Skip setting SPTEs if no change is expected. Reviewed-by: Peter Feiner <pfeiner@xxxxxxxxxx> Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx> --- v1 -> v2 - Merged no-op checks into exiting old_spte check arch/x86/kvm/mmu/tdp_mmu.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) 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; -- 2.30.0.365.g02bc693789-goog
