linux-kernel - Re: [PATCH v2 0/2] KVM: x86/mmu: Fix a TDP MMU leak and optimize zap all

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Message-ID: <93efa388-ed99-f6b4-4a2b-352632aa8a18@redhat.com>
Date:   Fri, 13 Aug 2021 09:36:21 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Ben Gardon <bgardon@...gle.com>
Subject: Re: [PATCH v2 0/2] KVM: x86/mmu: Fix a TDP MMU leak and optimize zap
 all

On 12/08/21 20:14, Sean Christopherson wrote:
> Patch 1 fixes a leak of root-1 shadow pages, patch 2 is a minor
> optimization to the zap all flow that avoids re-reading and re-checking
> the root-1 SPTEs after they've been zapped by "zap all" flows.
> 
> I'm still somewhat on the fence for patch 2, feel free to drop it.
> 
> v2:
>   - Replaced magic number silliness with Paolo's much more clever suggestion.
>   - Elaborated on the benefits of the optimization.
>   - Add Ben's somewhat reluctant review for the optimization.
> 
> v1: https://lkml.kernel.org/r/20210812050717.3176478-1-seanjc@google.com
> 
> Sean Christopherson (2):
>    KVM: x86/mmu: Don't leak non-leaf SPTEs when zapping all SPTEs
>    KVM: x86/mmu: Don't step down in the TDP iterator when zapping all
>      SPTEs
> 
>   arch/x86/kvm/mmu/tdp_mmu.c | 35 ++++++++++++++++++++++++-----------
>   1 file changed, 24 insertions(+), 11 deletions(-)
> 

Queued, thanks.

Paolo