On Tue, Feb 28, 2023 at 09:57:50PM +0000, "Huang, Kai" <kai.huang@xxxxxxxxx> wrote: > On Mon, 2023-02-27 at 13:26 -0800, Isaku Yamahata wrote: > > > > TDX attestation includes the maximum number of vcpu that the guest can > > > > accommodate. > > > > > > > > > > I don't understand why "attestation" is the reason here. Let's say TDX is > > > used > > > w/o attestation, I don't think this patch can be discarded? > > > > > > IMHO the true reason is TDX has it's own control of maximum number of vcpus, > > > i.e. asking you to specify the value when creating the TD. Therefore, the > > > constant KVM_MAX_VCPUS doesn't work for TDX guest anymore. > > > > Without TDX attestation, this can be discarded. The TD is created with > > max_vcpus=KVM_MAX_VCPUS by default. > > This parses like: > > If we have attestation, the TD can be created with a user-specified non-default > value. Otherwise, the TD is always created with default value. > > It doesn't make sense, right? > > Because architecturally whether TD can be created with a user specified value > doesn't depend on attestation at all. I'm not sure if I got your point. Even without attestation, it's allowed to specify max vcpus. Not "always". -- Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
