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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?OfwFlmdjOo/9Dinmk84pjtzz4qIKYXQ9kVBdGE++l21T9w4ztJH6oW2T9rSy?= =?us-ascii?Q?WJJUrhKspOzAGbMHhFQBO2ra++mS2iYwO5EOO+zrX6BMbFB74K9zpyUUjaD3?= =?us-ascii?Q?g2i7TvRz9ThinOHZRwr5g63vKGaya2B6/ISmf38Bw54x48cRlUHMpwY1cAE+?= =?us-ascii?Q?aeKgJQTz7XURfdYT028gFTzJdHk+s2KbFraAxZBse442FKpPL2ll9v2Uonj/?= =?us-ascii?Q?uq00qocmp1f8QqwyD2XoAGcdAeFLw2FU2UQKPqHzhEHuFCWdqYI1gQ87n89M?= =?us-ascii?Q?xy3gxByf1OMAFVswfuJJp+ByF25Bf8GPyrIYdgKT9+yZGCaYM/Bm/iNMov5h?= =?us-ascii?Q?rM3Rx7uHgDAeI1E6FAX9Ut30unwG/BSgXbIcFo5OSYnaf1B0gBsWiIrifrTk?= =?us-ascii?Q?qrObPBhBrexYXakfQkCWE2EU4zbzDgj8zJM8Aspv25POoYYJYRD/EsEImlxR?= =?us-ascii?Q?4cE506xGhHqIsU22BKISWxrUYVQsleKJdwrghfBoSqqmLT1N8QgGbUKCvYVI?= =?us-ascii?Q?eo+9stQjqWe+jJ4+HJmGQqjhILHaTONUfy+KuuNSjtBpHtBAuxJ3EqEPM3U/?= =?us-ascii?Q?9tHRY7YGOsMPuBZcGihtQQlOXtMuFqj1hLmSrovWUrc4esQywTqD8uoGWe4b?= =?us-ascii?Q?ANe8cYg4Y3PutA4tifiKcq/FuPUuVMBrMw+IPcs0desbHzAfgjLU1bdc+B2y?= =?us-ascii?Q?Yv86+EMz/q0iK6uxOmA2vAxXwSkCUTiP/pnCXBsYt01T4rv8kRWLf3FWtOoe?= =?us-ascii?Q?NYzXHFRxEpM660VhxquCBsn+rCmc4GZF1fN3JCmG5B2eOoZoyd7hc4rd+WEa?= =?us-ascii?Q?Io3NusV6ixLF8zL08dr/xm1hWZaP0QB3KHdew+lQO/xoONo2lzuOpwZexHRR?= =?us-ascii?Q?1v/nBEg3AmuhH/XHKeeHbAsHYkvkpOWIMosxd1l96giireWdYYeKDVcuZhVu?= =?us-ascii?Q?105Xelr0XTSAeaYqc5VlXx2xEgnXi2uq+r/cpfsqC8HTSzbCjbAoS/v9273W?= =?us-ascii?Q?AfmCJol3q0lYSJxI7mTsMZhqLTbZo3NofHNTNQhZxx1J2M4xhpnf6sXiwwOu?= =?us-ascii?Q?/840rOzK48+fvg7zN4jaQ9ZT1FoPKgTUEBnRCxQdVYvPgPwrCnt0h1QprZJj?= =?us-ascii?Q?kGQP89b+Eqnq64JILaJ9Q/wFquCeJjlshed0z54K5e0mXCwKE9igRakx3MgD?= =?us-ascii?Q?ZXADpCZrCfty3Q09PpLaeK/SN5SJ4Anw3ir6lcj2X7QOkW9Q5bjoMOuPfAJM?= =?us-ascii?Q?HNUJjxHjuh5hlQF+VGk8SUqbGqSUkW5EuyBerS5hZhGnrglN3pooAuR6bJ6s?= =?us-ascii?Q?YwCX/bWt2WXXJ1jpHxl14YqnfZNTUkgBTiSphq8HfM6CgC+PZDaPuCFW6duv?= =?us-ascii?Q?Rz2hWazPqAH8ygl9us12Wm942wT8h8t0MqQKy/mUThQjiXLOve6jsBFziCec?= =?us-ascii?Q?neU1rfvPt1aChWNhG406u4in6xLXown7/7dcsbP0kIU7H6o+Mo0Dbxgaz3sk?= =?us-ascii?Q?a4TRpFIYmIZHsK/AmbUYYhR9lbo62ivffJy3kfvtUT5W431pZsaOHVTtz/N6?= =?us-ascii?Q?iYcHumnV6qpOH3HE/Kw=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 608d45b6-290e-4749-6164-08d9efb7dc2c X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Feb 2022 12:45:20.4241 (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: XTV1GEGPhCLnkg07wfovayEI6RB/5t5k0RUvggaO8975iw+73adManUZX5Gj7xDD X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR12MB1594 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 14, 2022 at 12:09:36PM +0000, Robin Murphy wrote: > On 2022-01-06 02:20, Lu Baolu wrote: > > Expose an interface to replace the domain of an iommu group for frameworks > > like vfio which claims the ownership of the whole iommu group. > > But if the underlying point is the new expectation that > iommu_{attach,detach}_device() operate on the device's whole group where > relevant, why should we invent some special mechanism for VFIO to be > needlessly inconsistent? > > I said before that it's trivial for VFIO to resolve a suitable device if it > needs to; by now I've actually written the patch ;) > > https://gitlab.arm.com/linux-arm/linux-rm/-/commit/9f37d8c17c9b606abc96e1f1001c0b97c8b93ed5 Er, how does locking work there? What keeps busdev from being concurrently unplugged? How can iommu_group_get() be safely called on this pointer? All of the above only works normally inside a probe/remove context where the driver core is blocking concurrent unplug and descruction. I think I said this last time you brought it up that lifetime was the challenge with this idea. Jason