diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 7b8aab7..c31c2fa 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -645,9 +645,8 @@
     return entry;
 }
 
-static int pci_bus_hotplug_support(struct pci_bus *bus)
+static int pci_bus_hotplug_support(struct pci_bus *bus, u8 pcie_cap)
 {
-    u8 pcie_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_EXP, 0);
     u8 shpc_cap;
 
     if (pcie_cap) {
@@ -727,7 +726,8 @@
              */
             parent = &busses[0];
         int type;
-        int hotplug_support = pci_bus_hotplug_support(s);
+        u8 pcie_cap = pci_find_capability(s->bus_dev, PCI_CAP_ID_EXP, 0);
+        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;
@@ -736,7 +736,8 @@
             if (pci_region_align(&s->r[type]) > align)
                  align = pci_region_align(&s->r[type]);
             u64 sum = pci_region_sum(&s->r[type]);
-            if (!sum && hotplug_support)
+            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);
             int is64 = pci_bios_bridge_region_is64(&s->r[type],