[PATCH v8 02/11] KVM: arm64: Document KVM_ARM_GET_REG_WRITABLE_MASKS

[Cornelia Huck]

On Thu, Aug 17 2023, Marc Zyngier <maz at kernel.org> wrote:

> On Thu, 17 Aug 2023 09:16:56 +0100,
> Cornelia Huck <cohuck at redhat.com> wrote:
>> 
>> On Mon, Aug 14 2023, Jing Zhang <jingzhangos at google.com> wrote:
>> 
>> > Maybe it'd be better to leave this to whenever we do need to add other
>> > range support?
>> 
>> My point is: How does userspace figure out if the kernel that is running
>> supports ranges other than id regs? If this is just an insurance against
>> changes that might arrive or not, we can live with the awkward "just try
>> it out" approach; if we think it's likely that we'll need to extend it,
>> we need to add the mechanism for userspace to find out about it now, or
>> it would need to probe for presence of the mechanism...
>
> Agreed. Nothing like the present to address this sort of things. it
> really doesn't cost much, and I'd rather have it right now.
>
> Here's a vague attempt at an advertising mechanism. If people are OK
> with it, I can stash that on top of Jing's series.

I think that looks reasonable.