diff --git a/hypervisor/dm/vpci/vpci.c b/hypervisor/dm/vpci/vpci.c
index ca20da30d..f2777ecbd 100644
--- a/hypervisor/dm/vpci/vpci.c
+++ b/hypervisor/dm/vpci/vpci.c
@@ -85,7 +85,7 @@ static bool pci_cfgaddr_io_write(struct acrn_vm *vm, uint16_t addr, size_t bytes
 
 	if ((addr == (uint16_t)PCI_CONFIG_ADDR) && (bytes == 4U)) {
 		pi->cached_bdf.value = (uint16_t)(val >> 8U);
-		pi->cached_reg = val & PCI_REGMAX;
+		pi->cached_reg = val & PCI_REGMASK;
 		pi->cached_enable = ((val & PCI_CFG_ENABLE) == PCI_CFG_ENABLE);
 	}
 
diff --git a/hypervisor/include/hw/pci.h b/hypervisor/include/hw/pci.h
index d4eb6e47e..dc44ba8af 100644
--- a/hypervisor/include/hw/pci.h
+++ b/hypervisor/include/hw/pci.h
@@ -49,6 +49,7 @@
 #define PCI_FUNCMAX           0x7U
 #define PCI_BAR_COUNT         0x6U
 #define PCI_REGMAX            0xFFU
+#define PCI_REGMASK           0xFCU
 
 /* I/O ports */
 #define PCI_CONFIG_ADDR       0xCF8U