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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?/WxaAkErYVKWOAEMlEM1jajEJtqsN9yfEyOXQPELo8Zw71DwQJWyaUwV6olx?= =?us-ascii?Q?a9ux3zhAfm4cvjwTDIOnvJwgHFlQLjf7hkhrMacP8Lmc1URdYiRDcydwT0GY?= =?us-ascii?Q?Q1jo1/W8g150oUjxk4qTyroHC2qUhqHrYXXAVEDSZ1vpfEtyWzwPRiv0SWn4?= =?us-ascii?Q?PSWG+XYVTY4RKYTcXjiZjO3baafnrxm4n80ZV1qaW49V0tg3NFON+0V7DL9P?= =?us-ascii?Q?tbVhgdk5f7pUMON8Jq6NizFQay0serubFrbKdDp65D5KP92DT0rVvEi08lKv?= =?us-ascii?Q?HFLBj08s3v+wLdi8ySn2N955Ez23qRjlnyKCc6SVmvfRtT1ANuf8uuWfPzuE?= =?us-ascii?Q?OZ8RhZPsXVGnU/rr7boEyF/RhrSBE54Rd1h9c/4dZnZcxF91rzUcoF/DUUNV?= =?us-ascii?Q?bIKRGBlcHp/XCak6ioWwYSsVZtchaQpsFo6T8SZhfHG99aEdGQFbDHJiLA01?= =?us-ascii?Q?c5nz/mnfWDKsWcEO0Nx+K9hwUOrG5DFtui8d7i0032vchrlwKLdZjyYivqXd?= =?us-ascii?Q?f+4uY3UiHpVhlC/wR5RVp/cxnwmbAgp+HK7iV9Bh09zvuYSwgyGu6I3o3K1w?= =?us-ascii?Q?T9+qYBViT0h9u9P7F469BayfFihpTpLUTzf9Lwt330PjV77LpblnNfZC3fRZ?= =?us-ascii?Q?mW1Ui7HZciFO+KXfdPKloqEVQo0MeXQfedrguM13wHBWTrhiKnQIbY24zDxp?= =?us-ascii?Q?XZrCeKtHPcyYTnFmgho0DWIH/8eSGBNAtmWB/JH+P4Jqe/oLQEuRSoSNGXiS?= =?us-ascii?Q?tKrt97sF7YJluQeWNCrNP67OzXMb7zcCxuJVzgbjVzoFjs9BUd5AmpiqsWyT?= =?us-ascii?Q?czf+chSebGk78GetYYqbUCEJyeVO6CgXxbpgdy5U0TpHAnifu/F83wkuxWXA?= =?us-ascii?Q?9WJ3fxbuI5PjZQ1x38XZ/8wg33tx/G38grN99ihFpLhxQ0t829Lxzc4WGhIo?= =?us-ascii?Q?fCA8A9P9B3fHhXRb+kqhRQl2pqG/nSgCXHkcUZboweKKqMoDZ9BaZkXbxXAe?= =?us-ascii?Q?s1zWbZcO4uRldhRR5vzueCwPFuw/a8xWJe8VyWiDT2ve2pgyhZy8XQcHGLhZ?= =?us-ascii?Q?rHrgSn0NqXTsT5L0ZqcyMXzsWuir0H8A3/VUhX9xezrO/d1vpR8N0baiFTN7?= =?us-ascii?Q?ju3W9Ftlny8vdmoxaCs/jIQHfg0qRPmIMcVj8w0DV8gT26NImfapZnpgXzBc?= =?us-ascii?Q?LP7IdM+13G+2W0hiDIOiSMdYyLly/ZMdZpgtrDKySj/HDo7cKuKtpe7sPVy8?= =?us-ascii?Q?45I8v6NeivSCiwOFFxTIDImvK9ZV1tHtPddElrh43fAaRaYyxWqOv55F7LrN?= =?us-ascii?Q?YsbHVFXqwL1CrMq1lM179HfcLCGClcbyCxqXz4rX48G3AXRutXaV9GOoAFLg?= =?us-ascii?Q?zrvPXpmX6VeWBf3j++wsZ2PLbbLuLjDcIuapibMeggXxdBhZDSHz9zKbvrSf?= =?us-ascii?Q?VDnmLh1QeYKDjfICuZZGgogec1TK82SG9MEqCCTUwrm1IQHjTaRPFxsHKFcc?= =?us-ascii?Q?gzHf2iaS3a0rWtZ+EtZpN9+vS3ZcVwUzYg1Ujcc3TSSR+8xu5oDTEebatb41?= =?us-ascii?Q?C6qYZ6A/0/jkaseugMQ=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 691c6b0d-996d-433b-47e3-08dc60756b3b X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB3849.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Apr 2024 13:34:20.8002 (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: bXHYdSd68KL7XFDhD3n4iBmtVa8h8xhwChSv2OZCvYg1FJR3dWtW8ZmfWk3pDEPf X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB5665 On Wed, Apr 17, 2024 at 05:02:16PM -0600, Alex Williamson wrote: > > > sure but we at least need to reach consensus on a minimal required > > > uapi covering both PF/VF to move forward so the user doesn't need > > > to touch different contracts for PF vs. VF. > > > > Do we? The situation where the VMM needs to wholly make a up a PASID > > capability seems completely new and seperate from just using an > > existing PASID capability as in the PF case. > > But we don't actually expose the PASID capability on the PF and as > argued in path 4/ we can't because it would break existing > userspace. Are we sure about that argument? Exposing the PF's PASID cap to qemu shouldn't break qemu at all - it will just pass it over into a vPCI function? Ultimately the guest will observe a vPCI device with a PASID cap. This is not really so different from plugging in a new PCI device with the PASID cap into an old HW system that doesn't support PASID. So does a guest break? I'd expect no - the viommu's created by qemu should not advertise PASID support already. So the guest can't use PASID - just like an old HW system. Is there a known concrete thing that breaks there? > > If it needs to make another system call or otherwise to do that then > > that seems fine to do incrementally?? > > With PASID currently hidden, VF and PF support really seem too similar > not to handle them both at the same time. What's missing is a > mechanism to describe unused config space where userspace can implement > an emulated PASID capability. Yes, sure the unused config space is a great idea. I thought we were talking about doing the fixup in userspace, but a kernel solution is good too. But also if we are set on the dvsec, in kernel or user, then we can move ahead with the core PASID enablement immediately? Jason