Re: [PATCH 1/9] KVM: x86/mmu: Use SHADOW_NONPRESENT_VALUE for atomic zap in TDP MMU

From: Huang, Kai
Date: Mon May 20 2024 - 08:38:35 EST


On Fri, 2024-05-17 at 17:04 -0700, Sean Christopherson wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> Use SHADOW_NONPRESENT_VALUE when zapping TDP MMU SPTEs with mmu_lock held
> for read, tdp_mmu_zap_spte_atomic() was simply missed during the initial
> development.
>
> Fixes: 7f01cab84928 ("KVM: x86/mmu: Allow non-zero value for non-present SPTE and removed SPTE")
> Not-yet-signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> [sean: write changelog]
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index 1259dd63defc..36539c1b36cd 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -626,7 +626,7 @@ static inline int tdp_mmu_zap_spte_atomic(struct kvm *kvm,
> * SPTEs.
> */
> handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte,
> - 0, iter->level, true);
> + SHADOW_NONPRESENT_VALUE, iter->level, true);
>
> return 0;
> }

Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx>