From patchwork Thu Dec 24 09:11:21 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 7915851 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 180F9BEEE5 for ; Thu, 24 Dec 2015 09:18:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6433E20601 for ; Thu, 24 Dec 2015 09:18:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F04F205FF for ; Thu, 24 Dec 2015 09:18:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932573AbbLXJSA (ORCPT ); Thu, 24 Dec 2015 04:18:00 -0500 Received: from mga09.intel.com ([134.134.136.24]:31153 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932259AbbLXJR5 (ORCPT ); Thu, 24 Dec 2015 04:17:57 -0500 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga102.jf.intel.com with ESMTP; 24 Dec 2015 01:17:56 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,473,1444719600"; d="scan'208,223";a="714012507" Received: from xiao.sh.intel.com ([10.239.159.82]) by orsmga003.jf.intel.com with ESMTP; 24 Dec 2015 01:17:54 -0800 Subject: Re: [PATCH v2 09/11] KVM: MMU: simplify mmu_need_write_protect To: Kai Huang , pbonzini@redhat.com References: <1450869954-30273-1-git-send-email-guangrong.xiao@linux.intel.com> <1450869954-30273-10-git-send-email-guangrong.xiao@linux.intel.com> <567BAE8E.6080400@linux.intel.com> Cc: gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, jike.song@intel.com From: Xiao Guangrong Message-ID: <567BB6B9.3000200@linux.intel.com> Date: Thu, 24 Dec 2015 17:11:21 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <567BAE8E.6080400@linux.intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, T_TVD_MIME_EPI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On 12/24/2015 04:36 PM, Kai Huang wrote: > > > On 12/23/2015 07:25 PM, Xiao Guangrong wrote: >> Now, all non-leaf shadow page are page tracked, if gfn is not tracked >> there is no non-leaf shadow page of gfn is existed, we can directly >> make the shadow page of gfn to unsync >> >> Signed-off-by: Xiao Guangrong >> --- >> arch/x86/kvm/mmu.c | 26 ++++++++------------------ >> 1 file changed, 8 insertions(+), 18 deletions(-) >> >> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c >> index 5a2ca73..f89e77f 100644 >> --- a/arch/x86/kvm/mmu.c >> +++ b/arch/x86/kvm/mmu.c >> @@ -2461,41 +2461,31 @@ static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) >> kvm_mmu_mark_parents_unsync(sp); >> } >> -static void kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn) >> +static bool kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn, >> + bool can_unsync) >> { >> struct kvm_mmu_page *s; >> for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) { >> + if (!can_unsync) >> + return true; >> + >> if (s->unsync) >> continue; >> WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL); >> __kvm_unsync_page(vcpu, s); >> } >> + >> + return false; >> } > I hate to say but it looks odd to me that kvm_unsync_pages takes a bool parameter called can_unsync, > and return a bool (which looks like suggesting whether the unsync has succeeded or not). How about > calling __kvm_unsync_pages directly in mmu_need_write_protect, and leave kvm_unsync_pages unchanged > (or even remove it as looks it is used nowhere else) ? But again it's to you and Paolo. > Make senses, the updated version is attached, count you review it? From a634f139dd9c8d0068f17b5c93cadcf979ac8acc Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Thu, 24 Dec 2015 17:03:04 +0800 Subject: [PATCH 09/11] KVM: MMU: simplify mmu_need_write_protect Now, all non-leaf shadow page are page tracked, if gfn is not tracked there is no non-leaf shadow page of gfn is existed, we can directly make the shadow page of gfn to unsync Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 29 +++++++---------------------- 1 file changed, 7 insertions(+), 22 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 5a2ca73..d6be758 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2452,7 +2452,7 @@ int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page); -static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) +static void kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) { trace_kvm_mmu_unsync_page(sp); ++vcpu->kvm->stat.mmu_unsync; @@ -2461,39 +2461,24 @@ static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) kvm_mmu_mark_parents_unsync(sp); } -static void kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn) -{ - struct kvm_mmu_page *s; - - for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) { - if (s->unsync) - continue; - WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL); - __kvm_unsync_page(vcpu, s); - } -} - static bool mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn, bool can_unsync) { - struct kvm_mmu_page *s; - bool need_unsync = false; + struct kvm_mmu_page *sp; if (kvm_page_track_check_mode(vcpu, gfn, KVM_PAGE_TRACK_WRITE)) return true; - for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) { + for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn) { if (!can_unsync) return true; - if (s->role.level != PT_PAGE_TABLE_LEVEL) - return true; + if (sp->unsync) + continue; - if (!s->unsync) - need_unsync = true; + WARN_ON(sp->role.level != PT_PAGE_TABLE_LEVEL); + kvm_unsync_page(vcpu, sp); } - if (need_unsync) - kvm_unsync_pages(vcpu, gfn); return false; } -- 1.8.3.1