Re: [PATCH v19 105/130] KVM: TDX: handle KVM hypercall with TDG.VP.VMCALL

[Binbin Wu]

On 4/4/2024 9:27 AM, Isaku Yamahata wrote:
> On Tue, Apr 02, 2024 at 04:52:46PM +0800,
> Chao Gao <chao.gao@xxxxxxxxx> wrote:
>
> > > +static int tdx_emulate_vmcall(struct kvm_vcpu *vcpu)
> > > +{
> > > +	unsigned long nr, a0, a1, a2, a3, ret;
> > > +
> > do you need to emulate xen/hyper-v hypercalls here?
>
> No. kvm_emulate_hypercall() handles xen/hyper-v hypercalls,
> __kvm_emulate_hypercall() doesn't.
So for TDX, kvm doesn't support xen/hyper-v, right?

Then, should KVM_CAP_XEN_HVM and KVM_CAP_HYPERV be filtered out for TDX?

> > Nothing tells userspace that xen/hyper-v hypercalls are not supported and
> > so userspace may expose related CPUID leafs to TD guests.