diff --git a/hw/pci_host.h b/hw/pci_host.h
index e2e428a271..c4f42a40e1 100644
--- a/hw/pci_host.h
+++ b/hw/pci_host.h
@@ -25,6 +25,16 @@
 /* Worker routines for a PCI host controller that uses an {address,data}
    register pair to access PCI configuration space.  */
 
+/* debug PCI */
+//#define DEBUG_PCI
+
+#ifdef DEBUG_PCI
+#define PCI_DPRINTF(fmt, args...) \
+do { printf("pci_host_data: " fmt , ##args); } while (0)
+#else
+#define PCI_DPRINTF(fmt, args...)
+#endif
+
 typedef struct {
     uint32_t config_reg;
     PCIBus *bus;
@@ -33,6 +43,9 @@ typedef struct {
 static void pci_host_data_writeb(void* opaque, pci_addr_t addr, uint32_t val)
 {
     PCIHostState *s = opaque;
+
+    PCI_DPRINTF("writeb addr " TARGET_FMT_plx " val %x\n",
+                (target_phys_addr_t)addr, val);
     if (s->config_reg & (1u << 31))
         pci_data_write(s->bus, s->config_reg | (addr & 3), val, 1);
 }
@@ -43,6 +56,8 @@ static void pci_host_data_writew(void* opaque, pci_addr_t addr, uint32_t val)
 #ifdef TARGET_WORDS_BIGENDIAN
     val = bswap16(val);
 #endif
+    PCI_DPRINTF("writew addr " TARGET_FMT_plx " val %x\n",
+                (target_phys_addr_t)addr, val);
     if (s->config_reg & (1u << 31))
         pci_data_write(s->bus, s->config_reg | (addr & 3), val, 2);
 }
@@ -53,6 +68,8 @@ static void pci_host_data_writel(void* opaque, pci_addr_t addr, uint32_t val)
 #ifdef TARGET_WORDS_BIGENDIAN
     val = bswap32(val);
 #endif
+    PCI_DPRINTF("writel addr " TARGET_FMT_plx " val %x\n",
+                (target_phys_addr_t)addr, val);
     if (s->config_reg & (1u << 31))
         pci_data_write(s->bus, s->config_reg, val, 4);
 }
@@ -60,9 +77,14 @@ static void pci_host_data_writel(void* opaque, pci_addr_t addr, uint32_t val)
 static uint32_t pci_host_data_readb(void* opaque, pci_addr_t addr)
 {
     PCIHostState *s = opaque;
+    uint32_t val;
+
     if (!(s->config_reg & (1 << 31)))
         return 0xff;
-    return pci_data_read(s->bus, s->config_reg | (addr & 3), 1);
+    val = pci_data_read(s->bus, s->config_reg | (addr & 3), 1);
+    PCI_DPRINTF("readb addr " TARGET_FMT_plx " val %x\n",
+                (target_phys_addr_t)addr, val);
+    return val;
 }
 
 static uint32_t pci_host_data_readw(void* opaque, pci_addr_t addr)
@@ -72,6 +94,8 @@ static uint32_t pci_host_data_readw(void* opaque, pci_addr_t addr)
     if (!(s->config_reg & (1 << 31)))
         return 0xffff;
     val = pci_data_read(s->bus, s->config_reg | (addr & 3), 2);
+    PCI_DPRINTF("readw addr " TARGET_FMT_plx " val %x\n",
+                (target_phys_addr_t)addr, val);
 #ifdef TARGET_WORDS_BIGENDIAN
     val = bswap16(val);
 #endif
@@ -85,6 +109,8 @@ static uint32_t pci_host_data_readl(void* opaque, pci_addr_t addr)
     if (!(s->config_reg & (1 << 31)))
         return 0xffffffff;
     val = pci_data_read(s->bus, s->config_reg | (addr & 3), 4);
+    PCI_DPRINTF("readl addr " TARGET_FMT_plx " val %x\n",
+                (target_phys_addr_t)addr, val);
 #ifdef TARGET_WORDS_BIGENDIAN
     val = bswap32(val);
 #endif