iommu/amd: Limit the IOVA page range to the specified addresses

The extent of pages specified when applying a reserved region should
include up to the last page of the range, but not the page following
the range.

Signed-off-by: Gary R Hook <gary.hook@amd.com>
Fixes: 8d54d6c ('iommu/amd: Implement apply_dm_region call-back')
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/iommu/amd_iommu.c

@@ -3151,7 +3151,7 @@ static void amd_iommu_apply_resv_region(struct device *dev,
 	unsigned long start, end;
 
 	start = IOVA_PFN(region->start);
-	end   = IOVA_PFN(region->start + region->length);
+	end   = IOVA_PFN(region->start + region->length - 1);
 
 	WARN_ON_ONCE(reserve_iova(&dma_dom->iovad, start, end) == NULL);
 }