Messages in this thread | | | Date | Thu, 12 May 2022 14:16:36 +0800 | Subject | Re: [PATCH v6 08/12] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces | From | Baolu Lu <> |
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On 2022/5/12 13:44, Tian, Kevin wrote: >> From: Baolu Lu <baolu.lu@linux.intel.com> >> Sent: Thursday, May 12, 2022 1:17 PM >> >> On 2022/5/12 13:01, Tian, Kevin wrote: >>>> From: Baolu Lu <baolu.lu@linux.intel.com> >>>> Sent: Thursday, May 12, 2022 11:03 AM >>>> >>>> On 2022/5/11 22:53, Jason Gunthorpe wrote: >>>>>>> Also, given the current arrangement it might make sense to have a >>>>>>> struct iommu_domain_sva given that no driver is wrappering this in >>>>>>> something else. >>>>>> Fair enough. How about below wrapper? >>>>>> >>>>>> +struct iommu_sva_domain { >>>>>> + /* >>>>>> + * Common iommu domain header,*must* be put at the top >>>>>> + * of the structure. >>>>>> + */ >>>>>> + struct iommu_domain domain; >>>>>> + struct mm_struct *mm; >>>>>> + struct iommu_sva bond; >>>>>> +} >>>>>> >>>>>> The refcount is wrapped in bond. >>>>> I'm still not sure that bond is necessary >>>> >>>> "bond" is the sva handle that the device drivers get through calling >>>> iommu_sva_bind(). >>>> >>> >>> 'bond' was required before because we didn't have a domain to wrap >>> the page table at that time. >>> >>> Now we have a domain and it is 1:1 associated to bond. Probably >>> make sense now by just returning the domain as the sva handle >>> instead? >> >> It also includes the device information that the domain has been >> attached. So the sva_unbind() looks like this: >> >> /** >> * iommu_sva_unbind_device() - Remove a bond created with >> iommu_sva_bind_device >> * @handle: the handle returned by iommu_sva_bind_device() >> * >> * Put reference to a bond between device and address space. The device >> should >> * not be issuing any more transaction for this PASID. All outstanding page >> * requests for this PASID must have been flushed to the IOMMU. >> */ >> void iommu_sva_unbind_device(struct iommu_sva *handle) >> >> It's fine to replace the iommu_sva with iommu_sva_domain for sva handle, >> if we can include the device in the unbind() interface. > > can we just have unbind(domain, device)?
Yes. With this, we can remove bond.
This could be done in below phase 2.
> >> >> Anyway, I'd expect to achieve all these in two steps: >> >> - sva and iopf refactoring, only iommu internal changes; >> - sva interface refactoring, only interface changes. >> >> Does above work? >> >> Best regards, >> baolu
Best regards, baolu
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