From patchwork Mon Oct 19 06:13:29 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takuya Yoshikawa X-Patchwork-Id: 7433391 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 2B4DDBEEA4 for ; Mon, 19 Oct 2015 06:01:18 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4B24520603 for ; Mon, 19 Oct 2015 06:01:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6FBAB205C2 for ; Mon, 19 Oct 2015 06:01:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752078AbbJSGAv (ORCPT ); Mon, 19 Oct 2015 02:00:51 -0400 Received: from tama500.ecl.ntt.co.jp ([129.60.39.148]:46349 "EHLO tama500.ecl.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751658AbbJSGAc (ORCPT ); Mon, 19 Oct 2015 02:00:32 -0400 Received: from vc1.ecl.ntt.co.jp (vc1.ecl.ntt.co.jp [129.60.86.153]) by tama500.ecl.ntt.co.jp (8.13.8/8.13.8) with ESMTP id t9J60Q3N003166; Mon, 19 Oct 2015 15:00:26 +0900 Received: from vc1.ecl.ntt.co.jp (localhost [127.0.0.1]) by vc1.ecl.ntt.co.jp (Postfix) with ESMTP id 20BD25F590; Mon, 19 Oct 2015 15:00:26 +0900 (JST) Received: from imail2.m.ecl.ntt.co.jp (imail2.m.ecl.ntt.co.jp [129.60.5.247]) by vc1.ecl.ntt.co.jp (Postfix) with ESMTP id 129CF5F58A; Mon, 19 Oct 2015 15:00:26 +0900 (JST) Received: from localhost.localdomain ([129.60.241.165]) by imail2.m.ecl.ntt.co.jp (8.13.8/8.13.8) with SMTP id t9J60PE0028618; Mon, 19 Oct 2015 15:00:26 +0900 Date: Mon, 19 Oct 2015 15:13:29 +0900 From: Takuya Yoshikawa To: pbonzini@redhat.com Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] KVM: x86: MMU: Initialize force_pt_level before calling mapping_level() Message-Id: <20151019151329.cf4b7cbbfe1fdb15bb756d93@lab.ntt.co.jp> X-Mailer: Sylpheed 3.4.2 (GTK+ 2.24.28; x86_64-redhat-linux-gnu) Mime-Version: 1.0 X-TM-AS-MML: disable 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, 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 Commit fd1369021878 ("KVM: x86: MMU: Move mapping_level_dirty_bitmap() call in mapping_level()") forgot to initialize force_pt_level to false in FNAME(page_fault)() before calling mapping_level() like nonpaging_map() does. This can sometimes result in forcing page table level mapping unnecessarily. Fix this and move the first *force_pt_level check in mapping_level() before kvm_vcpu_gfn_to_memslot() call to make it a bit clearer that the variable must be initialized before mapping_level() gets called. This change can also avoid calling kvm_vcpu_gfn_to_memslot() when !check_hugepage_cache_consistency() check in tdp_page_fault() forces page table level mapping. Signed-off-by: Takuya Yoshikawa --- arch/x86/kvm/mmu.c | 7 ++++--- arch/x86/kvm/paging_tmpl.h | 2 +- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index dd2a7c6..7d85bca 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -886,10 +886,11 @@ static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn, int host_level, level, max_level; struct kvm_memory_slot *slot; - slot = kvm_vcpu_gfn_to_memslot(vcpu, large_gfn); + if (unlikely(*force_pt_level)) + return PT_PAGE_TABLE_LEVEL; - if (likely(!*force_pt_level)) - *force_pt_level = !memslot_valid_for_gpte(slot, true); + slot = kvm_vcpu_gfn_to_memslot(vcpu, large_gfn); + *force_pt_level = !memslot_valid_for_gpte(slot, true); if (unlikely(*force_pt_level)) return PT_PAGE_TABLE_LEVEL; diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index bf39d0f..b41faa9 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -698,7 +698,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code, int r; pfn_t pfn; int level = PT_PAGE_TABLE_LEVEL; - bool force_pt_level; + bool force_pt_level = false; unsigned long mmu_seq; bool map_writable, is_self_change_mapping;