[RFC PATCH v2 0/9] KVM: Enable Nested Virt selftests

[Ganapatrao Kulkarni]

On 6/19/2025 5:15 PM, Marc Zyngier wrote:
>>   >
>>> Also, running EL2 is the least of our worries, because that's pretty
>>> easy to deal with. It is running at EL1/0 when EL2 is present that is
>>> interesting, and I see no coverage on that front.
>>
>> Sorry, I did not get this comment fully.
>> When we run selftest on Host with -g option, the guest code will run in vEL2 as L1.
>> This is implemented as per comment in V1.
>>
>> When we run same selftest from L1 shell, then guest_code will be running in EL0/1 like running from L0.
> 
> What good does this bring us if we need to boot a full guest OS to run
> tests? What we need is synthetic tests that implement the whole stack:
> 
> - L1 guest hypervisor
> - L2 guest hypervisor
> - L2 guest
> - L3 guest hypervisor
> - L3 guest
> - [...]

IIUC, selftest leverages host OS support and uses various IOCTLs to support the guest_code run. Are you saying to implement all this again (without OS help) in guest_code to run it as hypervisor and launch guest_code2 as NestedVM?. It seems to be complicated, doesn't it?

> 
> This is *one* test. Not a test that runs in a guest. That's what I've
> been asking since day one.
-- 
Thanks,
Gk