From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7ABBC43382 for ; Wed, 26 Sep 2018 20:23:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A2C492147D for ; Wed, 26 Sep 2018 20:23:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A2C492147D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727158AbeI0CiR (ORCPT ); Wed, 26 Sep 2018 22:38:17 -0400 Received: from mga02.intel.com ([134.134.136.20]:15554 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726422AbeI0CiP (ORCPT ); Wed, 26 Sep 2018 22:38:15 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Sep 2018 13:23:34 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,307,1534834800"; d="scan'208";a="86835322" Received: from kushalre-mobl.amr.corp.intel.com (HELO [10.251.20.48]) ([10.251.20.48]) by orsmga003.jf.intel.com with ESMTP; 26 Sep 2018 13:16:59 -0700 Subject: Re: [PATCH v14 09/19] x86/mm: x86/sgx: Signal SEGV_SGXERR for #PFs w/ PF_SGX To: Andy Lutomirski , Sean Christopherson References: <20180925130845.9962-1-jarkko.sakkinen@linux.intel.com> <20180925130845.9962-10-jarkko.sakkinen@linux.intel.com> <20180926173516.GA10920@linux.intel.com> <2D60780F-ADB4-48A4-AB74-15683493D369@amacapital.net> Cc: Andy Lutomirski , Jarkko Sakkinen , X86 ML , Platform Driver , nhorman@redhat.com, npmccallum@redhat.com, "Ayoun, Serge" , shay.katz-zamir@intel.com, linux-sgx@vger.kernel.org, Andy Shevchenko , Dave Hansen , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , LKML From: Dave Hansen Openpgp: preference=signencrypt 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/aCccJK18ZwNjFhqr4MliQARAQABzShEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gPGRhdmVAc3I3MS5uZXQ+wsF7BBMBAgAlAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAUCTo3k0QIZAQAKCRBoNZUwcMmSsMO2D/421Xg8pimb9mPzM5N7khT0 2MCnaGssU1T59YPE25kYdx2HntwdO0JA27Wn9xx5zYijOe6B21ufrvsyv42auCO85+oFJWfE K2R/IpLle09GDx5tcEmMAHX6KSxpHmGuJmUPibHVbfep2aCh9lKaDqQR07gXXWK5/yU1Dx0r VVFRaHTasp9fZ9AmY4K9/BSA3VkQ8v3OrxNty3OdsrmTTzO91YszpdbjjEFZK53zXy6tUD2d e1i0kBBS6NLAAsqEtneplz88T/v7MpLmpY30N9gQU3QyRC50jJ7LU9RazMjUQY1WohVsR56d ORqFxS8ChhyJs7BI34vQusYHDTp6PnZHUppb9WIzjeWlC7Jc8lSBDlEWodmqQQgp5+6AfhTD kDv1a+W5+ncq+Uo63WHRiCPuyt4di4/0zo28RVcjtzlGBZtmz2EIC3vUfmoZbO/Gn6EKbYAn rzz3iU/JWV8DwQ+sZSGu0HmvYMt6t5SmqWQo/hyHtA7uF5Wxtu1lCgolSQw4t49ZuOyOnQi5 f8R3nE7lpVCSF1TT+h8kMvFPv3VG7KunyjHr3sEptYxQs4VRxqeirSuyBv1TyxT+LdTm6j4a mulOWf+YtFRAgIYyyN5YOepDEBv4LUM8Tz98lZiNMlFyRMNrsLV6Pv6SxhrMxbT6TNVS5D+6 UorTLotDZKp5+M7BTQRUY85qARAAsgMW71BIXRgxjYNCYQ3Xs8k3TfAvQRbHccky50h99TUY sqdULbsb3KhmY29raw1bgmyM0a4DGS1YKN7qazCDsdQlxIJp9t2YYdBKXVRzPCCsfWe1dK/q 66UVhRPP8EGZ4CmFYuPTxqGY+dGRInxCeap/xzbKdvmPm01Iw3YFjAE4PQ4hTMr/H76KoDbD cq62U50oKC83ca/PRRh2QqEqACvIH4BR7jueAZSPEDnzwxvVgzyeuhwqHY05QRK/wsKuhq7s UuYtmN92Fasbxbw2tbVLZfoidklikvZAmotg0dwcFTjSRGEg0Gr3p/xBzJWNavFZZ95Rj7Et db0lCt0HDSY5q4GMR+SrFbH+jzUY/ZqfGdZCBqo0cdPPp58krVgtIGR+ja2Mkva6ah94/oQN lnCOw3udS+Eb/aRcM6detZr7XOngvxsWolBrhwTQFT9D2NH6ryAuvKd6yyAFt3/e7r+HHtkU kOy27D7IpjngqP+b4EumELI/NxPgIqT69PQmo9IZaI/oRaKorYnDaZrMXViqDrFdD37XELwQ gmLoSm2VfbOYY7fap/AhPOgOYOSqg3/Nxcapv71yoBzRRxOc4FxmZ65mn+q3rEM27yRztBW9 AnCKIc66T2i92HqXCw6AgoBJRjBkI3QnEkPgohQkZdAb8o9WGVKpfmZKbYBo4pEAEQEAAcLB XwQYAQIACQUCVGPOagIbDAAKCRBoNZUwcMmSsJeCEACCh7P/aaOLKWQxcnw47p4phIVR6pVL e4IEdR7Jf7ZL00s3vKSNT+nRqdl1ugJx9Ymsp8kXKMk9GSfmZpuMQB9c6io1qZc6nW/3TtvK pNGz7KPPtaDzvKA4S5tfrWPnDr7n15AU5vsIZvgMjU42gkbemkjJwP0B1RkifIK60yQqAAlT YZ14P0dIPdIPIlfEPiAWcg5BtLQU4Wg3cNQdpWrCJ1E3m/RIlXy/2Y3YOVVohfSy+4kvvYU3 lXUdPb04UPw4VWwjcVZPg7cgR7Izion61bGHqVqURgSALt2yvHl7cr68NYoFkzbNsGsye9ft M9ozM23JSgMkRylPSXTeh5JIK9pz2+etco3AfLCKtaRVysjvpysukmWMTrx8QnI5Nn5MOlJj 1Ov4/50JY9pXzgIDVSrgy6LYSMc4vKZ3QfCY7ipLRORyalFDF3j5AGCMRENJjHPD6O7bl3Xo 4DzMID+8eucbXxKiNEbs21IqBZbbKdY1GkcEGTE7AnkA3Y6YB7I/j9mQ3hCgm5muJuhM/2Fr OPsw5tV/LmQ5GXH0JQ/TZXWygyRFyyI2FqNTx4WHqUn3yFj8rwTAU1tluRUYyeLy0ayUlKBH ybj0N71vWO936MqP6haFERzuPAIpxj2ezwu0xb1GjTk4ynna6h5GjnKgdfOWoRtoWndMZxbA z5cecg== Message-ID: <9835e288-ba98-2f9e-ac73-504db9512bb9@intel.com> Date: Wed, 26 Sep 2018 13:16:59 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <2D60780F-ADB4-48A4-AB74-15683493D369@amacapital.net> 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 09/26/2018 11:12 AM, Andy Lutomirski wrote: >> e omniscient. >> >> How about this? With formatting changes since it's long-winded... >> >> /* >> * Access is blocked by the Enclave Page Cache Map (EPCM), i.e. the >> * access is allowed by the PTE but not the EPCM. This usually happens >> * when the EPCM is yanked out from under us, e.g. by hardware after a >> * suspend/resume cycle. In any case, software, i.e. the kernel, can't >> * fix the source of the fault as the EPCM can't be directly modified >> * by software. Handle the fault as an access error in order to signal >> * userspace, e.g. so that userspace can rebuild their enclave(s), even >> * though userspace may not have actually violated access permissions. >> */ >> > Looks good to me. Including the actual architectural definition of the bit might add some clarity. The SDM explicitly says (Vol 3a section 4.7): The fault resulted from violation of SGX-specific access-control requirements. Which totally squares with returning true from access_error(). There's also a tidbit that says: This flag is 1 if the exception is unrelated to paging and resulted from violation of SGX-specific access-control requirements. ... such a violation can occur only if there is no ordinary page fault... This is pretty important. It means that *none* of the other paging-related stuff that we're doing applies. We also need to clarify how this can happen. Is it through something than an app does, or is it solely when the hardware does something under the covers, like suspend/resume. From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH v14 09/19] x86/mm: x86/sgx: Signal SEGV_SGXERR for #PFs w/ PF_SGX To: Andy Lutomirski , Sean Christopherson References: <20180925130845.9962-1-jarkko.sakkinen@linux.intel.com> <20180925130845.9962-10-jarkko.sakkinen@linux.intel.com> <20180926173516.GA10920@linux.intel.com> <2D60780F-ADB4-48A4-AB74-15683493D369@amacapital.net> CC: Andy Lutomirski , Jarkko Sakkinen , X86 ML , Platform Driver , , , "Ayoun, Serge" , , , Andy Shevchenko , Dave Hansen , Peter Zijlstra , "Thomas Gleixner" , Ingo Molnar , "Borislav Petkov" , "H. Peter Anvin" , LKML From: Dave Hansen Message-ID: <9835e288-ba98-2f9e-ac73-504db9512bb9@intel.com> Date: Wed, 26 Sep 2018 13:16:59 -0700 In-Reply-To: <2D60780F-ADB4-48A4-AB74-15683493D369@amacapital.net> Content-Type: text/plain; charset="utf-8" Return-Path: dave.hansen@intel.com MIME-Version: 1.0 List-ID: On 09/26/2018 11:12 AM, Andy Lutomirski wrote: >> e omniscient. >> >> How about this? With formatting changes since it's long-winded... >> >> /* >> * Access is blocked by the Enclave Page Cache Map (EPCM), i.e. the >> * access is allowed by the PTE but not the EPCM. This usually happens >> * when the EPCM is yanked out from under us, e.g. by hardware after a >> * suspend/resume cycle. In any case, software, i.e. the kernel, can't >> * fix the source of the fault as the EPCM can't be directly modified >> * by software. Handle the fault as an access error in order to signal >> * userspace, e.g. so that userspace can rebuild their enclave(s), even >> * though userspace may not have actually violated access permissions. >> */ >> > Looks good to me. Including the actual architectural definition of the bit might add some clarity. The SDM explicitly says (Vol 3a section 4.7): The fault resulted from violation of SGX-specific access-control requirements. Which totally squares with returning true from access_error(). There's also a tidbit that says: This flag is 1 if the exception is unrelated to paging and resulted from violation of SGX-specific access-control requirements. ... such a violation can occur only if there is no ordinary page fault... This is pretty important. It means that *none* of the other paging-related stuff that we're doing applies. We also need to clarify how this can happen. Is it through something than an app does, or is it solely when the hardware does something under the covers, like suspend/resume.