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_PASS,URIBL_BLOCKED, 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 51D47ECDE39 for ; Wed, 17 Oct 2018 18:32:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 26F8621476 for ; Wed, 17 Oct 2018 18:32:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 26F8621476 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728370AbeJRC3w (ORCPT ); Wed, 17 Oct 2018 22:29:52 -0400 Received: from mga12.intel.com ([192.55.52.136]:29659 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728348AbeJRC3w (ORCPT ); Wed, 17 Oct 2018 22:29:52 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Oct 2018 11:32:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,393,1534834800"; d="scan'208";a="82003891" Received: from skl-02.jf.intel.com ([10.54.74.62]) by orsmga007.jf.intel.com with ESMTP; 17 Oct 2018 11:32:56 -0700 From: Tim Chen To: Jiri Kosina , Thomas Gleixner Cc: Tim Chen , Tom Lendacky , Ingo Molnar , Peter Zijlstra , Josh Poimboeuf , Andrea Arcangeli , David Woodhouse , Andi Kleen , Dave Hansen , Casey Schaufler , Asit Mallick , Arjan van de Ven , Jon Masters , linux-kernel@vger.kernel.org, x86@kernel.org Subject: [Patch v3 05/13] x86/smt: Create cpu_smt_enabled static key for SMT specific code Date: Wed, 17 Oct 2018 10:59:33 -0700 Message-Id: X-Mailer: git-send-email 2.9.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Create the cpu_smt_enabled static key to indicate if we are using SMT. SMT specific code paths are executed only when SMT code paths are enabled by this key. Signed-off-by: Tim Chen --- arch/x86/kernel/cpu/bugs.c | 2 +- arch/x86/kvm/vmx.c | 2 +- include/linux/cpu.h | 1 + kernel/cpu.c | 12 ++++++++++-- 4 files changed, 13 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 6ed82ea..0338fa1 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -358,7 +358,7 @@ void arch_smt_update(void) mutex_lock(&spec_ctrl_mutex); mask = x86_spec_ctrl_base; - if (cpu_smt_control == CPU_SMT_ENABLED) + if (static_branch_likely(&cpu_smt_enabled)) mask |= SPEC_CTRL_STIBP; else mask &= ~SPEC_CTRL_STIBP; diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 533a327..8ec0ea3 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -11072,7 +11072,7 @@ static int vmx_vm_init(struct kvm *kvm) * Warn upon starting the first VM in a potentially * insecure environment. */ - if (cpu_smt_control == CPU_SMT_ENABLED) + if (static_branch_likely(&cpu_smt_enabled)) pr_warn_once(L1TF_MSG_SMT); if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER) pr_warn_once(L1TF_MSG_L1D); diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 218df7f..b54f085 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -188,5 +188,6 @@ static inline void cpu_smt_disable(bool force) { } static inline void cpu_smt_check_topology_early(void) { } static inline void cpu_smt_check_topology(void) { } #endif +DECLARE_STATIC_KEY_TRUE(cpu_smt_enabled); #endif /* _LINUX_CPU_H_ */ diff --git a/kernel/cpu.c b/kernel/cpu.c index 3adecda..ad28afc 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -349,6 +349,8 @@ EXPORT_SYMBOL_GPL(cpu_hotplug_enable); #ifdef CONFIG_HOTPLUG_SMT enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; EXPORT_SYMBOL_GPL(cpu_smt_control); +DEFINE_STATIC_KEY_TRUE(cpu_smt_enabled); +EXPORT_SYMBOL_GPL(cpu_smt_enabled); static bool cpu_smt_available __read_mostly; @@ -364,6 +366,7 @@ void __init cpu_smt_disable(bool force) } else { cpu_smt_control = CPU_SMT_DISABLED; } + static_branch_disable(&cpu_smt_enabled); } /* @@ -373,8 +376,10 @@ void __init cpu_smt_disable(bool force) */ void __init cpu_smt_check_topology_early(void) { - if (!topology_smt_supported()) + if (!topology_smt_supported()) { cpu_smt_control = CPU_SMT_NOT_SUPPORTED; + static_branch_disable(&cpu_smt_enabled); + } } /* @@ -386,8 +391,10 @@ void __init cpu_smt_check_topology_early(void) */ void __init cpu_smt_check_topology(void) { - if (!cpu_smt_available) + if (!cpu_smt_available) { cpu_smt_control = CPU_SMT_NOT_SUPPORTED; + static_branch_disable(&cpu_smt_enabled); + } } static int __init smt_cmdline_disable(char *str) @@ -2072,6 +2079,7 @@ static int cpuhp_smt_enable(void) cpu_maps_update_begin(); cpu_smt_control = CPU_SMT_ENABLED; + static_branch_enable(&cpu_smt_enabled); arch_smt_update(); for_each_present_cpu(cpu) { /* Skip online CPUs and CPUs on offline nodes */ -- 2.9.4