Re: [PATCH 09/17] KVM: TDX: Add helper to handle mapping leaf SPTE into S-EPT

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

On Fri, Mar 27, 2026 at 01:14:13PM -0700, Rick Edgecombe wrote:
> From: Sean Christopherson <seanjc@google.com>
> 
> Add a helper, tdx_sept_map_leaf_spte(), to wrap and isolate PAGE.ADD and
> PAGE.AUG operations, and thus complete tdx_sept_set_private_spte()'s
> transition into a "dispatch" routine for setting/writing S-EPT entries.
> 
> No functional change intended.
> 
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
> ---
>  arch/x86/kvm/vmx/tdx.c | 21 +++++++++++++--------
>  1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index 92a846b91bac..361a75b42ae7 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -1689,18 +1689,12 @@ static int tdx_sept_link_private_spt(struct kvm *kvm, gfn_t gfn,
>  	return 0;
>  }
>  
> -static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn,
> -				     enum pg_level level, u64 mirror_spte)
> +static int tdx_sept_map_leaf_spte(struct kvm *kvm, gfn_t gfn, enum pg_level level,
> +				  u64 mirror_spte)
>  {
>  	struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
>  	kvm_pfn_t pfn = spte_to_pfn(mirror_spte);
>  
> -	if (KVM_BUG_ON(!is_shadow_present_pte(mirror_spte), kvm))
> -		return -EIO;
> -
> -	if (!is_last_spte(mirror_spte, level))
> -		return tdx_sept_link_private_spt(kvm, gfn, level, mirror_spte);
> -
>  	/* TODO: handle large pages. */
>  	if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm))
>  		return -EIO;
> @@ -1725,7 +1719,18 @@ static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn,
>  	return tdx_mem_page_aug(kvm, gfn, level, pfn);
>  }
>  
> +static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn,
> +				     enum pg_level level, u64 mirror_spte)
> +{
>  
> +	if (KVM_BUG_ON(!is_shadow_present_pte(mirror_spte), kvm))
> +		return -EIO;
> +
> +	if (!is_last_spte(mirror_spte, level))
> +		return tdx_sept_link_private_spt(kvm, gfn, level, mirror_spte);
For symmetry, what about renaming tdx_sept_link_private_spt() to
tdx_sept_map_nonleaf_spte()?

> +
> +	return tdx_sept_map_leaf_spte(kvm, gfn, level, mirror_spte);
> +}
>  
>  /*
>   * Ensure shared and private EPTs to be flushed on all vCPUs.
> -- 
> 2.53.0
>