2022-06-06 10:21:44

by Huang, Shaoqin

Subject: [PATCH v2] KVM: x86/mmu: Check every prev_roots in __kvm_mmu_free_obsolete_roots()

From: Shaoqin Huang <[email protected]>

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

Signed-off-by: Shaoqin Huang <[email protected]>
Fixes: 527d5cd7eece ("KVM: x86/mmu: Zap only obsolete roots if a root shadow page is zapped")
---
Changes in v2:
- Make the commit message more clearer.
- Fixed the missing idx.

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 f4653688fa6d..e826ee9138fa 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5179,7 +5179,7 @@ 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[i].hpa))
roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
}

--
2.30.2

2022-06-06 17:11:41

by Sean Christopherson

Subject: Re: [PATCH v2] KVM: x86/mmu: Check every prev_roots in __kvm_mmu_free_obsolete_roots()

On Mon, Jun 06, 2022, [email protected] wrote:
> From: Shaoqin Huang <[email protected]>
>
> When freeing obsolete previous roots, check prev_roots as intended, not
> the current root.
>
> Signed-off-by: Shaoqin Huang <[email protected]>
> Fixes: 527d5cd7eece ("KVM: x86/mmu: Zap only obsolete roots if a root shadow page is zapped")

Because KVM patches aren't guaranteed to be backported without it (though it's
"only" v5.18 that's affected), this needs:

Cc: [email protected]

Reviewed-by: Sean Christopherson <[email protected]>

2022-06-08 04:21:41

by Huang, Shaoqin

Subject: Re: [PATCH v2] KVM: x86/mmu: Check every prev_roots in __kvm_mmu_free_obsolete_roots()

Thanks Sean!

On 6/7/2022 12:56 AM, Sean Christopherson wrote:
> On Mon, Jun 06, 2022, [email protected] wrote:
>> From: Shaoqin Huang <[email protected]>
>>
>> When freeing obsolete previous roots, check prev_roots as intended, not
>> the current root.
>>
>> Signed-off-by: Shaoqin Huang <[email protected]>
>> Fixes: 527d5cd7eece ("KVM: x86/mmu: Zap only obsolete roots if a root shadow page is zapped")
>
> Because KVM patches aren't guaranteed to be backported without it (though it's
> "only" v5.18 that's affected), this needs:
>
> Cc: [email protected]
>
> Reviewed-by: Sean Christopherson <[email protected]>

2022-06-08 05:24:45

by Paolo Bonzini

Subject: Re: [PATCH v2] KVM: x86/mmu: Check every prev_roots in __kvm_mmu_free_obsolete_roots()

On 6/7/22 02:59, [email protected] wrote:
> From: Shaoqin Huang <[email protected]>
>
> When freeing obsolete previous roots, check prev_roots as intended, not
> the current root.
>
> Signed-off-by: Shaoqin Huang <[email protected]>
> Fixes: 527d5cd7eece ("KVM: x86/mmu: Zap only obsolete roots if a root shadow page is zapped")
> ---
> Changes in v2:
> - Make the commit message more clearer.
> - Fixed the missing idx.
>
> 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 f4653688fa6d..e826ee9138fa 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5179,7 +5179,7 @@ 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[i].hpa))
> roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
> }
>

Queued, thanks.

Paolo