From: "Tian, Kevin" <kevin.tian@intel.com> To: Jason Gunthorpe <jgg@nvidia.com> Cc: "Raj, Ashok" <ashok.raj@intel.com>, Will Deacon <will@kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Christoph Hellwig <hch@infradead.org>, Jean-Philippe Brucker <jean-philippe@linaro.com>, "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, "Pan, Jacob jun" <jacob.jun.pan@intel.com>, Robin Murphy <robin.murphy@arm.com> Subject: RE: [PATCH RFC v2 03/11] iommu/sva: Add iommu_domain type for SVA Date: Wed, 6 Apr 2022 01:00:13 +0000 [thread overview] Message-ID: <BN9PR11MB527660D99D154F922B0A628B8CE79@BN9PR11MB5276.namprd11.prod.outlook.com> (raw) In-Reply-To: <20220402233210.GM2120790@nvidia.com> > From: Jason Gunthorpe <jgg@nvidia.com> > Sent: Sunday, April 3, 2022 7:32 AM > > On Sat, Apr 02, 2022 at 08:43:16AM +0000, Tian, Kevin wrote: > > > > This assumes any domain is interchangeable with any device, which is > > > not the iommu model. We need a domain op to check if a device is > > > compatiable with the domain for vfio an iommufd, this should do the > > > same. > > > > This suggests that mm_struct needs to include the format information > > of the CPU page table so the format can be checked by the domain op? > > No, Linux does not support multiple formats for CPU page tables, > AFAICT, and creating the SVA domain in the first place should check > this. One interesting usage is when virtio-iommu supports vSVA one day. At that time there needs a way to know the format of the CPU page table and then virtio-iommu driver needs to check whether it is compatible with what the host iommu driver supports. But possibly this can wait to be solved until that usage comes... > > > > It means each mm can have a list of domains associated with it and a > > > new domain is auto-created if the device doesn't work with any of the > > > existing domains. > > > > mm has only one page table and one format. If a device is incompatible > > with an existing domain wrapping that page table, how come creating > > another domain could make it compatible? > > Because domains wrap more than just the IOPTE format, they have > additional data related to the IOMMU HW block itself. Imagine a SOC > with two IOMMU HW blocks that can both process the CPU IOPTE format, > but have different configuration. Curious. Is it hypothesis or real? If real can you help give a concrete example? > > So if device A users IOMMU A it needs an iommu_domain from driver A and > same for another device B, even if both iommu_domains are thin > wrappers around the same mm_struct. > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: "Tian, Kevin" <kevin.tian@intel.com> To: Jason Gunthorpe <jgg@nvidia.com> Cc: Lu Baolu <baolu.lu@linux.intel.com>, Joerg Roedel <joro@8bytes.org>, Christoph Hellwig <hch@infradead.org>, "Raj, Ashok" <ashok.raj@intel.com>, Will Deacon <will@kernel.org>, Robin Murphy <robin.murphy@arm.com>, Jean-Philippe Brucker <jean-philippe@linaro.com>, Eric Auger <eric.auger@redhat.com>, "Liu, Yi L" <yi.l.liu@intel.com>, "Pan, Jacob jun" <jacob.jun.pan@intel.com>, "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: RE: [PATCH RFC v2 03/11] iommu/sva: Add iommu_domain type for SVA Date: Wed, 6 Apr 2022 01:00:13 +0000 [thread overview] Message-ID: <BN9PR11MB527660D99D154F922B0A628B8CE79@BN9PR11MB5276.namprd11.prod.outlook.com> (raw) In-Reply-To: <20220402233210.GM2120790@nvidia.com> > From: Jason Gunthorpe <jgg@nvidia.com> > Sent: Sunday, April 3, 2022 7:32 AM > > On Sat, Apr 02, 2022 at 08:43:16AM +0000, Tian, Kevin wrote: > > > > This assumes any domain is interchangeable with any device, which is > > > not the iommu model. We need a domain op to check if a device is > > > compatiable with the domain for vfio an iommufd, this should do the > > > same. > > > > This suggests that mm_struct needs to include the format information > > of the CPU page table so the format can be checked by the domain op? > > No, Linux does not support multiple formats for CPU page tables, > AFAICT, and creating the SVA domain in the first place should check > this. One interesting usage is when virtio-iommu supports vSVA one day. At that time there needs a way to know the format of the CPU page table and then virtio-iommu driver needs to check whether it is compatible with what the host iommu driver supports. But possibly this can wait to be solved until that usage comes... > > > > It means each mm can have a list of domains associated with it and a > > > new domain is auto-created if the device doesn't work with any of the > > > existing domains. > > > > mm has only one page table and one format. If a device is incompatible > > with an existing domain wrapping that page table, how come creating > > another domain could make it compatible? > > Because domains wrap more than just the IOPTE format, they have > additional data related to the IOMMU HW block itself. Imagine a SOC > with two IOMMU HW blocks that can both process the CPU IOPTE format, > but have different configuration. Curious. Is it hypothesis or real? If real can you help give a concrete example? > > So if device A users IOMMU A it needs an iommu_domain from driver A and > same for another device B, even if both iommu_domains are thin > wrappers around the same mm_struct. >
next prev parent reply other threads:[~2022-04-06 1:00 UTC|newest] Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-03-29 5:37 [PATCH RFC v2 00/11] iommu: SVA and IOPF refactoring Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-29 5:37 ` [PATCH RFC v2 01/11] iommu: Add pasid_bits field in struct dev_iommu Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-29 21:00 ` Jacob Pan 2022-03-29 21:00 ` Jacob Pan 2022-03-30 4:30 ` Lu Baolu 2022-03-30 4:30 ` Lu Baolu 2022-03-30 7:05 ` Tian, Kevin 2022-03-30 7:05 ` Tian, Kevin 2022-03-30 11:58 ` Lu Baolu 2022-03-30 11:58 ` Lu Baolu 2022-03-29 5:37 ` [PATCH RFC v2 02/11] iommu: Add iommu_group_singleton_lockdown() Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-29 8:42 ` Tian, Kevin 2022-03-29 8:42 ` Tian, Kevin 2022-03-29 11:42 ` Jason Gunthorpe 2022-03-29 11:42 ` Jason Gunthorpe via iommu 2022-03-30 6:50 ` Tian, Kevin 2022-03-30 6:50 ` Tian, Kevin 2022-03-30 11:57 ` Lu Baolu 2022-03-30 11:57 ` Lu Baolu 2022-03-30 11:58 ` Jason Gunthorpe via iommu 2022-03-30 11:58 ` Jason Gunthorpe 2022-03-30 14:12 ` Tian, Kevin 2022-03-30 14:12 ` Tian, Kevin 2022-03-30 14:30 ` Jason Gunthorpe 2022-03-30 14:30 ` Jason Gunthorpe via iommu 2022-04-02 7:12 ` Tian, Kevin 2022-04-02 7:12 ` Tian, Kevin 2022-04-02 23:29 ` Jason Gunthorpe 2022-04-02 23:29 ` Jason Gunthorpe via iommu 2022-04-06 10:02 ` Lu Baolu 2022-04-06 10:02 ` Lu Baolu 2022-04-06 10:44 ` Tian, Kevin 2022-04-06 10:44 ` Tian, Kevin 2022-04-06 11:03 ` Lu Baolu 2022-04-06 11:03 ` Lu Baolu 2022-04-06 23:56 ` Tian, Kevin 2022-04-06 23:56 ` Tian, Kevin 2022-03-30 14:18 ` Tian, Kevin 2022-03-30 14:18 ` Tian, Kevin 2022-03-30 15:04 ` Alex Williamson 2022-03-30 15:04 ` Alex Williamson 2022-04-04 5:43 ` Lu Baolu 2022-04-04 5:43 ` Lu Baolu 2022-04-04 17:24 ` Jason Gunthorpe via iommu 2022-04-04 17:24 ` Jason Gunthorpe 2022-04-05 6:12 ` Lu Baolu 2022-04-05 6:12 ` Lu Baolu 2022-04-05 14:10 ` Jason Gunthorpe via iommu 2022-04-05 14:10 ` Jason Gunthorpe 2022-04-06 9:51 ` Lu Baolu 2022-04-06 9:51 ` Lu Baolu 2022-04-01 6:20 ` Yi Liu 2022-04-01 6:20 ` Yi Liu 2022-04-01 11:52 ` Jason Gunthorpe 2022-04-01 11:52 ` Jason Gunthorpe via iommu 2022-03-30 4:59 ` Lu Baolu 2022-03-30 4:59 ` Lu Baolu 2022-03-30 6:55 ` Tian, Kevin 2022-03-30 6:55 ` Tian, Kevin 2022-04-01 5:49 ` Yi Liu 2022-04-01 5:49 ` Yi Liu 2022-03-29 5:37 ` [PATCH RFC v2 03/11] iommu/sva: Add iommu_domain type for SVA Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-29 21:38 ` Jacob Pan 2022-03-29 21:38 ` Jacob Pan 2022-03-30 4:35 ` Lu Baolu 2022-03-30 4:35 ` Lu Baolu 2022-03-30 19:02 ` Jason Gunthorpe 2022-03-30 19:02 ` Jason Gunthorpe via iommu 2022-04-02 8:43 ` Tian, Kevin 2022-04-02 8:43 ` Tian, Kevin 2022-04-02 23:32 ` Jason Gunthorpe 2022-04-02 23:32 ` Jason Gunthorpe via iommu 2022-04-04 6:09 ` Lu Baolu 2022-04-04 6:09 ` Lu Baolu 2022-04-06 1:00 ` Tian, Kevin [this message] 2022-04-06 1:00 ` Tian, Kevin 2022-04-06 1:23 ` Jason Gunthorpe via iommu 2022-04-06 1:23 ` Jason Gunthorpe 2022-04-06 5:58 ` Tian, Kevin 2022-04-06 5:58 ` Tian, Kevin 2022-04-06 12:32 ` Robin Murphy 2022-04-06 12:32 ` Robin Murphy 2022-04-06 13:06 ` Jason Gunthorpe via iommu 2022-04-06 13:06 ` Jason Gunthorpe 2022-04-06 13:37 ` Robin Murphy 2022-04-06 13:37 ` Robin Murphy 2022-04-06 14:01 ` Jason Gunthorpe via iommu 2022-04-06 14:01 ` Jason Gunthorpe 2022-04-07 0:11 ` Tian, Kevin 2022-04-07 0:11 ` Tian, Kevin 2022-03-29 5:37 ` [PATCH RFC v2 04/11] iommu: Add attach/detach_dev_pasid domain ops Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-30 19:08 ` Jason Gunthorpe 2022-03-30 19:08 ` Jason Gunthorpe via iommu 2022-04-04 6:47 ` Lu Baolu 2022-04-04 6:47 ` Lu Baolu 2022-03-29 5:37 ` [PATCH RFC v2 05/11] iommu/vt-d: Remove SVM_FLAG_SUPERVISOR_MODE suport Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-29 5:37 ` [PATCH RFC v2 06/11] iommu/vt-d: Add SVA domain support Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-30 19:09 ` Jason Gunthorpe 2022-03-30 19:09 ` Jason Gunthorpe via iommu 2022-04-04 6:52 ` Lu Baolu 2022-04-04 6:52 ` Lu Baolu 2022-03-29 5:37 ` [PATCH RFC v2 07/11] arm-smmu-v3/sva: " Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-29 5:37 ` [PATCH RFC v2 08/11] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-31 20:59 ` Jacob Pan 2022-03-31 20:59 ` Jacob Pan 2022-03-31 22:26 ` Jason Gunthorpe 2022-03-31 22:26 ` Jason Gunthorpe via iommu 2022-04-04 5:55 ` Lu Baolu 2022-04-04 5:55 ` Lu Baolu 2022-03-29 5:37 ` [PATCH RFC v2 09/11] iommu: Remove SVA related callbacks from iommu ops Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-29 5:37 ` [PATCH RFC v2 10/11] iommu: Per-domain I/O page fault handling Lu Baolu 2022-03-29 5:37 ` Lu Baolu 2022-03-29 5:38 ` [PATCH RFC v2 11/11] iommu: Rename iommu-sva-lib.{c,h} Lu Baolu 2022-03-29 5:38 ` Lu Baolu
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