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([172.25.112.68]) by fmsmga004.fm.intel.com with ESMTP; 31 Jul 2023 00:10:14 -0700 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 515b0ea7-2f71-11ee-b254-6b7b168915f2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1690787424; x=1722323424; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=gEY4ZGGaaQpe3vscglEO/Z/ZNgQa2ejE/Ek77q9vAj0=; b=UnFfQfnNJscnWT6RKTRE2tctXo5xUHWP0H+pc6ZuyywJjgV+/VrFyVuU 3ljOHSVdPG8Zax0j1k2o93t75U31HpW1VlAxqCC759PaAjAElCjZTiRmr j77KUko2fnya6nkxyv/PcRWroNtlUUJPIhcIOnoXcAE71Y+VV8Hx6MoXu nDim3MZ0Nz08nVaEsXagIGCqhMWf8Aczs1949SE/gN6KJeuBRiBM6IUZr S3mQ/PdYh55/4mJc1TyxDWM5syVn6jCUh273vHVrPI9w+JzQHV2pFkEwT x0qBU5TnInRLUp25I0Ch4V1XCzwwgelIqRj7LL0n1WVegv1d03VclrMSh g==; X-IronPort-AV: E=McAfee;i="6600,9927,10787"; a="432750287" X-IronPort-AV: E=Sophos;i="6.01,244,1684825200"; d="scan'208";a="432750287" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10787"; a="798157816" X-IronPort-AV: E=Sophos;i="6.01,244,1684825200"; d="scan'208";a="798157816" From: Xin Li To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org Cc: Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Andy Lutomirski , Oleg Nesterov , Tony Luck , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Sean Christopherson , Peter Zijlstra , Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , Josh Poimboeuf , "Paul E . McKenney" , Catalin Marinas , Randy Dunlap , Steven Rostedt , Kim Phillips , Xin Li , Hyeonggon Yoo <42.hyeyoo@gmail.com>, "Liam R . Howlett" , Sebastian Reichel , "Kirill A . Shutemov" , Suren Baghdasaryan , Pawan Gupta , Jiaxi Chen , Babu Moger , Jim Mattson , Sandipan Das , Lai Jiangshan , Hans de Goede , Reinette Chatre , Daniel Sneddon , Breno Leitao , Nikunj A Dadhania , Brian Gerst , Sami Tolvanen , Alexander Potapenko , Andrew Morton , Arnd Bergmann , "Eric W . Biederman" , Kees Cook , Masami Hiramatsu , Masahiro Yamada , Ze Gao , Fei Li , Conghui , Ashok Raj , "Jason A . Donenfeld" , Mark Rutland , Jacob Pan , Jiapeng Chong , Jane Malalane , David Woodhouse , Boris Ostrovsky , Arnaldo Carvalho de Melo , Yantengsi , Christophe Leroy , Sathvika Vasireddy Subject: [PATCH v9 36/36] x86/fred: Disable FRED by default in its early stage Date: Sun, 30 Jul 2023 23:41:33 -0700 Message-Id: <20230731064133.3881-7-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230731064133.3881-1-xin3.li@intel.com> References: <20230731064133.3881-1-xin3.li@intel.com> MIME-Version: 1.0 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 --- Changes since v7: * Add a log message when FRED is enabled. --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ arch/x86/kernel/cpu/common.c | 3 +++ arch/x86/kernel/fred.c | 3 +++ 3 files changed, 10 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index a1457995fd41..cb12decfcdc0 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1513,6 +1513,10 @@ 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 b34a8a138755..38cf4f64a56e 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1451,6 +1451,9 @@ 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 diff --git a/arch/x86/kernel/fred.c b/arch/x86/kernel/fred.c index 7fdf79c964a8..a4a726ea9fc2 100644 --- a/arch/x86/kernel/fred.c +++ b/arch/x86/kernel/fred.c @@ -8,6 +8,9 @@ void cpu_init_fred_exceptions(void) { + /* When FRED is enabled by default, this log message may not needed */ + pr_info("Initialize FRED on CPU%d\n", smp_processor_id()); + wrmsrl(MSR_IA32_FRED_CONFIG, /* Reserve for CALL emulation */ FRED_CONFIG_REDZONE |