Re: [Qemu-devel] [PATCH 2/2] Route IOAPIC interrupts via ISA bus

[Avi Kivity <avi@redhat.com>]

On 08/27/2009 10:35 AM, Gerd Hoffmann wrote:
>>> BTW: Seems linux doesn't use IRQ 5 even with lots of PCI devices,
>>> instead it makes them share 10+11 ...
>>
>> We could change the defaults to include 5, but maybe it makes more sense
>> to fix Linux to distribute active PCI IRQs across the resources it has
>> at its disposal.
>
> i.e. Linux decides to stick with the defaults (starred) here ...
>
> ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
> ACPI: PCI Interrupt Link [LNKA] (IRQs 5 *10 11)
> ACPI: PCI Interrupt Link [LNKB] (IRQs 5 *10 11)
> ACPI: PCI Interrupt Link [LNKC] (IRQs 5 10 *11)
> ACPI: PCI Interrupt Link [LNKD] (IRQs 5 10 *11)
>
> ... instead of trying to minimize IRQ sharing by using IRQ 5?

Yes.  And if it turns out you have two active devices and 6 inactive 
devices, move the two active devices to private lines and pile up the 
inactive ones on the leftover.

>
>> They'll be slow regardless. I should be easy to support msi on e1000
>> though.
>
> What is needed on the guest side?  Looks like even 2.6.30 doesn't use 
> MSI for virtio-net ...

virtio msi support was merged in 2.6.31.  For e1000, guest support is 
presumably there, just need to wire it into the device.

-- 
error compiling committee.c: too many arguments to function