iommu: rename intr_remapping.[ch] to irq_remapping.[ch]

Make the file names consistent with the naming conventions of irq subsystem.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 1065 insertions, 0 deletions

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
new file mode 100644
index 0000000..b4d39507
--- /dev/null
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -0,0 +1,1065 @@
+#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 <asm/io_apic.h>
+#include <asm/smp.h>
+#include <asm/cpu.h>
+#include <linux/intel-iommu.h>
+#include <acpi/acpi.h>
+#include <asm/irq_remapping.h>
+#include <asm/pci-direct.h>
+#include <asm/msidef.h>
+
+#include "irq_remapping.h"
+
+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;
+};
+
+#define IR_X2APIC_MODE(mode) (mode ? (1 << 11) : 0)
+#define IRTE_DEST(dest) ((x2apic_mode) ? dest : dest << 8)
+
+static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
+static struct hpet_scope ir_hpet[MAX_HPET_TBS];
+static int ir_ioapic_num, ir_hpet_num;
+
+static DEFINE_RAW_SPINLOCK(irq_2_ir_lock);
+
+static struct irq_2_iommu *irq_2_iommu(unsigned int irq)
+{
+	struct irq_cfg *cfg = irq_get_chip_data(irq);
+	return cfg ? &cfg->irq_2_iommu : NULL;
+}
+
+int get_irte(int irq, struct irte *entry)
+{
+	struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
+	unsigned long flags;
+	int index;
+
+	if (!entry || !irq_iommu)
+		return -1;
+
+	raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
+
+	index = irq_iommu->irte_index + irq_iommu->sub_handle;
+	*entry = *(irq_iommu->iommu->ir_table->base + index);
+
+	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
+	return 0;
+}
+
+static int alloc_irte(struct intel_iommu *iommu, int irq, u16 count)
+{
+	struct ir_table *table = iommu->ir_table;
+	struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
+	u16 index, start_index;
+	unsigned int mask = 0;
+	unsigned long flags;
+	int i;
+
+	if (!count || !irq_iommu)
+		return -1;
+
+	/*
+	 * start the IRTE search from index 0.
+	 */
+	index = start_index = 0;
+
+	if (count > 1) {
+		count = __roundup_pow_of_two(count);
+		mask = ilog2(count);
+	}
+
+	if (mask > ecap_max_handle_mask(iommu->ecap)) {
+		printk(KERN_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);
+	do {
+		for (i = index; i < index + count; i++)
+			if  (table->base[i].present)
+				break;
+		/* empty index found */
+		if (i == index + count)
+			break;
+
+		index = (index + count) % INTR_REMAP_TABLE_ENTRIES;
+
+		if (index == start_index) {
+			raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
+			printk(KERN_ERR "can't allocate an IRTE\n");
+			return -1;
+		}
+	} while (1);
+
+	for (i = index; i < index + count; i++)
+		table->base[i].present = 1;
+
+	irq_iommu->iommu = iommu;
+	irq_iommu->irte_index =  index;
+	irq_iommu->sub_handle = 0;
+	irq_iommu->irte_mask = mask;
+
+	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.low = QI_IEC_IIDEX(index) | QI_IEC_TYPE | QI_IEC_IM(mask)
+		   | QI_IEC_SELECTIVE;
+	desc.high = 0;
+
+	return qi_submit_sync(&desc, iommu);
+}
+
+static int map_irq_to_irte_handle(int irq, u16 *sub_handle)
+{
+	struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
+	unsigned long flags;
+	int index;
+
+	if (!irq_iommu)
+		return -1;
+
+	raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
+	*sub_handle = irq_iommu->sub_handle;
+	index = irq_iommu->irte_index;
+	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
+	return index;
+}
+
+static int set_irte_irq(int irq, struct intel_iommu *iommu, u16 index, u16 subhandle)
+{
+	struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
+	unsigned long flags;
+
+	if (!irq_iommu)
+		return -1;
+
+	raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
+
+	irq_iommu->iommu = iommu;
+	irq_iommu->irte_index = index;
+	irq_iommu->sub_handle = subhandle;
+	irq_iommu->irte_mask = 0;
+
+	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
+
+	return 0;
+}
+
+static int modify_irte(int irq, struct irte *irte_modified)
+{
+	struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
+	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];
+
+	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);
+	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
+
+	return rc;
+}
+
+static struct intel_iommu *map_hpet_to_ir(u8 hpet_id)
+{
+	int i;
+
+	for (i = 0; i < MAX_HPET_TBS; i++)
+		if (ir_hpet[i].id == hpet_id)
+			return ir_hpet[i].iommu;
+	return NULL;
+}
+
+static struct intel_iommu *map_ioapic_to_ir(int apic)
+{
+	int i;
+
+	for (i = 0; i < MAX_IO_APICS; i++)
+		if (ir_ioapic[i].id == apic)
+			return ir_ioapic[i].iommu;
+	return NULL;
+}
+
+static struct intel_iommu *map_dev_to_ir(struct pci_dev *dev)
+{
+	struct dmar_drhd_unit *drhd;
+
+	drhd = dmar_find_matched_drhd_unit(dev);
+	if (!drhd)
+		return NULL;
+
+	return drhd->iommu;
+}
+
+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 + irq_iommu->sub_handle;
+
+	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);
+	}
+
+	return qi_flush_iec(iommu, index, irq_iommu->irte_mask);
+}
+
+static int free_irte(int irq)
+{
+	struct irq_2_iommu *irq_iommu = irq_2_iommu(irq);
+	unsigned long flags;
+	int rc;
+
+	if (!irq_iommu)
+		return -1;
+
+	raw_spin_lock_irqsave(&irq_2_ir_lock, flags);
+
+	rc = clear_entries(irq_iommu);
+
+	irq_iommu->iommu = NULL;
+	irq_iommu->irte_index = 0;
+	irq_iommu->sub_handle = 0;
+	irq_iommu->irte_mask = 0;
+
+	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
+
+	return rc;
+}
+
+/*
+ * 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;
+}
+
+static int set_ioapic_sid(struct irte *irte, int apic)
+{
+	int i;
+	u16 sid = 0;
+
+	if (!irte)
+		return -1;
+
+	for (i = 0; i < MAX_IO_APICS; i++) {
+		if (ir_ioapic[i].id == apic) {
+			sid = (ir_ioapic[i].bus << 8) | ir_ioapic[i].devfn;
+			break;
+		}
+	}
+
+	if (sid == 0) {
+		pr_warning("Failed to set source-id of IOAPIC (%d)\n", apic);
+		return -1;
+	}
+
+	set_irte_sid(irte, 1, 0, sid);
+
+	return 0;
+}
+
+static int set_hpet_sid(struct irte *irte, u8 id)
+{
+	int i;
+	u16 sid = 0;
+
+	if (!irte)
+		return -1;
+
+	for (i = 0; i < MAX_HPET_TBS; i++) {
+		if (ir_hpet[i].id == id) {
+			sid = (ir_hpet[i].bus << 8) | ir_hpet[i].devfn;
+			break;
+		}
+	}
+
+	if (sid == 0) {
+		pr_warning("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;
+}
+
+static int set_msi_sid(struct irte *irte, struct pci_dev *dev)
+{
+	struct pci_dev *bridge;
+
+	if (!irte || !dev)
+		return -1;
+
+	/* PCIe device or Root Complex integrated PCI device */
+	if (pci_is_pcie(dev) || !dev->bus->parent) {
+		set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16,
+			     (dev->bus->number << 8) | dev->devfn);
+		return 0;
+	}
+
+	bridge = pci_find_upstream_pcie_bridge(dev);
+	if (bridge) {
+		if (pci_is_pcie(bridge))/* this is a PCIe-to-PCI/PCIX bridge */
+			set_irte_sid(irte, SVT_VERIFY_BUS, SQ_ALL_16,
+				(bridge->bus->number << 8) | dev->bus->number);
+		else /* this is a legacy PCI bridge */
+			set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16,
+				(bridge->bus->number << 8) | bridge->devfn);
+	}
+
+	return 0;
+}
+
+static void iommu_set_irq_remapping(struct intel_iommu *iommu, int mode)
+{
+	u64 addr;
+	u32 sts;
+	unsigned long flags;
+
+	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 */
+	iommu->gcmd |= DMA_GCMD_SIRTP;
+	writel(iommu->gcmd, 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 before enabling
+	 * interrupt-remapping.
+	 */
+	qi_global_iec(iommu);
+
+	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);
+
+	raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
+}
+
+
+static int intel_setup_irq_remapping(struct intel_iommu *iommu, int mode)
+{
+	struct ir_table *ir_table;
+	struct page *pages;
+
+	ir_table = iommu->ir_table = kzalloc(sizeof(struct ir_table),
+					     GFP_ATOMIC);
+
+	if (!iommu->ir_table)
+		return -ENOMEM;
+
+	pages = alloc_pages_node(iommu->node, GFP_ATOMIC | __GFP_ZERO,
+				 INTR_REMAP_PAGE_ORDER);
+
+	if (!pages) {
+		printk(KERN_ERR "failed to allocate pages of order %d\n",
+		       INTR_REMAP_PAGE_ORDER);
+		kfree(iommu->ir_table);
+		return -ENOMEM;
+	}
+
+	ir_table->base = page_address(pages);
+
+	iommu_set_irq_remapping(iommu, mode);
+	return 0;
+}
+
+/*
+ * 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 = dmar_readq(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 int __init intel_irq_remapping_supported(void)
+{
+	struct dmar_drhd_unit *drhd;
+
+	if (disable_irq_remap)
+		return 0;
+
+	if (!dmar_ir_support())
+		return 0;
+
+	for_each_drhd_unit(drhd) {
+		struct intel_iommu *iommu = drhd->iommu;
+
+		if (!ecap_ir_support(iommu->ecap))
+			return 0;
+	}
+
+	return 1;
+}
+
+static int __init intel_enable_irq_remapping(void)
+{
+	struct dmar_drhd_unit *drhd;
+	int setup = 0;
+	int eim = 0;
+
+	if (parse_ioapics_under_ir() != 1) {
+		printk(KERN_INFO "Not enable interrupt remapping\n");
+		return -1;
+	}
+
+	if (x2apic_supported()) {
+		eim = !dmar_x2apic_optout();
+		WARN(!eim, KERN_WARNING
+			   "Your BIOS is broken and requested that x2apic be disabled\n"
+			   "This will leave your machine vulnerable to irq-injection attacks\n"
+			   "Use 'intremap=no_x2apic_optout' to override BIOS request\n");
+	}
+
+	for_each_drhd_unit(drhd) {
+		struct intel_iommu *iommu = drhd->iommu;
+
+		/*
+		 * If the queued invalidation is already initialized,
+		 * shouldn't disable it.
+		 */
+		if (iommu->qi)
+			continue;
+
+		/*
+		 * Clear previous faults.
+		 */
+		dmar_fault(-1, iommu);
+
+		/*
+		 * Disable intr remapping and queued invalidation, if already
+		 * enabled prior to OS handover.
+		 */
+		iommu_disable_irq_remapping(iommu);
+
+		dmar_disable_qi(iommu);
+	}
+
+	/*
+	 * check for the Interrupt-remapping support
+	 */
+	for_each_drhd_unit(drhd) {
+		struct intel_iommu *iommu = drhd->iommu;
+
+		if (!ecap_ir_support(iommu->ecap))
+			continue;
+
+		if (eim && !ecap_eim_support(iommu->ecap)) {
+			printk(KERN_INFO "DRHD %Lx: EIM not supported by DRHD, "
+			       " ecap %Lx\n", drhd->reg_base_addr, iommu->ecap);
+			return -1;
+		}
+	}
+
+	/*
+	 * Enable queued invalidation for all the DRHD's.
+	 */
+	for_each_drhd_unit(drhd) {
+		int ret;
+		struct intel_iommu *iommu = drhd->iommu;
+		ret = dmar_enable_qi(iommu);
+
+		if (ret) {
+			printk(KERN_ERR "DRHD %Lx: failed to enable queued, "
+			       " invalidation, ecap %Lx, ret %d\n",
+			       drhd->reg_base_addr, iommu->ecap, ret);
+			return -1;
+		}
+	}
+
+	/*
+	 * Setup Interrupt-remapping for all the DRHD's now.
+	 */
+	for_each_drhd_unit(drhd) {
+		struct intel_iommu *iommu = drhd->iommu;
+
+		if (!ecap_ir_support(iommu->ecap))
+			continue;
+
+		if (intel_setup_irq_remapping(iommu, eim))
+			goto error;
+
+		setup = 1;
+	}
+
+	if (!setup)
+		goto error;
+
+	irq_remapping_enabled = 1;
+	pr_info("Enabled IRQ remapping in %s mode\n", eim ? "x2apic" : "xapic");
+
+	return eim ? IRQ_REMAP_X2APIC_MODE : IRQ_REMAP_XAPIC_MODE;
+
+error:
+	/*
+	 * handle error condition gracefully here!
+	 */
+	return -1;
+}
+
+static void ir_parse_one_hpet_scope(struct acpi_dmar_device_scope *scope,
+				      struct intel_iommu *iommu)
+{
+	struct acpi_dmar_pci_path *path;
+	u8 bus;
+	int count;
+
+	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->dev, path->fn,
+					   PCI_SECONDARY_BUS);
+		path++;
+	}
+	ir_hpet[ir_hpet_num].bus   = bus;
+	ir_hpet[ir_hpet_num].devfn = PCI_DEVFN(path->dev, path->fn);
+	ir_hpet[ir_hpet_num].iommu = iommu;
+	ir_hpet[ir_hpet_num].id    = scope->enumeration_id;
+	ir_hpet_num++;
+}
+
+static void ir_parse_one_ioapic_scope(struct acpi_dmar_device_scope *scope,
+				      struct intel_iommu *iommu)
+{
+	struct acpi_dmar_pci_path *path;
+	u8 bus;
+	int count;
+
+	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->dev, path->fn,
+					   PCI_SECONDARY_BUS);
+		path++;
+	}
+
+	ir_ioapic[ir_ioapic_num].bus   = bus;
+	ir_ioapic[ir_ioapic_num].devfn = PCI_DEVFN(path->dev, path->fn);
+	ir_ioapic[ir_ioapic_num].iommu = iommu;
+	ir_ioapic[ir_ioapic_num].id    = scope->enumeration_id;
+	ir_ioapic_num++;
+}
+
+static int ir_parse_ioapic_hpet_scope(struct acpi_dmar_header *header,
+				      struct intel_iommu *iommu)
+{
+	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) {
+		scope = start;
+		if (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_IOAPIC) {
+			if (ir_ioapic_num == MAX_IO_APICS) {
+				printk(KERN_WARNING "Exceeded Max IO APICS\n");
+				return -1;
+			}
+
+			printk(KERN_INFO "IOAPIC id %d under DRHD base "
+			       " 0x%Lx IOMMU %d\n", scope->enumeration_id,
+			       drhd->address, iommu->seq_id);
+
+			ir_parse_one_ioapic_scope(scope, iommu);
+		} else if (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_HPET) {
+			if (ir_hpet_num == MAX_HPET_TBS) {
+				printk(KERN_WARNING "Exceeded Max HPET blocks\n");
+				return -1;
+			}
+
+			printk(KERN_INFO "HPET id %d under DRHD base"
+			       " 0x%Lx\n", scope->enumeration_id,
+			       drhd->address);
+
+			ir_parse_one_hpet_scope(scope, iommu);
+		}
+		start += scope->length;
+	}
+
+	return 0;
+}
+
+/*
+ * Finds the assocaition between IOAPIC's and its Interrupt-remapping
+ * hardware unit.
+ */
+int __init parse_ioapics_under_ir(void)
+{
+	struct dmar_drhd_unit *drhd;
+	int ir_supported = 0;
+
+	for_each_drhd_unit(drhd) {
+		struct intel_iommu *iommu = drhd->iommu;
+
+		if (ecap_ir_support(iommu->ecap)) {
+			if (ir_parse_ioapic_hpet_scope(drhd->hdr, iommu))
+				return -1;
+
+			ir_supported = 1;
+		}
+	}
+
+	if (ir_supported && ir_ioapic_num != nr_ioapics) {
+		printk(KERN_WARNING
+		       "Not all IO-APIC's listed under remapping hardware\n");
+		return -1;
+	}
+
+	return ir_supported;
+}
+
+int __init ir_dev_scope_init(void)
+{
+	if (!irq_remapping_enabled)
+		return 0;
+
+	return dmar_dev_scope_init();
+}
+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);
+	}
+}
+
+static int reenable_irq_remapping(int eim)
+{
+	struct dmar_drhd_unit *drhd;
+	int setup = 0;
+	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);
+		setup = 1;
+	}
+
+	if (!setup)
+		goto error;
+
+	return 0;
+
+error:
+	/*
+	 * handle error condition gracefully here!
+	 */
+	return -1;
+}
+
+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 int intel_setup_ioapic_entry(int irq,
+				    struct IO_APIC_route_entry *route_entry,
+				    unsigned int destination, int vector,
+				    struct io_apic_irq_attr *attr)
+{
+	int ioapic_id = mpc_ioapic_id(attr->ioapic);
+	struct intel_iommu *iommu = map_ioapic_to_ir(ioapic_id);
+	struct IR_IO_APIC_route_entry *entry;
+	struct irte irte;
+	int index;
+
+	if (!iommu) {
+		pr_warn("No mapping iommu for ioapic %d\n", ioapic_id);
+		return -ENODEV;
+	}
+
+	entry = (struct IR_IO_APIC_route_entry *)route_entry;
+
+	index = alloc_irte(iommu, irq, 1);
+	if (index < 0) {
+		pr_warn("Failed to allocate IRTE for ioapic %d\n", ioapic_id);
+		return -ENOMEM;
+	}
+
+	prepare_irte(&irte, vector, destination);
+
+	/* Set source-id of interrupt request */
+	set_ioapic_sid(&irte, ioapic_id);
+
+	modify_irte(irq, &irte);
+
+	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",
+		attr->ioapic, 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);
+
+	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	= attr->ioapic_pin;
+	entry->mask	= 0;			/* enable IRQ */
+	entry->trigger	= attr->trigger;
+	entry->polarity	= attr->polarity;
+
+	/* Mask level triggered irqs.
+	 * Use IRQ_DELAYED_DISABLE for edge triggered irqs.
+	 */
+	if (attr->trigger)
+		entry->mask = 1;
+
+	return 0;
+}
+
+/*
+ * 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_ioapic_set_affinity(struct irq_data *data, const struct cpumask *mask,
+			  bool force)
+{
+	struct irq_cfg *cfg = data->chip_data;
+	unsigned int dest, irq = data->irq;
+	struct irte irte;
+
+	if (!cpumask_intersects(mask, cpu_online_mask))
+		return -EINVAL;
+
+	if (get_irte(irq, &irte))
+		return -EBUSY;
+
+	if (assign_irq_vector(irq, cfg, mask))
+		return -EBUSY;
+
+	dest = apic->cpu_mask_to_apicid_and(cfg->domain, mask);
+
+	irte.vector = cfg->vector;
+	irte.dest_id = IRTE_DEST(dest);
+
+	/*
+	 * Atomically updates the IRTE with the new destination, vector
+	 * and flushes the interrupt entry cache.
+	 */
+	modify_irte(irq, &irte);
+
+	/*
+	 * After this point, all the interrupts will start arriving
+	 * at the new destination. So, time to cleanup the previous
+	 * vector allocation.
+	 */
+	if (cfg->move_in_progress)
+		send_cleanup_vector(cfg);
+
+	cpumask_copy(data->affinity, mask);
+	return 0;
+}
+
+static void intel_compose_msi_msg(struct pci_dev *pdev,
+				  unsigned int irq, unsigned int dest,
+				  struct msi_msg *msg, u8 hpet_id)
+{
+	struct irq_cfg *cfg;
+	struct irte irte;
+	u16 sub_handle;
+	int ir_index;
+
+	cfg = irq_get_chip_data(irq);
+
+	ir_index = map_irq_to_irte_handle(irq, &sub_handle);
+	BUG_ON(ir_index == -1);
+
+	prepare_irte(&irte, cfg->vector, dest);
+
+	/* Set source-id of interrupt request */
+	if (pdev)
+		set_msi_sid(&irte, pdev);
+	else
+		set_hpet_sid(&irte, hpet_id);
+
+	modify_irte(irq, &irte);
+
+	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(ir_index) |
+			  MSI_ADDR_IR_INDEX2(ir_index);
+}
+
+/*
+ * Map the PCI dev to the corresponding remapping hardware unit
+ * and allocate 'nvec' consecutive interrupt-remapping table entries
+ * in it.
+ */
+static int intel_msi_alloc_irq(struct pci_dev *dev, int irq, int nvec)
+{
+	struct intel_iommu *iommu;
+	int index;
+
+	iommu = map_dev_to_ir(dev);
+	if (!iommu) {
+		printk(KERN_ERR
+		       "Unable to map PCI %s to iommu\n", pci_name(dev));
+		return -ENOENT;
+	}
+
+	index = alloc_irte(iommu, irq, nvec);
+	if (index < 0) {
+		printk(KERN_ERR
+		       "Unable to allocate %d IRTE for PCI %s\n", nvec,
+		       pci_name(dev));
+		return -ENOSPC;
+	}
+	return index;
+}
+
+static int intel_msi_setup_irq(struct pci_dev *pdev, unsigned int irq,
+			       int index, int sub_handle)
+{
+	struct intel_iommu *iommu;
+
+	iommu = map_dev_to_ir(pdev);
+	if (!iommu)
+		return -ENOENT;
+	/*
+	 * setup the mapping between the irq and the IRTE
+	 * base index, the sub_handle pointing to the
+	 * appropriate interrupt remap table entry.
+	 */
+	set_irte_irq(irq, iommu, index, sub_handle);
+
+	return 0;
+}
+
+static int intel_setup_hpet_msi(unsigned int irq, unsigned int id)
+{
+	struct intel_iommu *iommu = map_hpet_to_ir(id);
+	int index;
+
+	if (!iommu)
+		return -1;
+
+	index = alloc_irte(iommu, irq, 1);
+	if (index < 0)
+		return -1;
+
+	return 0;
+}
+
+struct irq_remap_ops intel_irq_remap_ops = {
+	.supported		= intel_irq_remapping_supported,
+	.prepare		= dmar_table_init,
+	.enable			= intel_enable_irq_remapping,
+	.disable		= disable_irq_remapping,
+	.reenable		= reenable_irq_remapping,
+	.enable_faulting	= enable_drhd_fault_handling,
+	.setup_ioapic_entry	= intel_setup_ioapic_entry,
+	.set_affinity		= intel_ioapic_set_affinity,
+	.free_irq		= free_irte,
+	.compose_msi_msg	= intel_compose_msi_msg,
+	.msi_alloc_irq		= intel_msi_alloc_irq,
+	.msi_setup_irq		= intel_msi_setup_irq,
+	.setup_hpet_msi		= intel_setup_hpet_msi,
+};