Re: KVM NV + SVE host OS warning

[Marc Zyngier <maz@kernel.org>]

On Thu, 09 Oct 2025 15:41:28 +0100,
Jan Kotas <jank@cadence.com> wrote:
> 
> > On 9 Oct 2025, at 14:22, Marc Zyngier <maz@kernel.org> wrote:
> > 
> > As an alternative, and in an effort to keep at least VHE guests
> > running on V2 (and other machines suffering from the same situation),
> > I have posted a potential workaround at [1] for the guest to reliably
> > detect the situation.
> > 
> > Could you please test it with your setup and report whether this
> > allows you to boot a VHE guest? You will need to patch the guest.
> > 
> > Note that this still won't let you recursively virtualise EL2 (the HW
> > can do it, but KVM in the guest doesn't know it), but that's better
> > than nothing.
> 
> Thanks Marc,
> I tried it in my Guest, on top of 6.17.0. It seems to be working.
> 
> 
> Without HAS_EL2_E2H0:
> CPU features: detected: Virtualization Host Extensions
> CPU: All CPU(s) started at EL2
> kvm [1]: VHE mode initialized successfully
> 
> 
> With HAS_EL2_E2H0:
> CPU: All CPU(s) started at EL2
> kvm [1]: Hyp nVHE mode initialized successfully
> 
> In both cases SVE is also initialized properly.

Great. Would you mind replying to the patch with a Tested-by: tag?

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.