Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 850 insertions, 0 deletions

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
new file mode 100644
index 0000000000..ac12f76c12
--- /dev/null
+++ b/drivers/iommu/intel/svm.c
@@ -0,0 +1,850 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright © 2015 Intel Corporation.
+ *
+ * Authors: David Woodhouse <dwmw2@infradead.org>
+ */
+
+#include <linux/mmu_notifier.h>
+#include <linux/sched.h>
+#include <linux/sched/mm.h>
+#include <linux/slab.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 <linux/xarray.h>
+#include <asm/page.h>
+#include <asm/fpu/api.h>
+
+#include "iommu.h"
+#include "pasid.h"
+#include "perf.h"
+#include "../iommu-sva.h"
+#include "trace.h"
+
+static irqreturn_t prq_event_thread(int irq, void *d);
+
+static DEFINE_XARRAY_ALLOC(pasid_private_array);
+static int pasid_private_add(ioasid_t pasid, void *priv)
+{
+	return xa_alloc(&pasid_private_array, &pasid, priv,
+			XA_LIMIT(pasid, pasid), GFP_ATOMIC);
+}
+
+static void pasid_private_remove(ioasid_t pasid)
+{
+	xa_erase(&pasid_private_array, pasid);
+}
+
+static void *pasid_private_find(ioasid_t pasid)
+{
+	return xa_load(&pasid_private_array, pasid);
+}
+
+static struct intel_svm_dev *
+svm_lookup_device_by_dev(struct intel_svm *svm, struct device *dev)
+{
+	struct intel_svm_dev *sdev = NULL, *t;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(t, &svm->devs, list) {
+		if (t->dev == dev) {
+			sdev = t;
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	return sdev;
+}
+
+int intel_svm_enable_prq(struct intel_iommu *iommu)
+{
+	struct iopf_queue *iopfq;
+	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(IOMMU_IRQ_ID_OFFSET_PRQ + 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;
+		goto free_prq;
+	}
+	iommu->pr_irq = irq;
+
+	snprintf(iommu->iopfq_name, sizeof(iommu->iopfq_name),
+		 "dmar%d-iopfq", iommu->seq_id);
+	iopfq = iopf_queue_alloc(iommu->iopfq_name);
+	if (!iopfq) {
+		pr_err("IOMMU: %s: Failed to allocate iopf queue\n", iommu->name);
+		ret = -ENOMEM;
+		goto free_hwirq;
+	}
+	iommu->iopf_queue = iopfq;
+
+	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);
+		goto free_iopfq;
+	}
+	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);
+
+	init_completion(&iommu->prq_complete);
+
+	return 0;
+
+free_iopfq:
+	iopf_queue_free(iommu->iopf_queue);
+	iommu->iopf_queue = NULL;
+free_hwirq:
+	dmar_free_hwirq(irq);
+	iommu->pr_irq = 0;
+free_prq:
+	free_pages((unsigned long)iommu->prq, PRQ_ORDER);
+	iommu->prq = NULL;
+
+	return ret;
+}
+
+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;
+	}
+
+	if (iommu->iopf_queue) {
+		iopf_queue_free(iommu->iopf_queue);
+		iommu->iopf_queue = NULL;
+	}
+
+	free_pages((unsigned long)iommu->prq, PRQ_ORDER);
+	iommu->prq = NULL;
+
+	return 0;
+}
+
+void intel_svm_check(struct intel_iommu *iommu)
+{
+	if (!pasid_supported(iommu))
+		return;
+
+	if (cpu_feature_enabled(X86_FEATURE_GBPAGES) &&
+	    !cap_fl1gp_support(iommu->cap)) {
+		pr_err("%s SVM disabled, incompatible 1GB page capability\n",
+		       iommu->name);
+		return;
+	}
+
+	if (cpu_feature_enabled(X86_FEATURE_LA57) &&
+	    !cap_fl5lp_support(iommu->cap)) {
+		pr_err("%s SVM disabled, incompatible paging mode\n",
+		       iommu->name);
+		return;
+	}
+
+	iommu->flags |= VTD_FLAG_SVM_CAPABLE;
+}
+
+static void __flush_svm_range_dev(struct intel_svm *svm,
+				  struct intel_svm_dev *sdev,
+				  unsigned long address,
+				  unsigned long pages, int ih)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(sdev->dev);
+
+	if (WARN_ON(!pages))
+		return;
+
+	qi_flush_piotlb(sdev->iommu, sdev->did, svm->pasid, address, pages, ih);
+	if (info->ats_enabled) {
+		qi_flush_dev_iotlb_pasid(sdev->iommu, sdev->sid, info->pfsid,
+					 svm->pasid, sdev->qdep, address,
+					 order_base_2(pages));
+		quirk_extra_dev_tlb_flush(info, address, order_base_2(pages),
+					  svm->pasid, sdev->qdep);
+	}
+}
+
+static void intel_flush_svm_range_dev(struct intel_svm *svm,
+				      struct intel_svm_dev *sdev,
+				      unsigned long address,
+				      unsigned long pages, int ih)
+{
+	unsigned long shift = ilog2(__roundup_pow_of_two(pages));
+	unsigned long align = (1ULL << (VTD_PAGE_SHIFT + shift));
+	unsigned long start = ALIGN_DOWN(address, align);
+	unsigned long end = ALIGN(address + (pages << VTD_PAGE_SHIFT), align);
+
+	while (start < end) {
+		__flush_svm_range_dev(svm, sdev, start, align >> VTD_PAGE_SHIFT, ih);
+		start += align;
+	}
+}
+
+static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address,
+				unsigned long pages, int ih)
+{
+	struct intel_svm_dev *sdev;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sdev, &svm->devs, list)
+		intel_flush_svm_range_dev(svm, sdev, address, pages, ih);
+	rcu_read_unlock();
+}
+
+static void intel_flush_svm_all(struct intel_svm *svm)
+{
+	struct device_domain_info *info;
+	struct intel_svm_dev *sdev;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sdev, &svm->devs, list) {
+		info = dev_iommu_priv_get(sdev->dev);
+
+		qi_flush_piotlb(sdev->iommu, sdev->did, svm->pasid, 0, -1UL, 0);
+		if (info->ats_enabled) {
+			qi_flush_dev_iotlb_pasid(sdev->iommu, sdev->sid, info->pfsid,
+						 svm->pasid, sdev->qdep,
+						 0, 64 - VTD_PAGE_SHIFT);
+			quirk_extra_dev_tlb_flush(info, 0, 64 - VTD_PAGE_SHIFT,
+						  svm->pasid, sdev->qdep);
+		}
+	}
+	rcu_read_unlock();
+}
+
+/* Pages have been freed at this point */
+static void intel_arch_invalidate_secondary_tlbs(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);
+
+	if (start == 0 && end == -1UL) {
+		intel_flush_svm_all(svm);
+		return;
+	}
+
+	intel_flush_svm_range(svm, start,
+			      (end - start + PAGE_SIZE - 1) >> VTD_PAGE_SHIFT, 0);
+}
+
+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_tear_down_entry(sdev->iommu, sdev->dev,
+					    svm->pasid, true);
+	rcu_read_unlock();
+
+}
+
+static const struct mmu_notifier_ops intel_mmuops = {
+	.release = intel_mm_release,
+	.arch_invalidate_secondary_tlbs = intel_arch_invalidate_secondary_tlbs,
+};
+
+static int pasid_to_svm_sdev(struct device *dev, unsigned int pasid,
+			     struct intel_svm **rsvm,
+			     struct intel_svm_dev **rsdev)
+{
+	struct intel_svm_dev *sdev = NULL;
+	struct intel_svm *svm;
+
+	if (pasid == IOMMU_PASID_INVALID || pasid >= PASID_MAX)
+		return -EINVAL;
+
+	svm = pasid_private_find(pasid);
+	if (IS_ERR(svm))
+		return PTR_ERR(svm);
+
+	if (!svm)
+		goto out;
+
+	/*
+	 * If we found svm for the PASID, there must be at least one device
+	 * bond.
+	 */
+	if (WARN_ON(list_empty(&svm->devs)))
+		return -EINVAL;
+	sdev = svm_lookup_device_by_dev(svm, dev);
+
+out:
+	*rsvm = svm;
+	*rsdev = sdev;
+
+	return 0;
+}
+
+static int intel_svm_bind_mm(struct intel_iommu *iommu, struct device *dev,
+			     struct mm_struct *mm)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct intel_svm_dev *sdev;
+	struct intel_svm *svm;
+	unsigned long sflags;
+	int ret = 0;
+
+	svm = pasid_private_find(mm->pasid);
+	if (!svm) {
+		svm = kzalloc(sizeof(*svm), GFP_KERNEL);
+		if (!svm)
+			return -ENOMEM;
+
+		svm->pasid = mm->pasid;
+		svm->mm = mm;
+		INIT_LIST_HEAD_RCU(&svm->devs);
+
+		svm->notifier.ops = &intel_mmuops;
+		ret = mmu_notifier_register(&svm->notifier, mm);
+		if (ret) {
+			kfree(svm);
+			return ret;
+		}
+
+		ret = pasid_private_add(svm->pasid, svm);
+		if (ret) {
+			mmu_notifier_unregister(&svm->notifier, mm);
+			kfree(svm);
+			return ret;
+		}
+	}
+
+	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
+	if (!sdev) {
+		ret = -ENOMEM;
+		goto free_svm;
+	}
+
+	sdev->dev = dev;
+	sdev->iommu = iommu;
+	sdev->did = FLPT_DEFAULT_DID;
+	sdev->sid = PCI_DEVID(info->bus, info->devfn);
+	init_rcu_head(&sdev->rcu);
+	if (info->ats_enabled) {
+		sdev->qdep = info->ats_qdep;
+		if (sdev->qdep >= QI_DEV_EIOTLB_MAX_INVS)
+			sdev->qdep = 0;
+	}
+
+	/* Setup the pasid table: */
+	sflags = cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
+	ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, mm->pasid,
+					    FLPT_DEFAULT_DID, sflags);
+	if (ret)
+		goto free_sdev;
+
+	list_add_rcu(&sdev->list, &svm->devs);
+
+	return 0;
+
+free_sdev:
+	kfree(sdev);
+free_svm:
+	if (list_empty(&svm->devs)) {
+		mmu_notifier_unregister(&svm->notifier, mm);
+		pasid_private_remove(mm->pasid);
+		kfree(svm);
+	}
+
+	return ret;
+}
+
+void intel_svm_remove_dev_pasid(struct device *dev, u32 pasid)
+{
+	struct intel_svm_dev *sdev;
+	struct intel_iommu *iommu;
+	struct intel_svm *svm;
+	struct mm_struct *mm;
+
+	iommu = device_to_iommu(dev, NULL, NULL);
+	if (!iommu)
+		return;
+
+	if (pasid_to_svm_sdev(dev, pasid, &svm, &sdev))
+		return;
+	mm = svm->mm;
+
+	if (sdev) {
+		list_del_rcu(&sdev->list);
+		kfree_rcu(sdev, rcu);
+
+		if (list_empty(&svm->devs)) {
+			if (svm->notifier.ops)
+				mmu_notifier_unregister(&svm->notifier, mm);
+			pasid_private_remove(svm->pasid);
+			/*
+			 * 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);
+		}
+	}
+}
+
+/* Page request queue descriptor */
+struct page_req_dsc {
+	union {
+		struct {
+			u64 type:8;
+			u64 pasid_present:1;
+			u64 priv_data_present:1;
+			u64 rsvd:6;
+			u64 rid:16;
+			u64 pasid:20;
+			u64 exe_req:1;
+			u64 pm_req:1;
+			u64 rsvd2:10;
+		};
+		u64 qw_0;
+	};
+	union {
+		struct {
+			u64 rd_req:1;
+			u64 wr_req:1;
+			u64 lpig:1;
+			u64 prg_index:9;
+			u64 addr:52;
+		};
+		u64 qw_1;
+	};
+	u64 priv_data[2];
+};
+
+static bool is_canonical_address(u64 addr)
+{
+	int shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
+	long saddr = (long) addr;
+
+	return (((saddr << shift) >> shift) == saddr);
+}
+
+/**
+ * intel_drain_pasid_prq - Drain page requests and responses for a pasid
+ * @dev: target device
+ * @pasid: pasid for draining
+ *
+ * Drain all pending page requests and responses related to @pasid in both
+ * software and hardware. This is supposed to be called after the device
+ * driver has stopped DMA, the pasid entry has been cleared, and both IOTLB
+ * and DevTLB have been invalidated.
+ *
+ * It waits until all pending page requests for @pasid in the page fault
+ * queue are completed by the prq handling thread. Then follow the steps
+ * described in VT-d spec CH7.10 to drain all page requests and page
+ * responses pending in the hardware.
+ */
+void intel_drain_pasid_prq(struct device *dev, u32 pasid)
+{
+	struct device_domain_info *info;
+	struct dmar_domain *domain;
+	struct intel_iommu *iommu;
+	struct qi_desc desc[3];
+	struct pci_dev *pdev;
+	int head, tail;
+	u16 sid, did;
+	int qdep;
+
+	info = dev_iommu_priv_get(dev);
+	if (WARN_ON(!info || !dev_is_pci(dev)))
+		return;
+
+	if (!info->pri_enabled)
+		return;
+
+	iommu = info->iommu;
+	domain = info->domain;
+	pdev = to_pci_dev(dev);
+	sid = PCI_DEVID(info->bus, info->devfn);
+	did = domain_id_iommu(domain, iommu);
+	qdep = pci_ats_queue_depth(pdev);
+
+	/*
+	 * Check and wait until all pending page requests in the queue are
+	 * handled by the prq handling thread.
+	 */
+prq_retry:
+	reinit_completion(&iommu->prq_complete);
+	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 page_req_dsc *req;
+
+		req = &iommu->prq[head / sizeof(*req)];
+		if (!req->pasid_present || req->pasid != pasid) {
+			head = (head + sizeof(*req)) & PRQ_RING_MASK;
+			continue;
+		}
+
+		wait_for_completion(&iommu->prq_complete);
+		goto prq_retry;
+	}
+
+	iopf_queue_flush_dev(dev);
+
+	/*
+	 * Perform steps described in VT-d spec CH7.10 to drain page
+	 * requests and responses in hardware.
+	 */
+	memset(desc, 0, sizeof(desc));
+	desc[0].qw0 = QI_IWD_STATUS_DATA(QI_DONE) |
+			QI_IWD_FENCE |
+			QI_IWD_TYPE;
+	desc[1].qw0 = QI_EIOTLB_PASID(pasid) |
+			QI_EIOTLB_DID(did) |
+			QI_EIOTLB_GRAN(QI_GRAN_NONG_PASID) |
+			QI_EIOTLB_TYPE;
+	desc[2].qw0 = QI_DEV_EIOTLB_PASID(pasid) |
+			QI_DEV_EIOTLB_SID(sid) |
+			QI_DEV_EIOTLB_QDEP(qdep) |
+			QI_DEIOTLB_TYPE |
+			QI_DEV_IOTLB_PFSID(info->pfsid);
+qi_retry:
+	reinit_completion(&iommu->prq_complete);
+	qi_submit_sync(iommu, desc, 3, QI_OPT_WAIT_DRAIN);
+	if (readl(iommu->reg + DMAR_PRS_REG) & DMA_PRS_PRO) {
+		wait_for_completion(&iommu->prq_complete);
+		goto qi_retry;
+	}
+}
+
+static int prq_to_iommu_prot(struct page_req_dsc *req)
+{
+	int prot = 0;
+
+	if (req->rd_req)
+		prot |= IOMMU_FAULT_PERM_READ;
+	if (req->wr_req)
+		prot |= IOMMU_FAULT_PERM_WRITE;
+	if (req->exe_req)
+		prot |= IOMMU_FAULT_PERM_EXEC;
+	if (req->pm_req)
+		prot |= IOMMU_FAULT_PERM_PRIV;
+
+	return prot;
+}
+
+static int intel_svm_prq_report(struct intel_iommu *iommu, struct device *dev,
+				struct page_req_dsc *desc)
+{
+	struct iommu_fault_event event;
+
+	if (!dev || !dev_is_pci(dev))
+		return -ENODEV;
+
+	/* Fill in event data for device specific processing */
+	memset(&event, 0, sizeof(struct iommu_fault_event));
+	event.fault.type = IOMMU_FAULT_PAGE_REQ;
+	event.fault.prm.addr = (u64)desc->addr << VTD_PAGE_SHIFT;
+	event.fault.prm.pasid = desc->pasid;
+	event.fault.prm.grpid = desc->prg_index;
+	event.fault.prm.perm = prq_to_iommu_prot(desc);
+
+	if (desc->lpig)
+		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
+	if (desc->pasid_present) {
+		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+		event.fault.prm.flags |= IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID;
+	}
+	if (desc->priv_data_present) {
+		/*
+		 * Set last page in group bit if private data is present,
+		 * page response is required as it does for LPIG.
+		 * iommu_report_device_fault() doesn't understand this vendor
+		 * specific requirement thus we set last_page as a workaround.
+		 */
+		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
+		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
+		event.fault.prm.private_data[0] = desc->priv_data[0];
+		event.fault.prm.private_data[1] = desc->priv_data[1];
+	} else if (dmar_latency_enabled(iommu, DMAR_LATENCY_PRQ)) {
+		/*
+		 * If the private data fields are not used by hardware, use it
+		 * to monitor the prq handle latency.
+		 */
+		event.fault.prm.private_data[0] = ktime_to_ns(ktime_get());
+	}
+
+	return iommu_report_device_fault(dev, &event);
+}
+
+static void handle_bad_prq_event(struct intel_iommu *iommu,
+				 struct page_req_dsc *req, int result)
+{
+	struct qi_desc desc;
+
+	pr_err("%s: Invalid page request: %08llx %08llx\n",
+	       iommu->name, ((unsigned long long *)req)[0],
+	       ((unsigned long long *)req)[1]);
+
+	/*
+	 * Per VT-d spec. v3.0 ch7.7, system software must
+	 * respond with page group response if private data
+	 * is present (PDP) or last page in group (LPIG) bit
+	 * is set. This is an additional VT-d feature beyond
+	 * PCI ATS spec.
+	 */
+	if (!req->lpig && !req->priv_data_present)
+		return;
+
+	desc.qw0 = QI_PGRP_PASID(req->pasid) |
+			QI_PGRP_DID(req->rid) |
+			QI_PGRP_PASID_P(req->pasid_present) |
+			QI_PGRP_PDP(req->priv_data_present) |
+			QI_PGRP_RESP_CODE(result) |
+			QI_PGRP_RESP_TYPE;
+	desc.qw1 = QI_PGRP_IDX(req->prg_index) |
+			QI_PGRP_LPIG(req->lpig);
+
+	if (req->priv_data_present) {
+		desc.qw2 = req->priv_data[0];
+		desc.qw3 = req->priv_data[1];
+	} else {
+		desc.qw2 = 0;
+		desc.qw3 = 0;
+	}
+
+	qi_submit_sync(iommu, &desc, 1, 0);
+}
+
+static irqreturn_t prq_event_thread(int irq, void *d)
+{
+	struct intel_iommu *iommu = d;
+	struct page_req_dsc *req;
+	int head, tail, handled;
+	struct pci_dev *pdev;
+	u64 address;
+
+	/*
+	 * 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;
+	handled = (head != tail);
+	while (head != tail) {
+		req = &iommu->prq[head / sizeof(*req)];
+		address = (u64)req->addr << VTD_PAGE_SHIFT;
+
+		if (unlikely(!req->pasid_present)) {
+			pr_err("IOMMU: %s: Page request without PASID\n",
+			       iommu->name);
+bad_req:
+			handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
+			goto prq_advance;
+		}
+
+		if (unlikely(!is_canonical_address(address))) {
+			pr_err("IOMMU: %s: Address is not canonical\n",
+			       iommu->name);
+			goto bad_req;
+		}
+
+		if (unlikely(req->pm_req && (req->rd_req | req->wr_req))) {
+			pr_err("IOMMU: %s: Page request in Privilege Mode\n",
+			       iommu->name);
+			goto bad_req;
+		}
+
+		if (unlikely(req->exe_req && req->rd_req)) {
+			pr_err("IOMMU: %s: Execution request not supported\n",
+			       iommu->name);
+			goto bad_req;
+		}
+
+		/* Drop Stop Marker message. No need for a response. */
+		if (unlikely(req->lpig && !req->rd_req && !req->wr_req))
+			goto prq_advance;
+
+		pdev = pci_get_domain_bus_and_slot(iommu->segment,
+						   PCI_BUS_NUM(req->rid),
+						   req->rid & 0xff);
+		/*
+		 * If prq is to be handled outside iommu driver via receiver of
+		 * the fault notifiers, we skip the page response here.
+		 */
+		if (!pdev)
+			goto bad_req;
+
+		if (intel_svm_prq_report(iommu, &pdev->dev, req))
+			handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
+		else
+			trace_prq_report(iommu, &pdev->dev, req->qw_0, req->qw_1,
+					 req->priv_data[0], req->priv_data[1],
+					 iommu->prq_seq_number++);
+		pci_dev_put(pdev);
+prq_advance:
+		head = (head + sizeof(*req)) & PRQ_RING_MASK;
+	}
+
+	dmar_writeq(iommu->reg + DMAR_PQH_REG, tail);
+
+	/*
+	 * Clear the page request overflow bit and wake up all threads that
+	 * are waiting for the completion of this handling.
+	 */
+	if (readl(iommu->reg + DMAR_PRS_REG) & DMA_PRS_PRO) {
+		pr_info_ratelimited("IOMMU: %s: PRQ overflow detected\n",
+				    iommu->name);
+		head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
+		tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
+		if (head == tail) {
+			iopf_queue_discard_partial(iommu->iopf_queue);
+			writel(DMA_PRS_PRO, iommu->reg + DMAR_PRS_REG);
+			pr_info_ratelimited("IOMMU: %s: PRQ overflow cleared",
+					    iommu->name);
+		}
+	}
+
+	if (!completion_done(&iommu->prq_complete))
+		complete(&iommu->prq_complete);
+
+	return IRQ_RETVAL(handled);
+}
+
+int intel_svm_page_response(struct device *dev,
+			    struct iommu_fault_event *evt,
+			    struct iommu_page_response *msg)
+{
+	struct iommu_fault_page_request *prm;
+	struct intel_iommu *iommu;
+	bool private_present;
+	bool pasid_present;
+	bool last_page;
+	u8 bus, devfn;
+	int ret = 0;
+	u16 sid;
+
+	if (!dev || !dev_is_pci(dev))
+		return -ENODEV;
+
+	iommu = device_to_iommu(dev, &bus, &devfn);
+	if (!iommu)
+		return -ENODEV;
+
+	if (!msg || !evt)
+		return -EINVAL;
+
+	prm = &evt->fault.prm;
+	sid = PCI_DEVID(bus, devfn);
+	pasid_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+	private_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
+	last_page = prm->flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
+
+	if (!pasid_present) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (prm->pasid == 0 || prm->pasid >= PASID_MAX) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Per VT-d spec. v3.0 ch7.7, system software must respond
+	 * with page group response if private data is present (PDP)
+	 * or last page in group (LPIG) bit is set. This is an
+	 * additional VT-d requirement beyond PCI ATS spec.
+	 */
+	if (last_page || private_present) {
+		struct qi_desc desc;
+
+		desc.qw0 = QI_PGRP_PASID(prm->pasid) | QI_PGRP_DID(sid) |
+				QI_PGRP_PASID_P(pasid_present) |
+				QI_PGRP_PDP(private_present) |
+				QI_PGRP_RESP_CODE(msg->code) |
+				QI_PGRP_RESP_TYPE;
+		desc.qw1 = QI_PGRP_IDX(prm->grpid) | QI_PGRP_LPIG(last_page);
+		desc.qw2 = 0;
+		desc.qw3 = 0;
+
+		if (private_present) {
+			desc.qw2 = prm->private_data[0];
+			desc.qw3 = prm->private_data[1];
+		} else if (prm->private_data[0]) {
+			dmar_latency_update(iommu, DMAR_LATENCY_PRQ,
+				ktime_to_ns(ktime_get()) - prm->private_data[0]);
+		}
+
+		qi_submit_sync(iommu, &desc, 1, 0);
+	}
+out:
+	return ret;
+}
+
+static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
+				   struct device *dev, ioasid_t pasid)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct intel_iommu *iommu = info->iommu;
+	struct mm_struct *mm = domain->mm;
+
+	return intel_svm_bind_mm(iommu, dev, mm);
+}
+
+static void intel_svm_domain_free(struct iommu_domain *domain)
+{
+	kfree(to_dmar_domain(domain));
+}
+
+static const struct iommu_domain_ops intel_svm_domain_ops = {
+	.set_dev_pasid		= intel_svm_set_dev_pasid,
+	.free			= intel_svm_domain_free
+};
+
+struct iommu_domain *intel_svm_domain_alloc(void)
+{
+	struct dmar_domain *domain;
+
+	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
+	if (!domain)
+		return NULL;
+	domain->domain.ops = &intel_svm_domain_ops;
+
+	return &domain->domain;
+}