diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c
index 1360b97ab0..174033dd41 100644
--- a/hw/ppc/spapr_vio.c
+++ b/hw/ppc/spapr_vio.c
@@ -469,7 +469,7 @@ static void spapr_vio_busdev_realize(DeviceState *qdev, Error **errp)
     }
 
     if (pc->rtce_window_size) {
-        uint32_t liobn = SPAPR_VIO_BASE_LIOBN | dev->reg;
+        uint32_t liobn = SPAPR_VIO_LIOBN(dev->reg);
 
         memory_region_init(&dev->mrroot, OBJECT(dev), "iommu-spapr-root",
                            ram_size);
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 9a9bb90323..92ee72b24c 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -482,6 +482,7 @@ int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
 #define SPAPR_TCE_PAGE_MASK    (SPAPR_TCE_PAGE_SIZE - 1)
 
 #define SPAPR_VIO_BASE_LIOBN    0x00000000
+#define SPAPR_VIO_LIOBN(reg)    (0x00000000 | (reg))
 #define SPAPR_PCI_LIOBN(phb_index, window_num) \
     (0x80000000 | ((phb_index) << 8) | (window_num))
 #define SPAPR_PCI_DMA_WINDOW_NUM(liobn) ((liobn) & 0xff)