hw/pci/pci: Factor out pci_bus_map_irqs() from pci_bus_irqs()

pci_bus_irqs() coupled together the assignment of pci_set_irq_fn and
pci_map_irq_fn to a PCI bus. This coupling gets in the way when the
pci_map_irq_fn is board-specific while the pci_set_irq_fn is device-
specific.

For example, both of QEMU's PIIX south bridge models have different
pci_map_irq_fn implementations which are board-specific rather than
device-specific. These implementations should therefore reside in board
code. The pci_set_irq_fn's, however, should stay in the device models
because they access memory internal to the model.

Factoring out pci_bus_map_irqs() from pci_bus_irqs() allows the
assignments to be decoupled, resolving the problem described above.

Note also how pci_vpb_realize() which gets touched in this commit
assigns different pci_map_irq_fn's depending on the board.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230109172347.1830-5-shentey@gmail.com>
[PMD: Factor out in vfu_object_set_bus_irq()]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

1 files changed, 9 insertions, 3 deletions

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index c2fb88f9a3..39a7bb32aa 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -280,6 +280,7 @@ static void pci_change_irq_level(PCIDevice *pci_dev, int irq_num, int change)
     PCIBus *bus;
     for (;;) {
         bus = pci_get_bus(pci_dev);
+        assert(bus->map_irq);
         irq_num = bus->map_irq(pci_dev, irq_num);
         if (bus->set_irq)
             break;
@@ -518,16 +519,20 @@ void pci_root_bus_cleanup(PCIBus *bus)
     qbus_unrealize(BUS(bus));
 }
 
-void pci_bus_irqs(PCIBus *bus, pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
+void pci_bus_irqs(PCIBus *bus, pci_set_irq_fn set_irq,
                   void *irq_opaque, int nirq)
 {
     bus->set_irq = set_irq;
-    bus->map_irq = map_irq;
     bus->irq_opaque = irq_opaque;
     bus->nirq = nirq;
     bus->irq_count = g_malloc0(nirq * sizeof(bus->irq_count[0]));
 }
 
+void pci_bus_map_irqs(PCIBus *bus, pci_map_irq_fn map_irq)
+{
+    bus->map_irq = map_irq;
+}
+
 void pci_bus_irqs_cleanup(PCIBus *bus)
 {
     bus->set_irq = NULL;
@@ -549,7 +554,8 @@ PCIBus *pci_register_root_bus(DeviceState *parent, const char *name,
 
     bus = pci_root_bus_new(parent, name, address_space_mem,
                            address_space_io, devfn_min, typename);
-    pci_bus_irqs(bus, set_irq, map_irq, irq_opaque, nirq);
+    pci_bus_irqs(bus, set_irq, irq_opaque, nirq);
+    pci_bus_map_irqs(bus, map_irq);
     return bus;
 }