Re: [RFC PATCH 3/4] KVM: TDX: Exit to userspace for GetTdVmCallInfo

[Edgecombe, Rick P]

On Wed, 2025-06-11 at 22:34 +0800, Xiaoyao Li wrote:
> > What is the problem with using the existing exit opt-in interface?
> 
> It mixes up common KVM defined hypercall leafs (KVM_HC_*) with TDX 
> specific TDVMCALL leafs. Surely it can work but it just doesn't look 
> clean to me.

 - TDVMCallInfo is used to expose which TDVMCalls are expose to the guest
(clean)
 - KVM HC opt-in is used to expose which exits KVM should fwd to userspace
(seems clean to me)

There is an asymmetry in that what is returned in TDVMCallInfo can't be blindly
dumped into a KVM opt-in interface. But the logic matching TDVMCallInfo leaf <->
KVM HC needs to be somewhere. The default place should be userspace.

Did I miss anything?