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Thu, 16 Jun 2022 15:23:31 -0700 Date: Thu, 16 Jun 2022 15:23:30 -0700 From: Nicolin Chen To: "Tian, Kevin" 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" , "jgg@nvidia.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" , "christophe.jaillet@wanadoo.fr" , "john.garry@huawei.com" , "chenxiang66@hisilicon.com" , "saiprakash.ranjan@codeaurora.org" , "isaacm@codeaurora.org" , "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 v2 3/5] vfio/iommu_type1: Remove the domain->ops comparison Message-ID: References: <20220616000304.23890-1-nicolinc@nvidia.com> <20220616000304.23890-4-nicolinc@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; 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X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Jun 2022 22:24:08.0521 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 34a7c6cd-c395-44b9-2216-08da4fe6ee1c X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[12.22.5.238];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN8NAM11FT048.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN8PR12MB4595 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On Thu, Jun 16, 2022 at 06:40:14AM +0000, Tian, Kevin wrote: > > The domain->ops validation was added, as a precaution, for mixed-driver > > systems. However, at this moment only one iommu driver is possible. So > > remove it. > > It's true on a physical platform. But I'm not sure whether a virtual platform > is allowed to include multiple e.g. one virtio-iommu alongside a virtual VT-d > or a virtual smmu. It might be clearer to claim that (as Robin pointed out) > there is plenty more significant problems than this to solve instead of simply > saying that only one iommu driver is possible if we don't have explicit code > to reject such configuration. 😊 Will edit this part. Thanks!