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    Subject[PATCH 5.11 115/152] KVM: x86/mmu: Dont redundantly clear TDP MMU pt memory
    Date
    From: Ben Gardon <bgardon@google.com>

    [ Upstream commit 734e45b329d626d2c14e2bcf8be3d069a33c3316 ]

    The KVM MMU caches already guarantee that shadow page table memory will
    be zeroed, so there is no reason to re-zero the page in the TDP MMU page
    fault handler.

    No functional change intended.

    Reviewed-by: Peter Feiner <pfeiner@google.com>
    Reviewed-by: Sean Christopherson <seanjc@google.com>
    Acked-by: Paolo Bonzini <pbonzini@redhat.com>
    Signed-off-by: Ben Gardon <bgardon@google.com>
    Message-Id: <20210202185734.1680553-5-bgardon@google.com>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/x86/kvm/mmu/tdp_mmu.c | 1 -
    1 file changed, 1 deletion(-)

    diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
    index 6bd86bb4c089..4a2b8844f00f 100644
    --- a/arch/x86/kvm/mmu/tdp_mmu.c
    +++ b/arch/x86/kvm/mmu/tdp_mmu.c
    @@ -708,7 +708,6 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
    sp = alloc_tdp_mmu_page(vcpu, iter.gfn, iter.level);
    list_add(&sp->link, &vcpu->kvm->arch.tdp_mmu_pages);
    child_pt = sp->spt;
    - clear_page(child_pt);
    new_spte = make_nonleaf_spte(child_pt,
    !shadow_accessed_mask);

    --
    2.30.1


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