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Wed, 10 Jul 2024 04:13:20 +0000 Message-ID: <3eff5c86-8b5d-491a-955e-794198350ec3@intel.com> Date: Wed, 10 Jul 2024 12:17:17 +0800 User-Agent: Mozilla Thunderbird Subject: Re: [RFC] iommu_ops->domain_alloc_paging() enhancement to support AMD IOMMU driver To: Jason Gunthorpe CC: Vasant Hegde , Joerg Roedel , "iommu@lists.linux.dev" , Suravee Suthikulpanit , Will Deacon , Robin Murphy , Baolu Lu References: <7e249bc6-c578-40f0-aca7-835149a0ad39@amd.com> <20240628130330.GY791043@ziepe.ca> <26524622-971f-47f5-936e-d0173d342288@amd.com> <1f8f04e5-3b70-45de-bd93-e3c96fb0a555@amd.com> <68d300af-4d3d-497e-9338-d99dbf88dd21@amd.com> <8bfc6cb7-d2d7-4d4c-9970-f4f207fb54b4@intel.com> <20240709182303.GK14050@ziepe.ca> Content-Language: en-US From: Yi Liu In-Reply-To: <20240709182303.GK14050@ziepe.ca> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SG2PR02CA0029.apcprd02.prod.outlook.com (2603:1096:3:18::17) To DS0PR11MB7529.namprd11.prod.outlook.com (2603:10b6:8:141::20) Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR11MB7529:EE_|MW4PR11MB7101:EE_ X-MS-Office365-Filtering-Correlation-Id: aa7981db-6cc9-42c4-18c0-08dca096a22f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|1800799024; 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For AMD, can a single device be attached to multiple V1 page table? >> IIRC. looks like AMD has only one V1 page table pointer per BDF. But there >> is a PASID table which has multiple cr3 page table pointers. > > Yes, ARM and AMD both have kinds of iommu_domains that cannot be > attached to a PASID. I see. VT-d does not have such a limitation AFAIK. BTW. SVA domain shall not be attached to RID I suppose. This should be a common restriction across vendors. Do you think it is valuable to let iommu core block such an attempt? > We are going to have to deal with that as well at some > point. Currently ARM is always creating PASID compatible iommu > domains. > > While AMD would like to use a RID-only type by default. thanks for the explanation. -- Regards, Yi Liu