From patchwork Tue Dec 5 10:50:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13480081 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 17611C46CA0 for ; Tue, 5 Dec 2023 11:34:23 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.647651.1011121 (Exim 4.92) (envelope-from ) id 1rATgq-0007ii-Jl; Tue, 05 Dec 2023 11:34:12 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 647651.1011121; Tue, 05 Dec 2023 11:34:12 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rATgq-0007ib-F9; Tue, 05 Dec 2023 11:34:12 +0000 Received: by outflank-mailman (input) for mailman id 647651; Tue, 05 Dec 2023 11:34:10 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rATUm-0003dP-Us for xen-devel@lists.xenproject.org; Tue, 05 Dec 2023 11:21:44 +0000 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 7350f7e4-9360-11ee-9b0f-b553b5be7939; Tue, 05 Dec 2023 12:21:36 +0100 (CET) Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Dec 2023 03:21:25 -0800 Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga006.fm.intel.com with ESMTP; 05 Dec 2023 03:21:23 -0800 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: 7350f7e4-9360-11ee-9b0f-b553b5be7939 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701775297; x=1733311297; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=9l8F1WmhlJ7jRL54JQMm6v1HYP6GXYsOB2qRuf6ZAIU=; b=O9MIXii0i+RBpyZqynEC0q3ye+WYl3Ns6mOdYaKYj7I+9Wc1eosyxN45 uJqZ1dfRsAElj2xkzae3v6nkSjpI8wsgeDY9LPuGenZoRvZhHHymAgkeZ jPQ5MyzMVxQx0kvZ/ysH6wNtPAjceU958ukxKPVyUt56jvA0bVaR6NgaJ FsGDlv6JzRkVb6xI1NnS/C1R87pWFGSUiD+V9ii2PcBgCLXT5Uc7hLzDB UaBX3fHOZq24sa0JbPLFJqbytioYwOqUR4QZyLNzFSsx+bZn5+JlDaG+Z ZVATRGsRhBgCB0Urdca1Kgw20e0BO7Nw2zRJbsxBjBJ70oShkm5VWL5vu A==; X-IronPort-AV: E=McAfee;i="6600,9927,10914"; a="942608" X-IronPort-AV: E=Sophos;i="6.04,252,1695711600"; d="scan'208";a="942608" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10914"; a="1018192988" X-IronPort-AV: E=Sophos;i="6.04,252,1695711600"; d="scan'208";a="1018192988" 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: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, pbonzini@redhat.com, seanjc@google.com, peterz@infradead.org, jgross@suse.com, ravi.v.shankar@intel.com, mhiramat@kernel.org, andrew.cooper3@citrix.com, jiangshanlai@gmail.com, nik.borisov@suse.com, shan.kang@intel.com Subject: [PATCH v13 25/35] x86/fred: Add a machine check entry stub for FRED Date: Tue, 5 Dec 2023 02:50:14 -0800 Message-ID: <20231205105030.8698-26-xin3.li@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231205105030.8698-1-xin3.li@intel.com> References: <20231205105030.8698-1-xin3.li@intel.com> MIME-Version: 1.0 Like #DB, when occurred on different ring level, i.e., from user or kernel context, #MCE needs to be handled on different stack: User #MCE on current task stack, while kernel #MCE on a dedicated stack. This is exactly how FRED event delivery invokes an exception handler: ring 3 event on level 0 stack, i.e., current task stack; ring 0 event on the #MCE dedicated stack specified in the IA32_FRED_STKLVLS MSR. So unlike IDT, the FRED machine check entry stub doesn't do stack switch. Tested-by: Shan Kang Signed-off-by: Xin Li --- Changes since v5: * Disallow #DB inside #MCE for robustness sake (Peter Zijlstra). --- arch/x86/kernel/cpu/mce/core.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 1642018dd6c9..d524eb87f76c 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -53,6 +53,7 @@ #include #include #include +#include #include "internal.h" @@ -2150,6 +2151,31 @@ DEFINE_IDTENTRY_MCE_USER(exc_machine_check) exc_machine_check_user(regs); local_db_restore(dr7); } + +#ifdef CONFIG_X86_FRED +/* + * When occurred on different ring level, i.e., from user or kernel + * context, #MCE needs to be handled on different stack: User #MCE + * on current task stack, while kernel #MCE on a dedicated stack. + * + * This is exactly how FRED event delivery invokes an exception + * handler: ring 3 event on level 0 stack, i.e., current task stack; + * ring 0 event on the #MCE dedicated stack specified in the + * IA32_FRED_STKLVLS MSR. So unlike IDT, the FRED machine check entry + * stub doesn't do stack switch. + */ +DEFINE_FREDENTRY_MCE(exc_machine_check) +{ + unsigned long dr7; + + dr7 = local_db_save(); + if (user_mode(regs)) + exc_machine_check_user(regs); + else + exc_machine_check_kernel(regs); + local_db_restore(dr7); +} +#endif #else /* 32bit unified entry point */ DEFINE_IDTENTRY_RAW(exc_machine_check)