[2/2] 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_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(-)

On Mon, 2012-05-21 at 10:15 -0300, Jan Kiszka wrote:
> 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.

I think we could do this without inventing our out notifier mechanism,
Notifier + NotifierList, but it's better than what we've got now.  VFIO
will use this too.

Acked-by: Alex Williamson <alex.williamson@redhat.com>

> 
> 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);