diff --git a/drivers/iommu/intel/cache.c b/drivers/iommu/intel/cache.c
index 0a3bb38a5289..44e92638c0cd 100644
--- a/drivers/iommu/intel/cache.c
+++ b/drivers/iommu/intel/cache.c
@@ -246,6 +246,7 @@ static unsigned long calculate_psi_aligned_address(unsigned long start,
 		 */
 		shared_bits = ~(pfn ^ end_pfn) & ~bitmask;
 		mask = shared_bits ? __ffs(shared_bits) : MAX_AGAW_PFN_WIDTH;
+		aligned_pages = 1UL << mask;
 	}
 
 	*_pages = aligned_pages;