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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 SA2PEPF000015CC.mail.protection.outlook.com (10.167.241.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9846.18 via Frontend Transport; Wed, 29 Apr 2026 21:14:58 +0000 Received: from [10.236.188.223] (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, 29 Apr 2026 16:14:56 -0500 Message-ID: <0c647fd0-08bf-41bd-815b-59e14f793a92@amd.com> Date: Wed, 29 Apr 2026 16:14:56 -0500 Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: "Cheatham, Benjamin" Subject: Re: [PATCH v26 7/8] cxl: Avoid dax creation for accelerators To: , , , , , , , , CC: Alejandro Lucero , Jonathan Cameron , Davidlohr Bueso References: <20260423180528.17166-1-alejandro.lucero-palau@amd.com> <20260423180528.17166-8-alejandro.lucero-palau@amd.com> Content-Language: en-US In-Reply-To: <20260423180528.17166-8-alejandro.lucero-palau@amd.com> Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: TSapy13QPKtoLEAi001heVXORSlmJcIWTYLcBSYmm9bfqvraJjY2pF9HorSIf/MASVUT9cv8dy6svuZ8fvDcfRjkSNFLvO3xWIk4r+wuX4Km3w4Q8HaaW9c7iyuMGFl7LKVnv4oqcI0oHSz7UHa+wzBVwRsNMaHAoUcTi8PtGgAuvC4RytXOxPge5+bilSxDkrGpPVV4ZCLsQnj+z4+rsDDfus5Hv0dlhpbPjPy+t5AY5H/X+FKtIRhMAkErL9ZlRXSeb4xDyTSKTZza7oWB89Ik93P2CWg1V9CWvXbKeKs6uvGYawAICt2OxIVxr1gHrXd4WeCc1DrXJhrcrR3908xjlLj6fbl+vHAAELx2bBNVTCRjlZa19VdUxKiA4u7+4rY7Q/I16N1SxnqrRS2YDdFwlDyHGkfMyOWb+ezror/ghILynnfR9lFJUN71HasA X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Apr 2026 21:14:58.3016 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: f01075a3-9cda-44d4-f5c1-08dea6345e4a 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: SA2PEPF000015CC.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB4184 On 4/23/2026 1:05 PM, alejandro.lucero-palau@amd.com wrote: > From: Alejandro Lucero > > By definition a type2 cxl device will use the host managed memory for > specific functionality, therefore it should not be available to other > uses like DAX. > > Signed-off-by: Alejandro Lucero > Reviewed-by: Jonathan Cameron > Reviewed-by: Davidlohr Bueso > Reviewed-by: Dave Jiang > Reviewed-by: Ben Cheatham > --- > drivers/cxl/core/region.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 68f5a1fd1b1c..3af2aed6c6f1 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -4165,6 +4165,13 @@ static int cxl_region_probe(struct device *dev) > if (rc) > return rc; > > + /* > + * HDM-D[B] (device-memory) regions have accelerator specific usage. > + * Skip device-dax registration. > + */ > + if (cxlr->type == CXL_DECODER_DEVMEM) > + return 0; This should probably go before the call to cxl_region_can_probe() to avoid taking the cxl_rwsem. Not really a deal-breaker but would be a good optimization. Thanks, Ben > + > /* > * From this point on any path that changes the region's state away from > * CXL_CONFIG_COMMIT is also responsible for releasing the driver.