On 10/31/2024 5:37 PM, Tony Lindgren wrote:
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()?
That one did relate to old module, the module that without TDX_CONFIG_FLAGS_MAXGPA_VIRT reported in tdx_feature0.
I will sent an follow up patch to complement the handling if TDX module supports TDX_CONFIG_FLAGS_MAXGPA_VIRT.
Regards, Tony
