Re: [Qemu-devel] [PATCH v5 for-2.3 23/28] hw/pxb: add map_irq func

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Mar 10, 2015 at 05:32:09PM +0200, Marcel Apfelbaum wrote:
> The bios does not index the pxb slot number when
> it computes the IRQ because it resides on bus 0
> and not on the current bus.
> However Qemu routes the irq through bus 0 and adds
> the pxb slot to the IRQ computation.
> 
> Synchronize between bios and Qemu by canceling
> pxb's effect.
> 
> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
> ---
>  hw/pci-bridge/pci_expander_bridge.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c
> index 941f3c8..87515c1 100644
> --- a/hw/pci-bridge/pci_expander_bridge.c
> +++ b/hw/pci-bridge/pci_expander_bridge.c
> @@ -92,6 +92,24 @@ static const TypeInfo pxb_host_info = {
>      .class_init    = pxb_host_class_init,
>  };
>  
> +
> +static int pxb_map_irq_fn(PCIDevice *pci_dev, int pin)
> +{
> +    PCIDevice *pxb = pci_dev->bus->parent_dev;
> +
> +    /*
> +     * The bios does not index the pxb slot number when
> +     * it computes the IRQ because it resides on bus 0
> +     * and not on the current bus.
> +     * However QEMU routes the irq through bus 0 and adds
> +     * the pxb slot to the IRQ computation.

I know it's QEMU but which function exactly?

> +     *
> +     * Synchronize between bios and QEMU by canceling
> +     * pxb's effect.
> +     */
> +    return pin - PCI_SLOT(pxb->devfn);
> +}
> +
>  static int pxb_dev_initfn(PCIDevice *dev)
>  {
>      PXBDev *pxb = PXB_DEV(dev);
> @@ -118,7 +136,7 @@ static int pxb_dev_initfn(PCIDevice *dev)
>      bus->parent_dev = dev;
>      bus->address_space_mem = dev->bus->address_space_mem;
>      bus->address_space_io = dev->bus->address_space_io;
> -    bus->map_irq = pci_swizzle_map_irq_fn;
> +    bus->map_irq = pxb_map_irq_fn;
>  
>      bds = qdev_create(BUS(bus), "pci-bridge");
>      bds->id = dev_name;
> -- 
> 2.1.0