Re: [RFC PATCH 04/21] KVM: TDX: Enforce 4KB mapping level during TD build Time

[Yan Zhao]

On Thu, Apr 24, 2025 at 10:55:53AM +0300, Kirill A. Shutemov wrote:
> On Thu, Apr 24, 2025 at 11:05:00AM +0800, Yan Zhao wrote:
> > During the TD build phase (i.e., before the TD becomes RUNNABLE), enforce a
> > 4KB mapping level both in the S-EPT managed by the TDX module and the
> > mirror page table managed by KVM.
> > 
> > During this phase, TD's memory is added via tdh_mem_page_add(), which only
> > accepts 4KB granularity. Therefore, return PG_LEVEL_4K in TDX's
> > .private_max_mapping_level hook to ensure KVM maps at the 4KB level in the
> > mirror page table. Meanwhile, iterate over each 4KB page of a large gmem
> > backend page in tdx_gmem_post_populate() and invoke tdh_mem_page_add() to
> > map at the 4KB level in the S-EPT.
> > 
> > Still allow huge pages in gmem backend during TD build time. Based on [1],
> > which gmem series allows 2MB TPH and non-in-place conversion, pass in
> 
> s/TPH/THP/
Right. Thanks!