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 B5915C43217 for ; Thu, 6 Oct 2022 21:25:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232434AbiJFVZy (ORCPT ); Thu, 6 Oct 2022 17:25:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59940 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232233AbiJFVZw (ORCPT ); Thu, 6 Oct 2022 17:25:52 -0400 Received: from NAM04-BN8-obe.outbound.protection.outlook.com (mail-bn8nam04on2092.outbound.protection.outlook.com [40.107.100.92]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B1F7C14A0; Thu, 6 Oct 2022 14:25:50 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=S10nXs5B+5fdE9M+xsSsu79Zb/PKSqW//s9Sf3kEF9eyAaKF66uzOUdd1TfR2k5pfg6lXnRTBrQidWKpfB3p/lhVpZVVSLBrHq2p5ys4B0vmdfc22mKk4KmEWtldIIDnTP3SvUOvMz96a7e0STeYnjOyShOG0Ool282yZYNUghX0oc+Z0RG+eL1dD8DHGVVe560Mmjsb6tyToBRdK9YMC1546GVPL7hLxiGO5R2jm5JiKuDKamIa2B/rJ9zkTQdlrSntG/152yfu+vxvzd+13BA6AWUwpwaW7gVd4sM/464+JLG0rz6nf52fJmUoCAignC9fMSlKcxkfMxORNmn4xA== 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=mF9fF7D3PEWZ0S19xQvmYSjCA/58tc20mcdbIEn1iW4=; b=QGDdX0NCYM2MALyQsdUBJNE/x0kpodcgHX5OK8N3J8ylPuAAp2AgitTyXkiM9fXYCG0bbiv7iIlefbIF5jtR9GK9jTmVfELPqioBR23vfzIg1UHmROiXSoLKP2L+FBh18Ys39EmwgldrZlFSBMyoZFgSWeI1FFjWeWl5PJd6xRbiPuzi/GRmYGlO/Rcb/FC1La/B6mJ2CqsoBQ7vAbekrQ7x8S4xzq1eOQDF/hgIVmhnOH3t2Ql4+6X+6+WvWoU7unw9j6yp0f17l0q3JuIjPytR5hFL8SwO+hO/2XjLryXez9h09A452ls/lH+72EOQYpN497xkCJHkxo1Gl7Y4tw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=bu.edu; dmarc=pass action=none header.from=bu.edu; dkim=pass header.d=bu.edu; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bu.edu; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=mF9fF7D3PEWZ0S19xQvmYSjCA/58tc20mcdbIEn1iW4=; b=mOeG6j7DR1gzA1rvPSI4smCn88IQlTUxmUBOUIlLvYgvFt5ftaD49HCvqxDGKKqPIB3holzwHYAG5A4xwsmGHmweYC49TtHdo3odKKslwXHAgF01wNZ818f2/aN2vJpQAlk0Vhj4tXosvsBq4FyRRSo6ya6CH+es9VdWt1oC4ix1JFY1M1t43Twsxv0dMf5gK1XksLFVJF6zCXTgf8BAvwbs2T5VM0/rHURFXA32/0YokfsTscZHmNQrx2sw4E0S8TkGmCr/diQZzGQ1s3BCbQD/e4IIXMXbO28sRcgWslXPlRzqaOHHdHnFJUc58aRC0o1Vlmo5dRNFNEQ6YrkOPQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=bu.edu; Received: from BL0PR03MB4129.namprd03.prod.outlook.com (2603:10b6:208:65::33) by PH0PR03MB6381.namprd03.prod.outlook.com (2603:10b6:510:b4::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5632.16; Thu, 6 Oct 2022 21:25:47 +0000 Received: from BL0PR03MB4129.namprd03.prod.outlook.com ([fe80::9e2b:bf05:79ec:581]) by BL0PR03MB4129.namprd03.prod.outlook.com ([fe80::9e2b:bf05:79ec:581%4]) with mapi id 15.20.5676.034; Thu, 6 Oct 2022 21:25:47 +0000 Message-ID: <973e3ed5-8acd-abec-28a6-aceae6d67423@bu.edu> Date: Thu, 6 Oct 2022 17:25:44 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.1 Subject: Re: [RFC UKL 09/10] exec: Give userspace a method for starting UKL process Content-Language: en-US To: Andy Lutomirski , Linux Kernel Mailing List Cc: Jonathan Corbet , masahiroy@kernel.org, michal.lkml@markovi.net, Nick Desaulniers , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , "Eric W. Biederman" , Kees Cook , "Peter Zijlstra (Intel)" , Al Viro , Arnd Bergmann , juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, Steven Rostedt , Ben Segall , mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, Paolo Bonzini , jpoimboe@kernel.org, linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, the arch/x86 maintainers , rjones@redhat.com, munsoner@bu.edu, tommyu@bu.edu, drepper@redhat.com, lwoodman@redhat.com, mboydmcse@gmail.com, okrieg@bu.edu, rmancuso@bu.edu References: <20221003222133.20948-1-aliraza@bu.edu> <20221003222133.20948-10-aliraza@bu.edu> <20d483b6-da24-4ddc-b6d4-c0c23b8e5ea2@app.fastmail.com> From: Ali Raza In-Reply-To: <20d483b6-da24-4ddc-b6d4-c0c23b8e5ea2@app.fastmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MN2PR13CA0003.namprd13.prod.outlook.com (2603:10b6:208:160::16) To BL0PR03MB4129.namprd03.prod.outlook.com (2603:10b6:208:65::33) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL0PR03MB4129:EE_|PH0PR03MB6381:EE_ X-MS-Office365-Filtering-Correlation-Id: e4b6defe-5302-45d3-0468-08daa7e15569 X-LD-Processed: d57d32cc-c121-488f-b07b-dfe705680c71,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:BL0PR03MB4129.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(4636009)(366004)(136003)(376002)(39860400002)(346002)(396003)(451199015)(83380400001)(186003)(86362001)(31696002)(6506007)(53546011)(38100700002)(8936002)(7406005)(7416002)(5660300002)(66476007)(2616005)(8676002)(41320700001)(4326008)(66556008)(6486002)(316002)(478600001)(6666004)(41300700001)(786003)(66946007)(2906002)(26005)(75432002)(54906003)(6512007)(110136005)(36756003)(31686004)(45980500001)(43740500002);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ZUI3dEFJei9UUElLT3gxZ3dKRzA2MzJCa0xrMC9GVGorYksrSWdKOHplUWhn?= =?utf-8?B?d0Y1ZlFGdkc0V3cyMExQTlRFSVBBQ1ZwRGVKODcxZTdmZXpSdnA0L0ZKR2Jv?= =?utf-8?B?dkU4a3NWbTBKRGxuS1U2dXNXWDBuSldwWCtmWjEwTTVsOGdLMldFcUdxU0p6?= =?utf-8?B?WFJSZEJKUUl2REZEejlmTXFmQUZkblpqZUZSbXcyYnFJQk81QUJRNksyQ292?= =?utf-8?B?c09lMjU0TlNNT0svTFdnOSsrMkxqOE9Zc3pLeFltdWVBdkIwaUxjOWVhbDdK?= =?utf-8?B?ZUdTNzBhQmRPOGY3WUhSelBOUlZpQ1F3UGphUGxNSVdzUFRKM3ZFV0hrNU5D?= =?utf-8?B?Y0drdlBkWC9Bc1FzaWU5Qzd3djBXWERjekUwZVFYd2k3Y2pIcm1hQzZjSUVm?= =?utf-8?B?enlZTS9vaVM2aFFONnBBQ0h0Nm0rUjJlZkpTQmpnRThoeHRQQldod1pGT0Fv?= =?utf-8?B?dEZoZkZQa0g0d0JkMWFhTWRCN2tGeWxMSU9HcWIwa0lTYTBqb2dnK210Vm1Y?= =?utf-8?B?WTJ3UWFmWHdFWkl3aXZ0cVBZT3A3R215Y0t1NUtUL3g5UUxucmVpQjV3bjU0?= =?utf-8?B?WEdpU3RPY1hwMXcyaDdHNDV0V0dUQ3JybTl4cXZUTmc2aGVZbnJFek0yenlj?= =?utf-8?B?UzgxWnYyMDY1ZHdGcno5WlRzWTJRdUI3bnZmNitNK0s3RUxVU3k4T1Y0ajhs?= =?utf-8?B?RlVwYTZncUpyRGQ5RTRPYmpKWUJaUmYzRG9TTndUMmx3b0hOSmN3ME9RdndJ?= =?utf-8?B?TUQyK29Od1RRek1ndDU5N2YwNE5nSWo5dVo4K3EzRGpBdkZRU2tyR1VmZDVO?= =?utf-8?B?a3NPODBFak45ZGxYeHg2WUJNWVh1cHR0TGxjSWhvVnNUSHcxV2t1L2xCK09P?= =?utf-8?B?Z2E1aXZtMXVLbWNXR3JORmkrNlhMMHlkUUdUS0h6bHhrak1Ydi9uVGtqSlAx?= =?utf-8?B?QUJwY1E2ckNKSGgvbUMwbmx5eVBLek1rWnkwQ1cybmtDRERnNHpvUkUxaGZH?= =?utf-8?B?bnhCUHZMaGd2VVZQU005ejZxVis5TGUyMVBGY21LQys3MkdPZXV2VGFJeGdG?= =?utf-8?B?cG0yRlNzVmNUb2ZVUG0wcW1ZRlIvTXM5OUZ6bGdhOENOWXNoK25SWkJKYXR0?= =?utf-8?B?WlJzMG9aekZNcFU4QkxSQmNzajBHOSt1aUl2Nzgxb2NSK2NFS2loTTRNclZa?= =?utf-8?B?NHV5UnQ3N0R0a3JscXNpc21Ra2NYL01SaUhUUWEwekNjRUVSOUp3QmRmRzBp?= =?utf-8?B?WmVQU2R1TWhuQ0ZzUEtTaEg1VFJPZkdWaldTZTJIZWs2cXhYKzFOVjRHZk9C?= =?utf-8?B?ald2bCtERCtEVXA0RlhncXA5eUZJb2xXMDFFbk56aFVValVyVUtxQ2NiTCty?= =?utf-8?B?bzJ5VGpVbEhIb3JCNFp6Q0VoSGNqaHNnbllKRHZFcWdYVmJ2ZzRlMXM1Qi9k?= =?utf-8?B?OEFFenpYSWdPcGxFK0x0VG0ydWNPbkx4c0hiUFdKc0RtSWhId3lMMEJCZXdF?= =?utf-8?B?OHNqcDBLNWNUOFAzeVVoclpWaThuK241TlMwNjc3MnpiSnM5ZGt3VDlBRG9q?= =?utf-8?B?NjFLWmV1UFFsU1dSQ0ZuSjFJU3FXT1JScGthQXVNTk8yNnpPdExEY0dIbnh3?= =?utf-8?B?dHhuaFh2YThtQWRhY3Jnc2dkL3diSzlzbk5iS1EwTXFVQWd4dmM2bFNVSnM5?= =?utf-8?B?alM1UGJ4TnpmMWhXQzlXekplSUgrOGx2K1JYeDh3SExCSWxTK3ppQkZEV0FI?= =?utf-8?B?U3FHZVROTERWbU9mcVg2aVVQNXZJdWVzSUNkUjVkbnMwQ1dWdGNiakk3V3Bk?= =?utf-8?B?ZjA0TEhobEZ1OFBqSnFxUGpqU2RTbHl2bWpsbEdCYlBRbURaU0xBNXVRT1lW?= =?utf-8?B?bXM4WDNJeGgzYnF4S3RNUzVxYXcvbS9ZNUlFRWNEZ01HdUE1cHM5ZjI2aWtB?= =?utf-8?B?aXV5b1IwYkpuQXFXRE9CYzgzcVRsMjZRcFFlQ3BHUkJTQkZnQXZyZGRJcERr?= =?utf-8?B?VnZqWnFBc0JzUk1vNnpmZVBGdVZvblgwRStaWGVVV2tudlc0SnRkWi9QM0ZP?= =?utf-8?B?ZmJXa1NEZjd5RFpXcVdReWh1S01rWDhXUUpVSkNHbGJ3dkhHRndOWjNxWVdE?= =?utf-8?Q?s4elI+cQKXyIPEjdDX9fEiRfp?= X-OriginatorOrg: bu.edu X-MS-Exchange-CrossTenant-Network-Message-Id: e4b6defe-5302-45d3-0468-08daa7e15569 X-MS-Exchange-CrossTenant-AuthSource: BL0PR03MB4129.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Oct 2022 21:25:47.0803 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: d57d32cc-c121-488f-b07b-dfe705680c71 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 81K9+CjVMa5hOfmDH9ROiSZXJow/hjC+HtgyTlZ2RuZFGbEMLy+x5qiMqeD0YW1p X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR03MB6381 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 10/4/22 13:35, Andy Lutomirski wrote: > On Mon, Oct 3, 2022, at 3:21 PM, Ali Raza wrote: >> From: Eric B Munson >> >> From: Eric B Munson >> >> The UKL process might depend on setup that is to be done by user space >> prior to its initialization. We need a way to let userspace signal that it >> is ready for the UKL process to run. We will have setup a special name for >> this process in the kernel config and if this name is passed to exec that >> will start the UKL process. This way, if user space setup is required we >> can be sure that the process doesn't run until explicitly started. > > This is just bizarre IMO. Why is there one single UKL process? > > How about having a way to start a UKL process and then, if desired, start *another* UKL process? (And obviously there would be a security mode in which only a UKL process that is actually part of the kernel image can run or that only a UKL process with a hash that's part of the kernel image can run.) > > --Andy Again, the commit message could have been worded better. There can be two cases here, one where a UKL process forks or a new UKL process is run once the first finishes. In this case, there a single UKL application being run multiple times. The second case is where two different UKL applications (both linked with the kernel) are run in different processes, concurrently or one after the other. Lets look at both of these cases. For case 1, there is no restriction on how many UKL processes can run. UKL allows forking, so there can be multiple processes but they will have to share the text and data which is loaded along with the kernel text and data. In the future, one can borrow ideas from how glibc handles TLS i.e., where each UKL process would copy data into its user half of memory. But we have not designed or implemented that yet. We have tested applications that fork/clone. We have not tested running the same UKL process again after an earlier UKL process exits, but there is nothing stopping that from working. For case 2, we have not yet implemented that. But for discussion's sake, we can have two or more mutually trusting applications, all linked with the kernel. And if you do /UKL1 or /UKL2 (or some proper names), you should be able to run them concurrently. Again, although much of the plumbing for this is there, we haven't implemented it fully yet. Thank you again for the detailed feedback. --Ali