Re: [Qemu-devel] RFC: ioapic polarity vs. qemu os-x guest

[Gabriel L. Somlo]

On Mon, Feb 17, 2014 at 02:38:09PM -0500, Gabriel L. Somlo wrote:
> Oh, I think I'm starting to comprehend the problem here. The bits of
> "*irq_state" are indexed by "irq_source_id", which is dynamically
> assigned by kvm_request_irq_source_id().
> 
> So, doing the OR thing when assuming always-active-high makes
> sense. Doing AND based on an active-low assumption doesn't make
> sense, because there could ALWAYS be 0 bits that just weren't
> allocated (yet), and I'm having trouble imagining how I'd keep
> track of where the current allocation boundary is in a sane way :)

Hmm, I thought maybe I could use kvm->arch.irq_sources_bitmap, but
that's global across the whole VM, whereas irq_state belongs to
one given GSI. So, the per-GSI bitmap is sparse, so it's at least
as bad as I thought earlier, if not worse :)

Am I missing anything that would put this in a better light ?

Thanks,
--Gabriel