Re: [RFC PATCH v2 12/23] KVM: x86/mmu: Introduce kvm_split_cross_boundary_leafs()

[Huang, Kai]

On Thu, 2025-11-13 at 11:02 +0000, Huang, Kai wrote:
> I am thinking dropping both "Hunk 1" and "Hunk 3".  This at least makes
> kvm_split_cross_boundary_leafs() more reasonable, IMHO.
> 
> Something like below:
> 
> @@ -1558,7 +1558,9 @@ static int tdp_mmu_split_huge_page(struct kvm *kvm, struct
> tdp_iter *iter,
>  static int tdp_mmu_split_huge_pages_root(struct kvm *kvm,
>                                          struct kvm_mmu_page *root,
>                                          gfn_t start, gfn_t end,
> -                                        int target_level, bool shared)
> +                                        int target_level, bool shared,
> +                                        bool only_cross_boundary,
> +                                        bool *split)
>  {
>         struct kvm_mmu_page *sp = NULL;
>         struct tdp_iter iter;
> @@ -1584,6 +1586,9 @@ static int tdp_mmu_split_huge_pages_root(struct kvm *kvm,
>                 if (!is_shadow_present_pte(iter.old_spte) ||
> !is_large_pte(iter.old_spte))
>                         continue;
>  
> +               if (only_cross_boundary && !iter_cross_boundary(&iter, start,
> end))
> +                       continue;
> +
>                 if (!sp) {
>                         rcu_read_unlock();
>  
> @@ -1618,6 +1623,7 @@ static int tdp_mmu_split_huge_pages_root(struct kvm *kvm,
>                         goto retry;
>  
>                 sp = NULL;
> +               *split = true;
>         }

Forgot to say, if needed, we can update @split only when it is a valid pointer:

		if (split)
			*split = true;

This allows the caller to be able to just pass NULL when it doesn't care about
whether split has been done.