diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index df40bf74ea75..4e527e7893a8 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -185,7 +185,7 @@ static pteval_t pte_mfn_to_pfn(pteval_t val)
 	if (val & _PAGE_PRESENT) {
 		unsigned long mfn = (val & PTE_MASK) >> PAGE_SHIFT;
 		pteval_t flags = val & ~PTE_MASK;
-		val = (mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
+		val = ((pteval_t)mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
 	}
 
 	return val;
@@ -196,7 +196,7 @@ static pteval_t pte_pfn_to_mfn(pteval_t val)
 	if (val & _PAGE_PRESENT) {
 		unsigned long pfn = (val & PTE_MASK) >> PAGE_SHIFT;
 		pteval_t flags = val & ~PTE_MASK;
-		val = (pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
+		val = ((pteval_t)pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
 	}
 
 	return val;