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De Francesco" , Terry Bowman , Joshua Hahn , Robert Richter Subject: [PATCH v8 07/13] cxl/region: Use region data to get the root decoder Date: Tue, 9 Dec 2025 19:06:43 +0100 Message-ID: <20251209180659.208842-8-rrichter@amd.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251209180659.208842-1-rrichter@amd.com> References: <20251209180659.208842-1-rrichter@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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: MWH0EPF000989EA:EE_|PH7PR12MB6396:EE_ X-MS-Office365-Filtering-Correlation-Id: f5a21206-6671-43c3-4caa-08de374df185 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|1800799024|82310400026|7416014|376014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?i0qYTXD+TFhrlB3mYPwbbgsK93jHnCzrL/tBn3iv7/UZi/w045zXOow+CgNS?= =?us-ascii?Q?fiXJo2+JQjUEhKPJRoHDR7rmdv9R5C6pths+zjm8JN75TGJRbv2xPy8oTRTw?= =?us-ascii?Q?RhQCc/q9WFnQsdxbc+QYrmsto+pj7C114PsE3PFZdKIHgzf8Qhn7e+aehj++?= =?us-ascii?Q?IYi8rxbJIza2Yu7eYqG3lcW/ubU896oVRUzLLkX5Iyy9N/G58JHymuxDviT7?= =?us-ascii?Q?8J8wRhY0VRgHzv7HwUXcMsc3PR5dupwlG4/isD02XY1qtaQsvjfiLgUhFdPH?= =?us-ascii?Q?qCYUiudaVkL5MuDc+52hxltw1bUqjrlWzGdicZimBW3io7BJDHpuZNf4z26F?= =?us-ascii?Q?dC8d2S0bnb4tpRutFTpaNRPAVfbNQzDQR/I2mhsJAIbhT2k0Y5L/Job9Vm42?= =?us-ascii?Q?7IpLuLUksBMFeiWX6od3QYAx37wIKV75kSafXkZy/Po6/mjBzW+IH3DK7nn0?= =?us-ascii?Q?BRWcI6oFP+j3E6T04S5HiMYJ37SUBKccKUgqGAcqhYsklqL5VlBJ31IsjM5K?= =?us-ascii?Q?+Fcy8Xp1aSCHLGOg0R52KqHZWr/bTJs9Zi6/m89fqqo7c3y25V35a0s8KbJi?= =?us-ascii?Q?rf5udJsPi9S6nE/Tu0PFD3YK+yHetyOImjNPmQvux0EIj47wdHeVOyOLzedr?= =?us-ascii?Q?6tP+W/2TVBP+I7x2Y49oKbeIXnUXXaTm9HydlwidKjibPZ6kl071Cmsx0To5?= =?us-ascii?Q?f/9Fmmx81o+ID9h+Za4kjvqz8vHJ3HmSBv6cZl9dSJYfDK3fgUrbULlpEILH?= =?us-ascii?Q?pfoAzMaLHdJYmlSX9ywNqCH0H8zeUAksCTN2QOe8LeX4iDIACYbJiQtrXcDA?= =?us-ascii?Q?ULce8SXKwqSGo5x/mLCYRggUzpZVvm70UUrFQXWpOH8TIFcNPnrZ2sXds0S8?= =?us-ascii?Q?f5D/slWJK7jzgKTEdzXMD8Ha3c7QLDWxEmpip5fl9CzTiAVih7zdA5H4C20K?= =?us-ascii?Q?WD6rGAWav6Y9u1fPMRlOcA8mGO0nOGjCZpVU9Jxg5KypbZu77G4nVRsq250X?= =?us-ascii?Q?hGR0VCuOq2yoD5jZ+gqGMOnkYCqyhm0+ro6PKDusui3B1RPU1MS/XQGJsFlH?= =?us-ascii?Q?pfRFc90zfZBfDCUUxiPVNMuKyE/TU0w8LWpRhhfm6awW+WoyQM1yb1pYXoJy?= =?us-ascii?Q?mwUsTBwiJkszgoETg7Mb1SIExBELg3zjlb2DKoNvpPc9VBUBBS7a4MYrimM6?= =?us-ascii?Q?of6LuK7qaYc+bmEDZJ7AhzuUio+BD1Oto3Lq6XtzpWcs5ODgW2eHslRXK2NG?= =?us-ascii?Q?WtblDAgbHyQ7EQ6flhPHZobo/vfkNmqyB0/UHfTZg6xUXsAKfGlO/Ac5/GQU?= =?us-ascii?Q?sZuc8OFxWgkVZJDDfZebuR6vmKUxfNxfMdeyCtCzjcek0X0+5bUZ28O/UnmO?= =?us-ascii?Q?h3rUDN6lGW7rvJA4Zg0kVS0bkNn6FrxFpNPBtKNROE4T6oMGmO9GcFh56ald?= =?us-ascii?Q?02i+XmyVO4JEv0u3JmLNddrGdQdW/tm4j065LGc/F/1c47sfmUYdWFimfQTw?= =?us-ascii?Q?/Ij2ct8bP2H+bXbsZl9MJX6hffADxoO3U1K8++t3MMEzvABPzzwHuPN1/7mF?= =?us-ascii?Q?xwfMHyiMQbRd667TclU=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)(36860700013)(1800799024)(82310400026)(7416014)(376014);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Dec 2025 18:08:23.6470 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: f5a21206-6671-43c3-4caa-08de374df185 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: MWH0EPF000989EA.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB6396 Content-Type: text/plain; charset="utf-8" To find a region's root decoder, the endpoint's HPA range is used to search the matching decoder by its range. With address translation the endpoint decoder's range is in a different address space and thus cannot be used to determine the root decoder. The region parameters are encapsulated within struc cxl_region_context and may include the translated Host Physical Address (HPA) range. Use this context to identify the root decoder rather than relying on the endpoint. Modify cxl_find_root_decoder() and add the region context as parameter. Rename this function to get_cxl_root_decoder() as a counterpart to put_cxl_root_decoder(). Simplify the implementation by removing function cxl_port_find_switch_decode(). The function is unnecessary because it is not referenced or utilized elsewhere in the code. Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Tested-by: Gregory Price Signed-off-by: Robert Richter --- drivers/cxl/core/region.c | 50 +++++++++++++++++++-------------------- 1 file changed, 24 insertions(+), 26 deletions(-) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 71e80223f475..e4efb281def4 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -3466,47 +3466,44 @@ static int devm_cxl_add_dax_region(struct cxl_regio= n *cxlr) return rc; } =20 -static int match_decoder_by_range(struct device *dev, const void *data) +static int match_root_decoder(struct device *dev, const void *data) { const struct range *r1, *r2 =3D data; - struct cxl_decoder *cxld; + struct cxl_root_decoder *cxlrd; =20 - if (!is_switch_decoder(dev)) + if (!is_root_decoder(dev)) return 0; =20 - cxld =3D to_cxl_decoder(dev); - r1 =3D &cxld->hpa_range; - return range_contains(r1, r2); -} - -static struct cxl_decoder * -cxl_port_find_switch_decoder(struct cxl_port *port, struct range *hpa_rang= e) -{ - struct device *cxld_dev =3D device_find_child(&port->dev, hpa_range, - match_decoder_by_range); + cxlrd =3D to_cxl_root_decoder(dev); + r1 =3D &cxlrd->cxlsd.cxld.hpa_range; =20 - return cxld_dev ? to_cxl_decoder(cxld_dev) : NULL; + return range_contains(r1, r2); } =20 +/* + * Note, when finished with the device, drop the reference with + * put_device() or use the put_cxl_root_decoder helper. + */ static struct cxl_root_decoder * -cxl_find_root_decoder(struct cxl_endpoint_decoder *cxled) +get_cxl_root_decoder(struct cxl_endpoint_decoder *cxled, + struct cxl_region_context *ctx) { struct cxl_memdev *cxlmd =3D cxled_to_memdev(cxled); struct cxl_port *port =3D cxled_to_port(cxled); struct cxl_root *cxl_root __free(put_cxl_root) =3D find_cxl_root(port); - struct cxl_decoder *root, *cxld =3D &cxled->cxld; - struct range *hpa_range =3D &cxld->hpa_range; + struct device *cxlrd_dev; =20 - root =3D cxl_port_find_switch_decoder(&cxl_root->port, hpa_range); - if (!root) { + cxlrd_dev =3D device_find_child(&cxl_root->port.dev, &ctx->hpa_range, + match_root_decoder); + if (!cxlrd_dev) { dev_err(cxlmd->dev.parent, "%s:%s no CXL window for range %#llx:%#llx\n", - dev_name(&cxlmd->dev), dev_name(&cxld->dev), - hpa_range->start, hpa_range->end); - return NULL; + dev_name(&cxlmd->dev), dev_name(&cxled->cxld.dev), + ctx->hpa_range.start, ctx->hpa_range.end); + return ERR_PTR(-ENXIO); } =20 - return to_cxl_root_decoder(&root->dev); + return to_cxl_root_decoder(cxlrd_dev); } =20 static int match_region_by_range(struct device *dev, const void *data) @@ -3703,9 +3700,10 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *c= xled) }; =20 struct cxl_root_decoder *cxlrd __free(put_cxl_root_decoder) =3D - cxl_find_root_decoder(cxled); - if (!cxlrd) - return -ENXIO; + get_cxl_root_decoder(cxled, &ctx); + + if (IS_ERR(cxlrd)) + return PTR_ERR(cxlrd); =20 /* * Ensure that, if multiple threads race to construct_region() --=20 2.47.3