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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?t3PhhMLNcfNochtEtr2BTQyb3YFoyl57KNEyg0ks92iwyz4PVlIjh5UhvFB5?= =?us-ascii?Q?0kYXZFQvzGW9kx0AgDypG7fYAVqhJPk1D5VkymJFpBkB/m2NXteTdbW7FoPF?= =?us-ascii?Q?yySOigZeYSgFxPMB/1zWYRAXxd9m+fbh5zp1/2RpixuJJTVqLoA6sXR7sIId?= =?us-ascii?Q?wZKas3LoHS6HlieG0GeaBdxE4fP352oQqrax/qtHgdsH9wbfA+sZGmnWJFr/?= =?us-ascii?Q?YG/B1MuIEHyknlQ6cQqUzHiKdJAlz+Ih+/uAX+KeEO3azhyMu4UaesngICm0?= =?us-ascii?Q?EF/G13iitqbdxkK6a7BLG4z8cM0mix2bMboSppaKjuBItff/03CilbaoDeku?= =?us-ascii?Q?IqdP0SA51WunVFZ7d7bLdtaUTA4CfWtZhUp7ar7MBHkDIHM40w2ud2Y3QK05?= =?us-ascii?Q?8UooWKmHvZ5qmkykJjwUkpBLEGPjdmzgNSWx5RLYVUkTJ3GyUWZNkCF2t+Cj?= =?us-ascii?Q?pb3O3iqd8+nRUbZw4XjVhBerx3N9/x+pcKLxxAz36Lgy6LfIvugdXMxnBl3O?= =?us-ascii?Q?dSH9CsM2PwGZ4BL6iWzAV/Q492Kifx6KpDEBX8n7CwRq1yN5tiIKXyi+jlWc?= =?us-ascii?Q?DaJKU3IXg3FuahNDRLgHmUZLs90WGdwhFB4h/Tcewfph4FOp7Id4mKdh1y2y?= =?us-ascii?Q?dVnRED+kQSPEMwcWRthoIunuNTiwtKC2eg8O2iWPP7+NWFHm1g+qoPVjLLOd?= =?us-ascii?Q?qVxA0/4+ahouTMSNJQD2hNer+2KNyIbHEyjME5rQbCi58EE3MRhteQARw86a?= =?us-ascii?Q?jRO8zBIqnADb8J9L56rHm/eoR681djMa8Jwj7QHhgLOUVbFzxo/GnI3Idr55?= =?us-ascii?Q?zFSRgzBaMvFu4wDwlPR4o7wAToBTJ6i+kpC4sEuF/bF3CrSa3cy5yZ0WP+y0?= =?us-ascii?Q?yKB2XQCVWcs/9KCW2nM8n46PGyMxdfIC0tx0DbEYNllcmSVSrvRhZ6e4LZqd?= =?us-ascii?Q?XWvERu6v0afxrL3q3MgzLr9ugk73YHd0QNyWrhcD9jARQDLYNJGv8hJ48AQf?= =?us-ascii?Q?5D5EMddxzOeYkKP2SSjEf0QHnzwkRkN3Mpq56zMw21TGpvbYC+xsMy2XC9ll?= =?us-ascii?Q?3J67f8eicKC/rGlE1T6v1isRDtmYblxyfZJU/kAq0gkWoro1Th54Rk4JWegh?= =?us-ascii?Q?zhAFAFDuioLOTysLWMSSI1tspSVpMFx+LpDPUfyHnmLaAf8A1sGdmRf4MI1w?= =?us-ascii?Q?7PK8sDQTJCT/Bu5XBLEeDlXKigBFatAeqpPS3NUhVtasf+SgFdTe8Dxq9OP6?= =?us-ascii?Q?YMW3onXNfOI2E9K2ephMlvRjugoVbIYrDye0CHPYwna8YgOU2PVdQEGk5hUn?= =?us-ascii?Q?ZFsJDynEc6ISquwFxNTwm6SPgAKT2AHO/blyr5hqG/vNSoLkkhrHlFP8aDry?= =?us-ascii?Q?EyWjo/pDJUVqKPg0AyVB0N6g/8XORY4TwaGCcHAwvEk+8rweKQTcUvy6CrNe?= =?us-ascii?Q?rvc6H8UbGAFc2cjHke9hSSDa6jYN9/JxYBMNWiPT4JkMn+BIjt/KyEwYp0AN?= =?us-ascii?Q?F/Gw3tfO0Qzhj6aq3y8gkXFv5eOfgSM+jHOjOjWs/+tMtOEnChSFjturpJe9?= =?us-ascii?Q?4DqTWnJuVN5aLG8WndcRr2JMX/GW5MsVDkxQcC2w?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 109743d6-a85f-46ce-a72d-08ddfb628659 X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5757.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Sep 2025 12:04:33.9713 (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: d50CoGILJ3UGXXPQN9HxKEs87ZD9A1vRMsiHWEP/IdZSKtC2CBY38fReufr0Ur0t X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB4078 On Wed, Sep 24, 2025 at 04:34:46PM +0800, Lu Baolu wrote: > Dirty page tracking relies on the IOMMU atomically updating the dirty bit > in the paging-structure entry. For this operation to succeed, the paging- > structure memory must be coherent between the IOMMU and the CPU. In > another word, if the iommu page walk is incoherent, dirty page tracking > doesn't work. > > The Intel VT-d specification, Section 3.10 "Snoop Behavior" states: > > "Remapping hardware encountering the need to atomically update A/EA/D bits > in a paging-structure entry that is not snooped will result in a non- > recoverable fault." > > To prevent an IOMMU from being incorrectly configured for dirty page > tracking when it is operating in an incoherent mode, mark SSADS as > supported only when both ecap_slads and ecap_smpwc are supported. > > Signed-off-by: Lu Baolu > --- > drivers/iommu/intel/iommu.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) Reviewed-by: Jason Gunthorpe Basically due to the above spec the IOMMU implementation would be invalid to set slads and !smpwc ? Jason