Re: [PATCH v19 037/130] KVM: TDX: Make KVM_CAP_MAX_VCPUS backend specific

[Huang, Kai]

> > Currently, the KVM x86 always reports KVM_MAX_VCPUS for all VMs but doesn't
> > allow to enable KVM_CAP_MAX_VCPUS to configure the number of maximum vcpus
>                                                       maximum number of vcpus
> > on VM-basis.
> >
> > Add "per-VM maximum vcpus" to KVM x86/TDX to accommodate TDX's needs.
> >
> > The userspace-configured value then can be verified when KVM is actually
>                                               used
> > creating the TDX guest.
> > "

I think we still have two options regarding to how 'max_vcpus' is 
handled in ioctl() to do TDH.MNG.INIT:

1) Just use the 'max_vcpus' done in KVM_ENABLE_CAP(KVM_CAP_MAX_VCPUS),
2) Still pass the 'max_vcpus' as input, but KVM verifies it against the 
value that is saved in KVM_ENABLE_CAP(KVM_CAP_MAX_VCPUS).

2) seems unnecessary, so I don't have objection to use 1).  But it seems 
we could still mention it in the changelog in that patch?