[PATCH v2 3/4] KVM: arm64: Selftest for pKVM transitions

[Marc Zyngier]

On Tue, 25 Feb 2025 01:53:26 +0000,
Quentin Perret <qperret at google.com> wrote:
> 
> We have recently found a bug [1] in the pKVM memory ownership
> transitions by code inspection, but it could have been caught with a
> test.
> 
> Introduce a boot-time selftest exercising all the known pKVM memory
> transitions and importantly checks the rejection of illegal transitions.
> 
> The new test is hidden behind a new Kconfig option separate from
> CONFIG_EL2_NVHE_DEBUG on purpose as that has side effects on the
> transition checks ([1] doesn't reproduce with EL2 debug enabled).

That's a bit annoying, isn't it? Without EL2_DEBUG selected, you won't
get any stacktrace, and the WARN_ON()s are a guaranteed panic. Yes,
this is better than nothing, but I'm a bit worried this is going to be
hard to use.

Is there a way to reduce the impact the EL2 debug has on the rest of
the code? It feels like it is more invasive than it should be...

Thanks,

	M.

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