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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DAB19C36000 for ; Fri, 21 Mar 2025 13:37:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To: Content-Type:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=r19dy1h/efUoSCKQjibx6+2/93JkupqYItH8fkWVixY=; b=UYAl7nwGxa9S7P4zvH1Z3BM6PK +WkGpx3NvJdjhLVuB/AiGV6ZBgSfj/XtDvHhwJuWtFivB9x9ZBEE3DWNblS1uRxmYPrSGa5d8DdpZ asF882qqgry2AQks1ch4/J5MukpnjX19DAEFhpYOjAiqF45xBT1BVy108eRmBJ129ft+njupX3qLM mXvfM5VRLPbuYU1MPkGtykIqnIt7MulHvgd1yrnJxNl87dA7+4fs/pAgrcVGvu+UJ87+JgKh/GYIZ 9w8qbr9OlYEa8ZkKYJUZ3xe896RKMhQxC7skomI+JquREBJYljrvn5/Iw4BZYQgc1BbkGrqwSQyd1 I2V7ASDA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tvcYE-0000000EwbZ-3y0O; Fri, 21 Mar 2025 13:36:42 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tvcWY-0000000EwOF-3MVR; Fri, 21 Mar 2025 13:34:58 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=MIME-Version:In-Reply-To:Content-Type: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=r19dy1h/efUoSCKQjibx6+2/93JkupqYItH8fkWVixY=; b=FtbYW/LllHDtOz4StYRGsvkso/ 9481CTPssthokqxJmIknzPVeBEKb1zaej7gQYagzTCdYk6kguuqBYURCuB8MbXZybAHCStAGxiFZ5 +KisczDDtnA5SlFXbZ2MwrgkWjEJq/ePex8XuyDxO/k87ZT3avaBbg0c2kkosBCBO8PatcrBY0akL t2Gb9ZM30IA9Jytzw4xs9HuzyhKedV1naVzzgWWdu2TDgbW9Q3fzYLJqmI4+qJafXwqWYpkjPR303 pHPI/G/D41sJBwbP1/wnu4HZlTxMb+6aPkwhDbz0LKCS516JJR0x8VaJzOXxjRN9p/e7Z9P67Sih7 vXKiijkw==; Received: from mail-dm3nam02on2060a.outbound.protection.outlook.com ([2a01:111:f403:2405::60a] helo=NAM02-DM3-obe.outbound.protection.outlook.com) by desiato.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tvcWV-00000004MPK-3PVU; Fri, 21 Mar 2025 13:34:57 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=SvHf3KddWjGaG7JFvOzRSXMj+VF0HVo5ogsnVMc5aI3+/8LNsasWSBFUz4yzg+LrJKXAgzF2FSNtbHv0HShCinZwoCvTLKxtbKllrGWnPTCgivZdR+YEb9RLt3WgtHTe7PeDUZjHclj4J41BfZ0PmSAux5Lr2jfpnA8bAA9Tem0lhvnaAywoRMMCDphdGdEA0/E3SfW0UKHFNT5aVBF6JYkXYiXW/bXY2wloh58GX2hCOkIl7SA+mgmBe77kQ3aOl7y8WII+lZgBesdFLBwFcFsJ8StcuEIv8Te15suyzj31mJliXTrnDMHWMVcggFhtoxoRxHPV6/H6fYQ12AkAqg== 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=r19dy1h/efUoSCKQjibx6+2/93JkupqYItH8fkWVixY=; b=s7ClVZVQyMj5zOGrZ6OZhxsXkSKE9sicHZUVJ3VZKXCaKOF2Di1E3FKS69FACiq7s4yU0wQQO85+0XOyM6q1kfgKmbaBPrDw14q1/7AvZaPPVN7xH705JLQhv0b253nvQ+Qi4lzKiX/XQQj2jx/jUwXyq2JV0OGinW+B+cw+nzrlnjAIVtn1VOwJsHC9y3u4KAqmAZAEmFFPO74BKAe4D6lGolaD0kTvdY9aur1NGUaSmy8b3fIeg9kJEBd8Qtb902luF9fG7osp/bcnm1DIoQI9p7PG11qtfp7WvjQHc1CvCD3Ymhpwf7p+Cyu5ds/QPw+H/5+vR6xCajhM4lQLEw== 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=r19dy1h/efUoSCKQjibx6+2/93JkupqYItH8fkWVixY=; b=mmUwS8GS/ixtccZu0UTYiz4Z1lq0GQ2UlGW9EszZ4e8SkoG8R7NrMFdI1Xsyp6KLHwFY3YtJtUL953sg02OGcoeQfEY3E9P5LcfqJcuisxEBpO6DzHF61pzJbhc/NKyT6El7jXYq477a4KOprRbo5Rkk3Fh+y/b7rj0wioeF31umebLdrjGmBpb1KIl4xdoVOAhP8/nec6N9lLUlNPDZUPbtMOsXqyhs0kFvlx3baFcjBWbGGe6bWnUC4VUmUIn08oTW9aX8Yfyzrq+mboxUoiH6KWjQkpXovy0CaE/JYPm0v0XNNAunPHBDfQd69pN1vezmvJxO9AqI/AXBF7ZkEg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from CH3PR12MB8659.namprd12.prod.outlook.com (2603:10b6:610:17c::13) by MN0PR12MB5761.namprd12.prod.outlook.com (2603:10b6:208:374::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8534.34; Fri, 21 Mar 2025 13:34:49 +0000 Received: from CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732]) by CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732%4]) with mapi id 15.20.8534.036; Fri, 21 Mar 2025 13:34:48 +0000 Date: Fri, 21 Mar 2025 10:34:47 -0300 From: Jason Gunthorpe To: Changyuan Lyu Cc: linux-kernel@vger.kernel.org, graf@amazon.com, akpm@linux-foundation.org, luto@kernel.org, anthony.yznaga@oracle.com, arnd@arndb.de, ashish.kalra@amd.com, benh@kernel.crashing.org, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, dwmw2@infradead.org, ebiederm@xmission.com, mingo@redhat.com, jgowans@amazon.com, corbet@lwn.net, krzk@kernel.org, rppt@kernel.org, mark.rutland@arm.com, pbonzini@redhat.com, pasha.tatashin@soleen.com, hpa@zytor.com, peterz@infradead.org, ptyadav@amazon.de, robh+dt@kernel.org, robh@kernel.org, saravanak@google.com, skinsburskii@linux.microsoft.com, rostedt@goodmis.org, tglx@linutronix.de, thomas.lendacky@amd.com, usama.arif@bytedance.com, will@kernel.org, devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org Subject: Re: [PATCH v5 07/16] kexec: add Kexec HandOver (KHO) generation helpers Message-ID: <20250321133447.GA251739@nvidia.com> References: <20250320015551.2157511-1-changyuanl@google.com> <20250320015551.2157511-8-changyuanl@google.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250320015551.2157511-8-changyuanl@google.com> X-ClientProxiedBy: BL1PR13CA0416.namprd13.prod.outlook.com (2603:10b6:208:2c2::31) To CH3PR12MB8659.namprd12.prod.outlook.com (2603:10b6:610:17c::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR12MB8659:EE_|MN0PR12MB5761:EE_ X-MS-Office365-Filtering-Correlation-Id: 94e8a737-876f-48a0-8728-08dd687d267e X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|7416014|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?686swMVR76sdl35h7IhFiCO+06XxqMBVtd9wSydxcgG6fgrhc8JS4EbTpEjU?= =?us-ascii?Q?hFVQmDYOesHEiBeYW6N9gavUexIvlkDiFIjDNaYI6WQ+hCqZYp12f3nzI0HW?= =?us-ascii?Q?7DQjCC8iJKQjnENGAcOtIAmlIJGIISYMNL+MtbLX8HuWa5crrIY24j+wkCd+?= =?us-ascii?Q?th0zrnHtjSK+UAZAa8s5T3eV7KDtySYxo48sRh/THxKU9yQETCiiDixByiSq?= =?us-ascii?Q?U43Jg4c2wr/5OjF39AavHJax4ovBLtlX8Y//WYFdlbJ8OP0Cw13labsBuB5y?= =?us-ascii?Q?5zJSCVS7C3XhFCvRPCwsFoYTsuwRyu18WIdw7FerMqZjKaW2RvJt6lT4oyR8?= =?us-ascii?Q?BMW+U3DRVR5Znl/moiCIocgfrdOBmSuiXm5Aryx+SJLu4QNL57pLJBhy59TT?= =?us-ascii?Q?JkR2NqkNJMAXC5uTevmVQvyM6Yv/chGa1ZnAFtGL3+ChZxqBPmGxSyWFjr46?= =?us-ascii?Q?Rif8izTlzVX8tC8RqoDWyNw4WhS0htc2Fi1pHoUs2XEkSEMF/Z7/ARw0qd9b?= =?us-ascii?Q?XMwWNRFcYXfPHRiefl68MnspO/q2wByg/zAatP20d6FZNDSQNXdtBaeN68bo?= =?us-ascii?Q?BAhBMywJBeiQkl7oob1vi4Lr9qmqjLtmjLXi+pSoUdFd/QJw0aEE+DjLrHu/?= =?us-ascii?Q?4HxuBb6xXoAH37p3+lGP4VxVtjze8qx3wMxqzMv5RmQoPwJuLqrvESIpVjAe?= =?us-ascii?Q?39wBBl3Yq6sh/s/O/1Grzm4iipXr2Tm3g6Xy+NWrCgigQziBL1TOFm5OtCIV?= =?us-ascii?Q?7AsMKXi277ZgFyj1CMVrNIb2gT0sq1DGGaEYj28RX4FxsvBsEjdqPnV/nAzZ?= =?us-ascii?Q?jaJw94cc87u9WtlZr+ibcBL8Vp3z8T1GNMDQK0797dCPec2YbgTn+lba1OWA?= =?us-ascii?Q?UhbGcOSoSjfpFgsOjwcNiI5cz5NmxxkBjFZ0j2Svdg2U3aDBJLIICmcRYtYn?= =?us-ascii?Q?XrYdDdu8jkcV5Ng/buNEtqea/UqAdf7FGD+11Z9AYHiIHwYkqMDVt4tiXCV7?= =?us-ascii?Q?AVgjVJP5mlxUPmm0HWG9811uoTmaXZhqkf5FTInJ21/9R0CyI+jQOV0Qbo+6?= =?us-ascii?Q?EwC8YVDjGTDDpikq0PodkovRuwc4BhbcO92Pz/DtXi/Fbtb1xqmn6dyFg529?= =?us-ascii?Q?s/IyJ4u9gtHdRKRy1iRnTzqMNiyzVFJCRdvsWdtEvbNXDK/7v4l2S/9Wzb0+?= =?us-ascii?Q?6aJ+tjObpvzbQHMQQR0AokukCOmq2bJRmmAVQHKXU53McRsaxiQJT8WoD64I?= =?us-ascii?Q?2/nvxylGGksGQtIsZFNJgPvopAMQdJaEf+uIuSngTig7/C+22mgah9UnZUgG?= =?us-ascii?Q?zqjqWut3TQdVTaXuboIWCCSuoSYo47v6EeSycThHBw6AT6Dn7Sefhlzh5aOK?= =?us-ascii?Q?ocmeV0z0IarGesys68ZZyVWejfoS?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR12MB8659.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(376014)(7416014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?mtjm435sHx8Zw7oJLc0CovVcZP4stk6QDQJEa5WMyKEXLFhxLLLbZvhuqsVF?= =?us-ascii?Q?jF0GDHecfZctrKWvDQrjoThdraTR76K9L9TjDD+bLrObqj8cZkvZcbT9AwIK?= =?us-ascii?Q?BtMjSzgQeX5JCn1aVcxKJhsQ/mzW4ZFBo9c4Bwx6L8F0ffVThQgRTJZ0UZbi?= =?us-ascii?Q?m2ngJHEt7lOqsHQ246HTfU1UifitSPwi+sUlIEyizut2N7OtesCavDCD52/o?= =?us-ascii?Q?Hsvs9CN02iVUlENrDSULCYI6ThpQGelQMY1X0zmUzxYSmSihN29iIp2Z8SSa?= =?us-ascii?Q?0yTWMBK4N4PKplJVdsOlZlK6Zn+2PqjaHHteo/GlSnd5PIVfyuhT3HPhXQbd?= =?us-ascii?Q?oQ0vstP4WqeNRITkifPBy3CA0uYxCas5IQmp9LGU/k5RgKsc+NugyZ98Z3Nl?= =?us-ascii?Q?YUhxxmt2rly1CWhK+FTKra9s+dE38FU8qEDrX3wVS/QpU1bGwU/5biNSGiJV?= =?us-ascii?Q?HmQaxEyCRHXplw/nG7jl5+o45C1Ha71IOMOmwyjUp6iRNVfPFKJksmNna9Hg?= =?us-ascii?Q?TpVDe95cWGlc8yTfAUmK9eVQJHZp256OEr611SC0NIpAvLyS4lmkOYreEaY6?= =?us-ascii?Q?KL3y07Ho1JV1jc3xcbnEeEmO6CMqyz1yrPGfh69Vt3M9p6NKLINYrOVwXd1N?= =?us-ascii?Q?XUGLoz0vsK05byC4pE6wiNjxrEBXag6iWBjeTSOEC067a4nV8omu+0YT6erd?= =?us-ascii?Q?MmpPO4TJtUeMBnhijTjCJepXm5talYhkwBPZUckoIScFGSDwAjpAmj56yNga?= =?us-ascii?Q?HcmzGUShKVVwy7uQblizjHWkf/wLabxExKS/LgVrn4Jr/UUiXO/4BRsnGxEr?= =?us-ascii?Q?n2KqvBhPOfs+13SqxnQ67qWrBx8T2MoRzgRYPGB+vUtYP0b+/YUQWOjy9BRW?= =?us-ascii?Q?Sjpp34nA50pZfK7SjBL1Hn89kWhLfSCqyFrSY5TRaHPiPubA1W6ZvInmAQFU?= =?us-ascii?Q?XLg8CWYfh2Y0C3x35+869NsRa2paHHp3mkcCsOQNhoKKk3nXFx/zaf1yV0O+?= =?us-ascii?Q?UVWDsDrc/ZfFXhHWn3ALS1w7GNn0CUCnAjp6j/GIbYTqMsfTg+SapU3x2B8J?= =?us-ascii?Q?RlxC18R4iRgdoNl3kALUVG7k5JiIG7mF5M5TjK0ouh6CwnIavGFbuBTkagwf?= =?us-ascii?Q?NgmHHot+rTYGYIemrAZTN/Ca6enLUvgvgzVm9JW4nlRKJvcxv8eHWOHIkYME?= =?us-ascii?Q?tx4rtzGTzidsXZ45COBi3aPDZfR2LBttKiHmZdZYgFCm1pepZGHu2jWk/rX6?= =?us-ascii?Q?cLvL4FERdM0Sn4tfpY8kBdmsipLvjGU8Asy9L4np22wmSy9XtOF/NANFAmHn?= =?us-ascii?Q?0D9iqJsYvKUnXJcQd8yr26jX+YikUVM/xlbefRJFAvl5PUAcR6USTZeCknHz?= =?us-ascii?Q?D38T2wACEj4rsEMAnE/2glfusyJIicr9aEazyNVpCbYLVUfyvZF3MK0jB3DK?= =?us-ascii?Q?yr+rUoEg6FaXEGwZstgI0W/VebiWgiCxuSuZ0nv9jYwcse35VcVoCWgj+Dgw?= =?us-ascii?Q?qpG6g0fzP/4ADB3yzkErYTSVh/v1SR39RsgJzPAOb0bBary5ns6ZGA/oE7GA?= =?us-ascii?Q?eQS4kHTaiBryVFSJaGY7X/GWPa9VuLAk5E1iuywE?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 94e8a737-876f-48a0-8728-08dd687d267e X-MS-Exchange-CrossTenant-AuthSource: CH3PR12MB8659.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Mar 2025 13:34:48.7320 (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: 2IuKN+c69obwKlXgvMZcNaAn7QIs6xSQ3A/LOHPLvALE5hVpcbucYwMIZQZ7Ol0j X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN0PR12MB5761 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250321_133455_903364_0D5B01BB X-CRM114-Status: GOOD ( 17.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Mar 19, 2025 at 06:55:42PM -0700, Changyuan Lyu wrote: > From: Alexander Graf > > Add the core infrastructure to generate Kexec HandOver metadata. Kexec > HandOver is a mechanism that allows Linux to preserve state - arbitrary > properties as well as memory locations - across kexec. > > It does so using 2 concepts: > > 1) State Tree - Every KHO kexec carries a state tree that describes the > state of the system. The state tree is represented as hash-tables. > Device drivers can add/remove their data into/from the state tree at > system runtime. On kexec, the tree is converted to FDT (flattened > device tree). Why are we changing this? I much prefered the idea of having recursive FDTs than this notion copying eveything into tables then out into FDT? Now that we have the preserved pages mechanism there is a pretty direct path to doing recursive FDT. I feel like this patch is premature, it should come later in the project along with a stronger justification for this approach. IHMO keep things simple for this series, just the very basics. > +int register_kho_notifier(struct notifier_block *nb) > +{ > + return blocking_notifier_chain_register(&kho_out.chain_head, nb); > +} > +EXPORT_SYMBOL_GPL(register_kho_notifier); And another different set of notifiers? :( > +static int kho_finalize(void) > +{ > + int err = 0; > + void *fdt; > + > + fdt = kvmalloc(kho_out.fdt_max, GFP_KERNEL); > + if (!fdt) > + return -ENOMEM; We go to all the trouble of keeping track of stuff in dynamic hashes but still can't automatically size the fdt and keep the dumb uapi to have the user say? :( :( Jason