diff --git a/hw/pci-host/pnv_phb3.c b/hw/pci-host/pnv_phb3.c
index c6e7871ecb..c78084cce7 100644
--- a/hw/pci-host/pnv_phb3.c
+++ b/hw/pci-host/pnv_phb3.c
@@ -1045,7 +1045,8 @@ static void pnv_phb3_realize(DeviceState *dev, Error **errp)
     memory_region_init(&phb->pci_mmio, OBJECT(phb), "pci-mmio",
                        PCI_MMIO_TOTAL_SIZE);
 
-    pci->bus = pci_register_root_bus(dev, "root-bus",
+    pci->bus = pci_register_root_bus(dev,
+                                     dev->id ? dev->id : NULL,
                                      pnv_phb3_set_irq, pnv_phb3_map_irq, phb,
                                      &phb->pci_mmio, &phb->pci_io,
                                      0, 4, TYPE_PNV_PHB3_ROOT_BUS);