[PATCH v8 01/69] arm64: Add ARM64_HAS_NESTED_VIRT cpufeature

[Oliver Upton]

On Tue, Jan 31, 2023 at 05:34:39PM +0000, Suzuki K Poulose wrote:
> On 31/01/2023 14:00, Marc Zyngier wrote:

[...]

> > What is exactly the objection here? NV is more or less a VHE++ mode,
> > but is also completely experimental and incomplete.
> 
> I am all in for making this an "optional", only enabled it when "I know
> what I want".
> 
> kvm-arm.mode=nv kind of seems that the KVM driver is conditioned
> mainly for running NV (comparing with the other existing options
> for kvm-arm.mode).
> 
> In reality, as you confirmed, NV is an *additional* capability
> of a VHE hypervisor. So it would be good to "opt" in for "nv" capability
> support.
> 
> e.g,
> 
>    kvm-arm.nv=on
> 
> Thinking more about it, either is fine.

Marc, I'm curious, how do you plan to glue hVHE + NV together (if at
all)? We may need two separate options for this so the user could
separately configure NV for their hVHE KVM instance.

-- 
Thanks,
Oliver