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De Francesco" , Terry Bowman , Joshua Hahn , Robert Richter Subject: [PATCH v6 07/11] cxl/region: Use region data to get the root decoder Date: Fri, 14 Nov 2025 01:40:12 +0100 Message-ID: <20251114004021.1310661-8-rrichter@amd.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251114004021.1310661-1-rrichter@amd.com> References: <20251114004021.1310661-1-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: SJ1PEPF000023D1:EE_|SA3PR12MB7806:EE_ X-MS-Office365-Filtering-Correlation-Id: 0c3631df-5a62-459c-d546-08de23168a9e X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|7416014|36860700013|376014|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?jB4cwi0TL9iUUPON6uDGji2jVAiaXqVu2XhBZTuNC+n+ELnczpiIVTcjYNGz?= =?us-ascii?Q?f9G2WjcHZfmWmVJsLWSSYDNbSCz9EqE/smhMMCnvUjklJjpwCUArPuMl9vw/?= =?us-ascii?Q?1ddxnvTUS9yho3z0B4WFx+xfWEHhV7mgtbR/55PqkIs0CZ9OTH2UXQ9PoqMm?= =?us-ascii?Q?OumetDzemJujfRsOFk1DKgStoNJ7+EX78s20185wbBKL2VsQ1gzceYqBbKhq?= =?us-ascii?Q?9UCAIiFb8CdPUCU+SUI5kyyrqHuT9AQ94lGThde/Vd5eAv0B4SBNOVn8+ooV?= =?us-ascii?Q?Wtd9VAEzWX2Nq12mv3T+9MbbNxs4EwQs/WZd+FTZyGM9NxuBTTa9kZXU6RTH?= =?us-ascii?Q?/RRPsVo87IXB/QsOWVTfHBWkDrMNIEVY75WQ+8BeZ0ZCoEzxsO1JBU9AKmFi?= =?us-ascii?Q?Exta+ZOVJ7/UdkT2nyQCrtYuAUEVFH+68an9xGpFosuXAfl6LcBcXlah2y6n?= =?us-ascii?Q?ZhZoxFDTFIGq3Mnze5aLW0Y7EyKbRpWjS3N5XtYfkhMmbljQ+mZiw+A9K/fJ?= =?us-ascii?Q?RB4b5zNPMr6psduquoTqGxp1S1+gz/4VTs+cloQkAGHK7710ulq6a0MzeTXM?= =?us-ascii?Q?8GpOR1mUev/bCKFX6RrMx3tsH/zvXwHd1xhvt3DKe61M4PE9jm2hmhZdHYPL?= =?us-ascii?Q?r0tZW9wF88av9+3vAea3CXEFXqc4Qin6i/H09xDJdLPDc3Sx2E54jLf3IqiC?= =?us-ascii?Q?C99oktGRHM2HVwXklkX9eUDId6aM3L5s26h3J5PY9RF9nZDnxc2eE3o9k1xY?= =?us-ascii?Q?34/KQoW/0tpDwpFZJkw02ljlANyHgJuziQ+rlOsnrLaTLBwd9wx+WniYV53p?= =?us-ascii?Q?kkbbf3S1Tf1hRCSodLSKekjWmrTaR2aEr9OJroxjxsdbQ1qH1C5ynRWmcUf7?= =?us-ascii?Q?G2z0cK1L1DgMO201roWj0Gg8FtOnSHKAK698NTLa9mB3BeKQMlXNWnN1lAVx?= =?us-ascii?Q?IPSPAZO+g+RGYS/AQ7vHdDt9tg0BjeXCdumrSykwi3sXxwGDLzFper+dEsxP?= =?us-ascii?Q?EUqodKtTPZ49um3f7NEKzgaVCOAQgNgYFAl3ygb1lWv5iH3+inifk7Qic3/z?= =?us-ascii?Q?h2UILH5A9Ixgg2F3vJHLfvEwAScWqGZsOINU83Al9+T2cbvOIxo/0bKL4ceq?= =?us-ascii?Q?6wP4yRpC4Xb5TwJ/m+b/R0BfvI/6bohl/uWUmnvCV/lDO6eU3sVeJ2miW6gT?= =?us-ascii?Q?ieAzk2AiyzgOSbF5rGVESTmKTzeADFVWH8RsLwKALtKNDSAXpoVik+bux7Os?= =?us-ascii?Q?rr53gSDH7WlXGIWBhYh9XJ9OX1ODmEQg8z1F36OOuFrSgtQFaNqG5NrPmiVc?= =?us-ascii?Q?VAlbNHb1lFbWdjmQCDaxcywJqzTd9sqhuy+wwqtmFAIlze05YBt7+5iLsP1f?= =?us-ascii?Q?+44/QP240xUqO2puiwb2/btys2nn8ygepB3X6mCLce9DCsQd/sxjWK7CuGUB?= =?us-ascii?Q?hzUrYyZYm3VCemM4mpFbzaFKWPrhwpHvqcRuUIdst+WL/wmSykRs0/4scVCR?= =?us-ascii?Q?AlUOJX0iUSQkhUvs8g38KecR1Dj9XAuXFPewDiScbk+Phz8eGdSmqqqHrcV6?= =?us-ascii?Q?+YIgQ3lj+tcY/Pw/0Gg=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(7416014)(36860700013)(376014)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Nov 2025 00:41:25.3767 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 0c3631df-5a62-459c-d546-08de23168a9e 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: SJ1PEPF000023D1.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA3PR12MB7806 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 01d23a42a6de..c028b772cfab 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -3340,47 +3340,44 @@ 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) @@ -3573,9 +3570,10 @@ 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