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client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by SJ5PEPF000001D0.mail.protection.outlook.com (10.167.242.52) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8922.22 via Frontend Transport; Tue, 15 Jul 2025 18:04:37 +0000 Received: from ethanolx50f7host.amd.com (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Tue, 15 Jul 2025 13:04:31 -0500 From: Smita Koralahalli To: , , , , CC: Davidlohr Bueso , Jonathan Cameron , Dave Jiang , "Alison Schofield" , Vishal Verma , Ira Weiny , Dan Williams , Matthew Wilcox , Jan Kara , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Li Ming , Jeff Johnson , "Ying Huang" , Yao Xingtao , Peter Zijlstra , Greg KH , Nathan Fontenot , Smita Koralahalli , Terry Bowman , Robert Richter , Benjamin Cheatham , PradeepVineshReddy Kodamati , Zhijian Li Subject: [PATCH v5 7/7] dax/hmem: Preserve fallback SOFT RESERVED regions if DAX HMEM loads late Date: Tue, 15 Jul 2025 18:04:07 +0000 Message-ID: <20250715180407.47426-8-Smita.KoralahalliChannabasappa@amd.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20250715180407.47426-1-Smita.KoralahalliChannabasappa@amd.com> References: <20250715180407.47426-1-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: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ5PEPF000001D0:EE_|DM4PR12MB7766:EE_ X-MS-Office365-Filtering-Correlation-Id: 9fae8456-d4d0-43e4-6ae4-08ddc3ca0fd7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|7416014|82310400026|376014|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?1+OLS+w25xnx1ozt0pjA/srbemWhaWb6fTqtW+jC53w+0HqWi1BAvldHlbIa?= =?us-ascii?Q?eSTDA+OkfhRmRZ4DXQLwpYh67mfzM1+nTLypIXfhceLmxMTLc6TXICejjGUF?= =?us-ascii?Q?dmzh/+v3vNKcIxOHUyJbR6/6K7w2vg3JUJyt4cpspLaSCFV7o0arRIgIu5VF?= =?us-ascii?Q?gOwKkwBnZZGcorAhiAxenWFffUg/dRAoXbLSLbLkn52hguZK4Hy5EIkYca+G?= =?us-ascii?Q?8n0mZGH3m6Tqb7VrMNDg/ZSgUsiwSKk+EHjF6pnsr7pycqatz3e/+AWM7Hud?= =?us-ascii?Q?zxo+fc4S515f10/N2/k2S/SY7/YUSzTxAb8iuXvJD8uFCkPZ4WKYvTIbSP88?= =?us-ascii?Q?FXeyd0KOlEadHsFERFIctm2M+ux2nRLN5nfAvbqvfodmBMFcq8dfS1V248gq?= =?us-ascii?Q?hKUjgB42VftfUvxto6imyCAncdPWDHn0SduTp6zqFwz9vZp8VBWg/6DrEdEf?= =?us-ascii?Q?BpmbvHk5CI9bFntZagbpQVo3A6Rl0xD7MBzGGwFccWfifp1UQZ89Up26gwkQ?= =?us-ascii?Q?O7G/sPEABIUQsTqKAEjeSIzIUcBZkwRLGQprLhQqRj1J8lTY5sA687MxdyYi?= =?us-ascii?Q?aTqd/1BoZ7q8peTmNwuuqXwNYadoQ1+1gvmy4b9mn2vIZopjyzfspB44+UI4?= =?us-ascii?Q?PnmbcWTataQSmGd65R/FUi3OwNnHUOhHx55vkz67QCbtodffzTodAPI/iYN1?= =?us-ascii?Q?bTmojKGhTtzbp8pciNolSiyUPAdSH8+/ssJbiZR5ESGbHnPK0MHPt29Va7Oh?= =?us-ascii?Q?6uqa9fHFA9a0TRN7tiRE2kWO4sEeca7JN2xyBSuHV6B2o44e4sH5bT8sNGcT?= =?us-ascii?Q?7TvZpyIsQBVHr9VP2bna1PzDRBbMO7H2RiE061pgvXk9HUbitu/2zv6MxBGy?= =?us-ascii?Q?8MX3Zn71d4T3w0OmZiGXPtdNFSfX9mUQ5Tu7tm9wbJMEPvv1/AXMTa3J+4FZ?= =?us-ascii?Q?cYSxAEUPmQGWxHq1RboMVguZ0fJxJz6aw4ErfRD9Hh7gszXsEp4N3brzUb4h?= =?us-ascii?Q?DimunDPkA5TFr/WT4yiPjyJ317Gy5yCKqNO00o76GYR5Zf4+lVRa2serbjh8?= =?us-ascii?Q?2DSxX0ND70bjJJM94l+AB+6MB0WNdhoeABtCwHIR/3nSEgerZ4duRl+Jr6F8?= =?us-ascii?Q?awkxPGF/mXYU3lx02ArGo6Pwfb3lKWJw7AfbKMG1RwiZk1x/OiXsrMwU1B5W?= =?us-ascii?Q?K5ERek0mJIrT+8FZ1LwpGR29NyUNo/lQXr9mLL5T3tvtGCr9JETBubjRslrD?= =?us-ascii?Q?eAEhAqQg5x2zmGJTk2mPVBrvy7JsOWnyzcFnmQogqkNH3NRl2SU/HGjxAOks?= =?us-ascii?Q?vweE5HvJqdxDK2yqGusOcFtKgzKqZBtmqaCJFdd/S8hB845evWipdpydHBLU?= =?us-ascii?Q?C8Hmuo02d3Q4VLyteVnNMAXEdwOS8QjkBOmEkuLMq2j03N50i6JvaSgcAAX1?= =?us-ascii?Q?5evQ4hqS7c6FEtjR/Z+zbBcqskElg7Gl+iEHswW5y+bRUVp1P4wlxJGgfPLR?= =?us-ascii?Q?vv5Mc07pPUQzn973OYxsGkSUKXF28eV8pQ+a?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(36860700013)(7416014)(82310400026)(376014)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Jul 2025 18:04:37.1719 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 9fae8456-d4d0-43e4-6ae4-08ddc3ca0fd7 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=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SJ5PEPF000001D0.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB7766 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" After CXL completes trimming SOFT RESERVED ranges that intersect with CXL regions, it invokes hmem_fallback_register_device() to register any leftover ranges. If this occurs before the DAX HMEM driver has initialized, the call becomes a no-op and those resources are lost. To prevent this, store fallback-registered resources in a separate deferred tree (hmem_deferred_active). When the DAX HMEM driver is initialized, it walks this deferred list to properly register DAX devices. Signed-off-by: Smita Koralahalli --- drivers/dax/hmem/device.c | 17 +++++++++++++---- drivers/dax/hmem/hmem.c | 1 - drivers/dax/hmem/hmem_notify.c | 2 ++ 3 files changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/dax/hmem/device.c b/drivers/dax/hmem/device.c index cc1ed7bbdb1a..41c5886a30d1 100644 --- a/drivers/dax/hmem/device.c +++ b/drivers/dax/hmem/device.c @@ -16,13 +16,21 @@ static struct resource hmem_active =3D { .flags =3D IORESOURCE_MEM, }; =20 +static struct resource hmem_deferred_active =3D { + .name =3D "Deferred HMEM devices", + .start =3D 0, + .end =3D -1, + .flags =3D IORESOURCE_MEM, +}; +static struct resource *hmem_resource_root =3D &hmem_active; + int walk_hmem_resources(walk_hmem_fn fn) { struct resource *res; int rc =3D 0; =20 mutex_lock(&hmem_resource_lock); - for (res =3D hmem_active.child; res; res =3D res->sibling) { + for (res =3D hmem_resource_root->child; res; res =3D res->sibling) { rc =3D fn((int) res->desc, res); if (rc) break; @@ -36,8 +44,8 @@ static void __hmem_register_resource(int target_nid, stru= ct resource *res) { struct resource *new; =20 - new =3D __request_region(&hmem_active, res->start, resource_size(res), "", - 0); + new =3D __request_region(hmem_resource_root, res->start, + resource_size(res), "", 0); if (!new) { pr_debug("hmem range %pr already active\n", res); return; @@ -72,7 +80,8 @@ static __init int hmem_init(void) walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED, IORESOURCE_MEM, 0, -1, NULL, hmem_register_one); - } + } else + hmem_resource_root =3D &hmem_deferred_active; =20 pdev =3D platform_device_alloc("hmem_platform", 0); if (!pdev) { diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c index 16873ae0a53b..76a381c274a8 100644 --- a/drivers/dax/hmem/hmem.c +++ b/drivers/dax/hmem/hmem.c @@ -131,7 +131,6 @@ static int dax_hmem_platform_probe(struct platform_devi= ce *pdev) =20 if (IS_ENABLED(CONFIG_CXL_ACPI)) { hmem_register_fallback_handler(hmem_register_device); - return 0; } =20 return walk_hmem_resources(hmem_register_device); diff --git a/drivers/dax/hmem/hmem_notify.c b/drivers/dax/hmem/hmem_notify.c index 1b366ffbda66..6c276c5bd51d 100644 --- a/drivers/dax/hmem/hmem_notify.c +++ b/drivers/dax/hmem/hmem_notify.c @@ -23,5 +23,7 @@ void hmem_fallback_register_device(int target_nid, const = struct resource *res) =20 if (hmem_fn) hmem_fn(target_nid, res); + else + hmem_register_resource(target_nid, (struct resource *)res); } EXPORT_SYMBOL_GPL(hmem_fallback_register_device); --=20 2.17.1