diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
index 58f3331520..db08d3c042 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -218,6 +218,9 @@ static struct arm_smmu_option_prop arm_smmu_options[] = {
 
 static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
 {
+	if ( !dom )
+		return NULL;
+
 	return container_of(dom, struct arm_smmu_domain, domain);
 }