From patchwork Tue Mar 12 23:00:32 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fenghua Yu X-Patchwork-Id: 10850173 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 417051515 for ; Tue, 12 Mar 2019 23:10:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3310A29614 for ; Tue, 12 Mar 2019 23:10:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 311A2297E4; Tue, 12 Mar 2019 23:10:40 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B45EE29935 for ; Tue, 12 Mar 2019 23:10:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727777AbfCLXKQ (ORCPT ); Tue, 12 Mar 2019 19:10:16 -0400 Received: from mga18.intel.com ([134.134.136.126]:65107 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727321AbfCLXIQ (ORCPT ); Tue, 12 Mar 2019 19:08:16 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Mar 2019 16:08:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,472,1544515200"; d="scan'208";a="326744255" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by fmsmga006.fm.intel.com with ESMTP; 12 Mar 2019 16:08:14 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "H Peter Anvin" , "Dave Hansen" , "Paolo Bonzini" , "Ashok Raj" , "Peter Zijlstra" , "Xiaoyao Li " , "Michael Chan" , "Ravi V Shankar" Cc: "linux-kernel" , "x86" , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, kvm@vger.kernel.org, Fenghua Yu Subject: [PATCH v5 14/18] x86/clearcpuid: Support multiple clearcpuid options Date: Tue, 12 Mar 2019 16:00:32 -0700 Message-Id: <1552431636-31511-15-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1552431636-31511-1-git-send-email-fenghua.yu@intel.com> References: <1552431636-31511-1-git-send-email-fenghua.yu@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently only one kernel option "clearcpuid=" can be picked up by kernel during boot time. In some cases, user may want to clear a few cpu caps. This may be useful to replace endless (new) kernel options like nosmep, nosmap, etc. We add support of multiple clearcpuid options to allow user to clear multiple cpu caps. Signed-off-by: Fenghua Yu --- arch/x86/include/asm/cmdline.h | 3 +++ arch/x86/kernel/fpu/init.c | 30 ++++++++++++++++++++---------- arch/x86/lib/cmdline.c | 17 +++++++++++++++-- 3 files changed, 38 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/cmdline.h b/arch/x86/include/asm/cmdline.h index 6faaf27e8899..059e29558bb3 100644 --- a/arch/x86/include/asm/cmdline.h +++ b/arch/x86/include/asm/cmdline.h @@ -5,5 +5,8 @@ int cmdline_find_option_bool(const char *cmdline_ptr, const char *option); int cmdline_find_option(const char *cmdline_ptr, const char *option, char *buffer, int bufsize); +int cmdline_find_option_in_range(const char *cmdline_ptr, int cmdline_size, + const char *option, char *buffer, int bufsize, + char **arg_pos); #endif /* _ASM_X86_CMDLINE_H */ diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index 6abd83572b01..88bbba7ee96a 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -243,16 +243,31 @@ static void __init fpu__init_system_ctx_switch(void) WARN_ON_FPU(current->thread.fpu.initialized); } +static void __init clear_cpuid(void) +{ + char arg[32], *argptr, *option_pos, clearcpuid_option[] = "clearcpuid"; + int bit, cmdline_size; + + /* Find each option in boot_command_line and clear specified cpu cap. */ + cmdline_size = COMMAND_LINE_SIZE; + while (cmdline_find_option_in_range(boot_command_line, cmdline_size, + clearcpuid_option, arg, + sizeof(arg), &option_pos) >= 0) { + /* Chang command line range for next search. */ + cmdline_size = option_pos - boot_command_line + 1; + argptr = arg; + if (get_option(&argptr, &bit) && + bit >= 0 && bit < NCAPINTS * 32) + setup_clear_cpu_cap(bit); + } +} + /* * We parse fpu parameters early because fpu__init_system() is executed * before parse_early_param(). */ static void __init fpu__init_parse_early_param(void) { - char arg[32]; - char *argptr = arg; - int bit; - if (cmdline_find_option_bool(boot_command_line, "no387")) setup_clear_cpu_cap(X86_FEATURE_FPU); @@ -271,12 +286,7 @@ static void __init fpu__init_parse_early_param(void) if (cmdline_find_option_bool(boot_command_line, "noxsaves")) setup_clear_cpu_cap(X86_FEATURE_XSAVES); - if (cmdline_find_option(boot_command_line, "clearcpuid", arg, - sizeof(arg)) && - get_option(&argptr, &bit) && - bit >= 0 && - bit < NCAPINTS * 32) - setup_clear_cpu_cap(bit); + clear_cpuid(); } /* diff --git a/arch/x86/lib/cmdline.c b/arch/x86/lib/cmdline.c index 3261abb21ef4..9cf1a0773877 100644 --- a/arch/x86/lib/cmdline.c +++ b/arch/x86/lib/cmdline.c @@ -114,13 +114,15 @@ __cmdline_find_option_bool(const char *cmdline, int max_cmdline_size, * @option: option string to look for * @buffer: memory buffer to return the option argument * @bufsize: size of the supplied memory buffer + * @option_pos: pointer to the option if found * * Returns the length of the argument (regardless of if it was * truncated to fit in the buffer), or -1 on not found. */ static int __cmdline_find_option(const char *cmdline, int max_cmdline_size, - const char *option, char *buffer, int bufsize) + const char *option, char *buffer, int bufsize, + char **arg_pos) { char c; int pos = 0, len = -1; @@ -164,6 +166,9 @@ __cmdline_find_option(const char *cmdline, int max_cmdline_size, len = 0; bufptr = buffer; state = st_bufcpy; + if (arg_pos) + *arg_pos = (char *)cmdline - + strlen(option) - 1; break; } else if (c == *opptr++) { /* @@ -211,5 +216,13 @@ int cmdline_find_option(const char *cmdline, const char *option, char *buffer, int bufsize) { return __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option, - buffer, bufsize); + buffer, bufsize, NULL); +} + +int cmdline_find_option_in_range(const char *cmdline, int cmdline_size, + char *option, char *buffer, int bufsize, + char **arg_pos) +{ + return __cmdline_find_option(cmdline, cmdline_size, option, buffer, + bufsize, arg_pos); }