5 files changed, 83 insertions, 0 deletions

diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 4d1ce2e7361e..1c409c7b0d56 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -26,6 +26,8 @@ obj-$(CONFIG_HT_IRQ) += htirq.o
 # Build Intel IOMMU support
 obj-$(CONFIG_DMAR) += dmar.o iova.o intel-iommu.o
 
+obj-$(CONFIG_INTR_REMAP) += dmar.o intr_remapping.o
+
 #
 # Some architectures use the generic PCI setup functions
 #
diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index 903f1701edff..127764cfbe27 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -423,6 +423,9 @@ int __init dmar_table_init(void)
                 printk(KERN_INFO PREFIX "No RMRR found\n");
 #endif
 
+#ifdef CONFIG_INTR_REMAP
+        parse_ioapics_under_ir();
+#endif
         return 0;
 }
 
diff --git a/drivers/pci/intel-iommu.h b/drivers/pci/intel-iommu.h
index 371e3b9caf32..eb167e39b464 100644
--- a/drivers/pci/intel-iommu.h
+++ b/drivers/pci/intel-iommu.h
@@ -114,6 +114,8 @@ static inline void dmar_writeq(void __iomem *addr, u64 val)
 #define ecap_max_iotlb_offset(e) \
         (ecap_iotlb_offset(e) + ecap_niotlb_iunits(e) * 16)
 #define ecap_coherent(e)        ((e) & 0x1)
+#define ecap_eim_support(e)     ((e >> 4) & 0x1)
+#define ecap_ir_support(e)      ((e >> 3) & 0x1)
 
 
 /* IOTLB_REG */
diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
new file mode 100644
index 000000000000..a80b87921c68
--- /dev/null
+++ b/drivers/pci/intr_remapping.c
@@ -0,0 +1,70 @@
+#include <linux/dmar.h>
+#include <asm/io_apic.h>
+#include "intel-iommu.h"
+#include "intr_remapping.h"
+
+static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
+static int ir_ioapic_num;
+
+static int ir_parse_ioapic_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\n", scope->enumeration_id,
+                               drhd->address);
+
+                        ir_ioapic[ir_ioapic_num].iommu = iommu;
+                        ir_ioapic[ir_ioapic_num].id = scope->enumeration_id;
+                        ir_ioapic_num++;
+                }
+                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_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;
+}
diff --git a/drivers/pci/intr_remapping.h b/drivers/pci/intr_remapping.h
new file mode 100644
index 000000000000..c4a40b2f33fa
--- /dev/null
+++ b/drivers/pci/intr_remapping.h
@@ -0,0 +1,6 @@
+#include "intel-iommu.h"
+
+struct ioapic_scope {
+        struct intel_iommu *iommu;
+        unsigned int id;
+};