Index: linux-2.6.21-rc5-mm2/arch/ia64/Kconfig
===================================================================
--- linux-2.6.21-rc5-mm2.orig/arch/ia64/Kconfig	2007-03-31 23:00:40.000000000 -0700
+++ linux-2.6.21-rc5-mm2/arch/ia64/Kconfig	2007-03-31 23:01:15.000000000 -0700
@@ -350,6 +350,10 @@ config ARCH_SPARSEMEM_ENABLE
 	def_bool y
 	depends on ARCH_DISCONTIGMEM_ENABLE
 
+config SPARSE_VIRTUAL
+	def_bool y
+	depends on ARCH_SPARSEMEM_ENABLE
+
 config ARCH_DISCONTIGMEM_DEFAULT
 	def_bool y if (IA64_SGI_SN2 || IA64_GENERIC || IA64_HP_ZX1 || IA64_HP_ZX1_SWIOTLB)
 	depends on ARCH_DISCONTIGMEM_ENABLE
Index: linux-2.6.21-rc5-mm2/arch/ia64/kernel/ivt.S
===================================================================
--- linux-2.6.21-rc5-mm2.orig/arch/ia64/kernel/ivt.S	2007-03-31 23:00:40.000000000 -0700
+++ linux-2.6.21-rc5-mm2/arch/ia64/kernel/ivt.S	2007-03-31 23:39:24.000000000 -0700
@@ -388,12 +388,28 @@ ENTRY(alt_dtlb_miss)
 (p8)	br.cond.dptk dtlb_fault
 #endif
 	cmp.ge p10,p11=r16,r24			// access to per_cpu_data?
+	tbit.nz p6,p7=r16,59			// Access to VMEMMAP?
 	tbit.z p12,p0=r16,61			// access to region 6?
 	mov r25=PERCPU_PAGE_SHIFT << 2
 	mov r26=PERCPU_PAGE_SIZE
-	nop.m 0
-	nop.b 0
 	;;
+	//
+	// VMemmap lookup of the granule
+	//
+(p6)	extr r25=r16, IA64_GRANULE_SHIFT, 32
+	LOAD_PHYSICAL(p6, r26, vmemmap_table)
+	;;
+(p6)	shl r25=r25,2
+	;;
+(p6)	add r26=r26,r25				// Index into vmemmap table
+	;;
+(p6)	ld4 r25=[r26]				// Get 32 bit descriptor */
+	;;
+(p6)	shl r19=r25, 12				// Shift to ppn field
+(p6)	tbit.z p7,p11=r25, 31			// Present bit set?
+(p7)	br.cond.dptk page_fault			// Page not present
+	;;
+	.pred.rel "mutex", p11, p10
 (p10)	mov r19=IA64_KR(PER_CPU_DATA)
 (p11)	and r19=r19,r16				// clear non-ppn fields
 	extr.u r23=r21,IA64_PSR_CPL0_BIT,2	// extract psr.cpl
Index: linux-2.6.21-rc5-mm2/arch/ia64/mm/discontig.c
===================================================================
--- linux-2.6.21-rc5-mm2.orig/arch/ia64/mm/discontig.c	2007-03-31 23:00:40.000000000 -0700
+++ linux-2.6.21-rc5-mm2/arch/ia64/mm/discontig.c	2007-03-31 23:22:12.000000000 -0700
@@ -44,6 +44,57 @@ struct early_node_data {
 	unsigned long max_pfn;
 };
 
+#ifdef CONFIG_SPARSE_VIRTUAL
+#define PAGE_STRUCT_SHIFT 6
+
+/*
+ * The vmemmap_table contains the number of the granule used to map
+ * that section of the virtual memmap.
+ *
+ * We support 50 address bits, 14 bits are used for the page size this
+ * leaves 36 bits (64G) for the pfn. Using page structs this is going to
+ * take around 4TB.
+ *
+ * We are mapping these 4 TB using 16M granule size which makes us end up
+ * less than 256k entries.
+ *
+ * Thus the common size of the needed vmemmap_table will be less than 1M.
+ */
+
+#define VMEMMAP_SIZE ((1UL << (MAX_PHYSMEM_BITS - PAGE_SHIFT)) \
+			* sizeof(struct page))
+
+/*
+ * Each vmemma_table entry describes a 16M block of memory. We have
+ * 32 bit here and use one bit to indicate that a page is present.
+ * That means 31 + 24 = 55 bits which is larger than
+ * the maximum memory (1 petabyte) supported by IA64.
+ */
+
+#define VMEMMAP_PRESENT (1UL << 31)
+u32 vmemmap_table[ALIGN(VMEMMAP_SIZE, IA64_GRANULE_SIZE)];
+
+void vmemmap_populate(struct page *start, unsigned long nr, int node)
+{
+	unsigned addr = GRANULEROUNDDOWN((unsigned long)start);
+	unsigned end = GRANULEROUNDUP((unsigned long)(start + nr));
+
+	BUG_ON(sizeof(struct page) > (1 << PAGE_STRUCT_SHIFT));
+
+	for(; addr < end; addr += IA64_GRANULE_SIZE) {
+		u32 *vmem_pp =
+			vmemmap_table + (addr >> IA64_GRANULE_SHIFT);
+
+		if (*vmem_pp & VMEMMAP_PRESENT)
+			continue;
+
+		*vmem_pp = VMEMMAP_PRESENT |
+			(__pa(vmemmap_alloc_block(IA64_GRANULE_SIZE, node))
+			>> IA64_GRANULE_SHIFT);
+	}
+}
+#endif
+
 static struct early_node_data mem_data[MAX_NUMNODES] __initdata;
 static nodemask_t memory_less_mask __initdata;
 
Index: linux-2.6.21-rc5-mm2/include/asm-ia64/page.h
===================================================================
--- linux-2.6.21-rc5-mm2.orig/include/asm-ia64/page.h	2007-03-31 23:00:40.000000000 -0700
+++ linux-2.6.21-rc5-mm2/include/asm-ia64/page.h	2007-03-31 23:01:15.000000000 -0700
@@ -98,6 +98,9 @@ do {						\
 
 #define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
 
+#define ARCH_POPULATES_VIRTUAL_MEMMAP
+#define vmemmap ((struct page *)(RGN_BASE(RGN_KERNEL) + (1UL << 59)))
+
 #define virt_addr_valid(kaddr)	pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 
 #ifdef CONFIG_VIRTUAL_MEM_MAP