Re: [PATCH] testdev: adjust for ISA irq changes

[Avi Kivity <avi@redhat.com>]

On 05/29/2011 06:21 PM, Jan Kiszka wrote:
> >  Suppose our motherboard wired
> >  the PCI links to GSI16-19 (or GSI16-23, as we once wanted before we had
> >  MSI-X)?  We'd need an API to access non-ISA interrupt lines.
> >
> >  So what's the clean fix here?  gsi_get_irq()?
>
> Maybe. Depends on the requirements of the testdev. If you also want to
> address PIC and IOAPIC separately or simulate injection from a specific
> device, we need more logic.

It's impossible to address them separately, the input lines are tied 
together (esp. with kvm irq routing).  I think using GSIs is the right 
thing here.

> We also need a better interface to discover and track legacy IRQ routes
> for device assignment. Markus is currently collecting requirements for
> qdev enhancements, and I think generic IRQ manipulation and discovery
> belongs there.

Possibly.  But note that attempting to shoehorn everything into 
bus/device model may not work.  Motherboard devices, especially, often 
bypass the bus/device relationship, just because everything is available 
to them on the motherboard, and because hardware designers didn't go to 
software engineering schools but instead do what's necessary to get 
things working.  We have to be prepared for exceptions.

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