Re: RFC/patch portability: split kvm_vm_ioctl v3

Arnd Bergmann
2007-11-05T10:03:59Z

On Monday 05 November 2007, Carsten Otte wrote:
> > Actually, you have neither irq numbers nor vectors on s390 right now.
> > I/O subchannels are do not fit into the IRQ handling in Linux at
> > all, and external interrupts are sufficiently different that you
> > should not treat them as IRQ lines in Linux.

<snip>

> The irq subsystem does not fit the external interrupt model, and you'd
> definitely want to argue with Martin before suggesting to introduce
> the IRQ subsystem on s390. "Only over my dead body" was the last
> statement I do remember.

Read again what I wrote above. I'm suggesting to have just one external
interrupt for virtio and use the generic IRQ abstraction to handle
everything that comes below that.

> Plus I don't see a benefit from pretending to have an interrupt
> controller: virtio abstracts from this, and can well be implemented
> over extint and hypercall like Christian has done it. What's the
> problem you're trying to solve?

Sorry, I can't find Christian's code right now, do you have a pointer
to the patches?

I suspect that he has done exactly what I was trying to explain, except
that the implementation is not using the generic IRQ layer, which means
you're duplicating some of the code.