diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 3e02aace38b1..4afb9cb99ea3 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -586,7 +586,11 @@ struct arm_smmu_device {
 
 	struct arm_smmu_strtab_cfg	strtab_cfg;
 
-	u32				sync_count;
+	/* Hi16xx adds an extra 32 bits of goodness to its MSI payload */
+	union {
+		u32			sync_count;
+		u64			padding;
+	};
 
 	/* IOMMU core code handle */
 	struct iommu_device		iommu;