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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 DS3PEPF0000C380.mail.protection.outlook.com (10.167.23.10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.19 via Frontend Transport; Sun, 22 Mar 2026 19:53:57 +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; Sun, 22 Mar 2026 14:53:55 -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 v8 3/9] dax/hmem: Request cxl_acpi and cxl_pci before walking Soft Reserved ranges Date: Sun, 22 Mar 2026 19:53:36 +0000 Message-ID: <20260322195343.206900-4-Smita.KoralahalliChannabasappa@amd.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20260322195343.206900-1-Smita.KoralahalliChannabasappa@amd.com> References: <20260322195343.206900-1-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: DS3PEPF0000C380:EE_|DS3PR12MB999218:EE_ X-MS-Office365-Filtering-Correlation-Id: a3dc9e3d-37e7-4d37-e5b2-08de884cc10a X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|36860700016|7416014|376014|30052699003|1800799024|18002099003|22082099003|56012099003; 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)(18002099003)(22082099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 7xi857Afszol2T7jFsFv36cEeGPG6L+EddHOSMUmgVjK3bnrYTur/EdMDy6DiCFyV3a44D59OtrogN0TufWnHP3aLLJleCf4Fs6OlDpPnwRuBg0g3MTbFFSq3TvnRhjZG4+nkWHQzmlN48rpkAaADsVBeiIsZ79tolAnnhYzxB+wR0Trx8DyXAbOeuspGiOMoThMPYoTTlrH0aTxkSzEEWJHecrqb38A5vlRsmD/J6oV1WExtwt7tImvuiv3goGLLW6b19vPryTEEzsXbmAh0p2MaWQGHuaUVCBgt9rScbH7sGFq/PdNNelnjLemDGYgrKNa1X8qbfBYo77TiE4AFslm2mkHvf10sxv9bIQEok5DUBCJ6/83Tq4JedsKh1YRsrcWdLs0bFhfaTuDhK43R27AOlBJO3qhfxUKGIqmINd3pprWEphF4EtBQiU0clkF X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Mar 2026 19:53:57.0009 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: a3dc9e3d-37e7-4d37-e5b2-08de884cc10a 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: DS3PEPF0000C380.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS3PR12MB999218 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 a3d45032355c..85e751675f65 100644 --- a/drivers/dax/hmem/hmem.c +++ b/drivers/dax/hmem/hmem.c @@ -145,6 +145,16 @@ 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; @@ -165,13 +175,6 @@ 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