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Fri, 16 May 2025 08:24:24 +0000 Message-ID: <792fbcfc-430d-4d3b-aabe-51cfb6d689a2@intel.com> Date: Fri, 16 May 2025 16:30:23 +0800 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 04/15] iommupt: Add the AMD IOMMU v1 page table format To: Jason Gunthorpe , Jonathan Corbet , , Joerg Roedel , Justin Stitt , Kevin Tian , , , , Bill Wendling , Nathan Chancellor , Nick Desaulniers , Miguel Ojeda , Robin Murphy , "Shuah Khan" , Suravee Suthikulpanit , Will Deacon CC: Alexey Kardashevskiy , Alejandro Jimenez , James Gowans , "Michael Roth" , Pasha Tatashin , References: <4-v2-5c26bde5c22d+58b-iommu_pt_jgg@nvidia.com> Content-Language: en-US From: Yi Liu In-Reply-To: <4-v2-5c26bde5c22d+58b-iommu_pt_jgg@nvidia.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SI2PR06CA0008.apcprd06.prod.outlook.com (2603:1096:4:186::23) To SN7PR11MB7540.namprd11.prod.outlook.com (2603:10b6:806:340::7) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SN7PR11MB7540:EE_|IA1PR11MB7296:EE_ X-MS-Office365-Filtering-Correlation-Id: edd27d41-99aa-43d6-bd90-08dd945310d0 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014|921020; 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Unlike other x86 page tables > this explicitly does not do sign extension as part of allowing the entire > 64 bit VA space to be supported. aha, do you mean the canonical requirement on the addresses when talking the singn extension? Actually, VT-d 2nd-stage page tables does not require it as well. "canonical address (i.e., address bits 63:N have the same value as address bit [N-1], where N is 48 bits with 4-level paging and 57 bits with 5-level paging" -- Regards, Yi Liu