Index: linux-2.6.21-rc5-mm2/arch/i386/Kconfig
===================================================================
--- linux-2.6.21-rc5-mm2.orig/arch/i386/Kconfig	2007-03-31 11:52:26.000000000 -0700
+++ linux-2.6.21-rc5-mm2/arch/i386/Kconfig	2007-03-31 11:53:08.000000000 -0700
@@ -671,6 +671,10 @@ config ARCH_SELECT_MEMORY_MODEL
 	def_bool y
 	depends on ARCH_SPARSEMEM_ENABLE
 
+config SPARSE_VIRTUAL
+	def_bool y
+	depends on ARCH_SPARSEMEM_ENABLE
+
 config ARCH_POPULATES_NODE_MAP
 	def_bool y