From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: [PATCH 2/2] KVM: MMU: optimize pte write path if don't have protected sp Date: Mon, 28 Mar 2011 10:30:42 +0800 Message-ID: <4D8FF2D2.9070109@cn.fujitsu.com> References: <4D8FF287.1040300@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , LKML , KVM To: Avi Kivity Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:54502 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753464Ab1C1C3u (ORCPT ); Sun, 27 Mar 2011 22:29:50 -0400 In-Reply-To: <4D8FF287.1040300@cn.fujitsu.com> Sender: kvm-owner@vger.kernel.org List-ID: Simplely return from kvm_mmu_pte_write path if no shadow page is write-protected, than we can avoid to walk all shadow pages and hold mmu-lock Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 2841805..ccac6c4 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3219,6 +3219,11 @@ static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn) set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte); } +static bool need_track_pte_changed(struct kvm_vcpu *vcpu) +{ + return !tdp_enabled || mmu_is_nested(vcpu); +} + void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, int bytes, bool guest_initiated) @@ -3233,6 +3238,9 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, int level, npte, invlpg_counter, r, flooded = 0; bool remote_flush, local_flush, zap_page; + if (!need_track_pte_changed(vcpu)) + return; + zap_page = remote_flush = local_flush = false; offset = offset_in_page(gpa); -- 1.7.4