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KVM: x86/mmu: Check every prev_roots in __kvm_mmu_free_obsolete_roots()

Message ID 20220523010948.2018342-1-shaoqin.huang@intel.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86/mmu: Check every prev_roots in __kvm_mmu_free_obsolete_roots() | expand

Commit Message

Huang, Shaoqin May 23, 2022, 1:09 a.m. UTC
From: Shaoqin Huang <shaoqin.huang@intel.com>

Iterate every prev_roots and only zap obsoleted roots.

Signed-off-by: Shaoqin Huang <shaoqin.huang@intel.com>
---
 arch/x86/kvm/mmu/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Sean Christopherson May 23, 2022, 4:17 p.m. UTC | #1
On Sun, May 22, 2022, shaoqin.huang@intel.com wrote:
> From: Shaoqin Huang <shaoqin.huang@intel.com>
> 
> Iterate every prev_roots and only zap obsoleted roots.

Better would be something like:

  When freeing obsolete previous roots, check prev_roots as intended, not
  the current root.

Ugh, my bad.  This escaped into v5.18 :-(

Fixes: 527d5cd7eece ("KVM: x86/mmu: Zap only obsolete roots if a root shadow page is zapped")
Cc: stable@vger.kernel.org

> 
> Signed-off-by: Shaoqin Huang <shaoqin.huang@intel.com>
> ---
>  arch/x86/kvm/mmu/mmu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 45e1573f8f1d..22803916a609 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5168,7 +5168,7 @@ static void __kvm_mmu_free_obsolete_roots(struct kvm *kvm, struct kvm_mmu *mmu)
>  		roots_to_free |= KVM_MMU_ROOT_CURRENT;
>  
>  	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
> -		if (is_obsolete_root(kvm, mmu->root.hpa))
> +		if (is_obsolete_root(kvm, mmu->prev_roots.hpa))

My version is bad, but at least it compiles ;-)

arch/x86/kvm/mmu/mmu.c: In function ‘__kvm_mmu_free_obsolete_roots’:
arch/x86/kvm/mmu/mmu.c:5182:58: error: ‘(struct kvm_mmu_root_info *)&mmu->prev_roots’ is a pointer; did you mean to use ‘->’?
 5182 |                 if (is_obsolete_root(kvm, mmu->prev_roots.hpa))
      |                                                          ^
      |                                                          ->


		if (is_obsolete_root(kvm, mmu->prev_roots[i].hpa))
		
>  			roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
>  	}
>  
> -- 
> 2.30.2
>
diff mbox series

Patch

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 45e1573f8f1d..22803916a609 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5168,7 +5168,7 @@  static void __kvm_mmu_free_obsolete_roots(struct kvm *kvm, struct kvm_mmu *mmu)
 		roots_to_free |= KVM_MMU_ROOT_CURRENT;
 
 	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
-		if (is_obsolete_root(kvm, mmu->root.hpa))
+		if (is_obsolete_root(kvm, mmu->prev_roots.hpa))
 			roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
 	}