diff --git a/hw/pass-through.c b/hw/pass-through.c
index a848164..1afbe5b 100644
--- a/hw/pass-through.c
+++ b/hw/pass-through.c
@@ -2031,7 +2031,8 @@ static void pt_bar_mapping_one(struct pt_dev *ptdev, int bar, int io_enable,
 
     /* check overlapped address */
     ret = pt_chk_bar_overlap(dev->bus, dev->devfn,
-                    r_addr, r_size, r->type);
+                    r_addr, r_size, r->type, bar);
+
     if (ret > 0)
         PT_LOG("Warning: ptdev[%02x:%02x.%x][Region:%d][Address:%08xh]"
             "[Size:%08xh] is overlapped.\n", pci_bus_num(dev->bus),
diff --git a/hw/pci.c b/hw/pci.c
index d7c516e..4f2e82c 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -919,13 +919,17 @@ PCIBus *pci_bridge_init(PCIBus *bus, int devfn, uint16_t vid, uint16_t did,
     return s->bus;
 }
 
+#define MEMORYSPACE_BAR_MASK   0xFFFFFC00
+#define IOSPACE_BAR_MASK       0xFFFFFFFC
+#define EXPANSION_ROM_BAR_MASK 0xFFFFFFFE
 int pt_chk_bar_overlap(PCIBus *bus, int devfn, uint32_t addr,
-                        uint32_t size, uint8_t type)
+                        uint32_t size, uint8_t type, int index)
 {
     PCIDevice *devices = NULL;
     PCIIORegion *r;
     int ret = 0;
     int i, j;
+    uint32_t mask=0xFFFFFFFF;
 
     /* check Overlapped to Base Address */
     for (i=0; i<256; i++)
@@ -951,7 +955,16 @@ int pt_chk_bar_overlap(PCIBus *bus, int devfn, uint32_t addr,
                     continue;
             }
 
-            if ((addr < (r->addr + r->size)) && ((addr + size) > r->addr))
+            if (index == PCI_ROM_SLOT)
+                mask = EXPANSION_ROM_BAR_MASK;
+            else if (type == PCI_ADDRESS_SPACE_IO)
+                mask = IOSPACE_BAR_MASK;
+            else if (type == PCI_ADDRESS_SPACE_MEM ||
+                     type == PCI_ADDRESS_SPACE_MEM_PREFETCH )
+                mask = MEMORYSPACE_BAR_MASK;
+
+            if (((addr&mask) < (r->addr + r->size)) &&
+                (((addr&mask) + size) > r->addr))
             {
                 printf("Overlapped to device[%02x:%02x.%x][Region:%d]"
                     "[Address:%08xh][Size:%08xh]\n", bus->bus_num,
diff --git a/hw/pci.h b/hw/pci.h
index d45b80c..e0c101d 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -225,7 +225,7 @@ void pci_register_io_region(PCIDevice *pci_dev, int region_num,
                             PCIMapIORegionFunc *map_func);
 
 int pt_chk_bar_overlap(PCIBus *bus, int devfn, uint32_t addr,
-                       uint32_t size, uint8_t type);
+                       uint32_t size, uint8_t type, int index);
 
 uint32_t pci_default_read_config(PCIDevice *d,
                                  uint32_t address, int len);