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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3957C77B62 for ; Tue, 4 Apr 2023 10:56:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234876AbjDDK4r (ORCPT ); Tue, 4 Apr 2023 06:56:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234881AbjDDK4Z (ORCPT ); Tue, 4 Apr 2023 06:56:25 -0400 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6E9B4C2B; Tue, 4 Apr 2023 03:54:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1680605662; x=1712141662; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=nd37h2vxkhLXg5jhh870M6BiFI8TxVn0dDXlR1ukIGo=; b=fJio8BMxUX6ApK4LuLMSK+FilafXGK5cD5f84wVU8iZo1cFs2zW5wwWB fxd+uircQ6Jes2IMZoPLzzShtyHA6tGuM73qe/eMRbbieMD2GiQWwYvIv 33B8cIZ0XABoScI4K9QHByfR4dui3VP7r4euRYnWV0Isy6GT3RV+TL7xD r2wlglu2jYvzPQK2pmMifv3ufnqkF2JO03Ry9XruteAYsLsuMiWodlqHD gmwladPFASv+sjOy4hhu8A5+yyzmzY9mQTEHQk71fXx+SqcRvi/hk5kZL umH+Td85Zpu59+eMZAgb67sGEl5Mgpd7W4fdg2pPrR3MMBekD3bpQ0HfO Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10669"; a="330734252" X-IronPort-AV: E=Sophos;i="5.98,317,1673942400"; d="scan'208";a="330734252" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Apr 2023 03:53:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10669"; a="775597874" X-IronPort-AV: E=Sophos;i="5.98,317,1673942400"; d="scan'208";a="775597874" Received: from unknown (HELO fred..) ([172.25.112.68]) by FMSMGA003.fm.intel.com with ESMTP; 04 Apr 2023 03:53:06 -0700 From: Xin Li To: linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, andrew.cooper3@citrix.com, seanjc@google.com, pbonzini@redhat.com, ravi.v.shankar@intel.com, jiangshanlai@gmail.com, shan.kang@intel.com Subject: [PATCH v7 32/33] x86/fred: disable FRED by default in its early stage Date: Tue, 4 Apr 2023 03:27:15 -0700 Message-Id: <20230404102716.1795-33-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230404102716.1795-1-xin3.li@intel.com> References: <20230404102716.1795-1-xin3.li@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Disable FRED by default in its early stage. To enable FRED, a new kernel command line option "fred" needs to be added. Tested-by: Shan Kang Signed-off-by: Xin Li --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ arch/x86/kernel/cpu/common.c | 3 +++ 2 files changed, 7 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6221a1d057dd..c55ea60e1a0c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1498,6 +1498,10 @@ Warning: use of this parameter will taint the kernel and may cause unknown problems. + fred + Forcefully enable flexible return and event delivery, + which is otherwise disabled by default. + ftrace=[tracer] [FTRACE] will set and start the specified tracer as early as possible in order to facilitate early diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index eea41cb8722e..4db5e619fc97 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1467,6 +1467,9 @@ static void __init cpu_parse_early_param(void) char *argptr = arg, *opt; int arglen, taint = 0; + if (!cmdline_find_option_bool(boot_command_line, "fred")) + setup_clear_cpu_cap(X86_FEATURE_FRED); + #ifdef CONFIG_X86_32 if (cmdline_find_option_bool(boot_command_line, "no387")) #ifdef CONFIG_MATH_EMULATION -- 2.34.1