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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C0AFC0015E for ; Tue, 1 Aug 2023 19:51:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232065AbjHATvI (ORCPT ); Tue, 1 Aug 2023 15:51:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38910 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229628AbjHATvG (ORCPT ); Tue, 1 Aug 2023 15:51:06 -0400 Received: from mgamail.intel.com (unknown [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 648FC2115 for ; Tue, 1 Aug 2023 12:51:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1690919465; x=1722455465; h=message-id:date:subject:to:references:from:in-reply-to: content-transfer-encoding:mime-version; bh=OCjlTcV8t7npJXB0qj248jQN1CJ2rE+B25JACd2JNIA=; b=ST6Ek7cXiKW0oAnyALwdw9HWH6ztzszE/UHMZJqr44MDhnCRnfhc/cee szgUkhwOX+aH6xVVeY0BkBlh0/KVgDJzExt1l9vc7SEF7l9FVP9P29XnH WC3eI5B/ft91sQG1P9ZduwDJKif35j5B1DHYbXzBpPV43C0wxwQonjXJ+ NzD/+pF1QaHtJX0DtXmsBUhJQlHpIoz30Y2aga+jvmHT3PizXb3eTeIIn i4ZGjxCvInWSzEzymimgFwoJH+VRaLHqg6toGGzvxdhspK87ygsk5hjBC uG6uHWWuJ1tI+znjViqQV2GIGD2cvlJg2jlIaoE044rHlIoLmrAjaoXVu A==; X-IronPort-AV: E=McAfee;i="6600,9927,10789"; a="372127999" X-IronPort-AV: E=Sophos;i="6.01,248,1684825200"; d="scan'208";a="372127999" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Aug 2023 12:51:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10789"; a="758465065" X-IronPort-AV: E=Sophos;i="6.01,248,1684825200"; d="scan'208";a="758465065" Received: from fmsmsx601.amr.corp.intel.com ([10.18.126.81]) by orsmga008.jf.intel.com with ESMTP; 01 Aug 2023 12:51:04 -0700 Received: from fmsmsx611.amr.corp.intel.com (10.18.126.91) by fmsmsx601.amr.corp.intel.com (10.18.126.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Tue, 1 Aug 2023 12:51:04 -0700 Received: from fmsmsx602.amr.corp.intel.com (10.18.126.82) by fmsmsx611.amr.corp.intel.com (10.18.126.91) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Tue, 1 Aug 2023 12:51:04 -0700 Received: from fmsedg601.ED.cps.intel.com (10.1.192.135) by fmsmsx602.amr.corp.intel.com (10.18.126.82) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27 via Frontend Transport; Tue, 1 Aug 2023 12:51:04 -0700 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (104.47.70.105) by edgegateway.intel.com (192.55.55.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.27; Tue, 1 Aug 2023 12:51:03 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ZIQJmLRe4vEj1YSXvIJaiHtqJPzKwv5SQpW2blIiLD3jeAJyWWNM3tHPvOxikLyQ8WoiH44gdeLjeGhIj5hXw4ob56/20wQ3r3L13CZIHO35Z9KNv5HERQc5qYxZlPSfb58Tz1U2MTtFp6e8Wv2zz9UY+/ys14mLK7wsrWA1LOVYxY5Nc5YP94YuyuMGfCiCnAmSmZeeXo99LZ9wyIp1LEzzH3+QC6LgfZDCR3A0CRes8dRJ342f7ytwFZM0pqGMUy03UoPLeOGTWuS9MNKxFy78/MZAh2Xpk/moFDK/v7AFFQoBgg2Fd5+9yohR9yAcJhCKrtYa1MjTv+y1eTANVg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=SnIYyhcWGRvGVLuz0JnWy44BOQGIjunh735lbJccoF4=; b=c38P6oWYthOmPDenPC2yXjhEWYDUeYsLDT5iG4K0nYc3ZZW0lp4NXNNcSOsVv6coyCoj4FOf+pnvueg5THTbn7Eh+LKmqoi5XVYfyAYok0y9p5DBgfDdiLdlKYUmC6NvrgooJK68skARXzBODCwOii6IwffdDSFkBhrd3HlFOw77ZgxTUc9njUghIaoNPvJTHpwjjws0iZT91PjGhAXQQp+XGpfzypJ1e1iJeHw5mHQxRd2WWHv2ae410kXqaBOva1Pgh8xM8yPorhmkfQzQJg66Bvn0wwocCSbs/xFqjOkwEvHKRFyaaHZp16UtVUc8B5GhIXUzhybm58/2OEB48g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from BYAPR11MB3320.namprd11.prod.outlook.com (2603:10b6:a03:18::25) by DS0PR11MB8083.namprd11.prod.outlook.com (2603:10b6:8:15e::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6631.42; Tue, 1 Aug 2023 19:50:58 +0000 Received: from BYAPR11MB3320.namprd11.prod.outlook.com ([fe80::b5c2:7049:2735:2943]) by BYAPR11MB3320.namprd11.prod.outlook.com ([fe80::b5c2:7049:2735:2943%6]) with mapi id 15.20.6631.043; Tue, 1 Aug 2023 19:50:58 +0000 Message-ID: <24f0902d-3375-b0de-e985-6174c70b394c@intel.com> Date: Tue, 1 Aug 2023 12:50:56 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v3 00/12] Enable Linear Address Space Separation support To: "Edgecombe, Rick P" , "Lutomirski, Andy" , "alexander.shishkin@linux.intel.com" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "Shankar, Ravi V" , "linux-kernel@vger.kernel.org" , "Luck, Tony" References: <20230609183632.48706-1-alexander.shishkin@linux.intel.com> Content-Language: en-US From: Sohil Mehta In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: BY5PR17CA0050.namprd17.prod.outlook.com (2603:10b6:a03:167::27) To BYAPR11MB3320.namprd11.prod.outlook.com (2603:10b6:a03:18::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BYAPR11MB3320:EE_|DS0PR11MB8083:EE_ X-MS-Office365-Filtering-Correlation-Id: 7f071df2-298c-4574-f3a8-08db92c89ff5 X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR11MB3320.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230028)(366004)(396003)(39860400002)(346002)(136003)(376002)(451199021)(2906002)(66556008)(66476007)(66946007)(6636002)(110136005)(44832011)(31686004)(5660300002)(41300700001)(316002)(4744005)(2616005)(6486002)(26005)(8936002)(6506007)(8676002)(53546011)(186003)(83380400001)(82960400001)(921005)(36756003)(478600001)(38100700002)(6512007)(31696002)(86362001)(43740500002)(45980500001);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?c1JFeit6QTZyVUxBNHhxODkyTHpwaEdjU0RrTmhyRmhjcGZtb25ySWdLaUZE?= =?utf-8?B?L3djbEFvS2ZmRVdtSTZHQmk1MkJvQll0S0k0U0VGdExmMEdMQi9oR3FwaXJE?= =?utf-8?B?dDRjQ0JqZTA1MC9aSm9nOTZ1eW0rbytPUG9lYkptd2dWSExrWngzV1Vwb2o2?= =?utf-8?B?SUJOSmN2RlRERmpwNndNS20xZUVwbmlmd3VFcVM4djArcVo2MXVkRXZwVFFL?= =?utf-8?B?T29ZMVdkeklXRGRXbVpMYnZZQ29pd0xkQUtKbEJ3VXEyWjlhNmx5bWhEQlR0?= =?utf-8?B?Y1BPejdnUkdNKzloaGpkUlZiNFVhZGx0T0xPUGd2RmNrNnRSTm85L09wbVJY?= =?utf-8?B?d25FVkN3SzIyU0VYMWR4cjd0andKQ1crYk5ZUFlZdkZYYkYyTWM0b2NiSUNu?= =?utf-8?B?b0d4cWJxUXUzZVBTWGRmbnpSSDVqUEdCb0pkbWs3U0REMWg5blFldGV0VmtF?= =?utf-8?B?eVhjV0N1KzI4U21VMDRxaThpczhudStWQklab1NyRmhldnd3TmtUc1VrNkpk?= =?utf-8?B?RHRqMHZwRFB3Qk9wU1d3QVloREw4N3ZEeVBWMWZkQVNYTjR0Vjd6c3c3ZUFJ?= =?utf-8?B?L1RNQ1ZCeGxsNmFtbDJlUUxYUm5zZWg1S2kzNVlYRUJKWHYxM1crNDlYYW5V?= =?utf-8?B?eTlkZnVCYUE4YjJkblZpbnBQOWpuY3M0Vng1YUVLMmxJeWRvK1pqRy9UUWtj?= =?utf-8?B?eWl3WDVZYnVkR1ZGRWxUSzBkVDRRalNWeXJHL2lCSkU4bWJuTmg3dFh1NjF4?= =?utf-8?B?disxdFNTQVpRNnNnVjV5RUErZXVMN2trbEVxMlFuL25GRXJxV0RhMU1SOTBz?= =?utf-8?B?RTVNMUEvRFd5OHhnMnZ4RFdLRkxNSVVrdGZJTVMzY2hYMTFxOWxaMVh5R1cr?= =?utf-8?B?b3ZEWjZSam80L2gyS1NkdkFVZjFtNjRSZnpJdkZOVWFubEh2SmZEa2Rod3JK?= =?utf-8?B?OE1wTFBPRlNIYkx6Qm1mT1VsaGg2YXUwS3FxNlNGMmJ4dXdnSVhWS1Y2MTUy?= =?utf-8?B?TFEvSFA3WWcrN1lDQ1U1ZnpMTjAxQ0pKc0ZUTEFqOW1lTUR1UU9aeHUyeDMx?= =?utf-8?B?SGhtZ3hsT2lUWHQ5TVl5SDRJaHU2SW9NUDlaYjlEN3A2bzN2LzdaSDdFRkNF?= =?utf-8?B?M201MHpsZDdlK3ZMQzNhVGxUQzA0R2wrZytlT0N1TGNzYndWRTlCY2o5aTRD?= =?utf-8?B?a1VleTJzQndEVkFaL3A1elB3bWVSQ3ZsMVN5OGZHNmp2R1Zkc0dGRjd0dGVB?= =?utf-8?B?RTVyZWdKMTlLTDN0UW5ZbnV5MFNxOVpFOTVUVit4cEVIejZ0eTdXd2xBUUo0?= =?utf-8?B?NXB4bXBDMWdySGtUbmZ1MEx0SksyR1ViekJmVXV4WThYVlp2L1oydkFZalVi?= =?utf-8?B?eFYyNWJNdXk4Y01LWUtpVnVvMlJ0MGxiUmVpRWFWVi9YcjFJc0k3ZGVMMity?= =?utf-8?B?Z1V0cDdGU3FyYTJvd2xmZS9NLzloTy96ZTdCaDlNK1loTzlTd0MwVmUwV2hB?= =?utf-8?B?ZW9vazUxYnJqR3g5SDEvelBPWUZOa3lqbGR6dzgrTXNla2I4bUxTUC95ZTVm?= =?utf-8?B?ZHBNa1ZEaXdnbWZJV2Y4eW50QU5YaHpodWphbXk3Z09KeTQ4TVBUYUhCRlJG?= =?utf-8?B?cW5FWnAvMUpOMUZSTTRkdzQ3V2wxd2RYZlZsc0QyVUJEMXdjYzBMTXEvcnNs?= =?utf-8?B?Zk9YL2YzbTVqOS9wSmIrelhyK2dNaG1PaHZ4S0pOcDFPb25kRTdDcmFoUlo4?= =?utf-8?B?QzgvYlNmb2VkNFo1MXgyUVBrWTlrQTQwaHg2c0R3TjZkZ1k4THprNFZXdU5x?= =?utf-8?B?aDdoTDVCSm9EWHp5eVZ6UkEwMVJxUVNwdzQ1N2ZGREE0TjR5OVhvZFNvYnQx?= =?utf-8?B?aTR6aHlNY21KRnY4VU83azhGbHhHMUlQSmltS0RhWG9zSjJCdm1icWpFQ2pB?= =?utf-8?B?ZW1SY0g0Uzkzakd2M1RxOWhIb0doYStsMEdGbTZCRXVHdDV4cmtuR3hPaTJI?= =?utf-8?B?a1U4TENTWWt6Zk1sN253QWFHbzFYZml2MTM5Rzg5ZDNHck4rRjJDNE9aSDF1?= =?utf-8?B?ZmFENjYxZW9NOEF2Zm5LTXJ2QjlyMWp3a3o4cm9nV2JiVmhPMnhXRmw0L3hq?= =?utf-8?Q?XduC3eFnc2mR5cvY0ttFzUOJj?= X-MS-Exchange-CrossTenant-Network-Message-Id: 7f071df2-298c-4574-f3a8-08db92c89ff5 X-MS-Exchange-CrossTenant-AuthSource: BYAPR11MB3320.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Aug 2023 19:50:57.9429 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: iEjLTjg0dhyIAnTK1RZIX25E1q+RWiHvtslakVA1oGgHdp9DKAdSoTTID0buMSw7OY7HMOYKV31uIdmI/WoRiQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR11MB8083 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/31/2023 3:36 PM, Edgecombe, Rick P wrote: > CET introduces this unusual instruction called WRUSS. It allows you to > make user memory accesses while executing in the kernel. Because of > this special property, the CET shadow stack patches don't toggle > stac/clac while executing this instruction. So I think LASS will need > it to behave more like a normal userspace access from the kernel. > Shadow stack is not upstream yet, so just something to keep in mind for > the future. > This is a good point. We should definitely test this out to confirm. But, isn't WRUSS already defined as a user-mode access? So, in theory, a user-mode access to a user address space *should* not be blocked by LASS (even with CPL=0). Are you suggesting that we might need to do something special for WRUSS with LASS enabled? Sohil