For TDX, there is an RFC relating to using descriptively
named parameters instead of register names for tdh_vp_enter():
https://lore.kernel.org/all/fa817f29-e3ba-4c54-8600-e28cf6ab1953@xxxxxxxxx/
Please do give some feedback on that approach. Note we
need both KVM and x86 maintainer approval for SEAMCALL
wrappers like tdh_vp_enter().
As proposed, that ends up with putting the values back into
vcpu->arch.regs[] for __kvm_emulate_hypercall() which is not
pretty: