diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c
index e3195d54497..7e7322486c2 100644
--- a/hw/arm/sbsa-ref.c
+++ b/hw/arm/sbsa-ref.c
@@ -673,7 +673,7 @@ static void create_pcie(SBSAMachineState *sms)
     /* Map IO port space */
     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 2, base_pio);
 
-    for (i = 0; i < GPEX_NUM_IRQS; i++) {
+    for (i = 0; i < PCI_NUM_PINS; i++) {
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), i,
                            qdev_get_gpio_in(sms->gic, irq + i));
         gpex_set_irq_num(GPEX_HOST(dev), i, irq + i);
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 8b2b991d978..bd3b17be2ea 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1547,7 +1547,7 @@ static void create_pcie(VirtMachineState *vms)
     /* Map IO port space */
     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 2, base_pio);
 
-    for (i = 0; i < GPEX_NUM_IRQS; i++) {
+    for (i = 0; i < PCI_NUM_PINS; i++) {
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), i,
                            qdev_get_gpio_in(vms->gic, irq + i));
         gpex_set_irq_num(GPEX_HOST(dev), i, irq + i);
diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
index 40edcee7af2..216a169c413 100644
--- a/hw/i386/microvm.c
+++ b/hw/i386/microvm.c
@@ -139,7 +139,7 @@ static void create_gpex(MicrovmMachineState *mms)
                                     mms->gpex.mmio64.base, mmio64_alias);
     }
 
-    for (i = 0; i < GPEX_NUM_IRQS; i++) {
+    for (i = 0; i < PCI_NUM_PINS; i++) {
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), i,
                            x86ms->gsi[mms->gpex.irq + i]);
     }
diff --git a/hw/loongarch/virt.c b/hw/loongarch/virt.c
index 75980b6e3c7..8eb7277a8d1 100644
--- a/hw/loongarch/virt.c
+++ b/hw/loongarch/virt.c
@@ -703,7 +703,7 @@ static void virt_devices_init(DeviceState *pch_pic,
     memory_region_add_subregion(get_system_memory(), VIRT_PCI_IO_BASE,
                                 pio_alias);
 
-    for (i = 0; i < GPEX_NUM_IRQS; i++) {
+    for (i = 0; i < PCI_NUM_PINS; i++) {
         sysbus_connect_irq(d, i,
                            qdev_get_gpio_in(pch_pic, 16 + i));
         gpex_set_irq_num(GPEX_HOST(gpex_dev), i, 16 + i);
diff --git a/hw/mips/loongson3_virt.c b/hw/mips/loongson3_virt.c
index 2067b4fecb5..acafd73129d 100644
--- a/hw/mips/loongson3_virt.c
+++ b/hw/mips/loongson3_virt.c
@@ -458,7 +458,7 @@ static inline void loongson3_virt_devices_init(MachineState *machine,
                                 virt_memmap[VIRT_PCIE_PIO].base, s->pio_alias);
     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 2, virt_memmap[VIRT_PCIE_PIO].base);
 
-    for (i = 0; i < GPEX_NUM_IRQS; i++) {
+    for (i = 0; i < PCI_NUM_PINS; i++) {
         irq = qdev_get_gpio_in(pic, PCIE_IRQ_BASE + i);
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), i, irq);
         gpex_set_irq_num(GPEX_HOST(dev), i, PCIE_IRQ_BASE + i);
diff --git a/hw/openrisc/virt.c b/hw/openrisc/virt.c
index f8a68a6a6b1..16a5676c4bb 100644
--- a/hw/openrisc/virt.c
+++ b/hw/openrisc/virt.c
@@ -318,7 +318,7 @@ static void create_pcie_irq_map(void *fdt, char *nodename, int irq_base,
 {
     int pin, dev;
     uint32_t irq_map_stride = 0;
-    uint32_t full_irq_map[GPEX_NUM_IRQS * GPEX_NUM_IRQS * 6] = {};
+    uint32_t full_irq_map[PCI_NUM_PINS * PCI_NUM_PINS * 6] = {};
     uint32_t *irq_map = full_irq_map;
 
     /*
@@ -330,11 +330,11 @@ static void create_pcie_irq_map(void *fdt, char *nodename, int irq_base,
      * possible slot) seeing the interrupt-map-mask will allow the table
      * to wrap to any number of devices.
      */
-    for (dev = 0; dev < GPEX_NUM_IRQS; dev++) {
+    for (dev = 0; dev < PCI_NUM_PINS; dev++) {
         int devfn = dev << 3;
 
-        for (pin = 0; pin < GPEX_NUM_IRQS; pin++) {
-            int irq_nr = irq_base + ((pin + PCI_SLOT(devfn)) % GPEX_NUM_IRQS);
+        for (pin = 0; pin < PCI_NUM_PINS; pin++) {
+            int irq_nr = irq_base + ((pin + PCI_SLOT(devfn)) % PCI_NUM_PINS);
             int i = 0;
 
             /* Fill PCI address cells */
@@ -357,7 +357,7 @@ static void create_pcie_irq_map(void *fdt, char *nodename, int irq_base,
     }
 
     qemu_fdt_setprop(fdt, nodename, "interrupt-map", full_irq_map,
-                     GPEX_NUM_IRQS * GPEX_NUM_IRQS *
+                     PCI_NUM_PINS * PCI_NUM_PINS *
                      irq_map_stride * sizeof(uint32_t));
 
     qemu_fdt_setprop_cells(fdt, nodename, "interrupt-map-mask",
@@ -409,7 +409,7 @@ static void openrisc_virt_pcie_init(OR1KVirtState *state,
     memory_region_add_subregion(get_system_memory(), pio_base, alias);
 
     /* Connect IRQ lines. */
-    for (i = 0; i < GPEX_NUM_IRQS; i++) {
+    for (i = 0; i < PCI_NUM_PINS; i++) {
         pcie_irq = get_per_cpu_irq(cpus, num_cpus, irq_base + i);
 
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), i, pcie_irq);
diff --git a/hw/pci-host/gpex.c b/hw/pci-host/gpex.c
index e9cf455bf52..4aca0a95771 100644
--- a/hw/pci-host/gpex.c
+++ b/hw/pci-host/gpex.c
@@ -32,6 +32,7 @@
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "hw/irq.h"
+#include "hw/pci/pci_bus.h"
 #include "hw/pci-host/gpex.h"
 #include "hw/qdev-properties.h"
 #include "migration/vmstate.h"
@@ -50,7 +51,7 @@ static void gpex_set_irq(void *opaque, int irq_num, int level)
 
 int gpex_set_irq_num(GPEXHost *s, int index, int gsi)
 {
-    if (index >= GPEX_NUM_IRQS) {
+    if (index >= s->nr_irqs) {
         return -EINVAL;
     }
 
@@ -74,14 +75,29 @@ static PCIINTxRoute gpex_route_intx_pin_to_irq(void *opaque, int pin)
     return route;
 }
 
+static int gpex_swizzle_map_irq_fn(PCIDevice *pci_dev, int pin)
+{
+    PCIBus *bus = pci_device_root_bus(pci_dev);
+
+    return (PCI_SLOT(pci_dev->devfn) + pin) % bus->nirq;
+}
+
 static void gpex_host_realize(DeviceState *dev, Error **errp)
 {
     PCIHostState *pci = PCI_HOST_BRIDGE(dev);
     GPEXHost *s = GPEX_HOST(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
     PCIExpressHost *pex = PCIE_HOST_BRIDGE(dev);
+    pci_map_irq_fn map_irq_fn = pci_swizzle_map_irq_fn;
     int i;
 
+    s->irq = g_malloc0(s->nr_irqs * sizeof(*s->irq));
+    s->irq_num = g_malloc0(s->nr_irqs * sizeof(*s->irq_num));
+
+    if (s->nr_irqs != PCI_NUM_PINS) {
+        map_irq_fn = gpex_swizzle_map_irq_fn;
+    }
+
     pcie_host_mmcfg_init(pex, PCIE_MMCFG_SIZE_MAX);
     sysbus_init_mmio(sbd, &pex->mmio);
 
@@ -128,19 +144,27 @@ static void gpex_host_realize(DeviceState *dev, Error **errp)
         sysbus_init_mmio(sbd, &s->io_ioport);
     }
 
-    for (i = 0; i < GPEX_NUM_IRQS; i++) {
+    for (i = 0; i < s->nr_irqs; i++) {
         sysbus_init_irq(sbd, &s->irq[i]);
         s->irq_num[i] = -1;
     }
 
-    pci->bus = pci_register_root_bus(dev, "pcie.0", gpex_set_irq,
-                                     pci_swizzle_map_irq_fn, s, &s->io_mmio,
-                                     &s->io_ioport, 0, 4, TYPE_PCIE_BUS);
+    pci->bus = pci_register_root_bus(dev, "pcie.0", gpex_set_irq, map_irq_fn,
+                                     s, &s->io_mmio, &s->io_ioport, 0,
+                                     s->nr_irqs, TYPE_PCIE_BUS);
 
     pci_bus_set_route_irq_fn(pci->bus, gpex_route_intx_pin_to_irq);
     qdev_realize(DEVICE(&s->gpex_root), BUS(pci->bus), &error_fatal);
 }
 
+static void gpex_host_unrealize(DeviceState *dev)
+{
+    GPEXHost *s = GPEX_HOST(dev);
+
+    g_free(s->irq);
+    g_free(s->irq_num);
+}
+
 static const char *gpex_host_root_bus_path(PCIHostState *host_bridge,
                                           PCIBus *rootbus)
 {
@@ -166,6 +190,7 @@ static Property gpex_host_properties[] = {
                        gpex_cfg.mmio64.base, 0),
     DEFINE_PROP_SIZE(PCI_HOST_ABOVE_4G_MMIO_SIZE, GPEXHost,
                      gpex_cfg.mmio64.size, 0),
+    DEFINE_PROP_UINT32("nr-irqs", GPEXHost, nr_irqs, PCI_NUM_PINS),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -176,6 +201,7 @@ static void gpex_host_class_init(ObjectClass *klass, void *data)
 
     hc->root_bus_path = gpex_host_root_bus_path;
     dc->realize = gpex_host_realize;
+    dc->unrealize = gpex_host_unrealize;
     set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
     dc->fw_name = "pci";
     device_class_set_props(dc, gpex_host_properties);
diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index cef41c150aa..6c3ed4b3d9c 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -167,7 +167,7 @@ static void create_pcie_irq_map(RISCVVirtState *s, void *fdt, char *nodename,
 {
     int pin, dev;
     uint32_t irq_map_stride = 0;
-    uint32_t full_irq_map[GPEX_NUM_IRQS * GPEX_NUM_IRQS *
+    uint32_t full_irq_map[PCI_NUM_PINS * PCI_NUM_PINS *
                           FDT_MAX_INT_MAP_WIDTH] = {};
     uint32_t *irq_map = full_irq_map;
 
@@ -179,11 +179,11 @@ static void create_pcie_irq_map(RISCVVirtState *s, void *fdt, char *nodename,
      * possible slot) seeing the interrupt-map-mask will allow the table
      * to wrap to any number of devices.
      */
-    for (dev = 0; dev < GPEX_NUM_IRQS; dev++) {
+    for (dev = 0; dev < PCI_NUM_PINS; dev++) {
         int devfn = dev * 0x8;
 
-        for (pin = 0; pin < GPEX_NUM_IRQS; pin++) {
-            int irq_nr = PCIE_IRQ + ((pin + PCI_SLOT(devfn)) % GPEX_NUM_IRQS);
+        for (pin = 0; pin < PCI_NUM_PINS; pin++) {
+            int irq_nr = PCIE_IRQ + ((pin + PCI_SLOT(devfn)) % PCI_NUM_PINS);
             int i = 0;
 
             /* Fill PCI address cells */
@@ -209,7 +209,7 @@ static void create_pcie_irq_map(RISCVVirtState *s, void *fdt, char *nodename,
     }
 
     qemu_fdt_setprop(fdt, nodename, "interrupt-map", full_irq_map,
-                     GPEX_NUM_IRQS * GPEX_NUM_IRQS *
+                     PCI_NUM_PINS * PCI_NUM_PINS *
                      irq_map_stride * sizeof(uint32_t));
 
     qemu_fdt_setprop_cells(fdt, nodename, "interrupt-map-mask",
@@ -1157,7 +1157,7 @@ static inline DeviceState *gpex_pcie_init(MemoryRegion *sys_mem,
 
     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 2, pio_base);
 
-    for (i = 0; i < GPEX_NUM_IRQS; i++) {
+    for (i = 0; i < PCI_NUM_PINS; i++) {
         irq = qdev_get_gpio_in(irqchip, PCIE_IRQ + i);
 
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), i, irq);
diff --git a/hw/xtensa/virt.c b/hw/xtensa/virt.c
index 5310a888613..8f5c2009d29 100644
--- a/hw/xtensa/virt.c
+++ b/hw/xtensa/virt.c
@@ -93,7 +93,7 @@ static void create_pcie(MachineState *ms, CPUXtensaState *env, int irq_base,
     /* Connect IRQ lines. */
     extints = xtensa_get_extints(env);
 
-    for (i = 0; i < GPEX_NUM_IRQS; i++) {
+    for (i = 0; i < PCI_NUM_PINS; i++) {
         void *q = extints[irq_base + i];
 
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), i, q);
diff --git a/include/hw/pci-host/gpex.h b/include/hw/pci-host/gpex.h
index dce883573ba..8f87a3872cb 100644
--- a/include/hw/pci-host/gpex.h
+++ b/include/hw/pci-host/gpex.h
@@ -32,8 +32,6 @@ OBJECT_DECLARE_SIMPLE_TYPE(GPEXHost, GPEX_HOST)
 #define TYPE_GPEX_ROOT_DEVICE "gpex-root"
 OBJECT_DECLARE_SIMPLE_TYPE(GPEXRootState, GPEX_ROOT_DEVICE)
 
-#define GPEX_NUM_IRQS 4
-
 struct GPEXRootState {
     /*< private >*/
     PCIDevice parent_obj;
@@ -60,8 +58,9 @@ struct GPEXHost {
     MemoryRegion io_mmio;
     MemoryRegion io_ioport_window;
     MemoryRegion io_mmio_window;
-    qemu_irq irq[GPEX_NUM_IRQS];
-    int irq_num[GPEX_NUM_IRQS];
+    uint32_t nr_irqs;
+    qemu_irq *irq;
+    int *irq_num;
 
     bool allow_unmapped_accesses;
 
