Re: [RFC PATCH 02/12] KVM: x86/mmu: Add dedicated API to map guest_memfd pfn into TDP MMU

["Edgecombe, Rick P" <rick.p.edgecombe@intel.com>]

On Wed, 2025-08-27 at 16:25 +0800, Yan Zhao wrote:
> > +{
> > +	struct kvm_page_fault fault = {
> > +		.addr = gfn_to_gpa(gfn),
> > +		.error_code = PFERR_GUEST_FINAL_MASK |
> > PFERR_PRIVATE_ACCESS,
> > +		.prefetch = true,
> > +		.is_tdp = true,
> > +		.nx_huge_page_workaround_enabled =
> > is_nx_huge_page_enabled(vcpu->kvm),
> > +
> > +		.max_level = KVM_MAX_HUGEPAGE_LEVEL,
> Looks the kvm_tdp_mmu_map_private_pfn() is only for initial memory mapping,
> given that ".prefetch = true" and RET_PF_SPURIOUS is not a valid return value.

Hmm, what are you referring to regarding RET_PF_SPURIOUS?

> 
> Then, what about setting
>                 .max_level = PG_LEVEL_4K,
> directly?
> 
> Otherwise, the "(KVM_BUG_ON(level != PG_LEVEL_4K, kvm)" would be triggered in
> tdx_sept_set_private_spte().

Yes this fails to boot a TD. With max_level = PG_LEVEL_4K it passes the full
tests. I don't think it's ideal to encode PAGE.ADD details here though.

But I'm not immediately clear what is going wrong. The old struct kvm_page_fault
looks pretty similar. Did you root cause it?