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[23.128.96.18]) by mx.google.com with ESMTP id cx13si6549841edb.500.2021.02.12.11.23.34; Fri, 12 Feb 2021 11:23:57 -0800 (PST) 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 S232080AbhBLTVG (ORCPT + 99 others); Fri, 12 Feb 2021 14:21:06 -0500 Received: from mga01.intel.com ([192.55.52.88]:59017 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232052AbhBLTU4 (ORCPT ); Fri, 12 Feb 2021 14:20:56 -0500 IronPort-SDR: YEi9ZUWzdfsnPPG4raILHTYavo993eQxXRgZDgOXgJvNTpBZ0R8WHm1bwCcc7S3UKwNsoCC1yZ JZ5NHoyGUmGw== X-IronPort-AV: E=McAfee;i="6000,8403,9893"; a="201615308" X-IronPort-AV: E=Sophos;i="5.81,174,1610438400"; d="scan'208";a="201615308" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Feb 2021 11:20:15 -0800 IronPort-SDR: kFhkyXG5sEkgmqJ515kT/FVqlL49dKN2YNiEohcNUQGIvvxkXGC6jzWeDBxyyjb/ThxIx7fE2V IDLNRZxZVolw== X-IronPort-AV: E=Sophos;i="5.81,174,1610438400"; d="scan'208";a="364032931" Received: from nmustaf1-mobl.amr.corp.intel.com (HELO [10.212.81.109]) ([10.212.81.109]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Feb 2021 11:20:15 -0800 Subject: Re: [RFC v1 05/26] x86/traps: Add #VE support for TDX guest To: Kuppuswamy Sathyanarayanan , Peter Zijlstra , Andy Lutomirski Cc: Andi Kleen , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Dan Williams , Raj Ashok , Sean Christopherson , linux-kernel@vger.kernel.org, Sean Christopherson References: <48a702f536ccf953eee5778023ed6d1a452f6dcf.1612563142.git.sathyanarayanan.kuppuswamy@linux.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: <48a702f536ccf953eee5778023ed6d1a452f6dcf.1612563142.git.sathyanarayanan.kuppuswamy@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/5/21 3:38 PM, Kuppuswamy Sathyanarayanan wrote: > More details on cases where #VE exceptions are allowed/not-allowed: > > The #VE exception do not occur in the paranoid entry paths, like NMIs. > While other operations during an NMI might cause #VE, these are in the > NMI code that can handle nesting, so there is no concern about > reentrancy. This is similar to how #PF is handled in NMIs. > > The #VE exception also cannot happen in entry/exit code with the > wrong gs, such as the SWAPGS code, so it's entry point does not > need "paranoid" handling. Considering: https://lore.kernel.org/lkml/20200825171903.GA20660@sjchrist-ice/ I would suggest revisiting this part of the changelog.