Re: [RFC PATCH] KVM: TDX: Decouple TDX init mem region from kvm_gmem_populate()

[Yan Zhao <yan.y.zhao@intel.com>]

On Mon, Jul 14, 2025 at 08:46:59AM -0700, Sean Christopherson wrote:
> > > 	folio = __kvm_gmem_get_pfn(file, slot, index, &pfn, &is_prepared, &max_order);
> > If max_order > 0 is returned, the next invocation of __kvm_gmem_populate() for
> > GFN+1 will return is_prepared == true.
> 
> I don't see any reason to try and make the current code truly work with hugepages.
> Unless I've misundertood where we stand, the correctness of hugepage support is
Hmm. I thought your stand was to address the AB-BA lock issue which will be
introduced by huge pages, so you moved the get_user_pages() from vendor code to
the common code in guest_memfd :)

> going to depend heavily on the implementation for preparedness.  I.e. trying to
> make this all work with per-folio granulartiy just isn't possible, no?
Ah. I understand now. You mean the right implementation of __kvm_gmem_get_pfn()
should return is_prepared at 4KB granularity rather than per-folio granularity.

So, huge pages still has dependency on the implementation for preparedness.


Will you post code [1][2] to fix non-hugepages first? Or can I pull them to use
as prerequisites for TDX huge page v2?

[1] https://lore.kernel.org/all/aG_pLUlHdYIZ2luh@google.com/
[2] https://lore.kernel.org/all/aHEwT4X0RcfZzHlt@google.com/

Thanks!