[EXTERNAL] Re: [PATCH v5 2/6] firmware: smccc: Detect hypervisor via RSI host call in CCA Realms

[Dexuan Cui]

> From: Catalin Marinas <catalin.marinas at arm.com>
> Sent: Monday, November 2, 2026 3:58 AM
> To: Dexuan Cui <DECUI at microsoft.com>
>  ...
> My point is not the RSI host call itself to query the UUID but what the
> Realm does afterwards. kvm_init_hyp_services() gets a positive answer
> for the KVM UUID and continues with an SMCCC 1.1 invocation to query the
> supported KVM features. The latter is not an RSI host call but an
> ordinary SMC call, to which the RMM responds with -1 in res.a0 (all
> lower 32 bits set). So we end up treating KVM hyp services as available
> in a Realm but their calls still use the SMC conduit and are rejected by
> the RMM.
> ...
> Catalin

Thanks for the clarification! Now I understood this patch is incorrect
for a realm on KVM, and v6 is correct.

Thanks,
Dexuan