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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?dLdliAQvDOtIMyhDh3+4VgdOAU4PkFxd0tbPde9v9EygEVOJjs9y3/xqr71X?= =?us-ascii?Q?hrPxWjBbahYS3t2imtUUxz8s3BMHwvYDDpWlEb0rlRGvMhdWhU53SWT/SKY8?= =?us-ascii?Q?SRjcICoWw8U3ZDfn9u17zx6277wV5bO9g7+wdX/Kh7I1zdTd+Wu85nJVzIQc?= =?us-ascii?Q?Mjjnd/oOK+Kv669Zd8+i0s+wrkUuqyco4U36m/Akb8SPJXmSDcHv8gH643Pr?= =?us-ascii?Q?y16BcboCJXwBZlST/PBu1r1e70KuHHOma5alijL1xR9BbGiMJNcrVB0xdEN4?= =?us-ascii?Q?yPLMbgMfip0D471jx/D7TNluD432WArz7JmRN2C6W0sICcosDP6uRXjN/q0Q?= =?us-ascii?Q?kPxiSo2WOCBn52R0s9XgzL0dmNGFMev+OxpgPAvZSxveqGHak3KQ2WjekRra?= =?us-ascii?Q?ePd4N+aMd+GxwgtAhVq85LwCVy2FQGkZRm7FL+fVUSQYgTQoggz48jHq9PIj?= =?us-ascii?Q?WV7gCL1iE3Gu/waRk8m4CF7DpcyafbJjPIEYwhCK3bzKh+qbluH1w9UsF07P?= =?us-ascii?Q?SvccrZjbMSUhXg+By+bR83rWELjqM0/hqYeEyGlSkRmgwCCqW9cyQLaOatGO?= =?us-ascii?Q?7zLErtLQTgdYPn/MBXd/r8Sub1mJcwpmB7r1v605ysjLnk69p0TDSq5U7yGe?= =?us-ascii?Q?iILmx+AxxVEsoj3DR20K6/OVcZE9pVWMOfr0Z8YgA1a9yaTjIi5PsNl7kiAF?= =?us-ascii?Q?Ejlt+x2sRot760Gm6p4U/V9HubPQncyxysT0evd0kjoILjZSFjAlRTNZA1qv?= =?us-ascii?Q?fFjK5qI491qADU4WkMJj1cXTFSABg0MXSM2/g69WiyyVT8jod4NSDX5duhA3?= =?us-ascii?Q?K9XZ7r2kNPexqawAe7BIYlOvaco8kAxHXAR8Sz3fiVTrlrhQY3pcivsBjGZq?= =?us-ascii?Q?19Gkd1VVwvywNmlQDUCL++5wLmFUf5XMGj3QLSo+yKfZ2pEtay0GM7C/HKN9?= =?us-ascii?Q?iduD+7Y1yKOj85YCfXFI5DVY+pm34e0lgO86EcI+MzzQLsUzJbYeRDgjqZGc?= =?us-ascii?Q?Y7yp5miU8qwwqc+cZ3b9xI82PJruw+vqMoP/4MXhxINJX2MTWV/gVNQJnFC0?= =?us-ascii?Q?WQx/lDAHHQP9+VpNyl5Sihf9F3iobgji7Zy4tmFPNnpxVe47U0TSxll6FVzg?= =?us-ascii?Q?UdeUvbuJxFwFx1Zr/34z9skR7/N+VXBiTQc4O4Jjt/cNhSDIrgPAaZEOI7K3?= =?us-ascii?Q?+mQpXw4Wx++PUtWgqqJnrf19ou7ppd3V+qnC7AQmebr2iHIURYVBduJ/5E3J?= =?us-ascii?Q?9KUZMsa3gFnJqADgDkRNERbkg+brg2M++91BDCINhFoT7YmqwGNoYsUPqAkk?= =?us-ascii?Q?vWcZD0sxIRoa06wKcvHHo4El7iPWfwzMH6ZRXFS7Ay28WqrumK1yosHzB0IL?= =?us-ascii?Q?I3CMF/r65j2J2dU0fTqkhKK+rCeu3rFGQwOh+jDBdZDj9lRl3dTm/d3Ff8J1?= =?us-ascii?Q?5Il/PrS2k+HpTDFPOPBTojJdBSZJ0QATLgL9jePgLSwk3aV2rCEnaH61/sU1?= =?us-ascii?Q?Ys3bibU3cAH6TNV2kz4l9hCw/eNKn6SSCLB1jfejlYou11I9jCz1SNiAGLoF?= =?us-ascii?Q?Ys5E0FR3Kl8Ys+DmtLRNfv+PT3tSUOvjBEtBuHk2?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 30c9ca51-c4f2-4d7e-73e8-08da91a2471b X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Sep 2022 13:58:59.0994 (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: 88eNfAThi8+0dOJ2YbSPsi02CNNk43xdWcF3kemecRm5BqhdhqhJJGJCFo6R62oJ X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB5602 On Thu, Sep 08, 2022 at 02:47:11PM +0100, Robin Murphy wrote: > On 2022-09-08 14:30, Joerg Roedel wrote: > > On Thu, Sep 08, 2022 at 10:19:18AM -0300, Jason Gunthorpe wrote: > > > What is the use case for having PASID nested under another level of > > > translation? > > > > Virtualization. Basically having a device access process address spaces > > inside a virtual machine. That got never put into code, but it was the > > rationale behind it. > > For SMMUv3 it did actually get as far as a prototype[1] before the iommufd > work interjected. I believe there are cloud vendors using those patches in > their deployments :O This is a bit different, this is just normal nested translation stuff. AMD decision has effectively nested the PASID under the RID, while typically nested translation nests PASID and RID equally under a parent table. I can't think of a use case for nesting the PASID under the RID, in every scenario this seems to be problematic. Glad to see it is undone with the new HW. Jason