Re: [Intel-gfx] [PATCH v2 11/27] KVM: x86/mmu: Don't rely on page-track mechanism to flush on memslot change

[Yan Zhao]

On Fri, Mar 10, 2023 at 04:22:42PM -0800, Sean Christopherson wrote:
...
> -static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm,
> -                     struct kvm_memory_slot *slot,
> -                     struct kvm_page_track_notifier_node *node)
> -{
> -     kvm_mmu_zap_all_fast(kvm);
> -}
> -
>  int kvm_mmu_init_vm(struct kvm *kvm)
>  {
>       struct kvm_page_track_notifier_node *node = &kvm->arch.mmu_sp_tracker;
> @@ -6110,7 +6103,6 @@ int kvm_mmu_init_vm(struct kvm *kvm)
>       }
>  
>       node->track_write = kvm_mmu_pte_write;
> -     node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
>       kvm_page_track_register_notifier(kvm, node);
>  
>       kvm->arch.split_page_header_cache.kmem_cache = mmu_page_header_cache;
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index f706621c35b8..29dd6c97d145 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -12662,6 +12662,8 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm)
>  void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
>                                  struct kvm_memory_slot *slot)
>  {
> +     kvm_mmu_zap_all_fast(kvm);
Could we still call kvm_mmu_invalidate_zap_pages_in_memslot() here?
As I know, for TDX, its version of
kvm_mmu_invalidate_zap_pages_in_memslot() is like

static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm,
                        struct kvm_memory_slot *slot,
                        struct kvm_page_track_notifier_node *node)
{
        if (kvm_gfn_shared_mask(kvm))
                kvm_mmu_zap_memslot(kvm, slot);
        else
                kvm_mmu_zap_all_fast(kvm);
}

Maybe this kind of judegment is better to be confined in mmu.c?

Thanks
Yan

> +
>       kvm_page_track_flush_slot(kvm, slot);
>  }
>