diff --git a/hw/pci-host/designware.c b/hw/pci-host/designware.c
index c07740bfaa..5598d18f47 100644
--- a/hw/pci-host/designware.c
+++ b/hw/pci-host/designware.c
@@ -371,7 +371,7 @@ static void designware_pcie_root_config_write(PCIDevice *d, uint32_t address,
 
     case DESIGNWARE_PCIE_ATU_UPPER_TARGET:
         viewport->target &= 0x00000000FFFFFFFFULL;
-        viewport->target |= val;
+        viewport->target |= (uint64_t)val << 32;
         break;
 
     case DESIGNWARE_PCIE_ATU_LIMIT: