Merge branch 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

* 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, ioapic: Consolidate the explicit EOI code
  x86, ioapic: Restore the mask bit correctly in eoi_ioapic_irq()
  x86, kdump, ioapic: Reset remote-IRR in clear_IO_APIC
  iommu: Rename the DMAR and INTR_REMAP config options
  x86, ioapic: Define irq_remap_modify_chip_defaults()
  x86, msi, intr-remap: Use the ioapic set affinity routine
  iommu: Cleanup ifdefs in detect_intel_iommu()
  iommu: No need to set dmar_disabled in check_zero_address()
  iommu: Move IOMMU specific code to intel-iommu.c
  intr_remap: Call dmar_dev_scope_init() explicitly
  x86, x2apic: Enable the bios request for x2apic optout

5 files changed, 244 insertions, 204 deletions

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index b57b3fa492f3..7d7eaa15e773 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -59,10 +59,14 @@ config AMD_IOMMU_STATS
 	  If unsure, say N.
 
 # Intel IOMMU support
-config DMAR
-	bool "Support for DMA Remapping Devices"
+config DMAR_TABLE
+	bool
+
+config INTEL_IOMMU
+	bool "Support for Intel IOMMU using DMA Remapping Devices"
 	depends on PCI_MSI && ACPI && (X86 || IA64_GENERIC)
 	select IOMMU_API
+	select DMAR_TABLE
 	help
 	  DMA remapping (DMAR) devices support enables independent address
 	  translations for Direct Memory Access (DMA) from devices.
@@ -70,18 +74,18 @@ config DMAR
 	  and include PCI device scope covered by these DMA
 	  remapping devices.
 
-config DMAR_DEFAULT_ON
+config INTEL_IOMMU_DEFAULT_ON
 	def_bool y
-	prompt "Enable DMA Remapping Devices by default"
-	depends on DMAR
+	prompt "Enable Intel DMA Remapping Devices by default"
+	depends on INTEL_IOMMU
 	help
 	  Selecting this option will enable a DMAR device at boot time if
 	  one is found. If this option is not selected, DMAR support can
 	  be enabled by passing intel_iommu=on to the kernel.
 
-config DMAR_BROKEN_GFX_WA
+config INTEL_IOMMU_BROKEN_GFX_WA
 	bool "Workaround broken graphics drivers (going away soon)"
-	depends on DMAR && BROKEN && X86
+	depends on INTEL_IOMMU && BROKEN && X86
 	---help---
 	  Current Graphics drivers tend to use physical address
 	  for DMA and avoid using DMA APIs. Setting this config
@@ -90,18 +94,19 @@ config DMAR_BROKEN_GFX_WA
 	  to use physical addresses for DMA, at least until this
 	  option is removed in the 2.6.32 kernel.
 
-config DMAR_FLOPPY_WA
+config INTEL_IOMMU_FLOPPY_WA
 	def_bool y
-	depends on DMAR && X86
+	depends on INTEL_IOMMU && X86
 	---help---
 	  Floppy disk drivers are known to bypass DMA API calls
 	  thereby failing to work when IOMMU is enabled. This
 	  workaround will setup a 1:1 mapping for the first
 	  16MiB to make floppy (an ISA device) work.
 
-config INTR_REMAP
+config IRQ_REMAP
 	bool "Support for Interrupt Remapping (EXPERIMENTAL)"
 	depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
+	select DMAR_TABLE
 	---help---
 	  Supports Interrupt remapping for IO-APIC and MSI devices.
 	  To use x2apic mode in the CPU's which support x2APIC enhancements or
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 4d4d77df7cac..6394994a2b9d 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_IOMMU_API) += iommu.o
 obj-$(CONFIG_MSM_IOMMU) += msm_iommu.o msm_iommu_dev.o
 obj-$(CONFIG_AMD_IOMMU) += amd_iommu.o amd_iommu_init.o
-obj-$(CONFIG_DMAR) += dmar.o iova.o intel-iommu.o
-obj-$(CONFIG_INTR_REMAP) += dmar.o intr_remapping.o
+obj-$(CONFIG_DMAR_TABLE) += dmar.o
+obj-$(CONFIG_INTEL_IOMMU) += iova.o intel-iommu.o
+obj-$(CONFIG_IRQ_REMAP) += intr_remapping.o
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 6dcc7e2d54de..587e8f2d38d8 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -46,7 +46,7 @@
  */
 LIST_HEAD(dmar_drhd_units);
 
-static struct acpi_table_header * __initdata dmar_tbl;
+struct acpi_table_header * __initdata dmar_tbl;
 static acpi_size dmar_tbl_size;
 
 static void __init dmar_register_drhd_unit(struct dmar_drhd_unit *drhd)
@@ -118,8 +118,8 @@ static int __init dmar_parse_one_dev_scope(struct acpi_dmar_device_scope *scope,
 	return 0;
 }
 
-static int __init dmar_parse_dev_scope(void *start, void *end, int *cnt,
-				       struct pci_dev ***devices, u16 segment)
+int __init dmar_parse_dev_scope(void *start, void *end, int *cnt,
+				struct pci_dev ***devices, u16 segment)
 {
 	struct acpi_dmar_device_scope *scope;
 	void * tmp = start;
@@ -217,133 +217,6 @@ static int __init dmar_parse_dev(struct dmar_drhd_unit *dmaru)
 	return ret;
 }
 
-#ifdef CONFIG_DMAR
-LIST_HEAD(dmar_rmrr_units);
-
-static void __init dmar_register_rmrr_unit(struct dmar_rmrr_unit *rmrr)
-{
-	list_add(&rmrr->list, &dmar_rmrr_units);
-}
-
-
-static int __init
-dmar_parse_one_rmrr(struct acpi_dmar_header *header)
-{
-	struct acpi_dmar_reserved_memory *rmrr;
-	struct dmar_rmrr_unit *rmrru;
-
-	rmrru = kzalloc(sizeof(*rmrru), GFP_KERNEL);
-	if (!rmrru)
-		return -ENOMEM;
-
-	rmrru->hdr = header;
-	rmrr = (struct acpi_dmar_reserved_memory *)header;
-	rmrru->base_address = rmrr->base_address;
-	rmrru->end_address = rmrr->end_address;
-
-	dmar_register_rmrr_unit(rmrru);
-	return 0;
-}
-
-static int __init
-rmrr_parse_dev(struct dmar_rmrr_unit *rmrru)
-{
-	struct acpi_dmar_reserved_memory *rmrr;
-	int ret;
-
-	rmrr = (struct acpi_dmar_reserved_memory *) rmrru->hdr;
-	ret = dmar_parse_dev_scope((void *)(rmrr + 1),
-		((void *)rmrr) + rmrr->header.length,
-		&rmrru->devices_cnt, &rmrru->devices, rmrr->segment);
-
-	if (ret || (rmrru->devices_cnt == 0)) {
-		list_del(&rmrru->list);
-		kfree(rmrru);
-	}
-	return ret;
-}
-
-static LIST_HEAD(dmar_atsr_units);
-
-static int __init dmar_parse_one_atsr(struct acpi_dmar_header *hdr)
-{
-	struct acpi_dmar_atsr *atsr;
-	struct dmar_atsr_unit *atsru;
-
-	atsr = container_of(hdr, struct acpi_dmar_atsr, header);
-	atsru = kzalloc(sizeof(*atsru), GFP_KERNEL);
-	if (!atsru)
-		return -ENOMEM;
-
-	atsru->hdr = hdr;
-	atsru->include_all = atsr->flags & 0x1;
-
-	list_add(&atsru->list, &dmar_atsr_units);
-
-	return 0;
-}
-
-static int __init atsr_parse_dev(struct dmar_atsr_unit *atsru)
-{
-	int rc;
-	struct acpi_dmar_atsr *atsr;
-
-	if (atsru->include_all)
-		return 0;
-
-	atsr = container_of(atsru->hdr, struct acpi_dmar_atsr, header);
-	rc = dmar_parse_dev_scope((void *)(atsr + 1),
-				(void *)atsr + atsr->header.length,
-				&atsru->devices_cnt, &atsru->devices,
-				atsr->segment);
-	if (rc || !atsru->devices_cnt) {
-		list_del(&atsru->list);
-		kfree(atsru);
-	}
-
-	return rc;
-}
-
-int dmar_find_matched_atsr_unit(struct pci_dev *dev)
-{
-	int i;
-	struct pci_bus *bus;
-	struct acpi_dmar_atsr *atsr;
-	struct dmar_atsr_unit *atsru;
-
-	dev = pci_physfn(dev);
-
-	list_for_each_entry(atsru, &dmar_atsr_units, list) {
-		atsr = container_of(atsru->hdr, struct acpi_dmar_atsr, header);
-		if (atsr->segment == pci_domain_nr(dev->bus))
-			goto found;
-	}
-
-	return 0;
-
-found:
-	for (bus = dev->bus; bus; bus = bus->parent) {
-		struct pci_dev *bridge = bus->self;
-
-		if (!bridge || !pci_is_pcie(bridge) ||
-		    bridge->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE)
-			return 0;
-
-		if (bridge->pcie_type == PCI_EXP_TYPE_ROOT_PORT) {
-			for (i = 0; i < atsru->devices_cnt; i++)
-				if (atsru->devices[i] == bridge)
-					return 1;
-			break;
-		}
-	}
-
-	if (atsru->include_all)
-		return 1;
-
-	return 0;
-}
-#endif
-
 #ifdef CONFIG_ACPI_NUMA
 static int __init
 dmar_parse_one_rhsa(struct acpi_dmar_header *header)
@@ -484,14 +357,10 @@ parse_dmar_table(void)
 			ret = dmar_parse_one_drhd(entry_header);
 			break;
 		case ACPI_DMAR_TYPE_RESERVED_MEMORY:
-#ifdef CONFIG_DMAR
 			ret = dmar_parse_one_rmrr(entry_header);
-#endif
 			break;
 		case ACPI_DMAR_TYPE_ATSR:
-#ifdef CONFIG_DMAR
 			ret = dmar_parse_one_atsr(entry_header);
-#endif
 			break;
 		case ACPI_DMAR_HARDWARE_AFFINITY:
 #ifdef CONFIG_ACPI_NUMA
@@ -557,34 +426,31 @@ dmar_find_matched_drhd_unit(struct pci_dev *dev)
 
 int __init dmar_dev_scope_init(void)
 {
+	static int dmar_dev_scope_initialized;
 	struct dmar_drhd_unit *drhd, *drhd_n;
 	int ret = -ENODEV;
 
+	if (dmar_dev_scope_initialized)
+		return dmar_dev_scope_initialized;
+
+	if (list_empty(&dmar_drhd_units))
+		goto fail;
+
 	list_for_each_entry_safe(drhd, drhd_n, &dmar_drhd_units, list) {
 		ret = dmar_parse_dev(drhd);
 		if (ret)
-			return ret;
+			goto fail;
 	}
 
-#ifdef CONFIG_DMAR
-	{
-		struct dmar_rmrr_unit *rmrr, *rmrr_n;
-		struct dmar_atsr_unit *atsr, *atsr_n;
-
-		list_for_each_entry_safe(rmrr, rmrr_n, &dmar_rmrr_units, list) {
-			ret = rmrr_parse_dev(rmrr);
-			if (ret)
-				return ret;
-		}
+	ret = dmar_parse_rmrr_atsr_dev();
+	if (ret)
+		goto fail;
 
-		list_for_each_entry_safe(atsr, atsr_n, &dmar_atsr_units, list) {
-			ret = atsr_parse_dev(atsr);
-			if (ret)
-				return ret;
-		}
-	}
-#endif
+	dmar_dev_scope_initialized = 1;
+	return 0;
 
+fail:
+	dmar_dev_scope_initialized = ret;
 	return ret;
 }
 
@@ -611,14 +477,6 @@ int __init dmar_table_init(void)
 		return -ENODEV;
 	}
 
-#ifdef CONFIG_DMAR
-	if (list_empty(&dmar_rmrr_units))
-		printk(KERN_INFO PREFIX "No RMRR found\n");
-
-	if (list_empty(&dmar_atsr_units))
-		printk(KERN_INFO PREFIX "No ATSR found\n");
-#endif
-
 	return 0;
 }
 
@@ -682,9 +540,6 @@ int __init check_zero_address(void)
 	return 1;
 
 failed:
-#ifdef CONFIG_DMAR
-	dmar_disabled = 1;
-#endif
 	return 0;
 }
 
@@ -696,22 +551,21 @@ int __init detect_intel_iommu(void)
 	if (ret)
 		ret = check_zero_address();
 	{
-#ifdef CONFIG_INTR_REMAP
 		struct acpi_table_dmar *dmar;
 
 		dmar = (struct acpi_table_dmar *) dmar_tbl;
-		if (ret && cpu_has_x2apic && dmar->flags & 0x1)
+
+		if (ret && intr_remapping_enabled && cpu_has_x2apic &&
+		    dmar->flags & 0x1)
 			printk(KERN_INFO
-			       "Queued invalidation will be enabled to support "
-			       "x2apic and Intr-remapping.\n");
-#endif
-#ifdef CONFIG_DMAR
+			       "Queued invalidation will be enabled to support x2apic and Intr-remapping.\n");
+
 		if (ret && !no_iommu && !iommu_detected && !dmar_disabled) {
 			iommu_detected = 1;
 			/* Make sure ACS will be enabled */
 			pci_request_acs();
 		}
-#endif
+
 #ifdef CONFIG_X86
 		if (ret)
 			x86_init.iommu.iommu_init = intel_iommu_init;
@@ -758,7 +612,6 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
 		goto err_unmap;
 	}
 
-#ifdef CONFIG_DMAR
 	agaw = iommu_calculate_agaw(iommu);
 	if (agaw < 0) {
 		printk(KERN_ERR
@@ -773,7 +626,6 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
 			iommu->seq_id);
 		goto err_unmap;
 	}
-#endif
 	iommu->agaw = agaw;
 	iommu->msagaw = msagaw;
 
@@ -817,9 +669,7 @@ void free_iommu(struct intel_iommu *iommu)
 	if (!iommu)
 		return;
 
-#ifdef CONFIG_DMAR
 	free_dmar_iommu(iommu);
-#endif
 
 	if (iommu->reg)
 		iounmap(iommu->reg);
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a88f3cbb100b..f28d933c7927 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -398,11 +398,11 @@ static long list_size;
 
 static void domain_remove_dev_info(struct dmar_domain *domain);
 
-#ifdef CONFIG_DMAR_DEFAULT_ON
+#ifdef CONFIG_INTEL_IOMMU_DEFAULT_ON
 int dmar_disabled = 0;
 #else
 int dmar_disabled = 1;
-#endif /*CONFIG_DMAR_DEFAULT_ON*/
+#endif /*CONFIG_INTEL_IOMMU_DEFAULT_ON*/
 
 static int dmar_map_gfx = 1;
 static int dmar_forcedac;
@@ -2157,7 +2157,7 @@ static inline int iommu_prepare_rmrr_dev(struct dmar_rmrr_unit *rmrr,
 		rmrr->end_address);
 }
 
-#ifdef CONFIG_DMAR_FLOPPY_WA
+#ifdef CONFIG_INTEL_IOMMU_FLOPPY_WA
 static inline void iommu_prepare_isa(void)
 {
 	struct pci_dev *pdev;
@@ -2180,7 +2180,7 @@ static inline void iommu_prepare_isa(void)
 {
 	return;
 }
-#endif /* !CONFIG_DMAR_FLPY_WA */
+#endif /* !CONFIG_INTEL_IOMMU_FLPY_WA */
 
 static int md_domain_init(struct dmar_domain *domain, int guest_width);
 
@@ -2491,7 +2491,7 @@ static int __init init_dmars(void)
 	if (iommu_pass_through)
 		iommu_identity_mapping |= IDENTMAP_ALL;
 
-#ifdef CONFIG_DMAR_BROKEN_GFX_WA
+#ifdef CONFIG_INTEL_IOMMU_BROKEN_GFX_WA
 	iommu_identity_mapping |= IDENTMAP_GFX;
 #endif
 
@@ -3399,6 +3399,151 @@ static void __init init_iommu_pm_ops(void)
 static inline void init_iommu_pm_ops(void) {}
 #endif	/* CONFIG_PM */
 
+LIST_HEAD(dmar_rmrr_units);
+
+static void __init dmar_register_rmrr_unit(struct dmar_rmrr_unit *rmrr)
+{
+	list_add(&rmrr->list, &dmar_rmrr_units);
+}
+
+
+int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header)
+{
+	struct acpi_dmar_reserved_memory *rmrr;
+	struct dmar_rmrr_unit *rmrru;
+
+	rmrru = kzalloc(sizeof(*rmrru), GFP_KERNEL);
+	if (!rmrru)
+		return -ENOMEM;
+
+	rmrru->hdr = header;
+	rmrr = (struct acpi_dmar_reserved_memory *)header;
+	rmrru->base_address = rmrr->base_address;
+	rmrru->end_address = rmrr->end_address;
+
+	dmar_register_rmrr_unit(rmrru);
+	return 0;
+}
+
+static int __init
+rmrr_parse_dev(struct dmar_rmrr_unit *rmrru)
+{
+	struct acpi_dmar_reserved_memory *rmrr;
+	int ret;
+
+	rmrr = (struct acpi_dmar_reserved_memory *) rmrru->hdr;
+	ret = dmar_parse_dev_scope((void *)(rmrr + 1),
+		((void *)rmrr) + rmrr->header.length,
+		&rmrru->devices_cnt, &rmrru->devices, rmrr->segment);
+
+	if (ret || (rmrru->devices_cnt == 0)) {
+		list_del(&rmrru->list);
+		kfree(rmrru);
+	}
+	return ret;
+}
+
+static LIST_HEAD(dmar_atsr_units);
+
+int __init dmar_parse_one_atsr(struct acpi_dmar_header *hdr)
+{
+	struct acpi_dmar_atsr *atsr;
+	struct dmar_atsr_unit *atsru;
+
+	atsr = container_of(hdr, struct acpi_dmar_atsr, header);
+	atsru = kzalloc(sizeof(*atsru), GFP_KERNEL);
+	if (!atsru)
+		return -ENOMEM;
+
+	atsru->hdr = hdr;
+	atsru->include_all = atsr->flags & 0x1;
+
+	list_add(&atsru->list, &dmar_atsr_units);
+
+	return 0;
+}
+
+static int __init atsr_parse_dev(struct dmar_atsr_unit *atsru)
+{
+	int rc;
+	struct acpi_dmar_atsr *atsr;
+
+	if (atsru->include_all)
+		return 0;
+
+	atsr = container_of(atsru->hdr, struct acpi_dmar_atsr, header);
+	rc = dmar_parse_dev_scope((void *)(atsr + 1),
+				(void *)atsr + atsr->header.length,
+				&atsru->devices_cnt, &atsru->devices,
+				atsr->segment);
+	if (rc || !atsru->devices_cnt) {
+		list_del(&atsru->list);
+		kfree(atsru);
+	}
+
+	return rc;
+}
+
+int dmar_find_matched_atsr_unit(struct pci_dev *dev)
+{
+	int i;
+	struct pci_bus *bus;
+	struct acpi_dmar_atsr *atsr;
+	struct dmar_atsr_unit *atsru;
+
+	dev = pci_physfn(dev);
+
+	list_for_each_entry(atsru, &dmar_atsr_units, list) {
+		atsr = container_of(atsru->hdr, struct acpi_dmar_atsr, header);
+		if (atsr->segment == pci_domain_nr(dev->bus))
+			goto found;
+	}
+
+	return 0;
+
+found:
+	for (bus = dev->bus; bus; bus = bus->parent) {
+		struct pci_dev *bridge = bus->self;
+
+		if (!bridge || !pci_is_pcie(bridge) ||
+		    bridge->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE)
+			return 0;
+
+		if (bridge->pcie_type == PCI_EXP_TYPE_ROOT_PORT) {
+			for (i = 0; i < atsru->devices_cnt; i++)
+				if (atsru->devices[i] == bridge)
+					return 1;
+			break;
+		}
+	}
+
+	if (atsru->include_all)
+		return 1;
+
+	return 0;
+}
+
+int dmar_parse_rmrr_atsr_dev(void)
+{
+	struct dmar_rmrr_unit *rmrr, *rmrr_n;
+	struct dmar_atsr_unit *atsr, *atsr_n;
+	int ret = 0;
+
+	list_for_each_entry_safe(rmrr, rmrr_n, &dmar_rmrr_units, list) {
+		ret = rmrr_parse_dev(rmrr);
+		if (ret)
+			return ret;
+	}
+
+	list_for_each_entry_safe(atsr, atsr_n, &dmar_atsr_units, list) {
+		ret = atsr_parse_dev(atsr);
+		if (ret)
+			return ret;
+	}
+
+	return ret;
+}
+
 /*
  * Here we only respond to action of unbound device from driver.
  *
@@ -3448,16 +3593,12 @@ int __init intel_iommu_init(void)
 		return 	-ENODEV;
 	}
 
-	if (dmar_dev_scope_init()) {
+	if (dmar_dev_scope_init() < 0) {
 		if (force_on)
 			panic("tboot: Failed to initialize DMAR device scope\n");
 		return 	-ENODEV;
 	}
 
-	/*
-	 * Check the need for DMA-remapping initialization now.
-	 * Above initialization will also be used by Interrupt-remapping.
-	 */
 	if (no_iommu || dmar_disabled)
 		return -ENODEV;
 
@@ -3467,6 +3608,12 @@ int __init intel_iommu_init(void)
 		return 	-ENODEV;
 	}
 
+	if (list_empty(&dmar_rmrr_units))
+		printk(KERN_INFO "DMAR: No RMRR found\n");
+
+	if (list_empty(&dmar_atsr_units))
+		printk(KERN_INFO "DMAR: No ATSR found\n");
+
 	if (dmar_init_reserved_ranges()) {
 		if (force_on)
 			panic("tboot: Failed to reserve iommu ranges\n");
diff --git a/drivers/iommu/intr_remapping.c b/drivers/iommu/intr_remapping.c
index 1a89d4a2cadf..cfb0dd4bf0b6 100644
--- a/drivers/iommu/intr_remapping.c
+++ b/drivers/iommu/intr_remapping.c
@@ -21,6 +21,7 @@ int intr_remapping_enabled;
 
 static int disable_intremap;
 static int disable_sourceid_checking;
+static int no_x2apic_optout;
 
 static __init int setup_nointremap(char *str)
 {
@@ -34,12 +35,20 @@ static __init int setup_intremap(char *str)
 	if (!str)
 		return -EINVAL;
 
-	if (!strncmp(str, "on", 2))
-		disable_intremap = 0;
-	else if (!strncmp(str, "off", 3))
-		disable_intremap = 1;
-	else if (!strncmp(str, "nosid", 5))
-		disable_sourceid_checking = 1;
+	while (*str) {
+		if (!strncmp(str, "on", 2))
+			disable_intremap = 0;
+		else if (!strncmp(str, "off", 3))
+			disable_intremap = 1;
+		else if (!strncmp(str, "nosid", 5))
+			disable_sourceid_checking = 1;
+		else if (!strncmp(str, "no_x2apic_optout", 16))
+			no_x2apic_optout = 1;
+
+		str += strcspn(str, ",");
+		while (*str == ',')
+			str++;
+	}
 
 	return 0;
 }
@@ -501,6 +510,15 @@ end:
 	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;
+}
+
 int __init intr_remapping_supported(void)
 {
 	struct dmar_drhd_unit *drhd;
@@ -521,16 +539,25 @@ int __init intr_remapping_supported(void)
 	return 1;
 }
 
-int __init enable_intr_remapping(int eim)
+int __init enable_intr_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;
 
@@ -606,8 +633,9 @@ int __init enable_intr_remapping(int eim)
 		goto error;
 
 	intr_remapping_enabled = 1;
+	pr_info("Enabled IRQ remapping in %s mode\n", eim ? "x2apic" : "xapic");
 
-	return 0;
+	return eim ? IRQ_REMAP_X2APIC_MODE : IRQ_REMAP_XAPIC_MODE;
 
 error:
 	/*
@@ -745,6 +773,15 @@ int __init parse_ioapics_under_ir(void)
 	return ir_supported;
 }
 
+int ir_dev_scope_init(void)
+{
+	if (!intr_remapping_enabled)
+		return 0;
+
+	return dmar_dev_scope_init();
+}
+rootfs_initcall(ir_dev_scope_init);
+
 void disable_intr_remapping(void)
 {
 	struct dmar_drhd_unit *drhd;