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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?utZ2MIgEvtTZ3mMeynVsProdJ5hpVfqoh9q6WXv4dj2ZG/DWHuK/bbQALhMO?= =?us-ascii?Q?9jcNo9MTRtddJQPiYB7x0znLm2refM954wwZDAswnpT6MqEvgfBSIx4Jo9p3?= =?us-ascii?Q?lMx3oTM6SsYsGF89sM0SlT0p8EKnltD9kagH7YhFpObGJPTPp6fd9JEJrUc7?= =?us-ascii?Q?K1HjcVcW5qD+RJBCrXli7L12qVea5CFaiNb9AiR3X6XwJEObPM/5fFiaenDr?= =?us-ascii?Q?eza1ZRyj9vQfbYvXpLdumPxCYpoGUlG9igC0sLVK/k1YAI6Yl0B7pu9pVS15?= =?us-ascii?Q?+vwf3Qukio1LHSvXNSTRfvVihLjn3j3prwEwSjTZBr/AI7XdhtdgcvB7zNYv?= =?us-ascii?Q?Wdbjlgh+S7s9LvIEjsPxEv8pZsqcPBCiE8FnfzhL/LRO2KA4XZflgLFoE1Px?= =?us-ascii?Q?TmQ+Yy+H+OfXH+wZStlVIzg9Hki6MngeCf/HpaLUlWy2WRjPCWyZhXKTe+c4?= =?us-ascii?Q?AHtEg+Yz55Lu7gM5WXb7SgcAR9iFLBE4xh2iJGTOdj2rKDazwQ3jaX5RslnD?= =?us-ascii?Q?4SwKq1MiwqIEg306bqGVaYfOkLLAd1kM3pI9Am8F+YzLqFPP6UNYY+Dc6xTl?= =?us-ascii?Q?ePB1Ii0K849fgDsDD1v/x5jIN+gjgb4LEJEi7KZGS11aL4wCoish/xmNhNo7?= =?us-ascii?Q?lsdxq0fKY8lYSIonEzyEt4uCy+C/QFomC5Vtas6WzWHTIpzLpWB5IsXksUQs?= =?us-ascii?Q?3IO+ZUzK8NqTy8C4R7lCq6gDOGbjsayTOCTBAbRt1vjN/siPocEU3GMgtPIp?= =?us-ascii?Q?duJnpewbStlb6jWhlgTuBiiopjtPkcY9NWKry5+eD+ZHWNZca5JxgqBGOhCM?= =?us-ascii?Q?kvlalTrZTfSvJU47jdqHS7nHbJPAZ6WQoYSV6ZS4eHFpY670mgLVmqPt7/Hk?= =?us-ascii?Q?YMMQKdNw6RUIWA+zRCMuQ2qq9gsq3ze/Sg59eAv95koGSa7WcAHo9ky0megu?= =?us-ascii?Q?Ftb3UoEKd9zLgZE/dthYQxplnt3Z8M+eeyTINJ274IuAZMOo22AMOp5bvMSW?= =?us-ascii?Q?zOTYD7ElSbew7tx+3fufnaEKmg2lxRtBOiMrLiCImE7MOeM4ngNgID+P8Sjm?= =?us-ascii?Q?f0tXz01WKOGEIDD95jqt8NZ5NxrYjzBuR/A67nhVSBU7IuPIscKMfumDu6Dj?= =?us-ascii?Q?pZ85lSfojrrRqQ3JfIeBs2+v5U0v2UwomUodxCZB+sWI7omAR6ua8ydIQ0Eu?= =?us-ascii?Q?X29KqZbgrzK+TkRJqDPouHE+xRsNC4GxGa0b1vRNQVL/rqXji3NMGUULU4Uf?= =?us-ascii?Q?bST5v4I9A1wIUysOh5JdsppqRrO5mKS54tjfkMpn7HaTEzk4nIr2UrAnZWg2?= =?us-ascii?Q?cCQQDzRS79MxK0lJnLYM9Be5l6FNBgBCMr6DAGV/6vf3lzIn5IRJV4I8v8Jm?= =?us-ascii?Q?xlsK9rPC8JgNXyAhmkZIb9V4rPhIcRGR5KDADzZnPnMxkB1Pp+GMI1sCx7Zp?= =?us-ascii?Q?dBEYSS7h9jgb4BSS6vktY5BG70COGRy6auPqstx+3AEZZCgXGDWMzlxVbrId?= =?us-ascii?Q?CW/DE10W6ipCnYmgwGaslmDkT5bTD77HlX6kP1ByjHsK7nGHbUb343j2sD/O?= =?us-ascii?Q?Fkr8C8S8S0oSufqv9pFIQJlEPHn6Vq9rjEwwHMvfXklafatVyKMkMMJZNBNR?= =?us-ascii?Q?EWZbgyckPmBiXRybA7GVEsGxHlpziOV3HqIkHsM70709D6ocn0ZWOo/xHBc3?= =?us-ascii?Q?Jf2vXBtrOB64AbQYQ8WH1etrKGLvoq9DaDDUanLS3MKoLEuH?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 752e8711-7e54-476f-0f70-08de8e5f3194 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Mar 2026 13:21:04.0230 (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: wSBalof84SFrIBDBF28Aby2gcRcIA7w7j2INjTeE6vinwSekC8sJ22v5JWOubdxT X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5898 On Thu, Mar 12, 2026 at 05:06:37PM +0800, Wei Wang wrote: > The enhanced ACS controls introduced by PCIe Gen 5 ensures better device > isolation. On devices that support the PCI_ACS_ECAP capability, the > controls are required to be enabled properly: > - ACS I/O Request Blocking needs to be enabled to avoid unintended > upstream I/O requests. > - ACS DSP and USP Memory Target Access Control needs to be set with > Request Redirect or Request Blocking to ensure the Downstream and > Upstream Port memory resource ranges are not accessed by upstream > memory requests. > - ACS Unclaimed Request Redirect needs to be enabled to ensure accesses to > areas that lies within a Switch's Upstream Port memory apertures but not > within any Downstream Port memory apertures get redirected. > > To maintain compatibility with legacy devices that lack PCI_ACS_ECAP > support, pci_acs_enabled() skips checking for the capability. This seems conservative enough Reviewed-by: Jason Gunthorpe Jason