Messages in this thread | | | Date | Thu, 12 May 2022 09:16:17 +0800 | Subject | Re: [PATCH v3 1/4] iommu/vt-d: Implement domain ops for attach_dev_pasid | From | Baolu Lu <> |
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On 2022/5/12 01:25, Jacob Pan wrote: > Hi Jason, > > On Wed, 11 May 2022 14:00:25 -0300, Jason Gunthorpe <jgg@nvidia.com> wrote: > >> On Wed, May 11, 2022 at 10:02:16AM -0700, Jacob Pan wrote: >>>>> If not global, perhaps we could have a list of pasids (e.g. xarray) >>>>> attached to the device_domain_info. The TLB flush logic would just >>>>> go through the list w/o caring what the PASIDs are for. Does it >>>>> make sense to you? >>>> >>>> Sort of, but we shouldn't duplicate xarrays - the group already has >>>> this xarray - need to find some way to allow access to it from the >>>> driver. >>>> >>> I am not following, here are the PASIDs for devTLB flush which is per >>> device. Why group? >> >> Because group is where the core code stores it. > I see, with singleton group. I guess I can let dma-iommu code call > > iommu_attach_dma_pasid { > iommu_attach_device_pasid(); > Then the PASID will be stored in the group xa. > The flush code can retrieve PASIDs from device_domain_info.device -> group > -> pasid_array. > Thanks for pointing it out, I missed the new pasid_array. >> >>> We could retrieve PASIDs from the device PASID table but xa would be >>> more efficient. >>> >>>>>>> Are you suggesting the dma-iommu API should be called >>>>>>> iommu_set_dma_pasid instead of iommu_attach_dma_pasid? >>>>>> >>>>>> No that API is Ok - the driver ops API should be 'set' not >>>>>> attach/detach >>>>> Sounds good, this operation has little in common with >>>>> domain_ops.dev_attach_pasid() used by SVA domain. So I will add a >>>>> new domain_ops.dev_set_pasid() >>>> >>>> What? No, their should only be one operation, 'dev_set_pasid' and it >>>> is exactly the same as the SVA operation. It configures things so that >>>> any existing translation on the PASID is removed and the PASID >>>> translates according to the given domain. >>>> >>>> SVA given domain or UNMANAGED given domain doesn't matter to the >>>> higher level code. The driver should implement per-domain ops as >>>> required to get the different behaviors. >>> Perhaps some code to clarify, we have >>> sva_domain_ops.dev_attach_pasid() = intel_svm_attach_dev_pasid; >>> default_domain_ops.dev_attach_pasid() = intel_iommu_attach_dev_pasid; >> >> Yes, keep that structure >> >>> Consolidate pasid programming into dev_set_pasid() then called by both >>> intel_svm_attach_dev_pasid() and intel_iommu_attach_dev_pasid(), right? >>> >> >> I was only suggesting that really dev_attach_pasid() op is misnamed, >> it should be called set_dev_pasid() and act like a set, not a paired >> attach/detach - same as the non-PASID ops. >> > Got it. Perhaps another patch to rename, Baolu?
Yes. I can rename it in my sva series if others are also happy with this naming.
Best regards, baolu
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