags & SVM_FLAG_PRIVATE_PASID))
+				continue;
+
+			svm = t;
+			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 > intel_pasid_max_id)
+			pasid_max = intel_pasid_max_id;
+
+		/* Do not use PASID 0 in caching mode (virtualised IOMMU) */
+		ret = intel_pasid_alloc_id(svm,
+					   !!cap_caching_mode(iommu->cap),
+					   pasid_max, GFP_KERNEL);
+		if (ret < 0) {
+			kfree(svm);
+			kfree(sdev);
+			goto out;
+		}
+		svm->pasid = ret;
+		svm->notifier.ops = &intel_mmuops;
+		svm->mm = mm;
+		svm->flags = flags;
+		INIT_LIST_HEAD_RCU(&svm->devs);
+		INIT_LIST_HEAD(&svm->list);
+		ret = -ENOMEM;
+		if (mm) {
+			ret = mmu_notifier_register(&svm->notifier, mm);
+			if (ret) {
+				intel_pasid_free_id(svm->pasid);
+				kfree(svm);
+				kfree(sdev);
+				goto out;
+			}
+			pasid_entry_val = (u64)__pa(mm->pgd) | PASID_ENTRY_P;
+		} else
+			pasid_entry_val = (u64)__pa(init_mm.pgd) |
+					  PASID_ENTRY_P | PASID_ENTRY_SRE;
+		if (cpu_feature_enabled(X86_FEATURE_LA57))
+			pasid_entry_val |= PASID_ENTRY_FLPM_5LP;
+
+		entry = intel_pasid_get_entry(dev, svm->pasid);
+		entry->val = pasid_entry_val;
+
+		wmb();
+
+		/*
+		 * Flush PASID cache when a PASID table entry becomes
+		 * present.
+		 */
+		if (cap_caching_mode(iommu->cap))
+			intel_flush_pasid_dev(svm, sdev, svm->pasid);
+
+		list_add_tail(&svm->list, &global_svm_list);
+	}
+	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)
+		goto out;
+
+	svm = intel_pasid_lookup_id(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);
+				intel_pasid_clear_entry(dev, svm->pasid);
+
+				if (list_empty(&svm->devs)) {
+					intel_pasid_free_id(svm->pasid);
+					if (svm->mm)
+						mmu_notifier_unregister(&svm->notifier, svm->mm);
+
+					list_del(&svm->list);
+
+					/* 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);
+
+int intel_svm_is_pasid_valid(struct device *dev, int pasid)
+{
+	struct intel_iommu *iommu;
+	struct intel_svm *svm;
+	int ret = -EINVAL;
+
+	mutex_lock(&pasid_mutex);
+	iommu = intel_svm_device_to_iommu(dev);
+	if (!iommu)
+		goto out;
+
+	svm = intel_pasid_lookup_id(pasid);
+	if (!svm)
+		goto out;
+
+	/* init_mm is used in this case */
+	if (!svm->mm)
+		ret = 1;
+	else if (atomic_read(&svm->mm->mm_users) > 0)
+		ret = 1;
+	else
+		ret = 0;
+
+ out:
+	mutex_unlock(&pasid_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(intel_svm_is_pasid_valid);
+
+/* 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 bool is_canonical_address(u64 addr)
+{
+	int shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
+	long saddr = (long) addr;
+
+	return (((saddr << shift) >> shift) == saddr);
+}
+
+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 result;
+		vm_fault_t ret;
+		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 no_pasid;
+		}
+
+		if (!svm || svm->pasid != req->pasid) {
+			rcu_read_lock();
+			svm = intel_pasid_lookup_id(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 address is not canonical, return invalid response */
+		if (!is_canonical_address(address))
+			goto bad_req;
+
+		/* If the mm is already defunct, don't handle faults. */
+		if (!mmget_not_zero(svm->mm))
+			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(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);
+}