Re: [RFC PATCH 03/21] x86/virt/tdx: Add SEAMCALL wrapper tdh_mem_page_demote()

[Yan Zhao]

On Fri, Apr 25, 2025 at 03:12:32PM +0800, Binbin Wu wrote:
> 
> 
> On 4/24/2025 11:04 AM, Yan Zhao wrote:
> > From: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> > 
> > Add a wrapper tdh_mem_page_demote() to invoke SEAMCALL TDH_MEM_PAGE_DEMOTE
> > to demote a huge leaf entry to a non-leaf entry in S-EPT. Currently, the
> > TDX module only supports demotion of a 2M huge leaf entry. After a
> > successful demotion, the old 2M huge leaf entry in S-EPT is replaced with a
> > non-leaf entry, linking to the newly-added page table page. The newly
> > linked page table page then contains 512 leaf entries, pointing to the 2M
> 
> 2M or 4K?
The 512 leaf entries point to 2M guest private pages together, each pointing to
4K.

> > guest private pages.