On Tue, 2024-05-14 at 17:59 -0700, Rick Edgecombe wrote:
> +static void handle_removed_private_spte(struct kvm *kvm, gfn_t gfn,
> + u64 old_spte, u64 new_spte,
> + int level)
> +{
> + bool was_present = is_shadow_present_pte(old_spte);
> + bool was_leaf = was_present && is_last_spte(old_spte, level);
> + kvm_pfn_t old_pfn = spte_to_pfn(old_spte);
> + int ret;
> +
> + /*
> + * Allow only leaf page to be zapped. Reclaim non-leaf page tables
> page
> + * at destroying VM.
> + */
> + if (!was_leaf)
> + return;
> +
> + /* Zapping leaf spte is allowed only when write lock is held. */
> + lockdep_assert_held_write(&kvm->mmu_lock);
> + ret = static_call(kvm_x86_zap_private_spte)(kvm, gfn, level);
> + /* Because write lock is held, operation should success. */
> + if (KVM_BUG_ON(ret, kvm))
> + return;
> +
> + ret = static_call(kvm_x86_remove_private_spte)(kvm, gfn, level,
> old_pfn);
I don't see why these (zap_private_spte and remove_private_spte) can't be a
single op. Was it to prepare for huge pages support or something? In the base
series they are both only called once.
> + KVM_BUG_ON(ret, kvm);
> +}
> +
