[v2,10/28] KVM: x86/mmu: Fix TDP MMU zap collapsible SPTEs
diff mbox series

Message ID 20210202185734.1680553-11-bgardon@google.com
State New, archived
Headers show
Series
  • Allow parallel MMU operations with TDP MMU
Related show

Commit Message

Ben Gardon Feb. 2, 2021, 6:57 p.m. UTC
There is a bug in the TDP MMU function to zap SPTEs which could be
replaced with a larger mapping which prevents the function from doing
anything. Fix this by correctly zapping the last level SPTEs.

Fixes: 14881998566d ("kvm: x86/mmu: Support disabling dirty logging for the tdp MMU")
Signed-off-by: Ben Gardon <bgardon@google.com>
---
 arch/x86/kvm/mmu/tdp_mmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Paolo Bonzini Feb. 3, 2021, 9:43 a.m. UTC | #1
On 02/02/21 19:57, Ben Gardon wrote:
> There is a bug in the TDP MMU function to zap SPTEs which could be
> replaced with a larger mapping which prevents the function from doing
> anything. Fix this by correctly zapping the last level SPTEs.
> 
> Fixes: 14881998566d ("kvm: x86/mmu: Support disabling dirty logging for the tdp MMU")
> Signed-off-by: Ben Gardon <bgardon@google.com>
> ---
>   arch/x86/kvm/mmu/tdp_mmu.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index c3075fb568eb..e3066d08c1dc 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -1098,8 +1098,8 @@ bool kvm_tdp_mmu_slot_set_dirty(struct kvm *kvm, struct kvm_memory_slot *slot)
>   }
>   
>   /*
> - * Clear non-leaf entries (and free associated page tables) which could
> - * be replaced by large mappings, for GFNs within the slot.
> + * Clear leaf entries which could be replaced by large mappings, for
> + * GFNs within the slot.
>    */
>   static void zap_collapsible_spte_range(struct kvm *kvm,
>   				       struct kvm_mmu_page *root,
> @@ -1111,7 +1111,7 @@ static void zap_collapsible_spte_range(struct kvm *kvm,
>   
>   	tdp_root_for_each_pte(iter, root, start, end) {
>   		if (!is_shadow_present_pte(iter.old_spte) ||
> -		    is_last_spte(iter.old_spte, iter.level))
> +		    !is_last_spte(iter.old_spte, iter.level))
>   			continue;
>   
>   		pfn = spte_to_pfn(iter.old_spte);
> 

Queued for 5.11-rc, thanks.

Paolo

Patch
diff mbox series

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index c3075fb568eb..e3066d08c1dc 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1098,8 +1098,8 @@  bool kvm_tdp_mmu_slot_set_dirty(struct kvm *kvm, struct kvm_memory_slot *slot)
 }
 
 /*
- * Clear non-leaf entries (and free associated page tables) which could
- * be replaced by large mappings, for GFNs within the slot.
+ * Clear leaf entries which could be replaced by large mappings, for
+ * GFNs within the slot.
  */
 static void zap_collapsible_spte_range(struct kvm *kvm,
 				       struct kvm_mmu_page *root,
@@ -1111,7 +1111,7 @@  static void zap_collapsible_spte_range(struct kvm *kvm,
 
 	tdp_root_for_each_pte(iter, root, start, end) {
 		if (!is_shadow_present_pte(iter.old_spte) ||
-		    is_last_spte(iter.old_spte, iter.level))
+		    !is_last_spte(iter.old_spte, iter.level))
 			continue;
 
 		pfn = spte_to_pfn(iter.old_spte);