[Qemu-devel] [PATCH 2/2] pci: Add INTx routing notifier

[Jan Kiszka <jan.kiszka@siemens.com>]

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_get_host_irq to check the effect of the
change.

Will be used by KVM PCI device assignment.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 hw/pci.c        |   19 +++++++++++++++++++
 hw/pci.h        |    7 +++++++
 hw/pci_bridge.c |    8 ++++++++
 hw/piix_pci.c   |    2 ++
 4 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index df4d93e..27ecc37 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -1084,6 +1084,25 @@ int pci_device_get_host_irq(PCIDevice *pci_dev, int irq_num)
     return bus->map_host_irq(bus->irq_opaque, irq_num);
 }
 
+void pci_bus_fire_intx_routing_notifier(PCIBus *bus)
+{
+    PCIDevice *dev;
+    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);
+        }
+    }
+}
+
+void pci_device_set_intx_routing_notifier(PCIDevice *pci_dev,
+                                          INTxRoutingNotifier notifier)
+{
+    pci_dev->intx_routing_notifier = notifier;
+}
+
 /***********************************************************/
 /* monitor info on PCI */
 
diff --git a/hw/pci.h b/hw/pci.h
index 29bc8bf..eaf7695 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -173,6 +173,7 @@ typedef struct PCIDeviceClass {
     const char *romfile;
 } PCIDeviceClass;
 
+typedef void (*INTxRoutingNotifier)(PCIDevice *dev);
 typedef int (*MSIVectorUseNotifier)(PCIDevice *dev, unsigned int vector,
                                       MSIMessage msg);
 typedef void (*MSIVectorReleaseNotifier)(PCIDevice *dev, unsigned int vector);
@@ -248,6 +249,9 @@ struct PCIDevice {
     MemoryRegion rom;
     uint32_t rom_bar;
 
+    /* INTx routing notifier */
+    INTxRoutingNotifier intx_routing_notifier;
+
     /* MSI-X notifiers */
     MSIVectorUseNotifier msix_vector_use_notifier;
     MSIVectorReleaseNotifier msix_vector_release_notifier;
@@ -307,6 +311,9 @@ PCIBus *pci_register_bus(DeviceState *parent, const char *name,
                          MemoryRegion *address_space_io,
                          uint8_t devfn_min, int nirq);
 int pci_device_get_host_irq(PCIDevice *pci_dev, int irq_num);
+void pci_bus_fire_intx_routing_notifier(PCIBus *bus);
+void pci_device_set_intx_routing_notifier(PCIDevice *pci_dev,
+                                          INTxRoutingNotifier notifier);
 void pci_device_reset(PCIDevice *dev);
 void pci_bus_reset(PCIBus *bus);
 
diff --git a/hw/pci_bridge.c b/hw/pci_bridge.c
index e0832b4..2490b2f 100644
--- a/hw/pci_bridge.c
+++ b/hw/pci_bridge.c
@@ -292,6 +292,13 @@ void pci_bridge_reset(DeviceState *qdev)
     pci_set_word(conf + PCI_BRIDGE_CONTROL, 0);
 }
 
+static void pci_bridge_intx_routing_update(PCIDevice *dev)
+{
+    PCIBridge *br = DO_UPCAST(PCIBridge, dev, dev);
+
+    pci_bus_fire_intx_routing_notifier(&br->sec_bus);
+}
+
 /* default qdev initialization function for PCI-to-PCI bridge */
 int pci_bridge_initfn(PCIDevice *dev)
 {
@@ -327,6 +334,7 @@ int pci_bridge_initfn(PCIDevice *dev)
     sec_bus->address_space_io = &br->address_space_io;
     memory_region_init(&br->address_space_io, "pci_bridge_io", 65536);
     pci_bridge_region_init(br);
+    pci_device_set_intx_routing_notifier(dev, pci_bridge_intx_routing_update);
     QLIST_INIT(&sec_bus->child);
     QLIST_INSERT_HEAD(&parent->child, sec_bus, sibling);
     return 0;
diff --git a/hw/piix_pci.c b/hw/piix_pci.c
index cfea97c..b0d1325 100644
--- a/hw/piix_pci.c
+++ b/hw/piix_pci.c
@@ -414,6 +414,8 @@ static void piix3_write_config(PCIDevice *dev,
     if (ranges_overlap(address, len, PIIX_PIRQC, 4)) {
         PIIX3State *piix3 = DO_UPCAST(PIIX3State, dev, dev);
         int pic_irq;
+
+        pci_bus_fire_intx_routing_notifier(piix3->dev.bus);
         piix3_update_irq_levels(piix3);
         for (pic_irq = 0; pic_irq < PIIX_NUM_PIC_IRQS; pic_irq++) {
             piix3_set_irq_pic(piix3, pic_irq);
-- 
1.7.3.4