diff --git a/hypervisor/dm/vpci/pci_pt.c b/hypervisor/dm/vpci/pci_pt.c
index 58c2707f7..9f14bad8d 100644
--- a/hypervisor/dm/vpci/pci_pt.c
+++ b/hypervisor/dm/vpci/pci_pt.c
@@ -379,7 +379,24 @@ static void init_bars(struct pci_vdev *vdev, bool is_sriov_bar)
 		if (is_pci_reserved_bar(vbar)) {
 			continue;
 		}
-		mask = (is_pci_io_bar(vbar)) ? PCI_BASE_ADDRESS_IO_MASK : PCI_BASE_ADDRESS_MEM_MASK;
+
+		if (is_pci_io_bar(vbar)) {
+			if (lo & ~IO_SPACE_BITMASK) {
+				/* 
+				 * Some buggy x86 BIOS may program an invalid I/O BAR whose upper 16 bits are not zero.
+				 * Such I/O BAR is not addressable on x86 platforms. Skip it when initializing the
+				 * virtual PCI function as I/O BAR reprogramming in VM is currently unsupported.
+				 */
+				pr_warn("%s: %02x:%02x.%x: IO BAR%d value 0x%08x has invalid bits, IO_SPACE_BITMASK "
+				        "is 0x%08x, Ignore this BAR in vdev",
+					__func__, vdev->bdf.bits.b, vdev->bdf.bits.d, vdev->bdf.bits.f, idx, lo,
+					IO_SPACE_BITMASK);
+				continue;
+			}
+			mask = PCI_BASE_ADDRESS_IO_MASK;
+		} else {
+			mask = PCI_BASE_ADDRESS_MEM_MASK;
+		}
 		vbar->base_hpa = (uint64_t)lo & mask;
 
 		if (is_pci_mem64lo_bar(vbar)) {
diff --git a/hypervisor/include/arch/x86/asm/io.h b/hypervisor/include/arch/x86/asm/io.h
index 42bf87bf3..9bf1f62ce 100644
--- a/hypervisor/include/arch/x86/asm/io.h
+++ b/hypervisor/include/arch/x86/asm/io.h
@@ -9,6 +9,9 @@
 
 #include <types.h>
 
+/* X86 architecture only supports 16 bits IO space */
+#define IO_SPACE_BITMASK 0xffffU
+
 /* Write 1 byte to specified I/O port */
 static inline void pio_write8(uint8_t value, uint16_t port)
 {