diff --git a/arch/x86/xen/mmu.h b/arch/x86/xen/mmu.h
index 24d1b44..da73026 100644
--- a/arch/x86/xen/mmu.h
+++ b/arch/x86/xen/mmu.h
@@ -11,6 +11,9 @@
 };
 
 
+bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
+bool install_p2mtop_page(unsigned long pfn, unsigned long *p);
+
 void set_pte_mfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags);