From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) (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 9EA318C06 for ; Thu, 12 Sep 2024 17:39:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726162776; cv=none; b=gZyQKszam+8LRwHjiEy5T8WaPNqYR/Qi9qaxx96AgUt6Yt4tl+VugnbLF/PLwLTsWYyqeODljiNqsBB21YkkgVdT7pgiMjZ54Ik5DDTXvj3XQXKdK6LUp7EhRgVXBzZ1y5u8kzcTvej1eh8OQfTJ7gBKbzMSvWEtGiz4anffBDg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726162776; c=relaxed/simple; bh=YSuOxOMKPrjC87yAd/7PntsCDdJ1POcDMGNMKlfpNzM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=bd+JLC/KeyaBWoLRWGpReLPDDwNoNIf1tOFqP2Km1dhN6JWMf9/Budw119NPvtXEG1hxBc8+sZvcoQN4tJPfVYhbIjEoMQY1n3W5B1reYEWRoPZco5AkucopIVisCwEanwhBdBBFFZloIx8WC4mRH0dGwpSivmgho/Px2E8OlzI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=IHdZHZkt; arc=none smtp.client-ip=198.175.65.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="IHdZHZkt" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1726162775; x=1757698775; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=YSuOxOMKPrjC87yAd/7PntsCDdJ1POcDMGNMKlfpNzM=; b=IHdZHZktGMcShlopy918CFEHfK21iF/Q3INzIxeMovdmVO7Pqcc84S9H qNoKaEEEQcyzui0GfSD1H35Dnoa89KsygIUvdBN/tpJIWqcBje5k3+YzL vkQSCk1FXrTR3jsYADI86cPW1dZLNssVTULno9IRIo14HQyoC7Kft659Y KV95mghwG425s4oyUaObENURRPLfhJ4u7jGNrIcfY3vHP81V+ZmHTCvq+ JZzVxR0IuTowwP9yKywG8fzg4f5/C7Klb/wltZFgvsioAUxC9cTejjXfM tov9lU7gTrSlwUaNdJsuG+C3AFl1PHaRF19/CYz4EH7XdacYFxV8Xwt9r w==; X-CSE-ConnectionGUID: cZ2hOx6mReC2GKQ5uPpqRQ== X-CSE-MsgGUID: wNdpPwAPQf+WBXMtwXroAw== X-IronPort-AV: E=McAfee;i="6700,10204,11193"; a="36175562" X-IronPort-AV: E=Sophos;i="6.10,223,1719903600"; d="scan'208";a="36175562" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2024 10:39:34 -0700 X-CSE-ConnectionGUID: 3ZqoAjAHQtSDu2mr4jG89g== X-CSE-MsgGUID: rgTlBG3yQFSHIjEilfxfFQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,223,1719903600"; d="scan'208";a="105245539" Received: from philliph-desk.amr.corp.intel.com (HELO [10.124.220.79]) ([10.124.220.79]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2024 10:39:33 -0700 Message-ID: Date: Thu, 12 Sep 2024 10:39:13 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 2/3] x86/entry_32: Clear CPU buffers after register restore in NMI return To: Pawan Gupta , Borislav Petkov , Dave Hansen Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Robert Gill , Jari Ruusu , Brian Gerst , "Linux regression tracking (Thorsten Leemhuis)" , antonio.gomez.iglesias@linux.intel.com, daniel.sneddon@linux.intel.com References: <20240905-fix-dosemu-vm86-v6-0-7aff8e53cbbf@linux.intel.com> <20240905-fix-dosemu-vm86-v6-2-7aff8e53cbbf@linux.intel.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzUVEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gKEludGVsIFdvcmsgQWRkcmVzcykgPGRhdmUuaGFuc2VuQGludGVs LmNvbT7CwXgEEwECACIFAlQ+9J0CGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEGg1 lTBwyZKwLZUP/0dnbhDc229u2u6WtK1s1cSd9WsflGXGagkR6liJ4um3XCfYWDHvIdkHYC1t MNcVHFBwmQkawxsYvgO8kXT3SaFZe4ISfB4K4CL2qp4JO+nJdlFUbZI7cz/Td9z8nHjMcWYF IQuTsWOLs/LBMTs+ANumibtw6UkiGVD3dfHJAOPNApjVr+M0P/lVmTeP8w0uVcd2syiaU5jB aht9CYATn+ytFGWZnBEEQFnqcibIaOrmoBLu2b3fKJEd8Jp7NHDSIdrvrMjYynmc6sZKUqH2 I1qOevaa8jUg7wlLJAWGfIqnu85kkqrVOkbNbk4TPub7VOqA6qG5GCNEIv6ZY7HLYd/vAkVY E8Plzq/NwLAuOWxvGrOl7OPuwVeR4hBDfcrNb990MFPpjGgACzAZyjdmYoMu8j3/MAEW4P0z F5+EYJAOZ+z212y1pchNNauehORXgjrNKsZwxwKpPY9qb84E3O9KYpwfATsqOoQ6tTgr+1BR CCwP712H+E9U5HJ0iibN/CDZFVPL1bRerHziuwuQuvE0qWg0+0SChFe9oq0KAwEkVs6ZDMB2 P16MieEEQ6StQRlvy2YBv80L1TMl3T90Bo1UUn6ARXEpcbFE0/aORH/jEXcRteb+vuik5UGY 5TsyLYdPur3TXm7XDBdmmyQVJjnJKYK9AQxj95KlXLVO38lczsFNBFRjzmoBEACyAxbvUEhd GDGNg0JhDdezyTdN8C9BFsdxyTLnSH31NRiyp1QtuxvcqGZjb2trDVuCbIzRrgMZLVgo3upr MIOx1CXEgmn23Zhh0EpdVHM8IKx9Z7V0r+rrpRWFE8/wQZngKYVi49PGoZj50ZEifEJ5qn/H Nsp2+Y+bTUjDdgWMATg9DiFMyv8fvoqgNsNyrrZTnSgoLzdxr89FGHZCoSoAK8gfgFHuO54B lI8QOfPDG9WDPJ66HCodjTlBEr/Cwq6GruxS5i2Y33YVqxvFvDa1tUtl+iJ2SWKS9kCai2DR 3BwVONJEYSDQaven/EHMlY1q8Vln3lGPsS11vSUK3QcNJjmrgYxH5KsVsf6PNRj9mp8Z1kIG qjRx08+nnyStWC0gZH6NrYyS9rpqH3j+hA2WcI7De51L4Rv9pFwzp161mvtc6eC/GxaiUGuH BNAVP0PY0fqvIC68p3rLIAW3f97uv4ce2RSQ7LbsPsimOeCo/5vgS6YQsj83E+AipPr09Caj 0hloj+hFoqiticNpmsxdWKoOsV0PftcQvBCCYuhKbZV9s5hjt9qn8CE86A5g5KqDf83Fxqm/ vXKgHNFHE5zgXGZnrmaf6resQzbvJHO0Fb0CcIohzrpPaL3YepcLDoCCgElGMGQjdCcSQ+Ci FCRl0Bvyj1YZUql+ZkptgGjikQARAQABwsFfBBgBAgAJBQJUY85qAhsMAAoJEGg1lTBwyZKw l4IQAIKHs/9po4spZDFyfDjunimEhVHqlUt7ggR1Hsl/tkvTSze8pI1P6dGp2XW6AnH1iayn yRcoyT0ZJ+Zmm4xAH1zqKjWplzqdb/dO28qk0bPso8+1oPO8oDhLm1+tY+cOvufXkBTm+whm +AyNTjaCRt6aSMnA/QHVGSJ8grrTJCoACVNhnXg/R0g90g8iV8Q+IBZyDkG0tBThaDdw1B2l asInUTeb9EiVfL/Zjdg5VWiF9LL7iS+9hTeVdR09vThQ/DhVbCNxVk+DtyBHsjOKifrVsYep WpRGBIAu3bK8eXtyvrw1igWTNs2wazJ71+0z2jMzbclKAyRHKU9JdN6Hkkgr2nPb561yjcB8 sIq1pFXKyO+nKy6SZYxOvHxCcjk2fkw6UmPU6/j/nQlj2lfOAgNVKuDLothIxzi8pndB8Jju KktE5HJqUUMXePkAYIxEQ0mMc8Po7tuXdejgPMwgP7x65xtfEqI0RuzbUioFltsp1jUaRwQZ MTsCeQDdjpgHsj+P2ZDeEKCbma4m6Ez/YWs4+zDm1X8uZDkZcfQlD9NldbKDJEXLIjYWo1PH hYepSffIWPyvBMBTW2W5FRjJ4vLRrJSUoEfJuPQ3vW9Y73foyo/qFoURHO48AinGPZ7PC7TF vUaNOTjKedrqHkaOcqB185ahG2had0xnFsDPlx5y In-Reply-To: <20240905-fix-dosemu-vm86-v6-2-7aff8e53cbbf@linux.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/5/24 09:00, Pawan Gupta wrote: > CPU buffers are currently cleared after call to exc_nmi, but before > register state is restored. This may be okay for MDS mitigation but not for > RDFS. Because RDFS mitigation requires CPU buffers to be cleared when > registers don't have any sensitive data. > > Move CLEAR_CPU_BUFFERS after RESTORE_ALL_NMI. This needs some grammar tweaking, but we can do that when it get applied. Acked-by: Dave Hansen