Adding upstream version 5.10.209.upstream/5.10.209

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

1 files changed, 1531 insertions, 0 deletions

diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c
new file mode 100644
index 000000000..b85388877
--- /dev/null
+++ b/drivers/iommu/intel/irq_remapping.c
@@ -0,0 +1,1531 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt)     "DMAR-IR: " fmt
+
+#include <linux/interrupt.h>
+#include <linux/dmar.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/hpet.h>
+#include <linux/pci.h>
+#include <linux/irq.h>
+#include <linux/intel-iommu.h>
+#include <linux/acpi.h>
+#include <linux/irqdomain.h>
+#include <linux/crash_dump.h>
+#include <asm/io_apic.h>
+#include <asm/apic.h>
+#include <asm/smp.h>
+#include <asm/cpu.h>
+#include <asm/irq_remapping.h>
+#include <asm/pci-direct.h>
+#include <asm/msidef.h>
+
+#include "../irq_remapping.h"
+
+enum irq_mode {
+	IRQ_REMAPPING,
+	IRQ_POSTING,
+};
+
+struct ioapic_scope {
+	struct intel_iommu *iommu;
+	unsigned int id;
+	unsigned int bus;	/* PCI bus number */
+	unsigned int devfn;	/* PCI devfn number */
+};
+
+struct hpet_scope {
+	struct intel_iommu *iommu;
+	u8 id;
+	unsigned int bus;
+	unsigned int devfn;
+};
+
+struct irq_2_iommu {
+	struct intel_iommu *iommu;
+	u16 irte_index;
+	u16 sub_handle;
+	u8  irte_mask;
+	enum irq_mode mode;
+};
+
+struct intel_ir_data {
+	struct irq_2_iommu			irq_2_iommu;
+	struct irte				irte_entry;
+	union {
+		struct msi_msg			msi_entry;
+	};
+};
+
+#define IR_X2APIC_MODE(mode) (mode ? (1 << 11) : 0)
+#define IRTE_DEST(dest) ((eim_mode) ? dest : dest << 8)
+
+static int __read_mostly eim_mode;
+static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
+static struct hpet_scope ir_hpet[MAX_HPET_TBS];
+
+/*
+ * Lock ordering:
+ * ->dmar_global_lock
+ *	->irq_2_ir_lock
+ *		->qi->q_lock
+ *	->iommu->register_lock
+ * Note:
+ * intel_irq_remap_ops.{supported,prepare,enable,disable,reenable} are called
+ * in single-threaded environment with interrupt disabled, so no need to tabke
+ * the dmar_global_lock.
+ */
+DEFINE_RAW_SPINLOCK(irq_2_ir_lock);
+static const struct irq_domain_ops intel_ir_domain_ops;
+
+static void iommu_disable_irq_remapping(struct intel_iommu *iommu);
+static int __init parse_ioapics_under_ir(void);
+
+static bool ir_pre_enabled(struct intel_iommu *iommu)
+{
+	return (iommu->flags & VTD_FLAG_IRQ_REMAP_PRE_ENABLED);
+}
+
+static void clear_ir_pre_enabled(struct intel_iommu *iommu)
+{
+	iommu->flags &= ~VTD_FLAG_IRQ_REMAP_PRE_ENABLED;
+}
+
+static void init_ir_status(struct intel_iommu *iommu)
+{
+	u32 gsts;
+
+	gsts = readl(iommu->reg + DMAR_GSTS_REG);
+	if (gsts & DMA_GSTS_IRES)
+		iommu->flags |= VTD_FLAG_IRQ_REMAP_PRE_ENABLED;
+}
+
+static int alloc_irte(struct intel_iommu *iommu,
+		      struct irq_2_iommu *irq_iommu, u16 count)
+{
+	struct ir_table *table = iommu->ir_table;
+	unsigned int mask = 0;
+	unsigned long flags;
+	int index;
+
+	if (!count || !irq_iommu)
+		return -1;
+
+	if (count > 1) {
+		count = __roundup_pow_of_two(count);
+		mask = ilog2(count);
+	}
+
+	if (mask > ecap_max_handle_mask(iommu->ecap)) {
+		pr_err("Requested mask %x exceeds the max invalidation handle"
+		       " mask value %Lx\n", mask,
+		       ecap_max_handle_mask(iommu->ecap));
+		return -1;
+	}
+
+	raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
+	index = bitmap_find_free_region(table->bitmap,
+					INTR_REMAP_TABLE_ENTRIES, mask);
+	if (index < 0) {
+		pr_warn("IR%d: can't allocate an IRTE\n", iommu->seq_id);
+	} else {
+		irq_iommu->iommu = iommu;
+		irq_iommu->irte_index =  index;
+		irq_iommu->sub_handle = 0;
+		irq_iommu->irte_mask = mask;
+		irq_iommu->mode = IRQ_REMAPPING;
+	}
+	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
+
+	return index;
+}
+
+static int qi_flush_iec(struct intel_iommu *iommu, int index, int mask)
+{
+	struct qi_desc desc;
+
+	desc.qw0 = QI_IEC_IIDEX(index) | QI_IEC_TYPE | QI_IEC_IM(mask)
+		   | QI_IEC_SELECTIVE;
+	desc.qw1 = 0;
+	desc.qw2 = 0;
+	desc.qw3 = 0;
+
+	return qi_submit_sync(iommu, &desc, 1, 0);
+}
+
+static int modify_irte(struct irq_2_iommu *irq_iommu,
+		       struct irte *irte_modified)
+{
+	struct intel_iommu *iommu;
+	unsigned long flags;
+	struct irte *irte;
+	int rc, index;
+
+	if (!irq_iommu)
+		return -1;
+
+	raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
+
+	iommu = irq_iommu->iommu;
+
+	index = irq_iommu->irte_index + irq_iommu->sub_handle;
+	irte = &iommu->ir_table->base[index];
+
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE)
+	if ((irte->pst == 1) || (irte_modified->pst == 1)) {
+		bool ret;
+
+		ret = cmpxchg_double(&irte->low, &irte->high,
+				     irte->low, irte->high,
+				     irte_modified->low, irte_modified->high);
+		/*
+		 * We use cmpxchg16 to atomically update the 128-bit IRTE,
+		 * and it cannot be updated by the hardware or other processors
+		 * behind us, so the return value of cmpxchg16 should be the
+		 * same as the old value.
+		 */
+		WARN_ON(!ret);
+	} else
+#endif
+	{
+		set_64bit(&irte->low, irte_modified->low);
+		set_64bit(&irte->high, irte_modified->high);
+	}
+	__iommu_flush_cache(iommu, irte, sizeof(*irte));
+
+	rc = qi_flush_iec(iommu, index, 0);
+
+	/* Update iommu mode according to the IRTE mode */
+	irq_iommu->mode = irte->pst ? IRQ_POSTING : IRQ_REMAPPING;
+	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
+
+	return rc;
+}
+
+static struct irq_domain *map_hpet_to_ir(u8 hpet_id)
+{
+	int i;
+
+	for (i = 0; i < MAX_HPET_TBS; i++) {
+		if (ir_hpet[i].id == hpet_id && ir_hpet[i].iommu)
+			return ir_hpet[i].iommu->ir_domain;
+	}
+	return NULL;
+}
+
+static struct intel_iommu *map_ioapic_to_iommu(int apic)
+{
+	int i;
+
+	for (i = 0; i < MAX_IO_APICS; i++) {
+		if (ir_ioapic[i].id == apic && ir_ioapic[i].iommu)
+			return ir_ioapic[i].iommu;
+	}
+	return NULL;
+}
+
+static struct irq_domain *map_ioapic_to_ir(int apic)
+{
+	struct intel_iommu *iommu = map_ioapic_to_iommu(apic);
+
+	return iommu ? iommu->ir_domain : NULL;
+}
+
+static struct irq_domain *map_dev_to_ir(struct pci_dev *dev)
+{
+	struct dmar_drhd_unit *drhd = dmar_find_matched_drhd_unit(dev);
+
+	return drhd ? drhd->iommu->ir_msi_domain : NULL;
+}
+
+static int clear_entries(struct irq_2_iommu *irq_iommu)
+{
+	struct irte *start, *entry, *end;
+	struct intel_iommu *iommu;
+	int index;
+
+	if (irq_iommu->sub_handle)
+		return 0;
+
+	iommu = irq_iommu->iommu;
+	index = irq_iommu->irte_index;
+
+	start = iommu->ir_table->base + index;
+	end = start + (1 << irq_iommu->irte_mask);
+
+	for (entry = start; entry < end; entry++) {
+		set_64bit(&entry->low, 0);
+		set_64bit(&entry->high, 0);
+	}
+	bitmap_release_region(iommu->ir_table->bitmap, index,
+			      irq_iommu->irte_mask);
+
+	return qi_flush_iec(iommu, index, irq_iommu->irte_mask);
+}
+
+/*
+ * source validation type
+ */
+#define SVT_NO_VERIFY		0x0  /* no verification is required */
+#define SVT_VERIFY_SID_SQ	0x1  /* verify using SID and SQ fields */
+#define SVT_VERIFY_BUS		0x2  /* verify bus of request-id */
+
+/*
+ * source-id qualifier
+ */
+#define SQ_ALL_16	0x0  /* verify all 16 bits of request-id */
+#define SQ_13_IGNORE_1	0x1  /* verify most significant 13 bits, ignore
+			      * the third least significant bit
+			      */
+#define SQ_13_IGNORE_2	0x2  /* verify most significant 13 bits, ignore
+			      * the second and third least significant bits
+			      */
+#define SQ_13_IGNORE_3	0x3  /* verify most significant 13 bits, ignore
+			      * the least three significant bits
+			      */
+
+/*
+ * set SVT, SQ and SID fields of irte to verify
+ * source ids of interrupt requests
+ */
+static void set_irte_sid(struct irte *irte, unsigned int svt,
+			 unsigned int sq, unsigned int sid)
+{
+	if (disable_sourceid_checking)
+		svt = SVT_NO_VERIFY;
+	irte->svt = svt;
+	irte->sq = sq;
+	irte->sid = sid;
+}
+
+/*
+ * Set an IRTE to match only the bus number. Interrupt requests that reference
+ * this IRTE must have a requester-id whose bus number is between or equal
+ * to the start_bus and end_bus arguments.
+ */
+static void set_irte_verify_bus(struct irte *irte, unsigned int start_bus,
+				unsigned int end_bus)
+{
+	set_irte_sid(irte, SVT_VERIFY_BUS, SQ_ALL_16,
+		     (start_bus << 8) | end_bus);
+}
+
+static int set_ioapic_sid(struct irte *irte, int apic)
+{
+	int i;
+	u16 sid = 0;
+
+	if (!irte)
+		return -1;
+
+	down_read(&dmar_global_lock);
+	for (i = 0; i < MAX_IO_APICS; i++) {
+		if (ir_ioapic[i].iommu && ir_ioapic[i].id == apic) {
+			sid = (ir_ioapic[i].bus << 8) | ir_ioapic[i].devfn;
+			break;
+		}
+	}
+	up_read(&dmar_global_lock);
+
+	if (sid == 0) {
+		pr_warn("Failed to set source-id of IOAPIC (%d)\n", apic);
+		return -1;
+	}
+
+	set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16, sid);
+
+	return 0;
+}
+
+static int set_hpet_sid(struct irte *irte, u8 id)
+{
+	int i;
+	u16 sid = 0;
+
+	if (!irte)
+		return -1;
+
+	down_read(&dmar_global_lock);
+	for (i = 0; i < MAX_HPET_TBS; i++) {
+		if (ir_hpet[i].iommu && ir_hpet[i].id == id) {
+			sid = (ir_hpet[i].bus << 8) | ir_hpet[i].devfn;
+			break;
+		}
+	}
+	up_read(&dmar_global_lock);
+
+	if (sid == 0) {
+		pr_warn("Failed to set source-id of HPET block (%d)\n", id);
+		return -1;
+	}
+
+	/*
+	 * Should really use SQ_ALL_16. Some platforms are broken.
+	 * While we figure out the right quirks for these broken platforms, use
+	 * SQ_13_IGNORE_3 for now.
+	 */
+	set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_13_IGNORE_3, sid);
+
+	return 0;
+}
+
+struct set_msi_sid_data {
+	struct pci_dev *pdev;
+	u16 alias;
+	int count;
+	int busmatch_count;
+};
+
+static int set_msi_sid_cb(struct pci_dev *pdev, u16 alias, void *opaque)
+{
+	struct set_msi_sid_data *data = opaque;
+
+	if (data->count == 0 || PCI_BUS_NUM(alias) == PCI_BUS_NUM(data->alias))
+		data->busmatch_count++;
+
+	data->pdev = pdev;
+	data->alias = alias;
+	data->count++;
+
+	return 0;
+}
+
+static int set_msi_sid(struct irte *irte, struct pci_dev *dev)
+{
+	struct set_msi_sid_data data;
+
+	if (!irte || !dev)
+		return -1;
+
+	data.count = 0;
+	data.busmatch_count = 0;
+	pci_for_each_dma_alias(dev, set_msi_sid_cb, &data);
+
+	/*
+	 * DMA alias provides us with a PCI device and alias.  The only case
+	 * where the it will return an alias on a different bus than the
+	 * device is the case of a PCIe-to-PCI bridge, where the alias is for
+	 * the subordinate bus.  In this case we can only verify the bus.
+	 *
+	 * If there are multiple aliases, all with the same bus number,
+	 * then all we can do is verify the bus. This is typical in NTB
+	 * hardware which use proxy IDs where the device will generate traffic
+	 * from multiple devfn numbers on the same bus.
+	 *
+	 * If the alias device is on a different bus than our source device
+	 * then we have a topology based alias, use it.
+	 *
+	 * Otherwise, the alias is for a device DMA quirk and we cannot
+	 * assume that MSI uses the same requester ID.  Therefore use the
+	 * original device.
+	 */
+	if (PCI_BUS_NUM(data.alias) != data.pdev->bus->number)
+		set_irte_verify_bus(irte, PCI_BUS_NUM(data.alias),
+				    dev->bus->number);
+	else if (data.count >= 2 && data.busmatch_count == data.count)
+		set_irte_verify_bus(irte, dev->bus->number, dev->bus->number);
+	else if (data.pdev->bus->number != dev->bus->number)
+		set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16, data.alias);
+	else
+		set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16,
+			     pci_dev_id(dev));
+
+	return 0;
+}
+
+static int iommu_load_old_irte(struct intel_iommu *iommu)
+{
+	struct irte *old_ir_table;
+	phys_addr_t irt_phys;
+	unsigned int i;
+	size_t size;
+	u64 irta;
+
+	/* Check whether the old ir-table has the same size as ours */
+	irta = dmar_readq(iommu->reg + DMAR_IRTA_REG);
+	if ((irta & INTR_REMAP_TABLE_REG_SIZE_MASK)
+	     != INTR_REMAP_TABLE_REG_SIZE)
+		return -EINVAL;
+
+	irt_phys = irta & VTD_PAGE_MASK;
+	size     = INTR_REMAP_TABLE_ENTRIES*sizeof(struct irte);
+
+	/* Map the old IR table */
+	old_ir_table = memremap(irt_phys, size, MEMREMAP_WB);
+	if (!old_ir_table)
+		return -ENOMEM;
+
+	/* Copy data over */
+	memcpy(iommu->ir_table->base, old_ir_table, size);
+
+	__iommu_flush_cache(iommu, iommu->ir_table->base, size);
+
+	/*
+	 * Now check the table for used entries and mark those as
+	 * allocated in the bitmap
+	 */
+	for (i = 0; i < INTR_REMAP_TABLE_ENTRIES; i++) {
+		if (iommu->ir_table->base[i].present)
+			bitmap_set(iommu->ir_table->bitmap, i, 1);
+	}
+
+	memunmap(old_ir_table);
+
+	return 0;
+}
+
+
+static void iommu_set_irq_remapping(struct intel_iommu *iommu, int mode)
+{
+	unsigned long flags;
+	u64 addr;
+	u32 sts;
+
+	addr = virt_to_phys((void *)iommu->ir_table->base);
+
+	raw_spin_lock_irqsave(&iommu->register_lock, flags);
+
+	dmar_writeq(iommu->reg + DMAR_IRTA_REG,
+		    (addr) | IR_X2APIC_MODE(mode) | INTR_REMAP_TABLE_REG_SIZE);
+
+	/* Set interrupt-remapping table pointer */
+	writel(iommu->gcmd | DMA_GCMD_SIRTP, iommu->reg + DMAR_GCMD_REG);
+
+	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
+		      readl, (sts & DMA_GSTS_IRTPS), sts);
+	raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
+
+	/*
+	 * Global invalidation of interrupt entry cache to make sure the
+	 * hardware uses the new irq remapping table.
+	 */
+	qi_global_iec(iommu);
+}
+
+static void iommu_enable_irq_remapping(struct intel_iommu *iommu)
+{
+	unsigned long flags;
+	u32 sts;
+
+	raw_spin_lock_irqsave(&iommu->register_lock, flags);
+
+	/* Enable interrupt-remapping */
+	iommu->gcmd |= DMA_GCMD_IRE;
+	writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
+	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
+		      readl, (sts & DMA_GSTS_IRES), sts);
+
+	/* Block compatibility-format MSIs */
+	if (sts & DMA_GSTS_CFIS) {
+		iommu->gcmd &= ~DMA_GCMD_CFI;
+		writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
+		IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
+			      readl, !(sts & DMA_GSTS_CFIS), sts);
+	}
+
+	/*
+	 * With CFI clear in the Global Command register, we should be
+	 * protected from dangerous (i.e. compatibility) interrupts
+	 * regardless of x2apic status.  Check just to be sure.
+	 */
+	if (sts & DMA_GSTS_CFIS)
+		WARN(1, KERN_WARNING
+			"Compatibility-format IRQs enabled despite intr remapping;\n"
+			"you are vulnerable to IRQ injection.\n");
+
+	raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
+}
+
+static int intel_setup_irq_remapping(struct intel_iommu *iommu)
+{
+	struct ir_table *ir_table;
+	struct fwnode_handle *fn;
+	unsigned long *bitmap;
+	struct page *pages;
+
+	if (iommu->ir_table)
+		return 0;
+
+	ir_table = kzalloc(sizeof(struct ir_table), GFP_KERNEL);
+	if (!ir_table)
+		return -ENOMEM;
+
+	pages = alloc_pages_node(iommu->node, GFP_KERNEL | __GFP_ZERO,
+				 INTR_REMAP_PAGE_ORDER);
+	if (!pages) {
+		pr_err("IR%d: failed to allocate pages of order %d\n",
+		       iommu->seq_id, INTR_REMAP_PAGE_ORDER);
+		goto out_free_table;
+	}
+
+	bitmap = bitmap_zalloc(INTR_REMAP_TABLE_ENTRIES, GFP_ATOMIC);
+	if (bitmap == NULL) {
+		pr_err("IR%d: failed to allocate bitmap\n", iommu->seq_id);
+		goto out_free_pages;
+	}
+
+	fn = irq_domain_alloc_named_id_fwnode("INTEL-IR", iommu->seq_id);
+	if (!fn)
+		goto out_free_bitmap;
+
+	iommu->ir_domain =
+		irq_domain_create_hierarchy(arch_get_ir_parent_domain(),
+					    0, INTR_REMAP_TABLE_ENTRIES,
+					    fn, &intel_ir_domain_ops,
+					    iommu);
+	if (!iommu->ir_domain) {
+		pr_err("IR%d: failed to allocate irqdomain\n", iommu->seq_id);
+		goto out_free_fwnode;
+	}
+	iommu->ir_msi_domain =
+		arch_create_remap_msi_irq_domain(iommu->ir_domain,
+						 "INTEL-IR-MSI",
+						 iommu->seq_id);
+
+	ir_table->base = page_address(pages);
+	ir_table->bitmap = bitmap;
+	iommu->ir_table = ir_table;
+
+	/*
+	 * If the queued invalidation is already initialized,
+	 * shouldn't disable it.
+	 */
+	if (!iommu->qi) {
+		/*
+		 * Clear previous faults.
+		 */
+		dmar_fault(-1, iommu);
+		dmar_disable_qi(iommu);
+
+		if (dmar_enable_qi(iommu)) {
+			pr_err("Failed to enable queued invalidation\n");
+			goto out_free_ir_domain;
+		}
+	}
+
+	init_ir_status(iommu);
+
+	if (ir_pre_enabled(iommu)) {
+		if (!is_kdump_kernel()) {
+			pr_warn("IRQ remapping was enabled on %s but we are not in kdump mode\n",
+				iommu->name);
+			clear_ir_pre_enabled(iommu);
+			iommu_disable_irq_remapping(iommu);
+		} else if (iommu_load_old_irte(iommu))
+			pr_err("Failed to copy IR table for %s from previous kernel\n",
+			       iommu->name);
+		else
+			pr_info("Copied IR table for %s from previous kernel\n",
+				iommu->name);
+	}
+
+	iommu_set_irq_remapping(iommu, eim_mode);
+
+	return 0;
+
+out_free_ir_domain:
+	if (iommu->ir_msi_domain)
+		irq_domain_remove(iommu->ir_msi_domain);
+	iommu->ir_msi_domain = NULL;
+	irq_domain_remove(iommu->ir_domain);
+	iommu->ir_domain = NULL;
+out_free_fwnode:
+	irq_domain_free_fwnode(fn);
+out_free_bitmap:
+	bitmap_free(bitmap);
+out_free_pages:
+	__free_pages(pages, INTR_REMAP_PAGE_ORDER);
+out_free_table:
+	kfree(ir_table);
+
+	iommu->ir_table  = NULL;
+
+	return -ENOMEM;
+}
+
+static void intel_teardown_irq_remapping(struct intel_iommu *iommu)
+{
+	struct fwnode_handle *fn;
+
+	if (iommu && iommu->ir_table) {
+		if (iommu->ir_msi_domain) {
+			fn = iommu->ir_msi_domain->fwnode;
+
+			irq_domain_remove(iommu->ir_msi_domain);
+			irq_domain_free_fwnode(fn);
+			iommu->ir_msi_domain = NULL;
+		}
+		if (iommu->ir_domain) {
+			fn = iommu->ir_domain->fwnode;
+
+			irq_domain_remove(iommu->ir_domain);
+			irq_domain_free_fwnode(fn);
+			iommu->ir_domain = NULL;
+		}
+		free_pages((unsigned long)iommu->ir_table->base,
+			   INTR_REMAP_PAGE_ORDER);
+		bitmap_free(iommu->ir_table->bitmap);
+		kfree(iommu->ir_table);
+		iommu->ir_table = NULL;
+	}
+}
+
+/*
+ * Disable Interrupt Remapping.
+ */
+static void iommu_disable_irq_remapping(struct intel_iommu *iommu)
+{
+	unsigned long flags;
+	u32 sts;
+
+	if (!ecap_ir_support(iommu->ecap))
+		return;
+
+	/*
+	 * global invalidation of interrupt entry cache before disabling
+	 * interrupt-remapping.
+	 */
+	qi_global_iec(iommu);
+
+	raw_spin_lock_irqsave(&iommu->register_lock, flags);
+
+	sts = readl(iommu->reg + DMAR_GSTS_REG);
+	if (!(sts & DMA_GSTS_IRES))
+		goto end;
+
+	iommu->gcmd &= ~DMA_GCMD_IRE;
+	writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
+
+	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
+		      readl, !(sts & DMA_GSTS_IRES), sts);
+
+end:
+	raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
+}
+
+static int __init dmar_x2apic_optout(void)
+{
+	struct acpi_table_dmar *dmar;
+	dmar = (struct acpi_table_dmar *)dmar_tbl;
+	if (!dmar || no_x2apic_optout)
+		return 0;
+	return dmar->flags & DMAR_X2APIC_OPT_OUT;
+}
+
+static void __init intel_cleanup_irq_remapping(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu;
+
+	for_each_iommu(iommu, drhd) {
+		if (ecap_ir_support(iommu->ecap)) {
+			iommu_disable_irq_remapping(iommu);
+			intel_teardown_irq_remapping(iommu);
+		}
+	}
+
+	if (x2apic_supported())
+		pr_warn("Failed to enable irq remapping. You are vulnerable to irq-injection attacks.\n");
+}
+
+static int __init intel_prepare_irq_remapping(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu;
+	int eim = 0;
+
+	if (irq_remap_broken) {
+		pr_warn("This system BIOS has enabled interrupt remapping\n"
+			"on a chipset that contains an erratum making that\n"
+			"feature unstable.  To maintain system stability\n"
+			"interrupt remapping is being disabled.  Please\n"
+			"contact your BIOS vendor for an update\n");
+		add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
+		return -ENODEV;
+	}
+
+	if (dmar_table_init() < 0)
+		return -ENODEV;
+
+	if (!dmar_ir_support())
+		return -ENODEV;
+
+	if (parse_ioapics_under_ir()) {
+		pr_info("Not enabling interrupt remapping\n");
+		goto error;
+	}
+
+	/* First make sure all IOMMUs support IRQ remapping */
+	for_each_iommu(iommu, drhd)
+		if (!ecap_ir_support(iommu->ecap))
+			goto error;
+
+	/* Detect remapping mode: lapic or x2apic */
+	if (x2apic_supported()) {
+		eim = !dmar_x2apic_optout();
+		if (!eim) {
+			pr_info("x2apic is disabled because BIOS sets x2apic opt out bit.");
+			pr_info("Use 'intremap=no_x2apic_optout' to override the BIOS setting.\n");
+		}
+	}
+
+	for_each_iommu(iommu, drhd) {
+		if (eim && !ecap_eim_support(iommu->ecap)) {
+			pr_info("%s does not support EIM\n", iommu->name);
+			eim = 0;
+		}
+	}
+
+	eim_mode = eim;
+	if (eim)
+		pr_info("Queued invalidation will be enabled to support x2apic and Intr-remapping.\n");
+
+	/* Do the initializations early */
+	for_each_iommu(iommu, drhd) {
+		if (intel_setup_irq_remapping(iommu)) {
+			pr_err("Failed to setup irq remapping for %s\n",
+			       iommu->name);
+			goto error;
+		}
+	}
+
+	return 0;
+
+error:
+	intel_cleanup_irq_remapping();
+	return -ENODEV;
+}
+
+/*
+ * Set Posted-Interrupts capability.
+ */
+static inline void set_irq_posting_cap(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu;
+
+	if (!disable_irq_post) {
+		/*
+		 * If IRTE is in posted format, the 'pda' field goes across the
+		 * 64-bit boundary, we need use cmpxchg16b to atomically update
+		 * it. We only expose posted-interrupt when X86_FEATURE_CX16
+		 * is supported. Actually, hardware platforms supporting PI
+		 * should have X86_FEATURE_CX16 support, this has been confirmed
+		 * with Intel hardware guys.
+		 */
+		if (boot_cpu_has(X86_FEATURE_CX16))
+			intel_irq_remap_ops.capability |= 1 << IRQ_POSTING_CAP;
+
+		for_each_iommu(iommu, drhd)
+			if (!cap_pi_support(iommu->cap)) {
+				intel_irq_remap_ops.capability &=
+						~(1 << IRQ_POSTING_CAP);
+				break;
+			}
+	}
+}
+
+static int __init intel_enable_irq_remapping(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu;
+	bool setup = false;
+
+	/*
+	 * Setup Interrupt-remapping for all the DRHD's now.
+	 */
+	for_each_iommu(iommu, drhd) {
+		if (!ir_pre_enabled(iommu))
+			iommu_enable_irq_remapping(iommu);
+		setup = true;
+	}
+
+	if (!setup)
+		goto error;
+
+	irq_remapping_enabled = 1;
+
+	set_irq_posting_cap();
+
+	pr_info("Enabled IRQ remapping in %s mode\n", eim_mode ? "x2apic" : "xapic");
+
+	return eim_mode ? IRQ_REMAP_X2APIC_MODE : IRQ_REMAP_XAPIC_MODE;
+
+error:
+	intel_cleanup_irq_remapping();
+	return -1;
+}
+
+static int ir_parse_one_hpet_scope(struct acpi_dmar_device_scope *scope,
+				   struct intel_iommu *iommu,
+				   struct acpi_dmar_hardware_unit *drhd)
+{
+	struct acpi_dmar_pci_path *path;
+	u8 bus;
+	int count, free = -1;
+
+	bus = scope->bus;
+	path = (struct acpi_dmar_pci_path *)(scope + 1);
+	count = (scope->length - sizeof(struct acpi_dmar_device_scope))
+		/ sizeof(struct acpi_dmar_pci_path);
+
+	while (--count > 0) {
+		/*
+		 * Access PCI directly due to the PCI
+		 * subsystem isn't initialized yet.
+		 */
+		bus = read_pci_config_byte(bus, path->device, path->function,
+					   PCI_SECONDARY_BUS);
+		path++;
+	}
+
+	for (count = 0; count < MAX_HPET_TBS; count++) {
+		if (ir_hpet[count].iommu == iommu &&
+		    ir_hpet[count].id == scope->enumeration_id)
+			return 0;
+		else if (ir_hpet[count].iommu == NULL && free == -1)
+			free = count;
+	}
+	if (free == -1) {
+		pr_warn("Exceeded Max HPET blocks\n");
+		return -ENOSPC;
+	}
+
+	ir_hpet[free].iommu = iommu;
+	ir_hpet[free].id    = scope->enumeration_id;
+	ir_hpet[free].bus   = bus;
+	ir_hpet[free].devfn = PCI_DEVFN(path->device, path->function);
+	pr_info("HPET id %d under DRHD base 0x%Lx\n",
+		scope->enumeration_id, drhd->address);
+
+	return 0;
+}
+
+static int ir_parse_one_ioapic_scope(struct acpi_dmar_device_scope *scope,
+				     struct intel_iommu *iommu,
+				     struct acpi_dmar_hardware_unit *drhd)
+{
+	struct acpi_dmar_pci_path *path;
+	u8 bus;
+	int count, free = -1;
+
+	bus = scope->bus;
+	path = (struct acpi_dmar_pci_path *)(scope + 1);
+	count = (scope->length - sizeof(struct acpi_dmar_device_scope))
+		/ sizeof(struct acpi_dmar_pci_path);
+
+	while (--count > 0) {
+		/*
+		 * Access PCI directly due to the PCI
+		 * subsystem isn't initialized yet.
+		 */
+		bus = read_pci_config_byte(bus, path->device, path->function,
+					   PCI_SECONDARY_BUS);
+		path++;
+	}
+
+	for (count = 0; count < MAX_IO_APICS; count++) {
+		if (ir_ioapic[count].iommu == iommu &&
+		    ir_ioapic[count].id == scope->enumeration_id)
+			return 0;
+		else if (ir_ioapic[count].iommu == NULL && free == -1)
+			free = count;
+	}
+	if (free == -1) {
+		pr_warn("Exceeded Max IO APICS\n");
+		return -ENOSPC;
+	}
+
+	ir_ioapic[free].bus   = bus;
+	ir_ioapic[free].devfn = PCI_DEVFN(path->device, path->function);
+	ir_ioapic[free].iommu = iommu;
+	ir_ioapic[free].id    = scope->enumeration_id;
+	pr_info("IOAPIC id %d under DRHD base  0x%Lx IOMMU %d\n",
+		scope->enumeration_id, drhd->address, iommu->seq_id);
+
+	return 0;
+}
+
+static int ir_parse_ioapic_hpet_scope(struct acpi_dmar_header *header,
+				      struct intel_iommu *iommu)
+{
+	int ret = 0;
+	struct acpi_dmar_hardware_unit *drhd;
+	struct acpi_dmar_device_scope *scope;
+	void *start, *end;
+
+	drhd = (struct acpi_dmar_hardware_unit *)header;
+	start = (void *)(drhd + 1);
+	end = ((void *)drhd) + header->length;
+
+	while (start < end && ret == 0) {
+		scope = start;
+		if (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_IOAPIC)
+			ret = ir_parse_one_ioapic_scope(scope, iommu, drhd);
+		else if (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_HPET)
+			ret = ir_parse_one_hpet_scope(scope, iommu, drhd);
+		start += scope->length;
+	}
+
+	return ret;
+}
+
+static void ir_remove_ioapic_hpet_scope(struct intel_iommu *iommu)
+{
+	int i;
+
+	for (i = 0; i < MAX_HPET_TBS; i++)
+		if (ir_hpet[i].iommu == iommu)
+			ir_hpet[i].iommu = NULL;
+
+	for (i = 0; i < MAX_IO_APICS; i++)
+		if (ir_ioapic[i].iommu == iommu)
+			ir_ioapic[i].iommu = NULL;
+}
+
+/*
+ * Finds the assocaition between IOAPIC's and its Interrupt-remapping
+ * hardware unit.
+ */
+static int __init parse_ioapics_under_ir(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu;
+	bool ir_supported = false;
+	int ioapic_idx;
+
+	for_each_iommu(iommu, drhd) {
+		int ret;
+
+		if (!ecap_ir_support(iommu->ecap))
+			continue;
+
+		ret = ir_parse_ioapic_hpet_scope(drhd->hdr, iommu);
+		if (ret)
+			return ret;
+
+		ir_supported = true;
+	}
+
+	if (!ir_supported)
+		return -ENODEV;
+
+	for (ioapic_idx = 0; ioapic_idx < nr_ioapics; ioapic_idx++) {
+		int ioapic_id = mpc_ioapic_id(ioapic_idx);
+		if (!map_ioapic_to_iommu(ioapic_id)) {
+			pr_err(FW_BUG "ioapic %d has no mapping iommu, "
+			       "interrupt remapping will be disabled\n",
+			       ioapic_id);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static int __init ir_dev_scope_init(void)
+{
+	int ret;
+
+	if (!irq_remapping_enabled)
+		return 0;
+
+	down_write(&dmar_global_lock);
+	ret = dmar_dev_scope_init();
+	up_write(&dmar_global_lock);
+
+	return ret;
+}
+rootfs_initcall(ir_dev_scope_init);
+
+static void disable_irq_remapping(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu = NULL;
+
+	/*
+	 * Disable Interrupt-remapping for all the DRHD's now.
+	 */
+	for_each_iommu(iommu, drhd) {
+		if (!ecap_ir_support(iommu->ecap))
+			continue;
+
+		iommu_disable_irq_remapping(iommu);
+	}
+
+	/*
+	 * Clear Posted-Interrupts capability.
+	 */
+	if (!disable_irq_post)
+		intel_irq_remap_ops.capability &= ~(1 << IRQ_POSTING_CAP);
+}
+
+static int reenable_irq_remapping(int eim)
+{
+	struct dmar_drhd_unit *drhd;
+	bool setup = false;
+	struct intel_iommu *iommu = NULL;
+
+	for_each_iommu(iommu, drhd)
+		if (iommu->qi)
+			dmar_reenable_qi(iommu);
+
+	/*
+	 * Setup Interrupt-remapping for all the DRHD's now.
+	 */
+	for_each_iommu(iommu, drhd) {
+		if (!ecap_ir_support(iommu->ecap))
+			continue;
+
+		/* Set up interrupt remapping for iommu.*/
+		iommu_set_irq_remapping(iommu, eim);
+		iommu_enable_irq_remapping(iommu);
+		setup = true;
+	}
+
+	if (!setup)
+		goto error;
+
+	set_irq_posting_cap();
+
+	return 0;
+
+error:
+	/*
+	 * handle error condition gracefully here!
+	 */
+	return -1;
+}
+
+/*
+ * Store the MSI remapping domain pointer in the device if enabled.
+ *
+ * This is called from dmar_pci_bus_add_dev() so it works even when DMA
+ * remapping is disabled. Only update the pointer if the device is not
+ * already handled by a non default PCI/MSI interrupt domain. This protects
+ * e.g. VMD devices.
+ */
+void intel_irq_remap_add_device(struct dmar_pci_notify_info *info)
+{
+	if (!irq_remapping_enabled || pci_dev_has_special_msi_domain(info->dev))
+		return;
+
+	dev_set_msi_domain(&info->dev->dev, map_dev_to_ir(info->dev));
+}
+
+static void prepare_irte(struct irte *irte, int vector, unsigned int dest)
+{
+	memset(irte, 0, sizeof(*irte));
+
+	irte->present = 1;
+	irte->dst_mode = apic->irq_dest_mode;
+	/*
+	 * Trigger mode in the IRTE will always be edge, and for IO-APIC, the
+	 * actual level or edge trigger will be setup in the IO-APIC
+	 * RTE. This will help simplify level triggered irq migration.
+	 * For more details, see the comments (in io_apic.c) explainig IO-APIC
+	 * irq migration in the presence of interrupt-remapping.
+	*/
+	irte->trigger_mode = 0;
+	irte->dlvry_mode = apic->irq_delivery_mode;
+	irte->vector = vector;
+	irte->dest_id = IRTE_DEST(dest);
+	irte->redir_hint = 1;
+}
+
+static struct irq_domain *intel_get_irq_domain(struct irq_alloc_info *info)
+{
+	if (!info)
+		return NULL;
+
+	switch (info->type) {
+	case X86_IRQ_ALLOC_TYPE_IOAPIC_GET_PARENT:
+		return map_ioapic_to_ir(info->devid);
+	case X86_IRQ_ALLOC_TYPE_HPET_GET_PARENT:
+		return map_hpet_to_ir(info->devid);
+	default:
+		WARN_ON_ONCE(1);
+		return NULL;
+	}
+}
+
+struct irq_remap_ops intel_irq_remap_ops = {
+	.prepare		= intel_prepare_irq_remapping,
+	.enable			= intel_enable_irq_remapping,
+	.disable		= disable_irq_remapping,
+	.reenable		= reenable_irq_remapping,
+	.enable_faulting	= enable_drhd_fault_handling,
+	.get_irq_domain		= intel_get_irq_domain,
+};
+
+static void intel_ir_reconfigure_irte(struct irq_data *irqd, bool force)
+{
+	struct intel_ir_data *ir_data = irqd->chip_data;
+	struct irte *irte = &ir_data->irte_entry;
+	struct irq_cfg *cfg = irqd_cfg(irqd);
+
+	/*
+	 * Atomically updates the IRTE with the new destination, vector
+	 * and flushes the interrupt entry cache.
+	 */
+	irte->vector = cfg->vector;
+	irte->dest_id = IRTE_DEST(cfg->dest_apicid);
+
+	/* Update the hardware only if the interrupt is in remapped mode. */
+	if (force || ir_data->irq_2_iommu.mode == IRQ_REMAPPING)
+		modify_irte(&ir_data->irq_2_iommu, irte);
+}
+
+/*
+ * Migrate the IO-APIC irq in the presence of intr-remapping.
+ *
+ * For both level and edge triggered, irq migration is a simple atomic
+ * update(of vector and cpu destination) of IRTE and flush the hardware cache.
+ *
+ * For level triggered, we eliminate the io-apic RTE modification (with the
+ * updated vector information), by using a virtual vector (io-apic pin number).
+ * Real vector that is used for interrupting cpu will be coming from
+ * the interrupt-remapping table entry.
+ *
+ * As the migration is a simple atomic update of IRTE, the same mechanism
+ * is used to migrate MSI irq's in the presence of interrupt-remapping.
+ */
+static int
+intel_ir_set_affinity(struct irq_data *data, const struct cpumask *mask,
+		      bool force)
+{
+	struct irq_data *parent = data->parent_data;
+	struct irq_cfg *cfg = irqd_cfg(data);
+	int ret;
+
+	ret = parent->chip->irq_set_affinity(parent, mask, force);
+	if (ret < 0 || ret == IRQ_SET_MASK_OK_DONE)
+		return ret;
+
+	intel_ir_reconfigure_irte(data, false);
+	/*
+	 * After this point, all the interrupts will start arriving
+	 * at the new destination. So, time to cleanup the previous
+	 * vector allocation.
+	 */
+	send_cleanup_vector(cfg);
+
+	return IRQ_SET_MASK_OK_DONE;
+}
+
+static void intel_ir_compose_msi_msg(struct irq_data *irq_data,
+				     struct msi_msg *msg)
+{
+	struct intel_ir_data *ir_data = irq_data->chip_data;
+
+	*msg = ir_data->msi_entry;
+}
+
+static int intel_ir_set_vcpu_affinity(struct irq_data *data, void *info)
+{
+	struct intel_ir_data *ir_data = data->chip_data;
+	struct vcpu_data *vcpu_pi_info = info;
+
+	/* stop posting interrupts, back to remapping mode */
+	if (!vcpu_pi_info) {
+		modify_irte(&ir_data->irq_2_iommu, &ir_data->irte_entry);
+	} else {
+		struct irte irte_pi;
+
+		/*
+		 * We are not caching the posted interrupt entry. We
+		 * copy the data from the remapped entry and modify
+		 * the fields which are relevant for posted mode. The
+		 * cached remapped entry is used for switching back to
+		 * remapped mode.
+		 */
+		memset(&irte_pi, 0, sizeof(irte_pi));
+		dmar_copy_shared_irte(&irte_pi, &ir_data->irte_entry);
+
+		/* Update the posted mode fields */
+		irte_pi.p_pst = 1;
+		irte_pi.p_urgent = 0;
+		irte_pi.p_vector = vcpu_pi_info->vector;
+		irte_pi.pda_l = (vcpu_pi_info->pi_desc_addr >>
+				(32 - PDA_LOW_BIT)) & ~(-1UL << PDA_LOW_BIT);
+		irte_pi.pda_h = (vcpu_pi_info->pi_desc_addr >> 32) &
+				~(-1UL << PDA_HIGH_BIT);
+
+		modify_irte(&ir_data->irq_2_iommu, &irte_pi);
+	}
+
+	return 0;
+}
+
+static struct irq_chip intel_ir_chip = {
+	.name			= "INTEL-IR",
+	.irq_ack		= apic_ack_irq,
+	.irq_set_affinity	= intel_ir_set_affinity,
+	.irq_compose_msi_msg	= intel_ir_compose_msi_msg,
+	.irq_set_vcpu_affinity	= intel_ir_set_vcpu_affinity,
+};
+
+static void intel_irq_remapping_prepare_irte(struct intel_ir_data *data,
+					     struct irq_cfg *irq_cfg,
+					     struct irq_alloc_info *info,
+					     int index, int sub_handle)
+{
+	struct IR_IO_APIC_route_entry *entry;
+	struct irte *irte = &data->irte_entry;
+	struct msi_msg *msg = &data->msi_entry;
+
+	prepare_irte(irte, irq_cfg->vector, irq_cfg->dest_apicid);
+	switch (info->type) {
+	case X86_IRQ_ALLOC_TYPE_IOAPIC:
+		/* Set source-id of interrupt request */
+		set_ioapic_sid(irte, info->devid);
+		apic_printk(APIC_VERBOSE, KERN_DEBUG "IOAPIC[%d]: Set IRTE entry (P:%d FPD:%d Dst_Mode:%d Redir_hint:%d Trig_Mode:%d Dlvry_Mode:%X Avail:%X Vector:%02X Dest:%08X SID:%04X SQ:%X SVT:%X)\n",
+			info->devid, irte->present, irte->fpd,
+			irte->dst_mode, irte->redir_hint,
+			irte->trigger_mode, irte->dlvry_mode,
+			irte->avail, irte->vector, irte->dest_id,
+			irte->sid, irte->sq, irte->svt);
+
+		entry = (struct IR_IO_APIC_route_entry *)info->ioapic.entry;
+		info->ioapic.entry = NULL;
+		memset(entry, 0, sizeof(*entry));
+		entry->index2	= (index >> 15) & 0x1;
+		entry->zero	= 0;
+		entry->format	= 1;
+		entry->index	= (index & 0x7fff);
+		/*
+		 * IO-APIC RTE will be configured with virtual vector.
+		 * irq handler will do the explicit EOI to the io-apic.
+		 */
+		entry->vector	= info->ioapic.pin;
+		entry->mask	= 0;			/* enable IRQ */
+		entry->trigger	= info->ioapic.trigger;
+		entry->polarity	= info->ioapic.polarity;
+		if (info->ioapic.trigger)
+			entry->mask = 1; /* Mask level triggered irqs. */
+		break;
+
+	case X86_IRQ_ALLOC_TYPE_HPET:
+	case X86_IRQ_ALLOC_TYPE_PCI_MSI:
+	case X86_IRQ_ALLOC_TYPE_PCI_MSIX:
+		if (info->type == X86_IRQ_ALLOC_TYPE_HPET)
+			set_hpet_sid(irte, info->devid);
+		else
+			set_msi_sid(irte, msi_desc_to_pci_dev(info->desc));
+
+		msg->address_hi = MSI_ADDR_BASE_HI;
+		msg->data = sub_handle;
+		msg->address_lo = MSI_ADDR_BASE_LO | MSI_ADDR_IR_EXT_INT |
+				  MSI_ADDR_IR_SHV |
+				  MSI_ADDR_IR_INDEX1(index) |
+				  MSI_ADDR_IR_INDEX2(index);
+		break;
+
+	default:
+		BUG_ON(1);
+		break;
+	}
+}
+
+static void intel_free_irq_resources(struct irq_domain *domain,
+				     unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *irq_data;
+	struct intel_ir_data *data;
+	struct irq_2_iommu *irq_iommu;
+	unsigned long flags;
+	int i;
+	for (i = 0; i < nr_irqs; i++) {
+		irq_data = irq_domain_get_irq_data(domain, virq  + i);
+		if (irq_data && irq_data->chip_data) {
+			data = irq_data->chip_data;
+			irq_iommu = &data->irq_2_iommu;
+			raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
+			clear_entries(irq_iommu);
+			raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
+			irq_domain_reset_irq_data(irq_data);
+			kfree(data);
+		}
+	}
+}
+
+static int intel_irq_remapping_alloc(struct irq_domain *domain,
+				     unsigned int virq, unsigned int nr_irqs,
+				     void *arg)
+{
+	struct intel_iommu *iommu = domain->host_data;
+	struct irq_alloc_info *info = arg;
+	struct intel_ir_data *data, *ird;
+	struct irq_data *irq_data;
+	struct irq_cfg *irq_cfg;
+	int i, ret, index;
+
+	if (!info || !iommu)
+		return -EINVAL;
+	if (nr_irqs > 1 && info->type != X86_IRQ_ALLOC_TYPE_PCI_MSI &&
+	    info->type != X86_IRQ_ALLOC_TYPE_PCI_MSIX)
+		return -EINVAL;
+
+	/*
+	 * With IRQ remapping enabled, don't need contiguous CPU vectors
+	 * to support multiple MSI interrupts.
+	 */
+	if (info->type == X86_IRQ_ALLOC_TYPE_PCI_MSI)
+		info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
+
+	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
+	if (ret < 0)
+		return ret;
+
+	ret = -ENOMEM;
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		goto out_free_parent;
+
+	down_read(&dmar_global_lock);
+	index = alloc_irte(iommu, &data->irq_2_iommu, nr_irqs);
+	up_read(&dmar_global_lock);
+	if (index < 0) {
+		pr_warn("Failed to allocate IRTE\n");
+		kfree(data);
+		goto out_free_parent;
+	}
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_data = irq_domain_get_irq_data(domain, virq + i);
+		irq_cfg = irqd_cfg(irq_data);
+		if (!irq_data || !irq_cfg) {
+			if (!i)
+				kfree(data);
+			ret = -EINVAL;
+			goto out_free_data;
+		}
+
+		if (i > 0) {
+			ird = kzalloc(sizeof(*ird), GFP_KERNEL);
+			if (!ird)
+				goto out_free_data;
+			/* Initialize the common data */
+			ird->irq_2_iommu = data->irq_2_iommu;
+			ird->irq_2_iommu.sub_handle = i;
+		} else {
+			ird = data;
+		}
+
+		irq_data->hwirq = (index << 16) + i;
+		irq_data->chip_data = ird;
+		irq_data->chip = &intel_ir_chip;
+		intel_irq_remapping_prepare_irte(ird, irq_cfg, info, index, i);
+		irq_set_status_flags(virq + i, IRQ_MOVE_PCNTXT);
+	}
+	return 0;
+
+out_free_data:
+	intel_free_irq_resources(domain, virq, i);
+out_free_parent:
+	irq_domain_free_irqs_common(domain, virq, nr_irqs);
+	return ret;
+}
+
+static void intel_irq_remapping_free(struct irq_domain *domain,
+				     unsigned int virq, unsigned int nr_irqs)
+{
+	intel_free_irq_resources(domain, virq, nr_irqs);
+	irq_domain_free_irqs_common(domain, virq, nr_irqs);
+}
+
+static int intel_irq_remapping_activate(struct irq_domain *domain,
+					struct irq_data *irq_data, bool reserve)
+{
+	intel_ir_reconfigure_irte(irq_data, true);
+	return 0;
+}
+
+static void intel_irq_remapping_deactivate(struct irq_domain *domain,
+					   struct irq_data *irq_data)
+{
+	struct intel_ir_data *data = irq_data->chip_data;
+	struct irte entry;
+
+	memset(&entry, 0, sizeof(entry));
+	modify_irte(&data->irq_2_iommu, &entry);
+}
+
+static const struct irq_domain_ops intel_ir_domain_ops = {
+	.alloc = intel_irq_remapping_alloc,
+	.free = intel_irq_remapping_free,
+	.activate = intel_irq_remapping_activate,
+	.deactivate = intel_irq_remapping_deactivate,
+};
+
+/*
+ * Support of Interrupt Remapping Unit Hotplug
+ */
+static int dmar_ir_add(struct dmar_drhd_unit *dmaru, struct intel_iommu *iommu)
+{
+	int ret;
+	int eim = x2apic_enabled();
+
+	if (eim && !ecap_eim_support(iommu->ecap)) {
+		pr_info("DRHD %Lx: EIM not supported by DRHD, ecap %Lx\n",
+			iommu->reg_phys, iommu->ecap);
+		return -ENODEV;
+	}
+
+	if (ir_parse_ioapic_hpet_scope(dmaru->hdr, iommu)) {
+		pr_warn("DRHD %Lx: failed to parse managed IOAPIC/HPET\n",
+			iommu->reg_phys);
+		return -ENODEV;
+	}
+
+	/* TODO: check all IOAPICs are covered by IOMMU */
+
+	/* Setup Interrupt-remapping now. */
+	ret = intel_setup_irq_remapping(iommu);
+	if (ret) {
+		pr_err("Failed to setup irq remapping for %s\n",
+		       iommu->name);
+		intel_teardown_irq_remapping(iommu);
+		ir_remove_ioapic_hpet_scope(iommu);
+	} else {
+		iommu_enable_irq_remapping(iommu);
+	}
+
+	return ret;
+}
+
+int dmar_ir_hotplug(struct dmar_drhd_unit *dmaru, bool insert)
+{
+	int ret = 0;
+	struct intel_iommu *iommu = dmaru->iommu;
+
+	if (!irq_remapping_enabled)
+		return 0;
+	if (iommu == NULL)
+		return -EINVAL;
+	if (!ecap_ir_support(iommu->ecap))
+		return 0;
+	if (irq_remapping_cap(IRQ_POSTING_CAP) &&
+	    !cap_pi_support(iommu->cap))
+		return -EBUSY;
+
+	if (insert) {
+		if (!iommu->ir_table)
+			ret = dmar_ir_add(dmaru, iommu);
+	} else {
+		if (iommu->ir_table) {
+			if (!bitmap_empty(iommu->ir_table->bitmap,
+					  INTR_REMAP_TABLE_ENTRIES)) {
+				ret = -EBUSY;
+			} else {
+				iommu_disable_irq_remapping(iommu);
+				intel_teardown_irq_remapping(iommu);
+				ir_remove_ioapic_hpet_scope(iommu);
+			}
+		}
+	}
+
+	return ret;
+}