Introduce a new pci_bus_irq_handler input IRQ handler that can be triggered by
each unique PCI devfn on the bus. Add a new pci_bus_init() instance init
function to initialise the IRQ array and a corresponding pci_bus_finalize()
instance finalize function to free it.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 hw/pci/pci.c             | 34 ++++++++++++++++++++++++++++++++++
 include/hw/pci/pci_bus.h |  3 +++
 2 files changed, 37 insertions(+)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index f29ac20895..9471f996a7 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -179,6 +179,24 @@ static void pci_bus_unrealize(BusState *qbus)
     vmstate_unregister(NULL, &vmstate_pcibus, bus);
 }
 
+static void pci_bus_irq_handler(void *opaque, int devfn, int level);
+
+static void pci_bus_init(Object *obj)
+{
+    PCIBus *bus = PCI_BUS(obj);
+
+    /* IRQs */
+    bus->irq_in = qemu_allocate_irqs(pci_bus_irq_handler, bus,
+                                     PCI_SLOT_MAX * PCI_FUNC_MAX);
+}
+
+static void pci_bus_finalize(Object *obj)
+{
+    PCIBus *bus = PCI_BUS(obj);
+
+    qemu_free_irqs(bus->irq_in, PCI_SLOT_MAX * PCI_FUNC_MAX);
+}
+
 static int pcibus_num(PCIBus *bus)
 {
     if (pci_bus_is_root(bus)) {
@@ -211,7 +229,9 @@ static void pci_bus_class_init(ObjectClass *klass, void *data)
 static const TypeInfo pci_bus_info = {
     .name = TYPE_PCI_BUS,
     .parent = TYPE_BUS,
+    .instance_init = pci_bus_init,
     .instance_size = sizeof(PCIBus),
+    .instance_finalize = pci_bus_finalize,
     .class_size = sizeof(PCIBusClass),
     .class_init = pci_bus_class_init,
 };
@@ -1636,6 +1656,20 @@ static void pci_irq_handler(void *opaque, int irq_num, int level)
     pci_change_irq_level(pci_dev, irq_num, change);
 }
 
+/* Bus IRQ handler */
+static void pci_bus_irq_handler(void *opaque, int devfn, int level)
+{
+    PCIBus *bus = PCI_BUS(opaque);
+    PCIDevice *pci_dev;
+    int intx;
+
+    assert(0 <= devfn && devfn < PCI_SLOT_MAX * PCI_FUNC_MAX);
+    pci_dev = bus->devices[devfn];
+    intx = pci_intx(pci_dev);
+
+    pci_irq_handler(pci_dev, intx, level);
+}
+
 qemu_irq pci_allocate_irq(PCIDevice *pci_dev)
 {
     int intx = pci_intx(pci_dev);
diff --git a/include/hw/pci/pci_bus.h b/include/hw/pci/pci_bus.h
index 5653175957..8486df283e 100644
--- a/include/hw/pci/pci_bus.h
+++ b/include/hw/pci/pci_bus.h
@@ -54,6 +54,9 @@ struct PCIBus {
     int nirq;
     int *irq_count;
 
+    /* Bus IRQ handler */
+    qemu_irq *irq_in;
+
     Notifier machine_done;
 };
 
-- 
2.30.2