diff --git a/[refs] b/[refs]
index 27df0b34a838..8579dbf4f3ae 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1153968a48e3ca3e2b7a437e8b82ec9e6f768e24
+refs/heads/master: 51dd660a2cd6eab4d470cfe1009c7f473832b786
diff --git a/trunk/arch/x86/xen/Kconfig b/trunk/arch/x86/xen/Kconfig
index c2cc99580871..20b49729bed5 100644
--- a/trunk/arch/x86/xen/Kconfig
+++ b/trunk/arch/x86/xen/Kconfig
@@ -6,8 +6,8 @@ config XEN
 	bool "Xen guest support"
 	select PARAVIRT
 	select PARAVIRT_CLOCK
-	depends on X86_32
-	depends on X86_CMPXCHG && X86_TSC && X86_PAE && !(X86_VISWS || X86_VOYAGER)
+	depends on X86_64 || (X86_32 && X86_PAE && !(X86_VISWS || X86_VOYAGER))
+	depends on X86_CMPXCHG && X86_TSC
 	help
 	  This is the Linux Xen port.  Enabling this will allow the
 	  kernel to boot in a paravirtualized environment under the
@@ -15,10 +15,11 @@ config XEN
 
 config XEN_MAX_DOMAIN_MEMORY
        int "Maximum allowed size of a domain in gigabytes"
-       default 8
+       default 8 if X86_32
+       default 32 if X86_64
        depends on XEN
        help
          The pseudo-physical to machine address array is sized
          according to the maximum possible memory size of a Xen
          domain.  This array uses 1 page per gigabyte, so there's no
-         need to be too stingy here.
\ No newline at end of file
+         need to be too stingy here.