Re: [Qemu-devel] [PATCH 05/13] pci: Add pci_device_route_intx_to_irq

[Michael S. Tsirkin]

On Mon, Jun 04, 2012 at 10:52:13AM +0200, Jan Kiszka wrote:
> @@ -1089,6 +1093,14 @@ static void pci_set_irq(void *opaque, int irq_num, int 
> level)
>      pci_change_irq_level(pci_dev, irq_num, change);
>  }
>  
> +PCIINTxRoute pci_device_route_intx_to_irq(PCIDevice *dev, int pin)
> +{
> +    PCIBus *bus = dev->host_bus;
> +
> +    assert(bus->route_intx_to_irq);
> +    return bus->route_intx_to_irq(bus->irq_opaque, dev->host_intx_pin[pin]);
> +}
> +
>  /***********************************************************/
>  /* monitor info on PCI */
>  

Just an idea: can devices cache this result, bypassing the
intx to irq lookup on data path?

> diff --git a/hw/pci.h b/hw/pci.h
> index 5b54e2d..bbba01e 100644
> --- a/hw/pci.h
> +++ b/hw/pci.h
> @@ -141,6 +141,15 @@ enum {
>  #define PCI_DEVICE_GET_CLASS(obj) \
>       OBJECT_GET_CLASS(PCIDeviceClass, (obj), TYPE_PCI_DEVICE)
>  
> +typedef struct PCIINTxRoute {
> +    enum {
> +        PCI_INTX_ENABLED,
> +        PCI_INTX_INVERTED,
> +        PCI_INTX_DISABLED,
> +    } mode;
> +    int irq;
> +} PCIINTxRoute;

Is this INTX route or IRQ route?
Is the INTX enabled/disabled/inverted or the IRQ?

I have the impression it's the IRQ, in the apic.
PCI INTX are never inverted they are always active low.