From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CH4PR04CU002.outbound.protection.outlook.com (mail-northcentralusazon11013067.outbound.protection.outlook.com [40.107.201.67]) (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 B67A8248F73; Tue, 2 Dec 2025 14:59:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.201.67 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764687572; cv=fail; b=JHqyLVn+r8yeMZ9vt+3fO2zyp85yzxwWKS2uCp0uf/RWbTouUD8eGrX8pPNO8727N6WxxZjFwfYrvm2kqbSuyT8LwhXkWnP+fAjgnHzecYmXKI1Mx7zjhEDDYqskWaZyZWefD6c+6BtzWz08nSwTK7jbYP/V0yAd/3UuJZaZDcE= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764687572; c=relaxed/simple; bh=ANvP3YygzIFG/JgM4yNRyC5FSE5XEmlIme13oEFURYU=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=hfGLlN9z8Y8c15RD/9YFKu/j4kLeUVmR/rXpQheis+Cfxyg0S0rjlj+w/4LyaAPbjxtx8gPk03f5oXdQi55NFXRv/6q2+E+obTXTmoYXGuMuhGopKD3hXSGxmedLz9FrkDix78268vZ14kxrmcYvNBcrSTXqaIPMgRWLcc5mTTs= 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=MlTSnyBC; arc=fail smtp.client-ip=40.107.201.67 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="MlTSnyBC" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=UvpiwrekuKx+vs8oyfoo3TMt5Mro73jUIObTrYfRq70TpWYLJUbemySVmH7/pOIzs1uW0RLic/vWR6NGOsm4P6yWX1TfwE55tboOzntjBD+dgjhnp+m7Gi3GVnMq7Is7qHZmed3I0hscdEQYb/BDFC+RmA0UcDr+z0DM92F6EXYESkMowpzuugylpb8Ke4i/r3hBTJ6GlK4jWvoOk150o+RYv/7kEfjtWPy7rk113ug6GXPnuJ6kaVNxCRSi9APME+yjxNDe2yGrczlW6i6oiJPrY+uegCJGmoEBnzI7dxMv+XsjBx2Q+I2meUBvMK3ghu6tjT3Dx8hmaD3TcAnZvg== 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=ANvP3YygzIFG/JgM4yNRyC5FSE5XEmlIme13oEFURYU=; b=ufbYqsOowqWo/GqMlgwAvzJcrhKWJrHIam77JTzOnHV+tBP4gFIVqZA2JR+M+l1XtWM1feVYpMTBw3AJI6TLNeIiehK6hwcZU3oyEjNuM13LzEjK6VUOuhE/uWLGOY3JM0VMPXpq4i/cnSw6ju/pY+/gPNREL+gMu4YV+BNpJOD7GyEpiVZA8mjxux4CHI0C2vuANvP8WawwnJ/rzxRh+bihoAs+bTapRI20wFgvIZ2zFIk09bL2hmBYUYw+yZDGrkB4rPTPtrop1FARUQmGOMi1Yl5a5R0y0hM6cwP2LORyq0i/zb6rnPYVIpEqwUQ1dmTMWlH0s5Wf17crgMMtMQ== 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=ANvP3YygzIFG/JgM4yNRyC5FSE5XEmlIme13oEFURYU=; b=MlTSnyBCGc1IY88E4vMXyxOwLfGVLkr8u9sw9hKL8q82+VMslojGH+0dMBhd2mkRjYn8pfQIYRXkCQlizde5U06Y6/9UWs/pBJpLXwb3hY8m8P9hjTxYE4O6pRj9Wtmia+qzMQIVqiCOVV+WeL4NArhtZ9ZnlVZaJyMYIsvmmQQ9WUit8tEkcyViWk0IpLJO6CuNfi8P8We/ZZxtVfkI8wwFEyc2E9f7SrpJoGWjvDDDemratbFYwSedUNSh69yjsvVCQKsn+EGH/d22mjvWG6lUOvWBI5ji/FtW/4eXyJpImP3mk4kUGTBt4mxT+cgP190coS0D2Yv2/ttr3hOuVQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from MN2PR12MB3613.namprd12.prod.outlook.com (2603:10b6:208:c1::17) by MN2PR12MB4287.namprd12.prod.outlook.com (2603:10b6:208:1dd::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9388.9; Tue, 2 Dec 2025 14:59:27 +0000 Received: from MN2PR12MB3613.namprd12.prod.outlook.com ([fe80::1b3b:64f5:9211:608b]) by MN2PR12MB3613.namprd12.prod.outlook.com ([fe80::1b3b:64f5:9211:608b%4]) with mapi id 15.20.9366.012; Tue, 2 Dec 2025 14:59:27 +0000 Date: Tue, 2 Dec 2025 10:59:25 -0400 From: Jason Gunthorpe To: Lukas Wunner Cc: David Matlack , Pasha Tatashin , Alex Williamson , Adithya Jayachandran , Alex Mastro , Alistair Popple , Andrew Morton , Bjorn Helgaas , Chris Li , David Rientjes , Jacob Pan , Josh Hilke , Kevin Tian , kvm@vger.kernel.org, Leon Romanovsky , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-pci@vger.kernel.org, Mike Rapoport , Parav Pandit , Philipp Stanner , Pratyush Yadav , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Tomita Moeko , Vipin Sharma , William Tu , Yi Liu , Yunxiang Li , Zhu Yanjun , Ilpo =?utf-8?B?SsOkcnZpbmVu?= Subject: Re: [PATCH 02/21] PCI: Add API to track PCI devices preserved across Live Update Message-ID: <20251202145925.GC1075897@nvidia.com> References: <20251126193608.2678510-1-dmatlack@google.com> <20251126193608.2678510-3-dmatlack@google.com> <20251130005113.GB760268@nvidia.com> <20251201132934.GA1075897@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: BL1PR13CA0199.namprd13.prod.outlook.com (2603:10b6:208:2be::24) To MN2PR12MB3613.namprd12.prod.outlook.com (2603:10b6:208:c1::17) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MN2PR12MB3613:EE_|MN2PR12MB4287:EE_ X-MS-Office365-Filtering-Correlation-Id: 4f57ed32-fa1a-43d1-872a-08de31b3634b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?OFnQS+M1xLKX4D5Fo++grYiP+3F+ML9jsYKn9QGmTxq9mpfN8+s5UHPTM102?= =?us-ascii?Q?IpMSwZaC4AiaVON8iKbSmybP/RAM7v/c0oDoeGsmdRluUh+sqIsLrWIb6hr8?= =?us-ascii?Q?TCqKqlHjj6RsS9B8T9gZfKNCc3+atAjadMgvEdNqwVQ/NO5BdPgw817SJckj?= =?us-ascii?Q?XRijw400GN9apuzlcSiCooPcr9P/rqbJUGUpgWcMbfkVkHd/LknVcHBMdotc?= =?us-ascii?Q?X4OeqShvTHtE11iicVK8sEFuDgWUz3Yt0YZdx2ZvUOaWqeTsifrgnaJ00nQR?= =?us-ascii?Q?qAmqHhS5xSb3B7M+UDeJlVQYH5JAI+SR3KIdISjEjbaRnxbCZ18BBZ5HKiHE?= =?us-ascii?Q?t8SQ7ULVMhMzTFFBXbISezXZpfvhkEYwCqwtkC3XlPCqvQnBvPFXl+1pGUZ2?= =?us-ascii?Q?36gGMXFJTNeRxFnq2JYrC7yQ0rVKopemd5og8npbdBHDQ0qUPjATt1wo2swA?= =?us-ascii?Q?9miMPqG4SNC2oddG0OnQYpuQrIhoGqB9LCxPbRy7yM8ebIEyKq6yWBlt9cQO?= =?us-ascii?Q?MCaHofpIM0vxhcfB/pD9+H2VyH7C00XkxQyVDwB7P5o1kFVf3XfAfcfg2JtT?= =?us-ascii?Q?N4E3razSescZhjULU9PeyVx/1NrCwfwE7PeZxZlj3rtJ1HJI2HAyS/wL9b4f?= =?us-ascii?Q?bzpnuZU7OiYpbIYtBLjwmgQTLQvxKBzCkK2sUz9mRIFc4IeyaAR/w03i5qJe?= =?us-ascii?Q?KyeazVEJkDcn9wvGUdL0BxFP1WxZyWxdJ6VES7yX5I0iSAsMukaZGRf0Fb40?= =?us-ascii?Q?rGgUI/a/1GUqL5HQi+/3wxMfIYPfAq3tcTKqVrKnPXpfeWwWunkF+8kbxjDo?= =?us-ascii?Q?d7R2KnHVyHRtmLHdgOtRyPzkWwIDrhUrScGtv3MZsEP3ecdwYjopmjD1t8hx?= =?us-ascii?Q?tl0i1wEHEou7RwdmgylM4qrDkAaEVKJIt1VrEe/MaQaiU1joz5dL2Z8OrW2n?= =?us-ascii?Q?fenafwYIK3ujbG3ZSsvgQsgQvDjF/PkEbJ1Qb0U3pylVMvjRrgja91mt2ZYF?= =?us-ascii?Q?8YMOEq9SVKga8oWXf2hZ+1qiIU9j0hiUuGjfm/tJrHXJTS1Uel5CgaeO/1yJ?= =?us-ascii?Q?nkXM4z9B5SZYduU4LEBWLF5aopmkuj2aQacsZHv5/xFGheoyK0I5XohKz5cE?= =?us-ascii?Q?8XSXirxxHtc/gMhMvlme1AwMwPNvRpvETR33HARuAJsjlRRQZ/fV0oB2+Gx5?= =?us-ascii?Q?7ufMW8n5+TyTybNFM8FNsMwlQbiFDTWbPCBNNYYRJx142GBZvOwnnfhSguIF?= =?us-ascii?Q?uqTeWtGjIqYCBZSQ1/lWnIBJKNyNAptJrKyhIfT3nFRe7dJScAUaJgDAS7Nb?= =?us-ascii?Q?X71OvoCQ3qSjbGxvg2j+uJulbpC+7RKQyi0y/j2LIg0+uGgzIXbiu1Kb4nhg?= =?us-ascii?Q?HAFZrBMywLSSq4mZmnTniymLAQ33fCsjkeBx2q/YtLbHtBQnkNOXc+tMmtBa?= =?us-ascii?Q?T6ls4U0/IVa9ZkrlbLZwzSYlvtXzb5lH?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MN2PR12MB3613.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(376014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?3heZVoRmcmlOM4RYvGRH/brSX3zFRhTaadd/nvVobOWd5Y3lDxS0D8YlhqS7?= =?us-ascii?Q?6nw954PW7JOAwiibOE9pHrn+IfBcev6gjbaWT3hjrCIYEiGRasqFbbBr5Iok?= =?us-ascii?Q?MOXD2h0Opds6sJis9qrtKvcijGECLfB5Q9KYktrLr8vOl5JTBL3ZS3QM3/nS?= =?us-ascii?Q?T6AbOLsLLm+kOkaiUf4khYRZZTUqI5+GPhYJkSpJy/bzjVudM1sZ9xuZs+84?= =?us-ascii?Q?vYRirR5D3hiWcAl1Xg7vPihPibYGYZagfBIik6j1yh32vQCz7xgq9tDW3jrr?= =?us-ascii?Q?gz3kl8zT+8vKNJpDbJhwVSkCOm6OIyhHl9IzJq/IQstV9M1wG8RxWMI9Zm7m?= =?us-ascii?Q?5vKRggoZ2rDo5nFIGT6wmeKq8AOeW+XuFm1ypP2swOweE4Wk8nO2K0OgufFG?= =?us-ascii?Q?5zoFfTf5X4BOvpI2cr+f11nqB/j+k1JglbIptqzEOZSQRfvFhtdnb1ihQzlN?= =?us-ascii?Q?UwwOCbvscSicloE4aDInNVqFdb5hsymBmuIiKRoQIBz6uhMRIAXWDH7rz267?= =?us-ascii?Q?B4r7AtVvqa4VY8xvtHCeATIaMnka+00lzbON6BFlJuONBqzrjAoYKXMQmhQE?= =?us-ascii?Q?KtlkQSDKWJoKrIgFtB1a4JR8Ef6Jqm8wBsLDH3h1Jc07G94EHT3W/fE11pf7?= =?us-ascii?Q?RlvxBWv0xA/z3AAytfzs6uKO5GUUyVU75wzt6cTPW92/hoUkA7emTdCXL+YV?= =?us-ascii?Q?46358RZf1BefZCyaY5t4l5GZmRoSavIwDgq2yArHroqxXXhrQgz1LBbf85kj?= =?us-ascii?Q?m5AST73k6/aayt3JO6xi/vJhbIQ5YmPiwJDNfvWFW8UWnsISDyRHEuF/WtKl?= =?us-ascii?Q?EPoY/DBE71/79Y+Igzkf92CjxMZaPPG7FADNHkzL0r1zso9Xw7CH4TWObxrE?= =?us-ascii?Q?PvOWKj1FptckAqkTtWMRNlosbsLVh5ZiE9nJItNQsk8nIjNn9/KNKmgI2+HF?= =?us-ascii?Q?vKy9kWlkAltgR6+N2fBplsC3v04KniEr0SYz4f4qlV6hDZlK3X5xOujQZkST?= =?us-ascii?Q?38kLSTJYiKM0xsc4vPeQBIOPRdQdoP2vwCp0igPSzzY/hwTYae6xS1EgdUCc?= =?us-ascii?Q?ZMQIb73dS+lm0yyvwLEVi6cYMyzTtIvLDh6PB8et/6sYBrL4L9S0Mdt3G81r?= =?us-ascii?Q?rxwFjwaDk5PeYpx4qtaP9GlzupwcdSHEABtL61urTz/IzFSIG9DJ6EAHdqZx?= =?us-ascii?Q?kvBibWuIuEx4p7kvz55IocrOMK5ign8A+DWOZIWA6s6pNSDNidWKx/l/7AFe?= =?us-ascii?Q?to2TySu4ipOq0VYh8nIBb3cgJDvdz7UmsE1NMHicgryURkranLxXpOvF7Knl?= =?us-ascii?Q?+kXLEvDudFSK6n0Tn9Zs66UMjRg8qwNxwEKnQixQr+E61goObZP3LPxiFbff?= =?us-ascii?Q?neb3NRmN9ay765E+/hNlcx5HPNX7t9npAl3UsDrqnSzcgFn5ACAtlTvm0ZWV?= =?us-ascii?Q?TxutM58JLmnZMYWCzrFr/0LHnOukHDSII46hGUcnl1OQ4pl44EdO7ZGx3c7Q?= =?us-ascii?Q?EL+Gs0y0cdFv46ti1RinXNzsKsXtMUjgzwuJ5J9Txvyq7cBAG67+oy1f4sQP?= =?us-ascii?Q?sIRpDeBmaps8+GzGu2s=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 4f57ed32-fa1a-43d1-872a-08de31b3634b X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB3613.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Dec 2025 14:59:27.0865 (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: 2eu32qSThj/JV6arCvUETdTjBR7Sfa3r6lA6G4Aj4tAm12f4WoKT3ppTLvaJ7xLv X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB4287 On Tue, Dec 02, 2025 at 07:20:23AM +0100, Lukas Wunner wrote: > But you do gain a bit of reliability if you don't assume bus numbers > to stay the same and instead use the "path from root" approach to > identify devices. Again, that's not reliability it is subtle bugs. The device is active during KHO, you CAN NOT do any resource reassignment, not bus numbers, not mmio. It must be fully disabled. Jason