diff --git a/src/hw/pci.c b/src/hw/pci.c
index 3df1dae4..f13cbdea 100644
--- a/src/hw/pci.c
+++ b/src/hw/pci.c
@@ -26,63 +26,93 @@ static u32 ioconfig_cmd(u16 bdf, u32 addr)
     return 0x80000000 | (bdf << 8) | (addr & 0xfc);
 }
 
+void pci_ioconfig_writel(u16 bdf, u32 addr, u32 val)
+{
+    outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
+    outl(val, PORT_PCI_DATA);
+}
+
 void pci_config_writel(u16 bdf, u32 addr, u32 val)
 {
     if (!MODESEGMENT && mmconfig) {
         writel(mmconfig_addr(bdf, addr), val);
     } else {
-        outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
-        outl(val, PORT_PCI_DATA);
+        pci_ioconfig_writel(bdf, addr, val);
     }
 }
 
+void pci_ioconfig_writew(u16 bdf, u32 addr, u16 val)
+{
+    outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
+    outw(val, PORT_PCI_DATA + (addr & 2));
+}
+
 void pci_config_writew(u16 bdf, u32 addr, u16 val)
 {
     if (!MODESEGMENT && mmconfig) {
         writew(mmconfig_addr(bdf, addr), val);
     } else {
-        outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
-        outw(val, PORT_PCI_DATA + (addr & 2));
+        pci_ioconfig_writew(bdf, addr, val);
     }
 }
 
+void pci_ioconfig_writeb(u16 bdf, u32 addr, u8 val)
+{
+    outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
+    outb(val, PORT_PCI_DATA + (addr & 3));
+}
+
 void pci_config_writeb(u16 bdf, u32 addr, u8 val)
 {
     if (!MODESEGMENT && mmconfig) {
         writeb(mmconfig_addr(bdf, addr), val);
     } else {
-        outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
-        outb(val, PORT_PCI_DATA + (addr & 3));
+        pci_ioconfig_writeb(bdf, addr, val);
     }
 }
 
+u32 pci_ioconfig_readl(u16 bdf, u32 addr)
+{
+    outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
+    return inl(PORT_PCI_DATA);
+}
+
 u32 pci_config_readl(u16 bdf, u32 addr)
 {
     if (!MODESEGMENT && mmconfig) {
         return readl(mmconfig_addr(bdf, addr));
     } else {
-        outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
-        return inl(PORT_PCI_DATA);
+        return pci_ioconfig_readl(bdf, addr);
     }
 }
 
+u16 pci_ioconfig_readw(u16 bdf, u32 addr)
+{
+    outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
+    return inw(PORT_PCI_DATA + (addr & 2));
+}
+
 u16 pci_config_readw(u16 bdf, u32 addr)
 {
     if (!MODESEGMENT && mmconfig) {
         return readw(mmconfig_addr(bdf, addr));
     } else {
-        outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
-        return inw(PORT_PCI_DATA + (addr & 2));
+        return pci_ioconfig_readw(bdf, addr);
     }
 }
 
+u8 pci_ioconfig_readb(u16 bdf, u32 addr)
+{
+    outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
+    return inb(PORT_PCI_DATA + (addr & 3));
+}
+
 u8 pci_config_readb(u16 bdf, u32 addr)
 {
     if (!MODESEGMENT && mmconfig) {
         return readb(mmconfig_addr(bdf, addr));
     } else {
-        outl(ioconfig_cmd(bdf, addr), PORT_PCI_CMD);
-        return inb(PORT_PCI_DATA + (addr & 3));
+        return pci_ioconfig_readb(bdf, addr);
     }
 }
 
diff --git a/src/hw/pci.h b/src/hw/pci.h
index 01c51f70..ee6acafc 100644
--- a/src/hw/pci.h
+++ b/src/hw/pci.h
@@ -32,6 +32,15 @@ static inline u16 pci_bus_devfn_to_bdf(int bus, u16 devfn) {
          ; BDF >= 0                                             \
          ; BDF=pci_next(BDF, (BUS)))
 
+// standard PCI configration access mechanism
+void pci_ioconfig_writel(u16 bdf, u32 addr, u32 val);
+void pci_ioconfig_writew(u16 bdf, u32 addr, u16 val);
+void pci_ioconfig_writeb(u16 bdf, u32 addr, u8 val);
+u32 pci_ioconfig_readl(u16 bdf, u32 addr);
+u16 pci_ioconfig_readw(u16 bdf, u32 addr);
+u8 pci_ioconfig_readb(u16 bdf, u32 addr);
+
+// PCI configuration access using either PCI CAM or PCIe ECAM
 void pci_config_writel(u16 bdf, u32 addr, u32 val);
 void pci_config_writew(u16 bdf, u32 addr, u16 val);
 void pci_config_writeb(u16 bdf, u32 addr, u8 val);
@@ -39,9 +48,10 @@ u32 pci_config_readl(u16 bdf, u32 addr);
 u16 pci_config_readw(u16 bdf, u32 addr);
 u8 pci_config_readb(u16 bdf, u32 addr);
 void pci_config_maskw(u16 bdf, u32 addr, u16 off, u16 on);
-void pci_enable_mmconfig(u64 addr, const char *name);
 u8 pci_find_capability(u16 bdf, u8 cap_id, u8 cap);
 int pci_next(int bdf, int bus);
+
+void pci_enable_mmconfig(u64 addr, const char *name);
 int pci_probe_host(void);
 void pci_reboot(void);