On Thu, Oct 31, 2024 at 05:23:57PM +0800, Xiaoyao Li wrote: > here it is to initialize the configurable CPUID bits that get reported to > userspace. Though TDX module doesn't allow them to be set in TD_PARAM for > KVM_TDX_INIT_VM, they get set to 0xff because KVM reuse these bits > EBX[23:16] as the interface for userspace to configure GPAW of TD guest > (implemented in setup_tdparams_eptp_controls() in patch 19). That's why they > need to be set as all-1 to allow userspace to configure. > > And the comment above it is wrong and vague. we need to change it to > something like > > /* > * Though TDX module doesn't allow the configuration of guest > * phys addr bits (EBX[23:16]), KVM uses it as the interface for > * userspace to configure the GPAW. So need to report these bits > * as configurable to userspace. > */ That sounds good to me. Hmm so care to check if we can also just leave out another "old module" comment in tdx_read_cpuid()? Regards, Tony