diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
index 1e857f915a..f2562acc38 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -338,7 +338,7 @@ static int platform_get_irq_byname_optional(struct device *dev,
 #define CR2_E2H				(1 << 0)
 
 #define ARM_SMMU_GBPA			0x44
-#define GBPA_UPDATE			(1 << 31)
+#define GBPA_UPDATE			(1U << 31)
 #define GBPA_ABORT			(1 << 20)
 
 #define ARM_SMMU_IRQ_CTRL		0x50
@@ -410,7 +410,7 @@ static int platform_get_irq_byname_optional(struct device *dev,
 
 #define Q_IDX(llq, p)			((p) & ((1 << (llq)->max_n_shift) - 1))
 #define Q_WRP(llq, p)			((p) & (1 << (llq)->max_n_shift))
-#define Q_OVERFLOW_FLAG			(1 << 31)
+#define Q_OVERFLOW_FLAG			(1U << 31)
 #define Q_OVF(p)			((p) & Q_OVERFLOW_FLAG)
 #define Q_ENT(q, p)			((q)->base +			\
 					 Q_IDX(&((q)->llq), p) *	\