diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 12c436e7f1..6c82ada3d4 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1093,21 +1093,13 @@ PcGuestInfo *pc_guest_info_init(ram_addr_t below_4g_mem_size,
     return guest_info;
 }
 
-void pc_init_pci64_hole(PcPciInfo *pci_info, uint64_t pci_hole64_start,
-                        uint64_t pci_hole64_size)
+/* setup pci memory address space mapping into system address space */
+void pc_pci_as_mapping_init(Object *owner, MemoryRegion *system_memory,
+                            MemoryRegion *pci_address_space)
 {
-    if ((sizeof(hwaddr) == 4) || (!pci_hole64_size)) {
-        return;
-    }
-    /*
-     * BIOS does not set MTRR entries for the 64 bit window, so no need to
-     * align address to power of two.  Align address at 1G, this makes sure
-     * it can be exactly covered with a PAT entry even when using huge
-     * pages.
-     */
-    pci_info->w64.begin = ROUND_UP(pci_hole64_start, 0x1ULL << 30);
-    pci_info->w64.end = pci_info->w64.begin + pci_hole64_size;
-    assert(pci_info->w64.begin <= pci_info->w64.end);
+    /* Set to lower priority than RAM */
+    memory_region_add_subregion_overlap(system_memory, 0x0,
+                                        pci_address_space, -1);
 }
 
 void pc_acpi_init(const char *default_dsdt)
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index ab562853b8..636f59ffd3 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -149,8 +149,6 @@ static void pc_init1(QEMUMachineInitArgs *args,
     if (pci_enabled) {
         pci_bus = i440fx_init(&i440fx_state, &piix3_devfn, &isa_bus, gsi,
                               system_memory, system_io, args->ram_size,
-                              below_4g_mem_size,
-                              0x100000000ULL - below_4g_mem_size,
                               above_4g_mem_size,
                               pci_memory, ram_memory);
     } else {
diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
index edc974ece3..63be7f6cee 100644
--- a/hw/pci-host/piix.c
+++ b/hw/pci-host/piix.c
@@ -103,8 +103,6 @@ struct PCII440FXState {
     MemoryRegion *system_memory;
     MemoryRegion *pci_address_space;
     MemoryRegion *ram_memory;
-    MemoryRegion pci_hole;
-    MemoryRegion pci_hole_64bit;
     PAMMemoryRegion pam_regions[13];
     MemoryRegion smram_region;
     uint8_t smm_enabled;
@@ -313,8 +311,6 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state,
                     MemoryRegion *address_space_mem,
                     MemoryRegion *address_space_io,
                     ram_addr_t ram_size,
-                    hwaddr pci_hole_start,
-                    hwaddr pci_hole_size,
                     ram_addr_t above_4g_mem_size,
                     MemoryRegion *pci_address_space,
                     MemoryRegion *ram_memory)
@@ -327,7 +323,6 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state,
     PCII440FXState *f;
     unsigned i;
     I440FXState *i440fx;
-    uint64_t pci_hole64_size;
 
     dev = qdev_create(NULL, TYPE_I440FX_PCI_HOST_BRIDGE);
     s = PCI_HOST_BRIDGE(dev);
@@ -355,23 +350,10 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state,
         i440fx->pci_info.w32.begin = 0xe0000000;
     }
 
-    memory_region_init_alias(&f->pci_hole, OBJECT(d), "pci-hole", f->pci_address_space,
-                             pci_hole_start, pci_hole_size);
-    memory_region_add_subregion(f->system_memory, pci_hole_start, &f->pci_hole);
+    /* setup pci memory mapping */
+    pc_pci_as_mapping_init(OBJECT(f), f->system_memory,
+                           f->pci_address_space);
 
-    pci_hole64_size = pci_host_get_hole64_size(i440fx->pci_hole64_size);
-
-    pc_init_pci64_hole(&i440fx->pci_info, 0x100000000ULL + above_4g_mem_size,
-                       pci_hole64_size);
-    memory_region_init_alias(&f->pci_hole_64bit, OBJECT(d), "pci-hole64",
-                             f->pci_address_space,
-                             i440fx->pci_info.w64.begin,
-                             pci_hole64_size);
-    if (pci_hole64_size) {
-        memory_region_add_subregion(f->system_memory,
-                                    i440fx->pci_info.w64.begin,
-                                    &f->pci_hole_64bit);
-    }
     memory_region_init_alias(&f->smram_region, OBJECT(d), "smram-region",
                              f->pci_address_space, 0xa0000, 0x20000);
     memory_region_add_subregion_overlap(f->system_memory, 0xa0000,
diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index c043998e32..81c82404d6 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -356,28 +356,11 @@ static int mch_init(PCIDevice *d)
 {
     int i;
     MCHPCIState *mch = MCH_PCI_DEVICE(d);
-    uint64_t pci_hole64_size;
 
-    /* setup pci memory regions */
-    memory_region_init_alias(&mch->pci_hole, OBJECT(mch), "pci-hole",
-                             mch->pci_address_space,
-                             mch->below_4g_mem_size,
-                             0x100000000ULL - mch->below_4g_mem_size);
-    memory_region_add_subregion(mch->system_memory, mch->below_4g_mem_size,
-                                &mch->pci_hole);
+    /* setup pci memory mapping */
+    pc_pci_as_mapping_init(OBJECT(mch), mch->system_memory,
+                           mch->pci_address_space);
 
-    pci_hole64_size = pci_host_get_hole64_size(mch->pci_hole64_size);
-    pc_init_pci64_hole(&mch->pci_info, 0x100000000ULL + mch->above_4g_mem_size,
-                       pci_hole64_size);
-    memory_region_init_alias(&mch->pci_hole_64bit, OBJECT(mch), "pci-hole64",
-                             mch->pci_address_space,
-                             mch->pci_info.w64.begin,
-                             pci_hole64_size);
-    if (pci_hole64_size) {
-        memory_region_add_subregion(mch->system_memory,
-                                    mch->pci_info.w64.begin,
-                                    &mch->pci_hole_64bit);
-    }
     /* smram */
     cpu_smm_register(&mch_set_smm, mch);
     memory_region_init_alias(&mch->smram_region, OBJECT(mch), "smram-region",
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 09652fb22c..8ea1a98728 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -128,17 +128,9 @@ PcGuestInfo *pc_guest_info_init(ram_addr_t below_4g_mem_size,
 #define PCI_HOST_PROP_PCI_HOLE64_SIZE  "pci-hole64-size"
 #define DEFAULT_PCI_HOLE64_SIZE (~0x0ULL)
 
-static inline uint64_t pci_host_get_hole64_size(uint64_t pci_hole64_size)
-{
-    if (pci_hole64_size == DEFAULT_PCI_HOLE64_SIZE) {
-        return 1ULL << 62;
-    } else {
-        return pci_hole64_size;
-    }
-}
 
-void pc_init_pci64_hole(PcPciInfo *pci_info, uint64_t pci_hole64_start,
-                        uint64_t pci_hole64_size);
+void pc_pci_as_mapping_init(Object *owner, MemoryRegion *system_memory,
+                            MemoryRegion *pci_address_space);
 
 FWCfgState *pc_memory_init(MemoryRegion *system_memory,
                            const char *kernel_filename,
@@ -187,8 +179,6 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state, int *piix_devfn,
                     MemoryRegion *address_space_mem,
                     MemoryRegion *address_space_io,
                     ram_addr_t ram_size,
-                    hwaddr pci_hole_start,
-                    hwaddr pci_hole_size,
                     ram_addr_t above_4g_mem_size,
                     MemoryRegion *pci_memory,
                     MemoryRegion *ram_memory);
diff --git a/include/hw/pci-host/q35.h b/include/hw/pci-host/q35.h
index 309065fa41..d0355b712b 100644
--- a/include/hw/pci-host/q35.h
+++ b/include/hw/pci-host/q35.h
@@ -53,8 +53,6 @@ typedef struct MCHPCIState {
     MemoryRegion *address_space_io;
     PAMMemoryRegion pam_regions[13];
     MemoryRegion smram_region;
-    MemoryRegion pci_hole;
-    MemoryRegion pci_hole_64bit;
     PcPciInfo pci_info;
     uint8_t smm_enabled;
     ram_addr_t below_4g_mem_size;