From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from SN4PR2101CU001.outbound.protection.outlook.com (mail-southcentralusazon11012005.outbound.protection.outlook.com [40.93.195.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E758C313E15; Mon, 13 Apr 2026 22:50:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.195.5 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776120656; cv=fail; b=Hb2rRFgu+jDUNqmCFptK5J3yvGJn1KRc+oqo4/sVEAXGZzS4N7c8o3DWHEWHEKdX7VWuKsDsAwEmEdsyfuA7v3F5bSzCev7mrS0NAwHkUY3v5m0irgnk0qoSk37uGC/t/LlH6+HSdepFS4KiMOFUoltROmGro4EMR+Z+eY+RgcE= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776120656; c=relaxed/simple; bh=AEEV9moAsNeORsrznOp1Oq3HI99Eps4HhCc/hcTJ+CM=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=PpdzdChiMr3wZdAVaw5oZurKhsp9Zol4VCXv+omne7w4P6zRUfBD6NJMhrxNpe2/0IwH70mIkrfMt/ktT5KOf1G226M2bCbSvmlGIbftvmv7CjMt8F/tde9kf7pf8S6rFHQ9Lxl5KIB0mvzJvLHD36qIEQhsWXwZia/vqQid2Zg= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=so6zbIw2; arc=fail smtp.client-ip=40.93.195.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="so6zbIw2" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=yRaMlx+CDnnE5cXqSVhpRlR/nNvLMQuAd4idpqXpLk4P2m/MbQsdSAqePPtg2Qh85fvHYK8+BayAFNmF0ywkF4KMtp/tOIUqP1I/S+pe6XEgwLeJZ5Y8xlr4Hlv97ZELXVfTKvfrw+wLh5znlLonlAOWVOQqggz0GmOMo6twszBFFjMfXEXK7ojqdTQ5EcAWZT2Yxatb1dW7knXk+KqF13PCUygAvV3+BndDb+4M6gR8nhfWdzHlC6Aut15PTzIIm4HaS1OEz1B6u/zVyh3jQgyd7mdMJVIl6hUVPShLnD8eKGC9DEHeQwvUXjfWvJWWURWIiisJehcKHxlmVHeSJw== 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=ySp9Df2sjx4MlIH0GYDivwTNp2bWFuedA+IYky3W4ws=; b=ewxJ3iyJYXpYOgTcdSvBEfKo3MCURJKb6uHYnMmMrHRqS8NrIVsM5AAIhYfOJTB336R3AtjSKvjahhGORHmNMitXNMOdx7K+BsP2DDPlghAFlbtIxC16MBboRhwtn0kpQ7InBuvEsP8ZmS7gbpQKCCC3dt43ETi+JQoZfuFszKi+WHX+BL2h8joECBdOeWaDrPr3/eGMmVRp3tHMO3wgGgkUYeD66+G1LYUarMcRJ3HPS6XuVxkyoMWK3A3vN81IB7lO3x2SinDWW9JVOa6a6Lk4rv2fChhTQk40CgjI9rgGRQQT+mBr0oEthhG4N5PHDE5MXIfGWDrkcibFJj2qHQ== 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=ySp9Df2sjx4MlIH0GYDivwTNp2bWFuedA+IYky3W4ws=; b=so6zbIw2zubRqnbTW1hfUU8p7Em1AY/Q4kFaDjycniK5iOtQd+qCmOfg1Zs5zcaJZRCNfdzrp3x1SiD8jAAAd8qDGC64hKOYG4IsWRMIK6VW3XFGu9R0ioWjQeCjoybx/AOmmPkwn+alZx1IoU/jy/ra6EKYkUEXSJMgRauuoBbMuEMeZEZe77oZV5IkdGL+JeSZ0Ourm655KrUo/4ux0nsMgQsoPya0sW2hFfJtQJB/g1Vaw+ibnxl3WxUIWbfZ64rqj8e9wJwoAWauH/uWr2gL6n30LH1dSFdMtR9IGK7vX1MRaYytFB4ZjbfKVAYQoIXM1S4UJoWeRN0zUsc0hw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DM3PR12MB9416.namprd12.prod.outlook.com (2603:10b6:0:4b::8) by PH7PR12MB6906.namprd12.prod.outlook.com (2603:10b6:510:1b8::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.48; Mon, 13 Apr 2026 22:50:46 +0000 Received: from DM3PR12MB9416.namprd12.prod.outlook.com ([fe80::8cdd:504c:7d2a:59c8]) by DM3PR12MB9416.namprd12.prod.outlook.com ([fe80::8cdd:504c:7d2a:59c8%5]) with mapi id 15.20.9769.046; Mon, 13 Apr 2026 22:50:46 +0000 Message-ID: <02211cad-71a9-4509-804f-39220eb63311@nvidia.com> Date: Mon, 13 Apr 2026 15:50:42 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 12/21] gpu: nova-core: mm: Add unified page table entry wrapper enums To: Joel Fernandes , Danilo Krummrich Cc: Eliot Courtney , linux-kernel@vger.kernel.org, Miguel Ojeda , Boqun Feng , Gary Guo , Bjorn Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Dave Airlie , Daniel Almeida , Koen Koning , dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org, Nikola Djukic , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jonathan Corbet , Alex Deucher , Christian Koenig , Jani Nikula , Joonas Lahtinen , Vivi Rodrigo , Tvrtko Ursulin , Rui Huang , Matthew Auld , Matthew Brost , Lucas De Marchi , Thomas Hellstrom , Helge Deller , Alex Gaynor , Boqun Feng , Alistair Popple , Timur Tabi , Edwin Peer , Alexandre Courbot , Andrea Righi , Andy Ritger , Zhi Wang , Balbir Singh , Philipp Stanner , Elle Rhumsaa , Alexey Ivanov , linux-doc@vger.kernel.org, amd-gfx@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-fbdev@vger.kernel.org References: <42dd707f-e23a-4725-8b6f-08ca346b0143@nvidia.com> <1775730646.3752.4760@nvidia.com> <56526b93-72a3-4b07-9aa7-7822bd561cd5@nvidia.com> Content-Language: en-US From: John Hubbard In-Reply-To: <56526b93-72a3-4b07-9aa7-7822bd561cd5@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: BYAPR06CA0008.namprd06.prod.outlook.com (2603:10b6:a03:d4::21) To DM3PR12MB9416.namprd12.prod.outlook.com (2603:10b6:0:4b::8) Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM3PR12MB9416:EE_|PH7PR12MB6906:EE_ X-MS-Office365-Filtering-Correlation-Id: 3d86338d-b258-4f47-72c0-08de99af1967 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|366016|56012099003|18002099003|22082099003|18096099003; 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:DM3PR12MB9416.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(366016)(56012099003)(18002099003)(22082099003)(18096099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ZVFFNi9rVzRzcm92R0F1MzJ6QWpESGI5UXNrRGVLNDhYc2FkYitzSG5wZksy?= =?utf-8?B?ek9YSDFXWlhMWVNWL3hzcWswaEFRQjZmVldBK2h4ZDJ5WnF4eW5QQ2ZOVVNM?= =?utf-8?B?aUl1RXhIZkdOd2Q5ZHNrSTJqaDBqWVZhQ3VxcGZybE9RdlphTkhqd21yQ1RB?= =?utf-8?B?SFdhTG55NmNWaTlKTHNCWDZ3RVkwQjRjQkE4OHY0N28xNFdObWtKSDFMM05M?= =?utf-8?B?U0RWV3VXcFdqRmg2ZjJzd2VsRVFMUFlQUHNGTmVBZ3NuU1JCT0V0SXBWNlhR?= =?utf-8?B?THh1ZThCWmhVZWw5OTdtRWZGZGpxdDZET2kyQUFZQjBkZkdiaWJhWWl0Zktw?= =?utf-8?B?b0FuWEJ5bzVjTjR2bzR2SWJ6QmxvKzdvVjVJT0gxc3c2Wjc5RjREMEk3dnU3?= =?utf-8?B?TWZhMFBIdUhRN3d0VkJqbjFKcHhNbTJhQzBjY3hTbi9FZ3hZK3FXVEg5bnU5?= =?utf-8?B?NVNZT1RJRmRrRGMzVHpGZ0t6K3ZwOFUzRlBrRmlwYVVvUEZIajB3SkE3TTdQ?= =?utf-8?B?MWFDdnNmMW91R1g3bnZXbk9EMktxcUYyZC9RQUlZZGlPb3MzSFdKRFZXSVpC?= =?utf-8?B?MERtWGVDVVhSdmVQZ1IxdkxaWTRGNXVmck13Y0VNY2FKMjh6elJxOGxseUJx?= =?utf-8?B?RkdKRmZQT0kxV3ZDZzY4S2JOTGZWOW84SGFaY3A3Vko4UzFYdTVUWVhTZ0du?= =?utf-8?B?RW8wTVNOVmNDSk02UFhQcGxRdXFFRGdEck5YSGR0Q2dsMU1EOCtzelNVRmhy?= =?utf-8?B?MHJLbEJZSC9jOWp2QXdyNS84U2VkSzVtS2NNUGRvUkZ2WkVta0F5M3lwalhl?= =?utf-8?B?aWxRdzM3aDQydG51SkVsVkxZcXlXZUN2SUZRVWhHVW9GZ3ByVUY4K0xQRUlS?= =?utf-8?B?aXdxdTlWSFc4NXhFWXBpTlVCZ2J4U296TFhZVVNyOCtWTmpEdGN4S3J2d29q?= =?utf-8?B?M2dJMVRXQW8xTElsU3J3S0Qza3d0QUk5UDA5cEpvKzQ4dUJ2cFFNWjVwbi8w?= =?utf-8?B?Vnl3T2lTUlNPNUlHY3ZLcHQySHliOWlzRHcyTG91WDU5OVFYcFBSYXUrczlm?= =?utf-8?B?UE9NcFFRTEdIb2c5blJzemlEVzRpS3IxanlIYVBFN0o1RVhYaHlXdHR4c1Mv?= =?utf-8?B?MDBLekEvL0NnS2FMQ3FuQ3Y0RUFtS05tV2p5NjNyVVFVd3pibCtrd1FJSm5K?= =?utf-8?B?aFMwb2R2VFR0cVQvRjQvdTM5bzJoSmgxVTFVajVYNG1mejBHWFI5Sk1FVFB0?= =?utf-8?B?WGt5WXpUVjV3UEpHb05JSVJuQjRiWE5QM1IzQnRrM1BRVDB3UGwxdlBDY1ZV?= =?utf-8?B?cEx6VnJBdDhrMUdwNTNodlZDeTJ3L2lIZ1h6U3A5ekVEOUZBOFZOcEE3bFJT?= =?utf-8?B?ck5VOVVIUW45TDJZVm1Ydnh5NVFEc3hQSXM3SjJ3RktvZzBhdW9KcmFWeWFL?= =?utf-8?B?WWVKV2cxQ2h6S25KRlZnQ09WNFJsbCtNaFNBcE9qZFpLMVhNYkkzNWJ0VEdh?= =?utf-8?B?cWxyeEJkYlZ1OGc3Z1FZeVg4YzBWWlZrUWNIc1ZIY0trUnRjWDVWZ0FFM3Vo?= =?utf-8?B?YzZrUW5nRjJta1lIcGlRKzduVDBrZ2ZUQS84NU10Uy9xU09VSzNNNFIzek8w?= =?utf-8?B?bXBFQUhNaVlQLzNEa3FVaFIydnpyTFhvaG0vMmVNQzZRN3lNc0FPRFkzc3F2?= =?utf-8?B?VU96TkFBRFNnNnBaYllHUTZMcVpuQis5NkF5ZzhuUXNwYll0SG4wcFlKb0hZ?= =?utf-8?B?bnVGbFFoZjgxR3FobmlCa1VLaG5TRWl5anptbkJVTHRLdkdpckl6WFNwOHpH?= =?utf-8?B?aUNvM24ySGRuT2o2YmJjeHg2SXV5eUlFQnpyRjNkdDlOMjFaU2dLNUQzU080?= =?utf-8?B?dit3YjVCUjhqL1FabnRUY0FSSlJPSGpySTM1TzZHcnRRNkI1RC9WSGcrNkhU?= =?utf-8?B?TEFsQ21NVldLMWxXNDJKR3A5U0FyT1V0SVZJRzNUSzZjdThCVE1hYkhrTUZF?= =?utf-8?B?OUV0YmF2RFV0MTJ4cENIRHk2T0p4OExhWTJCdXVoUXJTaFdkTzlteUpWb1JB?= =?utf-8?B?cmxNRDFFaGNBb2xyb2JST1JCNmk5eWtoeVZXV1hsd0hwdDB4RFVISnF4UVdK?= =?utf-8?B?YUZGSEt0ZmI1VDRHUkc4T1RqSnIySExCcjJsN0t2TTNsUzQ4U00zRFNMWlUr?= =?utf-8?B?dm1MUzVHWkJvdld4ZkFodUUrWEdDVldxWjNLcUFZWldNRlNoVC9wdk96aWh3?= =?utf-8?B?Zk9BdFZ0Y1p4NjZ3OG1RYnFkaWZxN0tLRlVyT2ZhVnc2elpPRjBkVFRuVmdJ?= =?utf-8?B?NTRFY3BDbDBOZWNHaEhJcWtFdWJ1UDhLMnA4dC9IOEpTSVJ1emNIZz09?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 3d86338d-b258-4f47-72c0-08de99af1967 X-MS-Exchange-CrossTenant-AuthSource: DM3PR12MB9416.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Apr 2026 22:50:46.0049 (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: hJFP4rwsAFoOIr2gm322ZrTeCsvvVoskmxhPwN2ZqhhfnKG51OBIRFV2TEyN1nFX3GwT2H8aeA7as7QaH0uASQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB6906 On 4/13/26 3:27 PM, Joel Fernandes wrote: > > > On 4/13/2026 4:10 PM, Joel Fernandes wrote: >> Hi Danilo, >> >> On 4/9/2026 7:00 AM, Danilo Krummrich wrote: >>> On Thu Apr 9, 2026 at 12:33 PM CEST, Joel Fernandes wrote: >>>> Since it is 3 against 1 here, I rest my case :-). >>> >>> That's not how I'd view it. :) >>> >>> Anyways, in case I'm included in "3", that's not my position. My point was to >>> ensure we keep discussing advantages and disadvantages on their merits, as I >>> think you both have good points. >> >> Heh, yes I actually *did not* include you in the 3 since you sounded to be open >> to both. ;-) >> >>> >>>> I am still in disagreement since I do not see much benefit (that is why I said >>>> pointless above). >>> >>> That is fair -- in this case please explain why the advantages pointed out by >>> others are not worth it, propose something that picks up the best of both >>> worlds, etc. >>> >>> You can also turn it around and ask people whether they can tweak their counter >>> proposal to get rid of specific parts you dislike for a reason. >>> >>> IOW, keep the ball rolling, so we can come up with the best possible solution. >> >> Good advice, thanks! I will try to come up with something that is acceptable to >> everyone and we can further debate pros/cons on v11. >> >> There are some merits on the alternative proposal from Eliot/Alex that I'd like >> to explore while seeing if I can keep some of the merits in mine as well. > I think I found a nice approach. IMO the MMU version dispatch does not belong in > Vmm/BarUser layers. Those are version-independent code. However I agree that > doing version dispatch at every low-level page table operation is a bit heavy on > matches (if we put the MMIO overhead counter-argument aside). > > So how about the following approach? > > PtWalk, PtMap and everything below it are monomorphized. Vmm and BarUser are > not. Version dispatch is handled on PtWalk and PtMap entry points. Conceptually it sounds pretty good. > > I think it makes it cleaner and splits the code up better too and the > organizations makes sense because the version differences are related to page > tables, not to generic concepts like Vmm and Bar. > > Thoughts? Here is a preview: > https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/commit/?h=pt-traits-v2&id=ff22ba64f729f9f73258777231763a7b9804123b > Probably impractical to review that here, so let's do the review in a v11 posting, I think. thanks, -- John Hubbard