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b=YLCXg8phU6tBnelGoAvupulPhfn05WpIsxI0fXg75W+Ox4Gice59hmliaC/0PMQ9UAesNzzSbt6IQsyjO6MbFqbl44RLGJpqKNAggE+3G6OfGMfVc4QhzT1ropHo+32HMlEMEOWW9jV1D4vf9EwF0q2tCRUNZKp4Eew26Y6PBYU= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from DSSPR12MB999236.namprd12.prod.outlook.com (2603:10b6:8:374::10) by CH3PR12MB8535.namprd12.prod.outlook.com (2603:10b6:610:160::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.92.8; Fri, 5 Jun 2026 08:45:53 +0000 Received: from DSSPR12MB999236.namprd12.prod.outlook.com ([fe80::8a48:f674:71b8:d21e]) by DSSPR12MB999236.namprd12.prod.outlook.com ([fe80::8a48:f674:71b8:d21e%5]) with mapi id 15.21.0092.006; Fri, 5 Jun 2026 08:45:53 +0000 Message-ID: <45462b05-1e92-43e6-907b-7440ad435a83@amd.com> Date: Fri, 5 Jun 2026 15:45:44 +0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 03/26] iommu/amd: Detect and initialize AMD vIOMMU feature To: Jason Gunthorpe Cc: linux-kernel@vger.kernel.org, iommu@lists.linux.dev, joro@8bytes.org, yi.l.liu@intel.com, kevin.tian@intel.com, nicolinc@nvidia.com, vasant.hegde@amd.com, jon.grimm@amd.com, santosh.shukla@amd.com, sairaj.arunkodilkar@amd.com, jay.chen@amd.com, wvw@google.com, wnliu@google.com, dantuluris@google.com, chriscli@google.com, kpsingh@google.com References: <20260528051738.596013-1-suravee.suthikulpanit@amd.com> <20260528051738.596013-4-suravee.suthikulpanit@amd.com> <20260601124305.GH3195266@nvidia.com> Content-Language: en-US From: "Suthikulpanit, Suravee" In-Reply-To: <20260601124305.GH3195266@nvidia.com> Content-Type: text/plain; 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Please see the AMD IOMMU >> specification[1] for more detail. >> >> Introduce a new global variable amd_iommu_viommu, which is used to >> control the feature enablement in the driver. Currently, the feature >> is default to disabled. Once the feature is fully supported, it will be >> changed to enabled by default along with a command-line option to disable >> if needed. > > Still no to command line option. Just don't use iommufd if you don't > want to use it. It must have no cost until iommufd activates it. > > Jason Noted. Just do not set CONFIG_AMD_IOMMU_IOMMUFD to remove viommu support. Suravee