x86: make sure the CPA test code's use of _PAGE_UNUSED1 is obvious

The CPA test code uses _PAGE_UNUSED1, so make sure its obvious.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index 04caa2f..eccd524 100644
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -19,6 +19,7 @@
 #define _PAGE_BIT_UNUSED3	11
 #define _PAGE_BIT_PAT_LARGE	12	/* On 2MB or 1GB pages */
 #define _PAGE_BIT_SPECIAL	_PAGE_BIT_UNUSED1
+#define _PAGE_BIT_CPA_TEST	_PAGE_BIT_UNUSED1
 #define _PAGE_BIT_NX           63       /* No execute: only valid after cpuid check */
 
 #define _PAGE_PRESENT	(_AT(pteval_t, 1) << _PAGE_BIT_PRESENT)
@@ -36,6 +37,7 @@
 #define _PAGE_PAT	(_AT(pteval_t, 1) << _PAGE_BIT_PAT)
 #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
 #define _PAGE_SPECIAL	(_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL)
+#define _PAGE_CPA_TEST	(_AT(pteval_t, 1) << _PAGE_BIT_CPA_TEST)
 #define __HAVE_ARCH_PTE_SPECIAL
 
 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)