diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 864954f..620b187 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -15,6 +15,7 @@
 #include "hw/pcidevice.h" // pci_probe_devices
 #include "hw/pci_ids.h" // PCI_VENDOR_ID_INTEL
 #include "hw/pci_regs.h" // PCI_COMMAND
+#include "fw/dev-pci.h" // REDHAT_CAP_RESOURCE_RESERVE
 #include "list.h" // struct hlist_node
 #include "malloc.h" // free
 #include "output.h" // dprintf
@@ -522,6 +523,32 @@ static void pci_bios_init_platform(void)
     }
 }
 
+static u8 pci_find_resource_reserve_capability(u16 bdf)
+{
+    if (pci_config_readw(bdf, PCI_VENDOR_ID) == PCI_VENDOR_ID_REDHAT &&
+        pci_config_readw(bdf, PCI_DEVICE_ID) ==
+                PCI_DEVICE_ID_REDHAT_ROOT_PORT) {
+        u8 cap = 0;
+        do {
+            cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, cap);
+        } while (cap &&
+                 pci_config_readb(bdf, cap + PCI_CAP_REDHAT_TYPE_OFFSET) !=
+                        REDHAT_CAP_RESOURCE_RESERVE);
+        if (cap) {
+            u8 cap_len = pci_config_readb(bdf, cap + PCI_CAP_FLAGS);
+            if (cap_len < RES_RESERVE_CAP_SIZE) {
+                dprintf(1, "PCI: QEMU resource reserve cap length %d is invalid\n",
+                        cap_len);
+            }
+        } else {
+            dprintf(1, "PCI: invalid QEMU resource reserve cap offset\n");
+        }
+        return cap;
+    } else {
+        dprintf(1, "PCI: QEMU resource reserve cap not found\n");
+        return 0;
+    }
+}
 
 /****************************************************************
  * Bus initialization
@@ -578,9 +605,28 @@ pci_bios_init_bus_rec(int bus, u8 *pci_bus)
         pci_bios_init_bus_rec(secbus, pci_bus);
 
         if (subbus != *pci_bus) {
+            u8 res_bus = 0;
+            u8 cap = pci_find_resource_reserve_capability(bdf);
+
+            if (cap) {
+                u32 tmp_res_bus = pci_config_readl(bdf,
+                        cap + RES_RESERVE_BUS_RES);
+                if (tmp_res_bus != (u32)-1) {
+                    res_bus = tmp_res_bus & 0xFF;
+                    if ((u8)(res_bus + secbus) < secbus ||
+                            (u8)(res_bus + secbus) < res_bus) {
+                        dprintf(1, "PCI: bus_reserve value %d is invalid\n",
+                                res_bus);
+                        res_bus = 0;
+                    }
+                }
+                res_bus = (*pci_bus > secbus + res_bus) ? *pci_bus
+                        : secbus + res_bus;
+            }
             dprintf(1, "PCI: subordinate bus = 0x%x -> 0x%x\n",
-                    subbus, *pci_bus);
-            subbus = *pci_bus;
+                    subbus, res_bus);
+            subbus = res_bus;
+            *pci_bus = res_bus;
         } else {
             dprintf(1, "PCI: subordinate bus = 0x%x\n", subbus);
         }
@@ -844,20 +890,65 @@ static int pci_bios_check_devices(struct pci_bus *busses)
              */
             parent = &busses[0];
         int type;
-        u8 pcie_cap = pci_find_capability(s->bus_dev->bdf, PCI_CAP_ID_EXP, 0);
+        u16 bdf = s->bus_dev->bdf;
+        u8 pcie_cap = pci_find_capability(bdf, PCI_CAP_ID_EXP, 0);
+        u8 qemu_cap = pci_find_resource_reserve_capability(bdf);
+
         int hotplug_support = pci_bus_hotplug_support(s, pcie_cap);
         for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) {
             u64 align = (type == PCI_REGION_TYPE_IO) ?
                 PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN;
             if (!pci_bridge_has_region(s->bus_dev, type))
                 continue;
+            u64 size = 0;
+            if (qemu_cap) {
+                u32 tmp_size;
+                u64 tmp_size_64;
+                switch(type) {
+                case PCI_REGION_TYPE_IO:
+                    tmp_size_64 = (pci_config_readl(bdf, qemu_cap + RES_RESERVE_IO) |
+                            (u64)pci_config_readl(bdf, qemu_cap + RES_RESERVE_IO + 4) << 32);
+                    if (tmp_size_64 != (u64)-1) {
+                        size = tmp_size_64;
+                    }
+                    break;
+                case PCI_REGION_TYPE_MEM:
+                    tmp_size = pci_config_readl(bdf, qemu_cap + RES_RESERVE_MEM);
+                    if (tmp_size != (u32)-1) {
+                        size = tmp_size;
+                    }
+                    break;
+                case PCI_REGION_TYPE_PREFMEM:
+                    tmp_size = pci_config_readl(bdf, qemu_cap + RES_RESERVE_PREF_MEM_32);
+                    tmp_size_64 = (pci_config_readl(bdf, qemu_cap + RES_RESERVE_PREF_MEM_64) |
+                            (u64)pci_config_readl(bdf, qemu_cap + RES_RESERVE_PREF_MEM_64 + 4) << 32);
+                    if (tmp_size != (u32)-1 && tmp_size_64 == (u64)-1) {
+                        size = tmp_size;
+                    } else if (tmp_size == (u32)-1 && tmp_size_64 != (u64)-1) {
+                        size = tmp_size_64;
+                    } else if (tmp_size != (u32)-1 && tmp_size_64 != (u64)-1) {
+                        dprintf(1, "PCI: resource reserve cap PREF32 and PREF64"
+                                " conflict\n");
+                    }
+                    break;
+                default:
+                    break;
+                }
+            }
             if (pci_region_align(&s->r[type]) > align)
                  align = pci_region_align(&s->r[type]);
             u64 sum = pci_region_sum(&s->r[type]);
             int resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
             if (!sum && hotplug_support && !resource_optional)
                 sum = align; /* reserve min size for hot-plug */
-            u64 size = ALIGN(sum, align);
+            if (size > sum) {
+                dprintf(1, "PCI: QEMU resource reserve cap: "
+                        "size %08llx type %s\n",
+                        size, region_type_name[type]);
+            } else {
+                size = sum;
+            }
+            size = ALIGN(size, align);
             int is64 = pci_bios_bridge_region_is64(&s->r[type],
                                             s->bus_dev, type);
             // entry->bar is -1 if the entry represents a bridge region
diff --git a/src/hw/pci_ids.h b/src/hw/pci_ids.h
index 4ac73b4..38fa2ca 100644
--- a/src/hw/pci_ids.h
+++ b/src/hw/pci_ids.h
@@ -2263,6 +2263,9 @@
 #define PCI_DEVICE_ID_KORENIX_JETCARDF0	0x1600
 #define PCI_DEVICE_ID_KORENIX_JETCARDF1	0x16ff
 
+#define PCI_VENDOR_ID_REDHAT		0x1b36
+#define PCI_DEVICE_ID_REDHAT_ROOT_PORT	0x000C
+
 #define PCI_VENDOR_ID_TEKRAM		0x1de1
 #define PCI_DEVICE_ID_TEKRAM_DC290	0xdc29
 
