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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?C2/81enQStCZQVLLcx448Z07PT7mqmG0JUcJ3pB1QW/+MZXjQWzL9aL8yyOg?= =?us-ascii?Q?IJD6vVUpspUAQiAlxuOBaES77RkojwuOtjh6eY62nmsnD44gjmZiirzEbvGc?= =?us-ascii?Q?HrSjNSw5At9M0F/cm17R2VQKKdyxSpNcNb5oi4ZGQ0ly5aKJK/HhqFlMvdLS?= =?us-ascii?Q?wMgOlc7g8Ji2vvOfpH3odv6jsgaekn/6JMUX8/0fxPxuL3rIfVvxQN+M+Oiv?= =?us-ascii?Q?Mn0o/eHfrJZcm4h+03JAQAYhbP037lKrkgIMcik7c+6mph2MWwhrzarc8c1V?= =?us-ascii?Q?XkejZIw+v9C6Egy4vSEItZ/cEu+YwuZWMggP5tcy1K1aCAgx6Cku+gcdxVg5?= =?us-ascii?Q?zLLRFZXMop9hNuqZSf4XdwVGjuDxgpG2+ILJW7YqWqZd1wptrDheUTpHZtyE?= =?us-ascii?Q?rmEGXgo5htmxt7Wzz9C6TbHW90i58X8tFzp/oIgVAsM1oPwEZH+Z8aoefa8H?= =?us-ascii?Q?/u28Wl3VMhpEC31J7HjxQRVp8iwtmdlLb62SsEA0/jtL53HOLzS9IbeE+31s?= =?us-ascii?Q?LCcuvUpysuZQa+Qm1NltSItZKoMTTlP3oA2aOa7RcQ3r0+CIBErpkwyQniBn?= =?us-ascii?Q?sxsdiyIuSHl45ZdmhuaAK3/z7SbzDyihxLnTcFYSiUM83ZQxGN6PZhXbN0H8?= =?us-ascii?Q?tdKRvnlAulKCcuoPG5TR7duOrDrYokWJe3Z4VIBISQMYs3OR5eTIWuYTecQC?= =?us-ascii?Q?IaAurSEc5U9m8yU14g3/+yTlOpUJc/AiyrFRKuyUVhP3bNi93XY72WQHEGLK?= =?us-ascii?Q?dl/t2DbRNMSHR0Sdir3teVn4XY01LGFRAoWPoapKGZa39wEX/GUQUeRu8/UT?= =?us-ascii?Q?q61tEp6FkjnmmOXalZB+9nltpS/E0ruP0+PlmgCwD8qj6/NVYnYeC3G7vkrU?= =?us-ascii?Q?Ct8O0M7KSicbQPEWtS2KRNdQ8Q02eepwd4+cgDZTnaD7G8Sj6arlus3tCu49?= =?us-ascii?Q?H1I5sKBRR+HXhW/JH7rDEVhe1vl/ospwB+SporVxy77h9ugOSzNc0vgMscqJ?= =?us-ascii?Q?z46BPXkv7XWtiisHLCftdV2XIBAqAOoafOyb5aKozJnY9ch+VV6TSV2+L85G?= =?us-ascii?Q?T7PPG1/Bk9Xi8m1FK1r4ZBHPhScSSDIhG5XeJSJTBmxo3BB1npVOkq6J6ZJM?= =?us-ascii?Q?b8JE4n8+gU4onz+KfovGScb6hhPXPEUOum6udAVJ72v/Y1Orp5XISCI3FoPU?= =?us-ascii?Q?96zprahSdN4XAoXmkfpn+33deSjIocf+qKUXjBiBBU7QIT/VpLK8jNExZxD7?= =?us-ascii?Q?2q2Ova8ux6+BdtUlXOA1DSa0BiaGyDeqnuuz3i88CXNHiSw6RInuOLf9Q3vI?= =?us-ascii?Q?iGXXGSY1U3aBh5qjoSAZF5+NEQnoRtGw2YI8VH31cLPaophGwBHHwCqKgeSX?= =?us-ascii?Q?ED6/fYWM5w6Mb9QR+cSuA7NrCYEhmNEK9iANgibliWGfYPjhRIG7jdnowmyz?= =?us-ascii?Q?DvdfUMhedELja7h21U757oi4opIYQxXUcgvNfsx1gpmfcuzt9Ni9K0HkL4wd?= =?us-ascii?Q?TQrWWU7RcEmf+Ujc84wS7Hlg5hMpcRIU0dvHrsFlKHhkO85W0z14bmcOJOom?= =?us-ascii?Q?HJUySvexxyBdYl2bUSK2pCG9Dr4hbUcQzS4dSYhD?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: e2a6a529-3af2-4aec-8f0b-08db02d3003a X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Jan 2023 15:02:26.9812 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 8bHlO+4SE2MNZelu9doaOWELncB4Dr7b1MGewgrv69qEJNjR8+2gaaMtJS7iMgvm X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA0PR12MB4446 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 28, 2023 at 01:18:09PM -0800, Nicolin Chen wrote: > From: Yi Liu > > Currently, hw_pagetable tracks the attached devices using a device list. > When attaching the first device to the kernel-managed hw_pagetable, it > should be linked to IOAS. When detaching the last device from this hwpt, > the link with IOAS should be removed too. And this first-or-last device > check is done with list_empty(hwpt->devices). > > However, with a nested configuration, when a device is attached to the > user-managed stage-1 hw_pagetable, it will be added to this user-managed > hwpt's device list instead of the kernel-managed stage-2 hwpt's one. And > this breaks the logic for a kernel-managed hw_pagetable link/disconnect > to/from IOAS/IOPT. e.g. the stage-2 hw_pagetable would be linked to IOAS > multiple times if multiple device is attached, but it will become empty > as soon as one device detached. Why this seems really weird to say. The stage 2 is linked explicitly to the IOAS that drives it's map/unmap Why is there any implicit activity here? There should be no implicit attach of the S2 to an IOAS ever. Jason