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[23.128.96.18]) by mx.google.com with ESMTP id i23si2343205ejj.578.2020.07.23.09.25.23; Thu, 23 Jul 2020 09:25:46 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727052AbgGWQXQ (ORCPT + 99 others); Thu, 23 Jul 2020 12:23:16 -0400 Received: from mga06.intel.com ([134.134.136.31]:48328 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726632AbgGWQXQ (ORCPT ); Thu, 23 Jul 2020 12:23:16 -0400 IronPort-SDR: gxQEbKt6Zgwo1Jv4dJl4CnSwOUKj3kgYJ76M543d4oChagD/INXos4Nxt4A0nWHoE296DPQADn DLHgMJhQ8PVA== X-IronPort-AV: E=McAfee;i="6000,8403,9691"; a="212103989" X-IronPort-AV: E=Sophos;i="5.75,387,1589266800"; d="scan'208";a="212103989" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2020 09:23:15 -0700 IronPort-SDR: YpUImzkJbhJ5GzpfHZafueCnTauiViLJnLUDexlubhGtA7MTuQD7ODVue/eLXjdqJ9WI8tlfXi ym0JuZ1Uj9UA== X-IronPort-AV: E=Sophos;i="5.75,387,1589266800"; d="scan'208";a="393047961" Received: from bhkleins-mobl.amr.corp.intel.com (HELO [10.252.140.192]) ([10.252.140.192]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2020 09:23:14 -0700 Subject: Re: [PATCH RFC V2 17/17] x86/entry: Preserve PKRS MSR across exceptions To: Fenghua Yu , Andy Lutomirski Cc: Weiny Ira , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Peter Zijlstra , Dave Hansen , X86 ML , Dan Williams , Vishal Verma , Andrew Morton , "open list:DOCUMENTATION" , LKML , linux-nvdimm , Linux FS Devel , Linux-MM , "open list:KERNEL SELFTEST FRAMEWORK" References: <20200717072056.73134-1-ira.weiny@intel.com> <20200717072056.73134-18-ira.weiny@intel.com> <20200723161818.GA77434@romley-ivt3.sc.intel.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200723161818.GA77434@romley-ivt3.sc.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/23/20 9:18 AM, Fenghua Yu wrote: > The PKRS MSR has been preserved in thread_info during kernel entry. We > don't need to preserve it in another place (i.e. idtentry_state). I'm missing how the PKRS MSR gets preserved in thread_info. Could you explain the mechanism by which this happens and point to the code implementing it, please?