Re: [Android-virt] [PATCH v5 05/13] ARM: KVM: Inject IRQs and FIQs from userspace

[Avi Kivity <avi@redhat.com>]

On 12/12/2011 06:31 PM, Peter Maydell wrote:
> On 11 December 2011 23:01, Jan Kiszka <jan.kiszka@web.de> wrote:
> > Enabling in-kernel irqchips usually means "switching worlds". So the
> > semantics of these particular IRQ inject interface details may change
> > without breaking anything.
> >
> > However, things might look different if there will be a need to inject
> > also the CPU IRQs directly, not only the irqchip inputs. In that case,
> > it may make some sense to reserve more space for interrupt types than
> > just one bit and use a common encoding scheme.
>
> I think with an in-kernel GIC model you'd only need to be able to set
> one of the (256 including internal-to-the-CPU inputs) GIC input lines;
> the GIC itself then connects directly to the vcpu IRQ and FIQ.
>
> So we could just have different semantics for the ioctl in the 'kernel
> GIC model enabled' config, as you suggest.

btw, since we use the KVM_IRQ_LINE ioctl, it may make sense to require
KVM_CREATE_IRQCHIP.  To create a kernel GIC model, just call
KVM_CREATE_IRQCHIP with a different parameter.  This removes an "except
for ARM" from the documentation.

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