Commit 51150c84 authored by Ben Gardon's avatar Ben Gardon Committed by Yu Zhang
Browse files

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

mainline inclusion
from mainline-v5.12-rc1
commit 734e45b3
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I7S3VQ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=734e45b329d626d2c14e2bcf8be3d069a33c3316



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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: default avatarPeter Feiner <pfeiner@google.com>
Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarBen Gardon <bgardon@google.com>
Message-Id: <20210202185734.1680553-5-bgardon@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarYu Zhang <yu.c.zhang@linux.intel.com>
parent 24e85ab6

arch/x86/kvm/mmu/tdp_mmu.c

+0 −1
Original line number Diff line number Diff line
@@ -657,7 +657,6 @@ 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);