diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 0b84aa4..fbea5d0 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -922,6 +922,21 @@ void pc_acpi_init(const char *default_dsdt)
     }
 }
 
+void pc_guest_info_init(PcGuestInfo *guest_info,
+                        ram_addr_t below_4g_mem_size,
+                        ram_addr_t above_4g_mem_size)
+{
+    guest_info->pci_info.w32.min = below_4g_mem_size;
+    guest_info->pci_info.w32.max = 0x100000000ULL - 0x1;
+    if (sizeof(hwaddr) == 4) {
+        guest_info->pci_info.w64.min = 0x100000000ULL + above_4g_mem_size;
+        guest_info->pci_info.w64.max =
+            range_get_last(guest_info->pci_info.w64.min, (0x1ULL << 62));
+    } else {
+        guest_info->pci_info.w64.min = guest_info->pci_info.w64.max =  0;
+    }
+}
+
 FWCfgState *pc_memory_init(MemoryRegion *system_memory,
                            const char *kernel_filename,
                            const char *kernel_cmdline,
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index da10e6d..539f72a 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -86,6 +86,7 @@ static void pc_init1(MemoryRegion *system_memory,
     MemoryRegion *pci_memory;
     MemoryRegion *rom_memory;
     FWCfgState *fw_cfg = NULL;
+    PcGuestInfo guest_info;
 
     pc_cpus_init(cpu_model);
     pc_acpi_init("acpi-dsdt.aml");
@@ -111,6 +112,7 @@ static void pc_init1(MemoryRegion *system_memory,
         rom_memory = system_memory;
     }
 
+    pc_guest_info_init(&guest_info, below_4g_mem_size, above_4g_mem_size);
     /* allocate ram and load rom/bios */
     if (!xen_enabled()) {
         fw_cfg = pc_memory_init(system_memory,
@@ -131,12 +133,10 @@ static void pc_init1(MemoryRegion *system_memory,
     if (pci_enabled) {
         pci_bus = i440fx_init(&i440fx_state, &piix3_devfn, &isa_bus, gsi,
                               system_memory, system_io, ram_size,
-                              below_4g_mem_size,
-                              0x100000000ULL - below_4g_mem_size,
-                              0x100000000ULL + above_4g_mem_size,
-                              (sizeof(hwaddr) == 4
-                               ? 0
-                               : ((uint64_t)1 << 62)),
+                              range_start(&guest_info.pci_info.w32),
+                              range_len(&guest_info.pci_info.w32),
+                              range_start(&guest_info.pci_info.w64),
+                              range_len(&guest_info.pci_info.w64),
                               pci_memory, ram_memory);
     } else {
         pci_bus = NULL;
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 6ac1a89..50dc14d 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -85,6 +85,7 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     ICH9LPCState *ich9_lpc;
     PCIDevice *ahci;
     qemu_irq *cmos_s3;
+    PcGuestInfo guest_info;
 
     pc_cpus_init(cpu_model);
     pc_acpi_init("q35-acpi-dsdt.aml");
@@ -109,6 +110,8 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
         rom_memory = get_system_memory();
     }
 
+    pc_guest_info_init(&guest_info, below_4g_mem_size, above_4g_mem_size);
+
     /* allocate ram and load rom/bios */
     if (!xen_enabled()) {
         pc_memory_init(get_system_memory(), kernel_filename, kernel_cmdline,
@@ -133,8 +136,8 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     q35_host->mch.pci_address_space = pci_memory;
     q35_host->mch.system_memory = get_system_memory();
     q35_host->mch.address_space_io = get_system_io();;
-    q35_host->mch.below_4g_mem_size = below_4g_mem_size;
-    q35_host->mch.above_4g_mem_size = above_4g_mem_size;
+    q35_host->mch.below_4g_mem_range = guest_info.pci_info.w32;
+    q35_host->mch.above_4g_mem_range = guest_info.pci_info.w64;
     /* pci */
     qdev_init_nofail(DEVICE(q35_host));
     host_bus = q35_host->host.pci.bus;
diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index 8467f86..c951255 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -240,25 +240,23 @@ static void mch_reset(DeviceState *qdev)
 static int mch_init(PCIDevice *d)
 {
     int i;
-    hwaddr pci_hole64_size;
     MCHPCIState *mch = MCH_PCI_DEVICE(d);
 
     /* setup pci memory regions */
     memory_region_init_alias(&mch->pci_hole, "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,
+                             range_start(&mch->below_4g_mem_range),
+                             range_len(&mch->below_4g_mem_range));
+    memory_region_add_subregion(mch->system_memory,
+                                range_len(&mch->below_4g_mem_range),
                                 &mch->pci_hole);
-    pci_hole64_size = (sizeof(hwaddr) == 4 ? 0 :
-                       ((uint64_t)1 << 62));
     memory_region_init_alias(&mch->pci_hole_64bit, "pci-hole64",
                              mch->pci_address_space,
-                             0x100000000ULL + mch->above_4g_mem_size,
-                             pci_hole64_size);
-    if (pci_hole64_size) {
+                             range_start(&mch->above_4g_mem_range),
+                             range_len(&mch->above_4g_mem_range));
+    if (range_valid(&mch->above_4g_mem_range)) {
         memory_region_add_subregion(mch->system_memory,
-                                    0x100000000ULL + mch->above_4g_mem_size,
+                                    range_len(&mch->above_4g_mem_range),
                                     &mch->pci_hole_64bit);
     }
     /* smram */
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index a65c6a0..cf3b263 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -10,9 +10,19 @@
 #include "exec/memory.h"
 #include "hw/i386/ioapic.h"
 #include "hw/nvram/fw_cfg.h"
+#include "qemu/range.h"
 
 /* PC-style peripherals (also used by other machines).  */
 
+typedef struct PciGuestInfo {
+    Range w32;
+    Range w64;
+} PciGuestInfo;
+
+typedef struct PcGuestInfo {
+    PciGuestInfo pci_info;
+} PcGuestInfo;
+
 /* parallel.c */
 static inline bool parallel_init(ISABus *bus, int index, CharDriverState *chr)
 {
@@ -81,6 +91,9 @@ void pc_acpi_smi_interrupt(void *opaque, int irq, int level);
 
 void pc_cpus_init(const char *cpu_model);
 void pc_acpi_init(const char *default_dsdt);
+void pc_guest_info_init(PcGuestInfo *guest_info,
+                        ram_addr_t below_4g_mem_size,
+                        ram_addr_t above_4g_mem_size);
 FWCfgState *pc_memory_init(MemoryRegion *system_memory,
                            const char *kernel_filename,
                            const char *kernel_cmdline,
diff --git a/include/hw/pci-host/q35.h b/include/hw/pci-host/q35.h
index e182c82..2766b6a 100644
--- a/include/hw/pci-host/q35.h
+++ b/include/hw/pci-host/q35.h
@@ -53,8 +53,8 @@ typedef struct MCHPCIState {
     MemoryRegion pci_hole;
     MemoryRegion pci_hole_64bit;
     uint8_t smm_enabled;
-    ram_addr_t below_4g_mem_size;
-    ram_addr_t above_4g_mem_size;
+    Range below_4g_mem_range;
+    Range above_4g_mem_range;
 } MCHPCIState;
 
 typedef struct Q35PCIHost {
