Re: [PATCH] Documentation: KVM: Fix the GICv5 KVM_IRQ_LINE PPI range

From: Marc Zyngier

Date: Thu Aug 20 2026 - 06:46:22 EST


On Sat, 15 Aug 2026 14:07:38 +0100,
Karl Mehltretter <kmehltretter@xxxxxxxxx> wrote:
>
> On Sat, Aug 15, 2026 at 11:57:24AM +0100, Marc Zyngier wrote:
> > > + in-kernel GICv5: PPI, irq_id between 0 and 63 (incl.), and
> >
> > No. Please understand the difference between *implementation* and
> > *architecture*.
>
> Got it. That distinction could perhaps be clearer in api.rst, but 0-127
> is intentional, not a missed doc update.

This is on purpose.

We are not going to go and update the documentation each time
something change in KVM (such as a new interrupt being controllable
from the VMM). So by describing everything in architectural terms and
giving the interfaces for userspace to introspect the implementation,
we avoid having to disclose all the decisions that we make when
implementing the hypervisor.

This is valid for the whole of KVM/arm64, not just the GIC, and
represent the intent of the ARM architecture.

Thanks,

M.

--
Jazz isn't dead. It just smells funny.