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Fri, 19 Mar 2021 16:28:51 +0000 Received: from DM6PR12MB3834.namprd12.prod.outlook.com ([fe80::1c62:7fa3:617b:ab87]) by DM6PR12MB3834.namprd12.prod.outlook.com ([fe80::1c62:7fa3:617b:ab87%6]) with mapi id 15.20.3955.018; Fri, 19 Mar 2021 16:28:51 +0000 Date: Fri, 19 Mar 2021 13:28:48 -0300 From: Jason Gunthorpe To: Christoph Hellwig Cc: Alex Williamson , Max Gurtovoy , Alexey Kardashevskiy , cohuck@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, liranl@nvidia.com, oren@nvidia.com, tzahio@nvidia.com, leonro@nvidia.com, yarong@nvidia.com, aviadye@nvidia.com, shahafs@nvidia.com, artemp@nvidia.com, kwankhede@nvidia.com, ACurrid@nvidia.com, cjia@nvidia.com, yishaih@nvidia.com, mjrosato@linux.ibm.com Subject: Re: [PATCH 8/9] vfio/pci: export nvlink2 support into vendor vfio_pci drivers Message-ID: <20210319162848.GZ2356281@nvidia.com> References: <20210309083357.65467-1-mgurtovoy@nvidia.com> <20210309083357.65467-9-mgurtovoy@nvidia.com> <19e73e58-c7a9-03ce-65a7-50f37d52ca15@ozlabs.ru> <8941cf42-0c40-776e-6c02-9227146d3d66@nvidia.com> <20210319092341.14bb179a@omen.home.shazbot.org> <20210319161722.GY2356281@nvidia.com> <20210319162033.GA18218@lst.de> Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData: =?us-ascii?Q?o8bykUjXFHcYmrdGNFPXHgrz/Y8i+diffvKxgQF262GakJTrh5gcAcGSCDcv?= =?us-ascii?Q?tQxFdC7MLv+Zla+wwTbU2c1c/CaEEhNQUCW+ZJ3eYQsutHnZ5St1wt/r1+jS?= =?us-ascii?Q?0gIM5dvnfSSMEtAqpdtctfXztoJzj9YTHSFhBh39iW16N38uTRB4YmtJxt1N?= =?us-ascii?Q?ytZgFqdkbtDWy6SBxNQqr4w1W48lPtrDR6i2N/CN9Fz+NdptzjphV7ivrJ+C?= =?us-ascii?Q?x1rcUquB8k2fymaBgqBba+q2xwpVtbkGfQoLNXdXdnPbFXhCNdRGVj/pgUH7?= =?us-ascii?Q?10PvRcndl67BRpusSku4F3mxMCxrD+O+o29banEjP31MagLahhE1VFpo/N17?= =?us-ascii?Q?im4aOCI49pEHoPmThZerH9O9QuW5WbAdF4pOz0Y/MTff78B7gd2oCSNTSiPW?= =?us-ascii?Q?ObQXyJi5y36mbJ+FwXjNS/IoEg9e2rHf/kF73iOJ8LOei/NmQUAC1w/G/T40?= =?us-ascii?Q?dni/x8e15c8EkHjk+kS+uTCcHb2UlCDZRKx9WiNbSAC7zNBTualbN1IAOPFU?= =?us-ascii?Q?IfhMSaO1/ccmGGHF4Q+5WJYrjsILSmylzSJr49z7TFWMQjPB5kDeCXxbjN/2?= =?us-ascii?Q?VvVebVeXSluZ4A1VtsAsr841R+MO91mrKoWBwCFaqdwLa2VnNqLsz1h50xak?= =?us-ascii?Q?JftdM3MOuAAiXOwT4VFA0hKkVbK01GvVuzbU+VSatyF8PIgQ8YDEC0iMzj6l?= =?us-ascii?Q?suy4+uIvF8Jcb/JJCgufC6s0Bxmi342cRJUE6YDg3Ri5tHbb8A6EQ5+AF0Zn?= =?us-ascii?Q?bHkz7hbwEUTPRaDYKRbmX3n1D4gD8BQc15d09YzpRZ0w8vJBbO9ni5MLaWtP?= =?us-ascii?Q?KzTWoQPB1q0R+9YLbENDW63Ge5imWN/g/oWxw5EvgmB9eqkS7l/sHcE2m4I8?= =?us-ascii?Q?iFPHoML3b/RXS3jgW+p0/bR9C3xlJED5ct2s2Er8wtmu92ydjAU+PAS6/ExK?= =?us-ascii?Q?Cny6iZbvCVzmE3rjr6IEkI57He9Xmy3nL5/MVVcvDnabmj8qCzgQei8Kv5Zm?= =?us-ascii?Q?bh1OF62R3jxhW9+UaOE3SzFK15ApTBIkxOYI4a8GeXuazeUGhaOYI0MpwZpA?= =?us-ascii?Q?DB7z+Ou64ib6flwo0b41csDRTVeP+u9EPLohyN72cXuGC75Cg0Gjp18mp7ED?= =?us-ascii?Q?fJq79ws309wGAH8xQsxQSbH9ttGEUupULGLno8eUvo96sClD/8uCd6OYXxIK?= =?us-ascii?Q?IRZoFKHy3ALKdCHK2gfuLph4xnLOfAGoc8ztxdPuhlZzDSWavwh3TnBwm6BS?= =?us-ascii?Q?3ih7uEYLG6vVWn8HEnqjv0a7xdCSXz6oqK1cm+zK8LOO78hzXEsPuCu+XMSk?= =?us-ascii?Q?D+34uzEaUyDHUsLXOxvlf63Eh3gyFtmIJdY4QPfZzIGsxQ=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 3c4580e4-b5fc-489b-8a6b-08d8eaf4141a X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB3834.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Mar 2021 16:28:50.8845 (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: UxllXnyvJaBpgWERniLVIM34ATr8IOxShwlptXECcJUe0uLFmJgcV54Yn9fWnjSC X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR12MB1545 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 19, 2021 at 05:20:33PM +0100, Christoph Hellwig wrote: > On Fri, Mar 19, 2021 at 01:17:22PM -0300, Jason Gunthorpe wrote: > > I think we talked about this.. We still need a better way to control > > binding of VFIO modules - now that we have device-specific modules we > > must have these match tables to control what devices they connect > > to. > > > > Previously things used the binding of vfio_pci as the "switch" and > > hardcoded all the matches inside it. > > > > I'm still keen to try the "driver flavour" idea I outlined earlier, > > but it is hard to say what will resonate with Greg. > > IMHO the only model that really works and makes sense is to turn the > whole model around and make vfio a library called by the actual driver > for the device. That is any device that needs device specific > funtionality simply needs a proper in-kernel driver, which then can be > switched to a vfio mode where all the normal subsystems are unbound > from the device, and VFIO functionality is found to it all while _the_ > driver that controls the PCI ID is still in charge of it. Yes, this is what I want to strive for with Greg. It would also resolve alot of the uncomfortable code I see in VFIO using the driver core. For instance, when a device is moved to 'vfio mode' it can go through and *lock* the entire group of devices to 'vfio mode' or completely fail. This would replace all the protective code that is all about ensuring the admin doesn't improperly mix & match in-kernel and vfio drivers within a security domain. The wrinkle I don't yet have an easy answer to is how to load vfio_pci as a universal "default" within the driver core lazy bind scheme and still have working module autoloading... I'm hoping to get some research into this.. Jason