pci: Add INTx routing notifier

This per-device notifier shall be triggered by any interrupt router
along the path of a device's legacy interrupt signal on routing changes.
For simplicity reasons and as this is a slow path anyway, no further
details on the routing changes are provided. Instead, the callback is
expected to use pci_device_route_intx_to_irq to check the effect of the
change.

Will be used by KVM PCI device assignment and VFIO.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/hw/pci.c b/hw/pci.c
index e80599f058..94601f28f9 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -1086,6 +1086,29 @@ PCIINTxRoute pci_device_route_intx_to_irq(PCIDevice *dev, int pin)
     return bus->route_intx_to_irq(bus->irq_opaque, pin);
 }
 
+void pci_bus_fire_intx_routing_notifier(PCIBus *bus)
+{
+    PCIDevice *dev;
+    PCIBus *sec;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
+        dev = bus->devices[i];
+        if (dev && dev->intx_routing_notifier) {
+            dev->intx_routing_notifier(dev);
+        }
+        QLIST_FOREACH(sec, &bus->child, sibling) {
+            pci_bus_fire_intx_routing_notifier(sec);
+        }
+    }
+}
+
+void pci_device_set_intx_routing_notifier(PCIDevice *dev,
+                                          PCIINTxRoutingNotifier notifier)
+{
+    dev->intx_routing_notifier = notifier;
+}
+
 /***********************************************************/
 /* monitor info on PCI */