KVM: arm64: Reject non compliant SMCCC function calls in pKVM

KVM: arm64: Reject non compliant SMCCC function calls in pKVM

Prevent the propagation of a function-id that has the top bits set since
this is not compliant with the SMCCC spec and can overlap with the
already known function-id decoders. (eg. if we invoke an smc with
0xffffffffc4000012 it will be decoded as a PSCI reset call). Instead,
make it clear that we don't support it and return an error.

Signed-off-by: Sebastian Ene <sebastianene@google.com>
Link: https://patch.msgid.link/20260408114118.422604-1-sebastianene@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>