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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by DS3PEPF000099DC.mail.protection.outlook.com (10.167.17.198) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9564.3 via Frontend Transport; Thu, 22 Jan 2026 04:55:56 +0000 Received: from ethanolx50f7host.amd.com (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Wed, 21 Jan 2026 22:55:54 -0600 From: Smita Koralahalli To: , , , , CC: Ard Biesheuvel , Alison Schofield , Vishal Verma , "Ira Weiny" , Dan Williams , Jonathan Cameron , Yazen Ghannam , Dave Jiang , Davidlohr Bueso , Matthew Wilcox , Jan Kara , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Li Ming , Jeff Johnson , "Ying Huang" , Yao Xingtao , Peter Zijlstra , Greg Kroah-Hartman , Nathan Fontenot , Terry Bowman , Robert Richter , Benjamin Cheatham , Zhijian Li , Borislav Petkov , Smita Koralahalli , Tomasz Wolski Subject: [PATCH v5 1/7] dax/hmem: Request cxl_acpi and cxl_pci before walking Soft Reserved ranges Date: Thu, 22 Jan 2026 04:55:37 +0000 Message-ID: <20260122045543.218194-2-Smita.KoralahalliChannabasappa@amd.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20260122045543.218194-1-Smita.KoralahalliChannabasappa@amd.com> References: <20260122045543.218194-1-Smita.KoralahalliChannabasappa@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: satlexmb08.amd.com (10.181.42.217) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS3PEPF000099DC:EE_|IA1PR12MB6460:EE_ X-MS-Office365-Filtering-Correlation-Id: 5af0b657-deb5-446e-e159-08de59728735 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|82310400026|30052699003|36860700013|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?AwTViOPY7mKAjMe+XLampD41rIjCC4Fr7IAdkmqhfiDsY0zi44P/96uA4Vma?= =?us-ascii?Q?OVNt93hzxDOtTIXRJaMxmGYuICz2DBS5sm/5hwhQITdg/FgE4gZhi1j+tm1S?= =?us-ascii?Q?K2HkWSOpBgkh3I84jVmTKrwhBmIC/rCfg3n3u0JhuXS5naed+sWnx5ny/33E?= =?us-ascii?Q?WEKS+eo7Gi7aVj9PRfzjVMCa8WAaXF6jHaETVFP8Lw2Q5wszUWN9CmpFlUdw?= =?us-ascii?Q?oEvh3QKJv+DqBbykvsVv/WWjjcrhGWeS11w+UC5H6ZmGh4iXQLHlYeN96jF9?= =?us-ascii?Q?jUe0ddEwz5ZvV58+BoYODfbf8JkGNUBCcMOYtvuda+DlZ3DN25dfCSyh2p9o?= =?us-ascii?Q?YxbWCl/MmKZAERfUHimIXGyS5X4FXgfD6ka8Of4vqKLpsQKw63ozGu/QjUfk?= =?us-ascii?Q?N54ZZUCIS1dNEuG6EpeLXvn8WSccl2HpVhFpVILMayqOFWbet6D48mkRnqWk?= =?us-ascii?Q?E5t+IY8tF8V4jkRlR7pTQZd6qPjn3ZqbY83+n7U/XpvcEHl0n56sbQdOVjGx?= =?us-ascii?Q?gL08sB9Iea6fdCRDjij3nehMMBKpIMYuugLkzgVtye3RWSxoRc7RgyQpBexq?= =?us-ascii?Q?LTVWV33up3ifl8Re0S0TSTM9FwLhz81zbXvLViyLBi53gUKURyXemxGt0moj?= =?us-ascii?Q?T+ApmRdXc6yT66YJ+FZcMTGSDom2Gh87Uk9l9ee9xrTncQFtGbdKoyv3rWrh?= =?us-ascii?Q?lGEXTDE7rMbMy/4n6a+Yu3m9JbaTRep9K8C4F+sr+f1bE9eoxcVsUt7AoHSm?= =?us-ascii?Q?/s4mjBz6KniUUXhkbxNhkvhHbRuipikgcO9ujBNKfJgzWNLfhijLLDAHqjtc?= =?us-ascii?Q?XZ9+yeLjFDvItSE8niQ3hMN5CcO118Oab4b1j14PIPC2QyGGJCZxNpTeJ2nr?= =?us-ascii?Q?s1oSJAdXCQknvIVt4UlnkD7YVkMwgw8Z6g5J/TUhQvr4PsGH+xduQqbrxGSg?= =?us-ascii?Q?KnYkRqC0ANi5JZNrZoZF/jkZTkhEb5eZEaGS7sl2BCrR82Gl+MVXoOScAtIi?= =?us-ascii?Q?yt+IEN0GlDfA6f0s7HyzenZ7t+DK3vkl+882FeoWW9HrPSPTkNgYxcktkf3O?= =?us-ascii?Q?9LgDXiXkjhSzkiwK77LtoUn7lT42r/4OdLzTBMeyGvL1j3uiwSRzv1s/xZW7?= =?us-ascii?Q?VX5sQ0LkiNc09ihsloL2BWu+Q/0ExugGKuLgBckJoUPC1MnaY29U4Yy8VQyq?= =?us-ascii?Q?l6wLB7EBIsvDJImhpxxI5hUn5i+iEcdTb/Tb6Mu+GNA8Hg/xLN5J9O8CBYVf?= =?us-ascii?Q?W8pLBIsoT9hLzY8Xhrq6CnVBEXZgiPx9bq2L91/z/H88hooDLAHq9YjI+lmG?= =?us-ascii?Q?ftEGlQ6pwKSA2pVwj+xWhsAPDix1bQifHWPCzl+Flue68iYdEN+eoX8AsI6f?= =?us-ascii?Q?H2SCzB5x6HG/m/hY6n3xuuBpJ7IcS6u/atdzQDmvjSKZhplMa00eRksVuZP+?= =?us-ascii?Q?4Fd+jwrtWjWBOm5VFW1/P01gZnVK6BRipl41BtluBqmGHKJmq0UvRvpYHsr1?= =?us-ascii?Q?/pzPX7AiG1t6Tl+tiPJUrw3HrZ3sr/t5XBiaMkmNf0hI6GkVI6xuliWHqjno?= =?us-ascii?Q?KwshR2sy/83E25YaOk2xUzIaPXxLbyGHb3FLV1gg9cvBTVS2KFalNdtsc1Z2?= =?us-ascii?Q?8SflOQnJU+EY78B1G5ZW0Zfr+HcjSoIYe5iJHXx27ukrD2lU6Rp2MnBcEENL?= =?us-ascii?Q?KuPBtg=3D=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(376014)(7416014)(82310400026)(30052699003)(36860700013)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Jan 2026 04:55:56.1996 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 5af0b657-deb5-446e-e159-08de59728735 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: DS3PEPF000099DC.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB6460 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Dan Williams Ensure cxl_acpi has published CXL Window resources before HMEM walks Soft Reserved ranges. Replace MODULE_SOFTDEP("pre: cxl_acpi") with an explicit, synchronous request_module("cxl_acpi"). MODULE_SOFTDEP() only guarantees eventual loading, it does not enforce that the dependency has finished init before the current module runs. This can cause HMEM to start before cxl_acpi has populated the resource tree, breaking detection of overlaps between Soft Reserved and CXL Windows. Also, request cxl_pci before HMEM walks Soft Reserved ranges. Unlike cxl_acpi, cxl_pci attach is asynchronous and creates dependent devices that trigger further module loads. Asynchronous probe flushing (wait_for_device_probe()) is added later in the series in a deferred context before HMEM makes ownership decisions for Soft Reserved ranges. Add an additional explicit Kconfig ordering so that CXL_ACPI and CXL_PCI must be initialized before DEV_DAX_HMEM. This prevents HMEM from consuming Soft Reserved ranges before CXL drivers have had a chance to claim them. Signed-off-by: Dan Williams Signed-off-by: Smita Koralahalli Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron --- drivers/dax/Kconfig | 2 ++ drivers/dax/hmem/hmem.c | 17 ++++++++++------- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig index d656e4c0eb84..3683bb3f2311 100644 --- a/drivers/dax/Kconfig +++ b/drivers/dax/Kconfig @@ -48,6 +48,8 @@ config DEV_DAX_CXL tristate "CXL DAX: direct access to CXL RAM regions" depends on CXL_BUS && CXL_REGION && DEV_DAX default CXL_REGION && DEV_DAX + depends on CXL_ACPI >=3D DEV_DAX_HMEM + depends on CXL_PCI >=3D DEV_DAX_HMEM help CXL RAM regions are either mapped by platform-firmware and published in the initial system-memory map as "System RAM", mapped diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c index 1cf7c2a0ee1c..008172fc3607 100644 --- a/drivers/dax/hmem/hmem.c +++ b/drivers/dax/hmem/hmem.c @@ -139,6 +139,16 @@ static __init int dax_hmem_init(void) { int rc; =20 + /* + * Ensure that cxl_acpi and cxl_pci have a chance to kick off + * CXL topology discovery at least once before scanning the + * iomem resource tree for IORES_DESC_CXL resources. + */ + if (IS_ENABLED(CONFIG_DEV_DAX_CXL)) { + request_module("cxl_acpi"); + request_module("cxl_pci"); + } + rc =3D platform_driver_register(&dax_hmem_platform_driver); if (rc) return rc; @@ -159,13 +169,6 @@ static __exit void dax_hmem_exit(void) module_init(dax_hmem_init); module_exit(dax_hmem_exit); =20 -/* Allow for CXL to define its own dax regions */ -#if IS_ENABLED(CONFIG_CXL_REGION) -#if IS_MODULE(CONFIG_CXL_ACPI) -MODULE_SOFTDEP("pre: cxl_acpi"); -#endif -#endif - MODULE_ALIAS("platform:hmem*"); MODULE_ALIAS("platform:hmem_platform*"); MODULE_DESCRIPTION("HMEM DAX: direct access to 'specific purpose' memory"); --=20 2.17.1