From: Ben Gardon <bgardon@google.com>
Date: Tue, 2 Feb 2021 18:57:10 +0000 (-0800)
Subject: KVM: x86/mmu: Don't redundantly clear TDP MMU pt memory
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=734e45b329d626d2c14e2bcf8be3d069a33c3316;p=uclinux-h8%2Flinux.git

KVM: x86/mmu: Don't redundantly clear TDP MMU pt memory

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>
---

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 05e6e2c4554f..810de3280b97 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -655,7 +655,6 @@ 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);