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{ "id": 2228583, "url": "http://patchwork.ozlabs.org/api/1.1/covers/2228583/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-pci/cover/cover.1777269009.git.nicolinc@nvidia.com/", "project": { "id": 28, "url": "http://patchwork.ozlabs.org/api/1.1/projects/28/?format=api", "name": "Linux PCI development", "link_name": "linux-pci", "list_id": "linux-pci.vger.kernel.org", "list_email": "linux-pci@vger.kernel.org", "web_url": null, "scm_url": null, "webscm_url": null }, "msgid": "<cover.1777269009.git.nicolinc@nvidia.com>", "date": "2026-04-27T05:53:59", "name": "[v4,0/3] Allow ATS to be always on for certain ATS-capable devices", "submitter": { "id": 82183, "url": "http://patchwork.ozlabs.org/api/1.1/people/82183/?format=api", "name": "Nicolin Chen", "email": "nicolinc@nvidia.com" }, "mbox": "http://patchwork.ozlabs.org/project/linux-pci/cover/cover.1777269009.git.nicolinc@nvidia.com/mbox/", "series": [ { "id": 501574, "url": "http://patchwork.ozlabs.org/api/1.1/series/501574/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-pci/list/?series=501574", "date": "2026-04-27T05:53:59", "name": "Allow ATS to be always on for certain ATS-capable devices", "version": 4, "mbox": "http://patchwork.ozlabs.org/series/501574/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2228583/comments/", "headers": { "Return-Path": "\n <linux-pci+bounces-53200-incoming=patchwork.ozlabs.org@vger.kernel.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linux-pci@vger.kernel.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=Nvidia.com header.i=@Nvidia.com header.a=rsa-sha256\n header.s=selector2 header.b=NbX+2/m6;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c09:e001:a7::12fc:5321; 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pr=C", "From": "Nicolin Chen <nicolinc@nvidia.com>", "To": "<jgg@nvidia.com>, <will@kernel.org>, <robin.murphy@arm.com>,\n\t<bhelgaas@google.com>", "CC": "<joro@8bytes.org>, <praan@google.com>, <baolu.lu@linux.intel.com>,\n\t<kevin.tian@intel.com>, <miko.lenczewski@arm.com>,\n\t<linux-arm-kernel@lists.infradead.org>, <iommu@lists.linux.dev>,\n\t<linux-kernel@vger.kernel.org>, <linux-pci@vger.kernel.org>,\n\t<dan.j.williams@intel.com>, <jonathan.cameron@huawei.com>,\n\t<vsethi@nvidia.com>, <linux-cxl@vger.kernel.org>, <nirmoyd@nvidia.com>", "Subject": "[PATCH v4 0/3] Allow ATS to be always on for certain ATS-capable\n devices", "Date": "Sun, 26 Apr 2026 22:53:59 -0700", "Message-ID": "<cover.1777269009.git.nicolinc@nvidia.com>", "X-Mailer": "git-send-email 2.43.0", "Precedence": "bulk", "X-Mailing-List": "linux-pci@vger.kernel.org", "List-Id": "<linux-pci.vger.kernel.org>", "List-Subscribe": "<mailto:linux-pci+subscribe@vger.kernel.org>", "List-Unsubscribe": "<mailto:linux-pci+unsubscribe@vger.kernel.org>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "Content-Type": "text/plain", "X-NV-OnPremToCloud": "ExternallySecured", "X-EOPAttributedMessage": "0", "X-MS-PublicTrafficType": "Email", "X-MS-TrafficTypeDiagnostic": "CY4PEPF0000EE31:EE_|LVXPR12MB999198:EE_", "X-MS-Office365-Filtering-Correlation-Id": "acda12f8-97e8-4edc-f167-08dea42171f3", "X-MS-Exchange-SenderADCheck": "1", "X-MS-Exchange-AntiSpam-Relay": "0", "X-Microsoft-Antispam": "\n\tBCL:0;ARA:13230040|36860700016|376014|7416014|1800799024|82310400026|56012099003|18002099003|13003099007;", "X-Microsoft-Antispam-Message-Info": "\n\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", "X-Forefront-Antispam-Report": "\n\tCIP:216.228.118.233;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc7edge2.nvidia.com;CAT:NONE;SFS:(13230040)(36860700016)(376014)(7416014)(1800799024)(82310400026)(56012099003)(18002099003)(13003099007);DIR:OUT;SFP:1101;", "X-MS-Exchange-AntiSpam-MessageData-ChunkCount": "1", "X-MS-Exchange-AntiSpam-MessageData-0": "\n\tQe6eQ+Z/QSwfP2BcxBTNXGUBBjx+bJpm+ZtNRrFveZaAGwbKIwf9odoIN5xJm8X/rF5MyBO7ryi8mnukAFaLE2CBY6zgOBvAFhcM2X7OIaFt246BZBf5tdWPlJL2iabKOhOydPmyGWzkdbCSgqqFXoxkiP8HpK1bsVya2FjieYUTvZKDLrtIvBak5Ajp8TJv9uW8+07PGo0vHNCTRHt5tkCZErBNFhpzBPKylzFzecZYXqOuL+AO8CuxCM0HyOQ2oLpbQNsBlRoimRX/9TivZ6Rfhr0pgzoGCQ0pcgn9nYT4DkQkqsFqnT6OemB044+4hgXknUrZ3VQnE1cBr8WndQ+S3tmT5bbUdX2hfsV4FBiL46ubBC8zyCmH2w9e8t9nQMWwHNot7yIiXZc/A8z61p299B+FRIADsJc2b6qdmjfMdwBpyiDIzdhWJc6UJrCR", "X-OriginatorOrg": "Nvidia.com", "X-MS-Exchange-CrossTenant-OriginalArrivalTime": "27 Apr 2026 05:54:28.4653\n (UTC)", "X-MS-Exchange-CrossTenant-Network-Message-Id": "\n acda12f8-97e8-4edc-f167-08dea42171f3", "X-MS-Exchange-CrossTenant-Id": "43083d15-7273-40c1-b7db-39efd9ccc17a", "X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp": "\n TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.118.233];Helo=[mail.nvidia.com]", "X-MS-Exchange-CrossTenant-AuthSource": "\n\tCY4PEPF0000EE31.namprd05.prod.outlook.com", "X-MS-Exchange-CrossTenant-AuthAs": "Anonymous", "X-MS-Exchange-CrossTenant-FromEntityHeader": "HybridOnPrem", "X-MS-Exchange-Transport-CrossTenantHeadersStamped": "LVXPR12MB999198" }, "content": "PCI ATS function is controlled by the IOMMU driver calling pci_enable_ats()\nand pci_disable_ats() helpers. In general, IOMMU driver only enables ATS\nwhen a translation channel is enabled on a PASID, typically for an SVA use\ncase. When a device's RID is IOMMU bypassed and its PASIDs are not running\nSVA use case, ATS is always disabled.\n\nHowever, certain PCIe devices require non-PASID ATS on the RID, even if the\nRID is IOMMU bypassed. E.g. CXL.cache capability requires ATS to access the\nphysical memory; some pre-CXL NVIDIA GPUs also require the ATS to be always\non even when their RIDs are IOMMU bypassed.\n\nProvide a helper function to detect CXL.cache capability and scan through a\npre-CXL device ID list.\n\nAs the initial use case, call the helper in ARM SMMUv3 driver and adapt the\ndriver accordingly with a per-device ats_always_on flag.\n\nThis is on Github:\nhttps://github.com/nicolinc/iommufd/commits/pci_ats_always_on-v4/\n\nChangelog\nv4\n * Rebase on v7.1-rc1\n * Added Reviewed/Tested/Acked-by lines\n * Update commit messages and inline comments\n * [pci-quirks] Add range-based scan for NVIDIA GPUs\n * [smmu] Add missing arm_smmu_remove_master() in error path\n * [pci-ats] Don't init \"cap=0\"; check pci_read_config_word error\nv3\n https://lore.kernel.org/all/cover.1772833963.git.nicolinc@nvidia.com/\n * Add Reviewed-by from Jonathan\n * Update function kdocs of PCI APIs\n * Simplify boolean return/variable computations\nv2\n https://lore.kernel.org/all/cover.1771886695.git.nicolinc@nvidia.com/\n * s/non-CXL/pre-CXL\n * Rebase on v7.0-rc1\n * Update inline comments and commit message\n * Add WARN_ON back at !ptr in arm_smmu_clear_cd()\n * Add NVIDIA CX10 Family NVlink-C2C to the pre-CXL list\n * Do not add boolean parameter to arm_smmu_attach_dev_ste()\nv1\n https://lore.kernel.org/all/cover.1768624180.git.nicolinc@nvidia.com/\n\nNicolin Chen (3):\n PCI: Allow ATS to be always on for CXL.cache capable devices\n PCI: Allow ATS to be always on for pre-CXL devices\n iommu/arm-smmu-v3: Allow ATS to be always on\n\n drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 1 +\n drivers/pci/pci.h | 9 +++\n include/linux/pci-ats.h | 3 +\n include/uapi/linux/pci_regs.h | 1 +\n drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 75 ++++++++++++++++++---\n drivers/pci/ats.c | 44 ++++++++++++\n drivers/pci/quirks.c | 38 +++++++++++\n 7 files changed, 163 insertions(+), 8 deletions(-)" }