On Mon, 2024-10-21 at 16:35 +0800, Xiaoyao Li wrote: > > > > How about adding it to the docs? > > OK for me. Can you propose something? > > > > > > > It's architectural valid that userspace VMM creates a TD with legacy > > > topology, i.e., topology enumerated via CPUID 0x1 and 0x4. > > > > > > > In that case, do you see a need for the vanilla tdh_vp_init() SEAMCALL > > > > wrapper? > > > > > > > > The TDX module version we need already supports enum_topology, so the > > > > code: > > > > if (modinfo->tdx_features0 & > > > > MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM) > > > > err = tdh_vp_init_apicid(tdx, vcpu_rcx, vcpu->vcpu_id); > > > > else > > > > err = tdh_vp_init(tdx, vcpu_rcx); > > > > > > > > The tdh_vp_init() branch shouldn't be hit. > > > > > > We cannot know what version of TDX module user might use thus we cannot > > > assume enum_topology is always there unless we make it a hard > > > requirement in KVM that TDX fails being enabled when > > > > > > !(modinfo->tdx_features0 & MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM) > > > > We will depend on bugs that are fixed in TDX Modules after enum topology, so > > it > > shouldn't be required in the normal case. So I think it would be simpler to > > add > > this tdx_features0 conditional. We can then export one less SEAMCALL and > > will > > have less configurations flows to worry about on the KVM side. > > I'm a little bit confused. what does "add this tdx_feature0 conditional" > mean? I was talking about your suggestion to check for MD_FIELD_ID_FEATURES0_TOPOLOGY_ENUM.
