From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67DCEC31E5B for ; Tue, 18 Jun 2019 22:52:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 466232082C for ; Tue, 18 Jun 2019 22:52:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731220AbfFRWwc (ORCPT ); Tue, 18 Jun 2019 18:52:32 -0400 Received: from mga05.intel.com ([192.55.52.43]:51708 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730853AbfFRWvN (ORCPT ); Tue, 18 Jun 2019 18:51:13 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Jun 2019 15:51:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,390,1557212400"; d="scan'208";a="358009377" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by fmsmga005.fm.intel.com with ESMTP; 18 Jun 2019 15:51:12 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "H Peter Anvin" , "Peter Zijlstra" , "Andrew Morton" , "Dave Hansen" , "Paolo Bonzini" , "Radim Krcmar" , "Christopherson Sean J" , "Ashok Raj" , "Tony Luck" , "Dan Williams" , "Xiaoyao Li " , "Sai Praneeth Prakhya" , "Ravi V Shankar" Cc: "linux-kernel" , "x86" , kvm@vger.kernel.org, Fenghua Yu Subject: [PATCH v9 12/17] x86/split_lock: Enable split lock detection by default Date: Tue, 18 Jun 2019 15:41:14 -0700 Message-Id: <1560897679-228028-13-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1560897679-228028-1-git-send-email-fenghua.yu@intel.com> References: <1560897679-228028-1-git-send-email-fenghua.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A split locked access locks bus and degrades overall memory access performance. When split lock detection feature is enumerated, enable the feature by default by writing 1 to bit 29 in MSR TEST_CTL to find any split lock issue. Signed-off-by: Fenghua Yu --- arch/x86/kernel/cpu/intel.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 16cf1631b7f9..4ccd890a45b0 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -627,6 +627,13 @@ static void init_intel_misc_features(struct cpuinfo_x86 *c) wrmsrl(MSR_MISC_FEATURES_ENABLES, msr); } +static void split_lock_update_msr(void) +{ + /* Enable split lock detection */ + this_cpu_or(msr_test_ctl_cached, MSR_TEST_CTL_SPLIT_LOCK_DETECT); + wrmsrl(MSR_TEST_CTL, this_cpu_read(msr_test_ctl_cached)); +} + static void split_lock_init(struct cpuinfo_x86 *c) { if (cpu_has(c, X86_FEATURE_SPLIT_LOCK_DETECT)) { @@ -635,6 +642,8 @@ static void split_lock_init(struct cpuinfo_x86 *c) /* Cache MSR TEST_CTL */ rdmsrl(MSR_TEST_CTL, test_ctl_val); this_cpu_write(msr_test_ctl_cached, test_ctl_val); + + split_lock_update_msr(); } } @@ -1012,9 +1021,13 @@ static const struct cpu_dev intel_cpu_dev = { cpu_dev_register(intel_cpu_dev); +#undef pr_fmt +#define pr_fmt(fmt) "x86/split lock detection: " fmt + static void __init split_lock_setup(void) { setup_force_cpu_cap(X86_FEATURE_SPLIT_LOCK_DETECT); + pr_info("enabled\n"); } void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) -- 2.19.1