x64, x2apic/intr-remap: Interrupt remapping infrastructure

Interrupt remapping (part of Intel Virtualization Tech for directed I/O)
infrastructure.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/drivers/pci/dma_remapping.h b/drivers/pci/dma_remapping.h
index 05aac8e..bff5c65 100644
--- a/drivers/pci/dma_remapping.h
+++ b/drivers/pci/dma_remapping.h
@@ -145,6 +145,8 @@
 extern int init_dmars(void);
 extern void free_dmar_iommu(struct intel_iommu *iommu);
 
+extern int dmar_disabled;
+
 #ifndef CONFIG_DMAR_GFX_WA
 static inline void iommu_prepare_gfx_mapping(void)
 {