From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752306AbbJSGAy (ORCPT ); Mon, 19 Oct 2015 02:00:54 -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 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 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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; -- 2.1.0