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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 SJ5PEPF00000204.mail.protection.outlook.com (10.167.244.37) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.19 via Frontend Transport; Thu, 19 Mar 2026 01:15:17 +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, 18 Mar 2026 20:15:15 -0500 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 v7 1/7] dax/hmem: Request cxl_acpi and cxl_pci before walking Soft Reserved ranges Date: Thu, 19 Mar 2026 01:14:54 +0000 Message-ID: <20260319011500.241426-2-Smita.KoralahalliChannabasappa@amd.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20260319011500.241426-1-Smita.KoralahalliChannabasappa@amd.com> References: <20260319011500.241426-1-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: SJ5PEPF00000204:EE_|DM4PR12MB5938:EE_ X-MS-Office365-Filtering-Correlation-Id: 3afc2214-50de-4d3f-1dbe-08de8554fbb3 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|36860700016|7416014|376014|30052699003|1800799024|56012099003|18002099003|22082099003; X-Microsoft-Antispam-Message-Info: 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 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)(82310400026)(36860700016)(7416014)(376014)(30052699003)(1800799024)(56012099003)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: lgDkLkM+QnRzxv9uZULp94QKeXfZiuz1Z8ZNC8228IuV08o9+AElD4mrMJ7ZN0TwiMJLdZVQzX7M74xrsDyDhyFwcMfnMEhvd7I9GloUzLsjVAp2WaV+b93KBqgLfrMwMaPnPa+c5/nRG8l7GeBxzu0yHg1Pbx5+tQ5hwZ7dUu/hottbH9e4QCN6WhC+OnnoAfe/A0gHFWT8aSiOpNaQi9fgPFTMXDnO/vsmMpJCWypo3UxxApJ7BUh5iW9HcjyauI0EuqjvBpUQ4Q6RJ1E2kG2JDtyQQf2PU89mnoEnRS/jZuIN03ubnbXEAQmernNj2ZwKUfJA8tLCraAF8Np9f0HCN/hw9YmaGAiML7VRr3AkfwVta4SGJQnVosoDV1ACHIhVd5+s/bBqG8NMwRrbfEly0F36qBjuA5xu3Bi9tEyvk6tNHuw3b+otmg8KnG3l X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Mar 2026 01:15:17.8421 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 3afc2214-50de-4d3f-1dbe-08de8554fbb3 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: SJ5PEPF00000204.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB5938 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 Reviewed-by: Alison Schofield --- 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