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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3D169FA3753 for ; Fri, 2 Jan 2026 18:58:50 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9DB306B0005; Fri, 2 Jan 2026 13:58:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 95E8F6B0089; Fri, 2 Jan 2026 13:58:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 808DF6B008A; Fri, 2 Jan 2026 13:58:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 6AA2C6B0005 for ; Fri, 2 Jan 2026 13:58:49 -0500 (EST) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 0C8B413BFD0 for ; Fri, 2 Jan 2026 18:58:49 +0000 (UTC) X-FDA: 84287935578.18.3C9786E Received: from CH5PR02CU005.outbound.protection.outlook.com (mail-northcentralusazon11012044.outbound.protection.outlook.com [40.107.200.44]) by imf02.hostedemail.com (Postfix) with ESMTP id 4BBDB8000E for ; Fri, 2 Jan 2026 18:58:46 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=K32N86G0; dmarc=pass (policy=reject) header.from=nvidia.com; spf=pass (imf02.hostedemail.com: domain of jgg@nvidia.com designates 40.107.200.44 as permitted sender) smtp.mailfrom=jgg@nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1767380326; a=rsa-sha256; cv=pass; b=FsfGMNynCeH67c8CrnYYql1BUnRW53ptpsHAadxtCbG18GHuO2DwfN9kHjogFQxS48DynG /HU+GR1H9OAmC2vVOFcr9rWd3cm4tfdCAFMw9F6+pL6G/uJlyeUqJ2ekPpYI4BIukU/0At WeyyfivCKhRtlLmpkqnowW5UKT//lTg= ARC-Authentication-Results: i=2; imf02.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=K32N86G0; dmarc=pass (policy=reject) header.from=nvidia.com; spf=pass (imf02.hostedemail.com: domain of jgg@nvidia.com designates 40.107.200.44 as permitted sender) smtp.mailfrom=jgg@nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1767380326; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=3s4rmC6euQE/0DADKFwWvfzb9ZpCyeKjuzQePEDApiA=; b=fAHuCt9g2G+vuB+bJgDomtXRY2DnOuGj4n9ScFpSdDm3shXkKJVqEhwmhZydvikJL8Fi2f TNfcqXYPSeojlgdtzWHlENbR6WmzXNNG+9UajCWb9lMa5Uq+TH0xn75gpyIKqulgMFGtm/ IwQ6epdrAEMNP8DsPD4vryfxtu6Ee9Y= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=gli7L9jxepcRZQMhedEH1PVVoYQIrGbkDJrf7eVd3NN0QsHVBONs8DfBguOTroxHR1Yg2dpiX0DL5p8eCS84/rMf1Cm5eKCUT47Kd/JAp0c32ykZUzpkM72FemMIAgc98Jd/dQBCUbduDCUE4ctd4JQ/SJmrf2UNDfB5KzcFaTDrYAxCBUxZf7DRh1lBjULpzPkJCtWNXtY+99JS1Ew2kFEt+VQErV32CcXqf7Tld/36ok1UdkWWOQlXY5Xvg9mP+tslDqsKzjObwY2vsHpmH7XBNv8R1aXFwHIxiC3tTGa2WVAdyGSj66agtye1UNz5kA92K6n4fIDcMqU4a9V7Gg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; 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=3s4rmC6euQE/0DADKFwWvfzb9ZpCyeKjuzQePEDApiA=; b=aZaqi8/F6n8zqQovsonQC5ssErWGSQutp8aFfw5UlgyYAY4P7DZtDiNaS7xPkeyu/Njxr+hzUYzFSAlTiWrvAl65OqQcjBP8TED2cJVOQwr1Mj3jCBvRBek0r21PGH8NWjGRSOpdLkszkLyWLBXoBtLVF6O9nbL0eLYWmCu0W4WruYRZ2C382IplyC/izwPVhju1ob8t7l6HCiLIfZC0vafDvr5Uqrwpx+ibaJjTA8nWmOfExWt/gf1+argzreP66SxoFJ8l7rCLIoRdTKFUY+Gzhpc/GjbJqd20kNpDt1IE1fXny9g9Ac17QXhnYvtwCjyvkXM+YufaRuoE0vDbXQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=3s4rmC6euQE/0DADKFwWvfzb9ZpCyeKjuzQePEDApiA=; b=K32N86G0BuAnOhJwZuZPCfcxHIQQ7vlzK116wx+An6tEbvdlRj6ZwpfXFaMcmAuHTsbUnShRzRlAm/lu161K1sDYcVDflqvFMBZDlibli6n5TgueWFwg4opKG2yO3NiILDuyrdKT/3AqjLE7Korkzcbh3W0krar2BHmGxmbIilobCsCRbWLzsy7nxKC3k2DmMOc4Ds+KPaHipb0oQUgnqWuvJTuJdOewy/Eei0mmb1DpFkJ9m+xWEm5JUoTduMdciTSHlmfHwyjBGdD7bCVVUtzhWeTS+VzsB+eWNaedYkLADJ0Bqjx7yc1Ms6x52qdjY7R5L34E9GITV4LoqC5Mbw== Received: from LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) by MN0PR12MB6055.namprd12.prod.outlook.com (2603:10b6:208:3cd::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9478.4; Fri, 2 Jan 2026 18:58:43 +0000 Received: from LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::1b59:c8a2:4c00:8a2c]) by LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::1b59:c8a2:4c00:8a2c%3]) with mapi id 15.20.9478.004; Fri, 2 Jan 2026 18:58:43 +0000 Date: Fri, 2 Jan 2026 14:58:42 -0400 From: Jason Gunthorpe To: Pratyush Yadav Cc: Alexander Graf , Arnd Bergmann , Pasha Tatashin , Mike Rapoport , Andrew Morton , Dan Carpenter , Samiullah Khawaja , David Matlack , David Rientjes , Jason Miu , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kexec@lists.infradead.org Subject: Re: [RFC PATCH] liveupdate: list all file handler versions in vmlinux section Message-ID: <20260102185842.GE125162@nvidia.com> References: <20251211042624.175517-1-pratyush@kernel.org> <86ecod7zb3.fsf@kernel.org> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <86ecod7zb3.fsf@kernel.org> X-ClientProxiedBy: BL6PEPF00013E0B.NAMP222.PROD.OUTLOOK.COM (2603:10b6:22e:400:0:1001:0:10) To LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR12MB9620:EE_|MN0PR12MB6055:EE_ X-MS-Office365-Filtering-Correlation-Id: f9657ce3-a3d4-4697-fcb5-08de4a30f317 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|366016|1800799024|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?A3YoHCMhg2O4S+fKBhomI+1vOvCqSMFfH2THk5nEdmuuqIXidp6zWkollBWA?= =?us-ascii?Q?FOjztEbqqWV8kkwchEEGxnZM1htDVmngVRGQxtq9F9rzC2QQEXYUQm/f27K1?= =?us-ascii?Q?tPlht9czsO2YVmEPi657h1+jNjy6yc2xMCLgEusXgZZkmmYbwe/1C1yrAO8E?= =?us-ascii?Q?RVnzbkx8XSelfolWmgeYkFm+/Cte4NeWZ5guSQhSG2nSCAkbGu9Zpx2iczj/?= =?us-ascii?Q?YJvEm2eVc9JZY08fP6GltqgCRV4pwWdmELtzhazhw9FZG3Ym/T/J5VBupBOp?= =?us-ascii?Q?PwrskOuYnEpAVioz7dqm6H7kV4VveESaooSUl75S+rdI2CdwCaxvgz8MeIhk?= =?us-ascii?Q?ZyE+VBZqDQ+UK5zUQlJNo1e8zPRn0PX+2lCmejI58Jz8Jp+SUv745BxCZP5Y?= =?us-ascii?Q?YPhGYQxWuCQvOlltobOrNsv+I8f4YA7iYwZHq2osg2sxE4wHnNhRotBiKwgk?= =?us-ascii?Q?5K7Kf4eTgaTa3ACHnC+AkUrW6dtZLwQiYBFPiHnGVDIfdMoYEysyNfhRfwlK?= =?us-ascii?Q?tg91RcminipzGfoGW0Bjzrn8T0+dnvoSmIGofxHshmsqPLjGgr2N3P4To7/D?= =?us-ascii?Q?B0wOU9UfziZpFQ1zcIO8LCx+5znIg2fBkGshjFYGuJxUpfLtiVNrn44onX3G?= =?us-ascii?Q?OgPgIkm0BkZN64M+F/PG8qoNvM6bTLqsPG0iBpsy6pyOr9Y1WqPnsgZmMhf7?= =?us-ascii?Q?H8Ab/d1Cy4R3MLsDz6ITeVFbHHumn63rMViIAton536AIMCJGclxB+T6riNX?= =?us-ascii?Q?EQCHB8x3pEjKqKZikuzUik/X1rbDb+TwsKv557k2o7wx5fAklPhMdk8Z/FPw?= =?us-ascii?Q?4Un6dK/WU5IBXfEIKFd0OVRH1URcG2m5HtzQHblASHP7PQU9ho2ibamZ0KPt?= =?us-ascii?Q?E6xkkn+LGK+lTvTY90sG/dD8UFgibrgIvWYM3UvG4gqCEMsbZp6slLFMlhme?= =?us-ascii?Q?BxK9ZBGHJu0Hx/fS7fDF2CoGaty7DliM0h6FV2VGBc4brFX3rBJq6C4KaE+o?= =?us-ascii?Q?daBSojV/KXL6uB0GPPawQmbvffIEbM5aUTRBoL44p20FkahITPWeMA+YO8d/?= =?us-ascii?Q?8iiMhVzWcd0U27NlijBScfmCA9Ng/TeWpsj2Izp0WQUtNj9zk8X8mBwvIlEf?= =?us-ascii?Q?o6psIwrPXnJu/I8yJP0Dm1rwsJ2DHLzCturTuBA5bESrxXPyUHxaPzaW97fF?= =?us-ascii?Q?6hkLQXoapiJ0iptdt7ZC2KPe4ID10wuAR7KNdaNxz3xJ/Ah6+tP2UrEQuRlb?= =?us-ascii?Q?ifWYSDuZNDOxCyQ5qhcGlevr5NKrMQIcOloLFfqFQO5V6jEK97mSTPbGdVa/?= =?us-ascii?Q?YCvEHZ4DpBdVo8airdge2Q9/unz4/VW2DViJjyPDE44+3bTe+b54Z+XXvkaR?= =?us-ascii?Q?UcMTsZPX0MkEzFGdGcOQ452vgOcj+NFzu1NDtNjrptzoVpoOmFD3vSCxrCts?= =?us-ascii?Q?3ey300q+FwwqC58TUesHDKzpYORElEU7?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV8PR12MB9620.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(366016)(1800799024)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?rGc3alB3KuvObve26vNbdB4GxzebVtfN0BA8n5vAwQd12I/zDx2K//zqvoIp?= =?us-ascii?Q?iFcBozY7196QXRHWar1fAOOQvrmQL7jNn+E9RUqBlxbqFGdlOvNOqjop+hlU?= =?us-ascii?Q?9hVmIli/UqY+dp0+cV5Oogqe9Lk1IT9oMUkLeUNwCEaXkB03EN80LUN/vGj4?= =?us-ascii?Q?pbfMO2Ov6J3UCFktdwtjso9HwY7LAVCADT+8k4/GiQZOX8OlJ6SGIfyNJbjE?= =?us-ascii?Q?yInHbs+T04SWF8ZH6W1tTrMPdK/uaTAZ54WLc5YLPYURT7gJLC9co0dTL40r?= =?us-ascii?Q?WW6bCvTl7J3jUurfvwtxdnQXj0QRdAPuQH+eJroZXnoaKD4MrQIknOfp2UtN?= =?us-ascii?Q?25KzD4InTOjvDzrGW9/sntcLyG5YClkSepYEbjs/evDwC9AWYKcswsYCRs7f?= =?us-ascii?Q?R7Uf4Nxpn7RGkZrDAB2gVBw74mdcmkfdl4R/+wQyUUa3/E9Uffu4Ei0RLqKj?= =?us-ascii?Q?uo7XBdQuJFgVodMVTsEu1jfSd8jp4aVv09O5+x1nhZkv4v65TFGO/lGt3+fz?= =?us-ascii?Q?SgvV6GNFnqS6p39YUMG0Rkg7MX/ZyQEzoGACaHg5EMCax+7A7+pimdTdbJu4?= =?us-ascii?Q?qjiZBWZ32v0SKhIRQiM5WaGL2LM/vP0d77eNLqprfeARF4ZTXG/kKZYleQIB?= =?us-ascii?Q?7hRUg6y0+Farf9AsdV1SsANMrXYl2vAjTCbgk+yySAnSV5jtK6fXC/aRaAJc?= =?us-ascii?Q?8p90c50zwXIjJevS36A/YA4luBDcE/hkzL7GWlq8Yl2qPOdhy2vhO2+iZCUU?= =?us-ascii?Q?ZE/y24e0QHQ9bGaWDUy/XppGBKOvnkqBb49RM6FdXBOwFaK55Lbqvf/p69R5?= =?us-ascii?Q?oLr6A7UcX2kg7RKrLl494XXBWHUlVicDPmdSuW84qzK4SD2ptT2FbJe0t7It?= =?us-ascii?Q?6o7hXXlRGHFx3QYkMF6TVv+77AZj2P8AEzxeLHK3QMPy0rGuAUGN37VRtHv+?= =?us-ascii?Q?0spnkG0voa/iE/0OIIayhuLzRUhRQxQr/9f4BWF+MeXq0N09KFZ9gdK/iakx?= =?us-ascii?Q?U6CKtycC7OgKVljM8krhi8L3w/AhYEr7nBbSeVPonsQIrrJSPrJcqZ0Hru+z?= =?us-ascii?Q?nw8pEmQVzWrY+7AMsRrLRthkAfnBptt2UJRv1sLkZtFriLmwcqdf+D4Bk6zG?= =?us-ascii?Q?FMQWNiGRjf/zo+RBuYBAcCgnVgrFHr1s0xITqIgA1hLkn5PnDtcJmiRIvc9u?= =?us-ascii?Q?/gbS7GU2/w7gm7ZBxmHO4JFpzt1V1mSd+lSW7Aqb3sV3HQaRC9ab2c3rZ75b?= =?us-ascii?Q?tVetFQHIwY66T0F26ECaOyqSPLFKSxd1jc8QT39Ok+hGEa4xJZWU8awVyPg8?= =?us-ascii?Q?iujFO66WTm0ISwo5HjuFJZpF+Fn8OEuN/G6Q9VfBFsf3ZMyVFxPYD1RGU9Vi?= =?us-ascii?Q?YxcIv2MR4Thw6fpHB5kxAqCb/WRBxXgEB31ifMBQ/9SOdUYyATBFxWStnMS/?= =?us-ascii?Q?bNvr2+ijCCnYBVTIGwBid3CclFlXOvRAdc0tJWxodDUicAcEkvlIaP8YMlUI?= =?us-ascii?Q?LqENCSEaOxiPW/tCP/VR5+dLEqBqrVhr/RvfvCi6UtmxkApRqho7vhpTnvlo?= =?us-ascii?Q?Eudfpg+ozFh5Q4ZkHpMDQjFOyr/lMzoHMbAQ7Ertz//tjp1qyCIF12YOqofP?= =?us-ascii?Q?pU4zvshCYxQ9EBLAJpAsAYY/VaK6VZTTdCttmJjJcP/yPsfta3U1+F/rUYEj?= =?us-ascii?Q?DomW0VZMVJPVuOk2IjCdno0Vx6vrFseXngQ+EIjfy3aTgeXQ62hD4yTmLH45?= =?us-ascii?Q?JE5RhNBqHA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: f9657ce3-a3d4-4697-fcb5-08de4a30f317 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Jan 2026 18:58:43.2599 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: UFJaNsHHJymirIh7jCFWvVeOdLjmtRC6WvIi1aikyG6rJsXg0rzBDIeQYj16LgVg X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN0PR12MB6055 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 4BBDB8000E X-Stat-Signature: jand1d5jzww4u7dwdoztabe6xgw51txh X-Rspam-User: X-HE-Tag: 1767380326-95920 X-HE-Meta: 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 y+vsZft0 UgkhUPizmlPaqx6DXIr6VG7swCXsXioeUKC29pyk9KFiy5uem/0e4DXa60wqC/fd1i6qg3GjiaTINjdcdQJ4qqc6FluGU9oB6PRIq29d6U1o4OafKbrWbkQDx7sYAQW2G8J2EzQ626f+UJECjSL21Yfhsb+2gq82uyi/lWNUCyJ8IluW++qNEx5ghDiL+AbAma/2LGr7AVwGDli64pNDs4sLhin7tK2wqbkGPDftUH1mfPubqlB37jriyP5W4XL5K0BCCEkyBXWw12Vjl3cmS7fe46o9hNnzceevcDv/p9wpo+i8zVPNnMx8sYHteuH20gQ6vLhp6IoCZ4eDl3a7RwLC4fC25b8QbxqRZ6UfaluT5FMt5ZA3YNTPGh0wuFVsWWCiesn0augKc9ShEfPOds3tGeCgS9NgqGXq2frKtzKn3lqLkEXKTLD4AgQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Dec 29, 2025 at 10:28:32PM +0100, Pratyush Yadav wrote: > On Sat, Dec 13 2025, Alexander Graf wrote: > > > Hi Pratyush, > > > > On 10.12.25 20:26, Pratyush Yadav wrote: > >> As live update evolves, there will be a need to update the serialization > >> formats for the different file types. This could be for adding new > >> features, for supporting a change in behaviour, or to fix bugs. > >> > >> If the current kernel does not understand the same set of versions as > >> the next kernel, live update will inevitably fail. The next kernel will > >> be unable to understand the handed over data and will be unable to > >> restore memory, devices, IOMMU page tables, etc. > >> > >> List the set of versions the kernel understands in a section in vmlinux. > >> This can then be used by userspace tooling to make sure the set of file > >> descriptors it uses have the same version between both kernels. If there > >> is a mismatch, the tooling can catch this early and abort live update > >> before it is too late. > >> > >> The versions are listed in a section called ".liveupdate_versions". The > >> section has a header that contains a magic number and the version of the > >> data format. The list of version strings directly follow this header. > >> Only the version strings are listed, and it is up to userspace to map > >> them to file descriptor types. > >> > >> The format of the section has the same ABI rules as the rest of LUO ABI. > >> > >> Introduce a LIVEUPDATE_FILE_HANDLER macro that makes it easy to define a > >> file handler while also adding its version string to the right section. > >> > >> Signed-off-by: Pratyush Yadav > > > > To support multi-version preservation and resume, how about you add a "profile" > > hint to the handlers? Then you can tag the handlers with "current" and a > > "previous". You then expose one section table with supported versions per > > profile. And that means you can from user space select the local profile to > > serialize and match that against the target profile of the target system. > > > > It also allows you to support more "profiles", such as elaborate downstream > > version combinations, that upstream will not have to care about. > > So in essence you want to tie the versions into a "version set"? If you > want to use a new version even for one component, you would create a new > version set. > > Interesting idea, but I am curious. Do you see a reason for grouping > versions together in this fashion? Why not let each version be changed > independently? I don't quite get the point either.. I think the ELF annotations are intended to give information to the userspace, but ultimately I think we should just rely on the userspace to implement anything complicated about compatibility policy. We also have the issue that not all versions *at runtime* are going to be supportable. Older versions may be information loosing and cannot be emitted based on the current system configuration. So to really make this work you have to dynamically query the current kernel, and cross that with the elf data from the next and try to cobble together a working set. IMHO most likely real users are going to want to latch onto fixed "profiles" and globally bump the profile cluster wide along with activating VMMs to consume new features enabled by the newer versions. There may be an early churn when we bump versions because we are messing things up, but the long term steady state will probably be new version = required if new features were used by the VMM Thus the version used for serializing and the features active in the VMMs should be linked together by the operator. Jason