diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
index 0f2573f004..67d7b2d0fd 100644
--- a/hw/arm/smmu-common.c
+++ b/hw/arm/smmu-common.c
@@ -301,6 +301,7 @@ SMMUPciBus *smmu_find_smmu_pcibus(SMMUState *s, uint8_t bus_num)
                 return smmu_pci_bus;
             }
         }
+        smmu_pci_bus = NULL;
     }
     return smmu_pci_bus;
 }