Re: [PATCH] KVM: arm64: nv: Set ISTATUS for emulated timers, If timer expired

[Oliver Upton]

Hey,

On Fri, Feb 07, 2025 at 05:45:33PM +0000, Marc Zyngier wrote:
> I found at least one issue that could fail the migration. Before the
> VM starts running, we limit the feature set to the subset we actually
> support with NV.
> 
> By doing this, we also change the value of IDreg fields that are not
> writable, because they describe features that we don't support.
> Obviously, that fails on restore.
> 
> I need to have a think...

We spoke about this a while ago (and I forgot til now), but I was
wondering if we could use vCPU feature flags to describe NV, including
the selection between FEAT_E2H0 and FEAT_VHE.

I think this might match userspace expectations a bit more closely where
the state of the ID registers after init gives the actual feature set
supported by the VM.

-- 
Thanks,
Oliver