From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA015BA31 for ; Mon, 13 Feb 2023 23:49:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676332142; x=1707868142; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=0x8prcfOkEmACeYEiOgHUm+WyjDXkIRz6t1uNF7BUGU=; b=Bz+2qnNbYpbL31mz3Lr7Qyh90PQZ75yCdzHxaqRacycyjxeUUnCgJf14 x9ExuCV+bkicFz7XWs1J9/y9ikwq5GcL0KVu5hBbwOBzgNdM//JFbOQg1 r9sepcmH5GFw/r+Yb4c7jIr+FfwVvCVyD5TreFnbm7dYTcCy7B4joX6jk ACkhT3LMo1HdooADUQCQgLb7u+84vMJVkjqTai08xsAfUon5RufJn309W h1tS95p/46eBySMBmBqH5Yr72NOw7DgIUQI2XN2Pdv3eN6v0cAd3/y5yN PVBtFWOPClxG3uM5QAXkByRl3jEKce/EHMI5KyCM/9DGY9AvzO+XJeKyX w==; X-IronPort-AV: E=McAfee;i="6500,9779,10620"; a="395645602" X-IronPort-AV: E=Sophos;i="5.97,294,1669104000"; d="scan'208";a="395645602" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Feb 2023 15:48:48 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10620"; a="732672802" X-IronPort-AV: E=Sophos;i="5.97,294,1669104000"; d="scan'208";a="732672802" Received: from iannetti-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.252.49.216]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Feb 2023 15:48:46 -0800 Received: by box.shutemov.name (Postfix, from userid 1000) id 62E0010CA34; Tue, 14 Feb 2023 02:48:43 +0300 (+03) From: "Kirill A. Shutemov" To: Dave Hansen , Borislav Petkov Cc: Kuppuswamy Sathyanarayanan , Thomas Gleixner , Isaku Yamahata , x86@kernel.org, linux-coco@lists.linux.dev, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCH 1/2] x86/kexec: Preserve CR4.MCE during kexec Date: Tue, 14 Feb 2023 02:48:35 +0300 Message-Id: <20230213234836.3683-2-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230213234836.3683-1-kirill.shutemov@linux.intel.com> References: <20230213234836.3683-1-kirill.shutemov@linux.intel.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit TDX guests are not allowed to clear CR4.MCE. Attempt to clear it leads to #VE. Preserve the flag during kexec. Signed-off-by: Kirill A. Shutemov --- arch/x86/kernel/relocate_kernel_64.S | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index 4a73351f87f8..18f19dcc40e9 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -145,8 +145,12 @@ 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 + * - Preserve MCE, if it was set. Clearing MCE may fault in some + * environments. */ - movl $X86_CR4_PAE, %eax + movq %cr4, %rax + andl $X86_CR4_MCE, %eax + orl $X86_CR4_PAE, %eax testq $X86_CR4_LA57, %r13 jz 1f orl $X86_CR4_LA57, %eax -- 2.39.1