From patchwork Sun Mar 13 03:10:29 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "lan,Tianyu" X-Patchwork-Id: 8572861 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 AE1DEC0554 for ; Sun, 13 Mar 2016 03:28:54 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E50642017E for ; Sun, 13 Mar 2016 03:28:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E55F20303 for ; Sun, 13 Mar 2016 03:28:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753974AbcCMD1M (ORCPT ); Sat, 12 Mar 2016 22:27:12 -0500 Received: from mga11.intel.com ([192.55.52.93]:34125 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753936AbcCMD1D (ORCPT ); Sat, 12 Mar 2016 22:27:03 -0500 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP; 12 Mar 2016 19:27:03 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,328,1455004800"; d="scan'208";a="922777411" Received: from lantianyu-ws.sh.intel.com (HELO localhost) ([10.239.159.159]) by fmsmga001.fm.intel.com with ESMTP; 12 Mar 2016 19:27:01 -0800 From: Lan Tianyu To: gleb@kernel.org, pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, guangrong.xiao@linux.intel.com Cc: Lan Tianyu , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 6/7] KVM/x86: update the comment of memory barrier in the vcpu_enter_guest() Date: Sun, 13 Mar 2016 11:10:29 +0800 Message-Id: <1457838631-26775-7-git-send-email-tianyu.lan@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1457838631-26775-1-git-send-email-tianyu.lan@intel.com> References: <1457838631-26775-1-git-send-email-tianyu.lan@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, 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 The barrier also orders the write to mode from any reads to the page tables done and so update the comment. Signed-off-by: Lan Tianyu --- arch/x86/kvm/x86.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index bcbce0f..4bdb4e6 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6589,8 +6589,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); - /* We should set ->mode before check ->requests, - * see the comment in make_all_cpus_request. + /* + * We should set ->mode before check ->requests, + * Please see the comment in kvm_make_all_cpus_request. + * This also orders the write to mode from any reads + * to the page tables done while the VCPU is running. + * Please see the comment in kvm_flush_remote_tlbs. */ smp_mb__after_srcu_read_unlock();