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Received: from MN2PR12MB4192.namprd12.prod.outlook.com (2603:10b6:208:1d5::15) by BL1PR12MB5047.namprd12.prod.outlook.com (2603:10b6:208:31a::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5373.17; Fri, 24 Jun 2022 18:28:34 +0000 Received: from MN2PR12MB4192.namprd12.prod.outlook.com ([fe80::ac35:7c4b:3282:abfb]) by MN2PR12MB4192.namprd12.prod.outlook.com ([fe80::ac35:7c4b:3282:abfb%3]) with mapi id 15.20.5373.016; Fri, 24 Jun 2022 18:28:34 +0000 Date: Fri, 24 Jun 2022 15:28:33 -0300 From: Jason Gunthorpe To: Nicolin Chen Cc: joro@8bytes.org, will@kernel.org, marcan@marcan.st, sven@svenpeter.dev, robin.murphy@arm.com, robdclark@gmail.com, baolu.lu@linux.intel.com, matthias.bgg@gmail.com, orsonzhai@gmail.com, baolin.wang7@gmail.com, zhang.lyra@gmail.com, jean-philippe@linaro.org, alex.williamson@redhat.com, kevin.tian@intel.com, suravee.suthikulpanit@amd.com, alyssa@rosenzweig.io, dwmw2@infradead.org, yong.wu@mediatek.com, mjrosato@linux.ibm.com, gerald.schaefer@linux.ibm.com, thierry.reding@gmail.com, vdumpa@nvidia.com, jonathanh@nvidia.com, cohuck@redhat.com, thunder.leizhen@huawei.com, tglx@linutronix.de, chenxiang66@hisilicon.com, christophe.jaillet@wanadoo.fr, john.garry@huawei.com, yangyingliang@huawei.com, jordan@cosmicpenguin.net, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org Subject: Re: [PATCH v3 3/5] vfio/iommu_type1: Remove the domain->ops comparison Message-ID: <20220624182833.GW4147@nvidia.com> References: <20220623200029.26007-1-nicolinc@nvidia.com> <20220623200029.26007-4-nicolinc@nvidia.com> Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?+nfaNgwDfdIN3qgQNSDFJS5f4iGVWBoGOYeOssLSyQvPBdhVAywMuPveYum5?= =?us-ascii?Q?efR9AmkeSJ7H0sdANCga+lXwmJ59NUsXVLiK7SF3x/GFNCpJtDLE0XbExwVx?= =?us-ascii?Q?g1ubuX4U/HHy8pkkW/n4E1EEXZKwzzOFvy/CeeeLRZYoPnfXDSO87NB8YSer?= =?us-ascii?Q?FvWXeJK27L//Uq+PTtAkn0iTO0zF2uTEvERwBZvvDiLsYMhtQFzVFK+bZ/cL?= =?us-ascii?Q?1MSYaXJ9pR7b8jqls5M8qW4o9aWq7AdpmDuIACr7AaRwBkNxgrdI9+qZuKHw?= =?us-ascii?Q?uWDSoMHN761J/7Wjr/F224WQwSmN7o0AP6+NCtRJQzaq7muMTDugSEAUMaN5?= =?us-ascii?Q?Ci8d64tQsMZO9C86HJ34XeNuA+Qd2EokQj18Wnh/4y9VUHruuK8TRth0SkPS?= =?us-ascii?Q?j3ljhI5EoFgMUuNfwXT+x9CWorlisps+uvNwfTFFis4DA65xnvY0QdikFELb?= =?us-ascii?Q?gAqiuXAA3CVn7GJ8ZNU3kHFQCr5vv0p3KcXLWiFHBHHfq3S/br2dT5Vo9n2w?= =?us-ascii?Q?7ITztfWgYNhEOBV90m8KuN3bDvhjwIrxVX2QrTQFFzQ2gSMiF9jCdKlzgp5G?= =?us-ascii?Q?I0wS//0eyjpZlW7V2tx53msF7L39imxR8CmOWVLazXMeY2FQaZuHm3juhqm0?= =?us-ascii?Q?IwqLxT6GvFpEHUL2vNVbjCGXMgX0WDtF8X9gerSap/BZcMXDaMMzGZgucZxl?= =?us-ascii?Q?DfqupfFFmRT/0R3JLaAXVP6+zM8XOBm0Yegbt/UjB77I7GfLwchkXXiaJ/Qr?= =?us-ascii?Q?x1lyhZjjB1hewqtKc9oc9jisIa90Lz/Dxw5oW0NW12Isz50mAjMaWC62P+uD?= =?us-ascii?Q?kp9hA33Q9FZ/+aqhUPH6FVYQfzviTEIStHwYUP3Sw0SNp9fxt3sqmBvTwxT1?= =?us-ascii?Q?7oSh6IbTzO4oNT4vvQiZGN/k51thUlPF2vLC2ktbxPD+5gWf+kOEAPlSbRbz?= =?us-ascii?Q?9hstLx30QvD38cE5xwMnJlLyP0otn2ohObDpl52XhSMeceLldfgA9TyBFAB5?= =?us-ascii?Q?imhz/PS3F5W4q8TnBEfXv2u7Cf3yOKmD++LYWXw9HYrFb0bxS2Ej+Wcz39mp?= =?us-ascii?Q?VEqp3ANSk+UqjKMyVtlUN81l+ooPPloaimj7kwNs70w36EOrhrgpL8NDNu8O?= =?us-ascii?Q?ug0zL4g3pFWNR3Z2eibySUJJKNFTwlPTsNCArw8Z7jB+UKOrsKX9cAFhZP2H?= =?us-ascii?Q?OthC3Kwwtnr4zgwsUS+Y1T+KJGvf8PKXKGtKSr+9EdFpzOFj140ZZxDyYdc0?= =?us-ascii?Q?1zrUkN/MbWx9OB47QNmPDpXI8cFV1N8yMDrfhBmit/HA9qNwZ6Ha4KZLVpqN?= =?us-ascii?Q?gdAq7zF7FwbpdWjD3GOmFVN79QkadhTRbYuQ5KlnHbIBrh3hBKpjQ39mbZZ2?= =?us-ascii?Q?ksutSKr5CKt7AzmyiTc41V0P8Ft471nO0W5D6qY9RKyXniSj4EpYjpWNNCaH?= =?us-ascii?Q?Ud+DOQGJU7BMJPeD4Lyp+bIyrVcFCwOtMr0sa80qE1jHCen4gZaewHLW75aE?= =?us-ascii?Q?rDSg4CGihyIpK+8EuL/eqx8CacStRtlLgBhPL1BDuWHJ+05wx9PsWtUSCVs3?= =?us-ascii?Q?17pa5RFV8DPYOSCR7pmdpkP22TUzci4FUiqx2aTC?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: ffa60662-7f2b-41fe-54e1-08da560f58eb X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Jun 2022 18:28:34.5786 (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: S4AngFHDJCZ6fQku18kZCub3Vfx1W6XDjWVJuRErhsyovk/e2is91jJXx0nRA44Z X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5047 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220624_112840_550944_5AD5145A X-CRM114-Status: GOOD ( 10.28 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Thu, Jun 23, 2022 at 01:00:27PM -0700, Nicolin Chen wrote: > The domain->ops validation was added, as a precaution, for mixed-driver > systems. > > Per Robin's remarks, > * While bus_set_iommu() still exists, the core code prevents multiple > drivers from registering, so we can't really run into a situation of > having a mixed-driver system: > https://lore.kernel.org/kvm/6e1280c5-4b22-ebb3-3912-6c72bc169982@arm.com/ > > * And there's plenty more significant problems than this to fix; in future > when many can be permitted, we will rely on the IOMMU core code to check > the domain->ops: > https://lore.kernel.org/kvm/6575de6d-94ba-c427-5b1e-967750ddff23@arm.com/ > > So remove the check in VFIO for simplicity. As discussed we can't remove this check, multiple iommus on different busses are allowed today and VFIO does not restrict its attempts to attach a pre-existing domain to a single group or bus. Please go back to the original version with the ops check in the core code. Jason