From nobody Wed Dec 17 09:44:25 2025 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 257CBC001DF for ; Fri, 20 Oct 2023 15:14:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377686AbjJTPN7 (ORCPT ); Fri, 20 Oct 2023 11:13:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377728AbjJTPNj (ORCPT ); Fri, 20 Oct 2023 11:13:39 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF637D63 for ; Fri, 20 Oct 2023 08:13:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1697814804; x=1729350804; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=EufwntLcxHa17lX7vkyRAITUbajJMYhr8ams+J+dhGY=; b=VzmNRa0LR2Ki07ZSrSHGzAEPkUHG25J0v3Ro+3WP5ni/MFatYeuZ8Jb1 pI+xZxa2YrJybgDeYkWlpY6GPHWwE/uo2lb1+AFfmPcZRaKaI0HHfgYtf dY223lfKQJUUvfIFrEe8CnVCmMnry7L0/lc8Nl2tM8WSPECTLnenbtVh6 Llx5qDfJSyHbRCLwdfkzTdQtQ6K/5heMzvhA4LrMnCtUr9LngcYfQ8iGe yDSj/Czt1YLy+2QyjW2vck0c0BK9pAWjSzSyqA8wYlfPhjg5LheaeM+d2 637zrrqNVSCVAk/BZgB4VoISLU+zUcBpGYmqnjPskxpfjuvTlARdXeNB5 g==; X-IronPort-AV: E=McAfee;i="6600,9927,10869"; a="366742888" X-IronPort-AV: E=Sophos;i="6.03,239,1694761200"; d="scan'208";a="366742888" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Oct 2023 08:13:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10869"; a="1004634219" X-IronPort-AV: E=Sophos;i="6.03,239,1694761200"; d="scan'208";a="1004634219" Received: from dgutows1-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.249.39.237]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Oct 2023 08:12:56 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 1C68810A297; Fri, 20 Oct 2023 18:12:45 +0300 (+03) From: "Kirill A. Shutemov" To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: "Rafael J. Wysocki" , Peter Zijlstra , Adrian Hunter , Kuppuswamy Sathyanarayanan , Elena Reshetova , Jun Nakajima , Rick Edgecombe , Tom Lendacky , "Kalra, Ashish" , Sean Christopherson , "Huang, Kai" , Baoquan He , kexec@lists.infradead.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv2 05/13] x86/kexec: Keep CR4.MCE set during kexec for TDX guest Date: Fri, 20 Oct 2023 18:12:34 +0300 Message-ID: <20231020151242.1814-6-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231020151242.1814-1-kirill.shutemov@linux.intel.com> References: <20231020151242.1814-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" TDX guests are not allowed to clear CR4.MCE. Attempt to clear it leads to #VE. Use alternatives to keep the flag during kexec for TDX guests. The change doesn't affect non-TDX-guest environments. Signed-off-by: Kirill A. Shutemov Reviewed-by: Kai Huang --- arch/x86/kernel/relocate_kernel_64.S | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocat= e_kernel_64.S index 56cab1bb25f5..bea89814b48e 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -145,11 +145,16 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped) * Set cr4 to a known state: * - physical address extension enabled * - 5-level paging, if it was enabled before + * - Machine check exception on TDX guest. Clearing MCE is not allowed + * in TDX guests. */ movl $X86_CR4_PAE, %eax testq $X86_CR4_LA57, %r13 jz 1f orl $X86_CR4_LA57, %eax +1: + ALTERNATIVE "jmp 1f", "", X86_FEATURE_TDX_GUEST + orl $X86_CR4_MCE, %eax 1: movq %rax, %cr4 =20 --=20 2.41.0