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

Binbin Wu
2024-04-17T06:17:03Z

On 4/4/2024 9:27 AM, Isaku Yamahata wrote:
> On Tue, Apr 02, 2024 at 04:52:46PM +0800,
> Chao Gao <chao.gao@intel.com> 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.
>>