From 0f99ee2c7a58fc281c084d3acc0f0013bec7ec5a Mon Sep 17 00:00:00 2001 From: Ben Gardon Date: Tue, 2 Feb 2021 10:57:21 -0800 Subject: KVM: x86/mmu: Skip no-op changes in TDP MMU functions Skip setting SPTEs if no change is expected. Reviewed-by: Peter Feiner Signed-off-by: Ben Gardon Message-Id: <20210202185734.1680553-16-bgardon@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/tdp_mmu.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index c8a1149cb229..aeb05f626b55 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -888,7 +888,8 @@ static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, continue; if (!is_shadow_present_pte(iter.old_spte) || - !is_last_spte(iter.old_spte, iter.level)) + !is_last_spte(iter.old_spte, iter.level) || + !(iter.old_spte & PT_WRITABLE_MASK)) continue; new_spte = iter.old_spte & ~PT_WRITABLE_MASK; @@ -1065,7 +1066,8 @@ static bool set_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, if (tdp_mmu_iter_cond_resched(kvm, &iter, false)) continue; - if (!is_shadow_present_pte(iter.old_spte)) + if (!is_shadow_present_pte(iter.old_spte) || + iter.old_spte & shadow_dirty_mask) continue; new_spte = iter.old_spte | shadow_dirty_mask; -- cgit v1.2.3