> From: Jason Gunthorpe <[email protected]> > Sent: Thursday, March 31, 2022 3:02 AM > > On Tue, Mar 29, 2022 at 01:37:52PM +0800, Lu Baolu wrote: > > @@ -95,6 +101,7 @@ struct iommu_domain { > > void *handler_token; > > struct iommu_domain_geometry geometry; > > struct iommu_dma_cookie *iova_cookie; > > + struct iommu_sva_cookie *sva_cookie; > > Cookie is still the wrong word to use here > > > +struct iommu_sva_cookie { > > + struct mm_struct *mm; > > + ioasid_t pasid; > > + refcount_t users; > > Really surprised to see a refcount buried inside the iommu_domain.. > > This design seems inside out, the SVA struct should 'enclose' the domain, not > be a pointer inside it. > > struct iommu_sva_domain { > struct kref_t kref; > struct mm_struct *mm; > ioasid_t pasid; > > /* All the domains that are linked to this */ > struct xarray domain_list; > }; > > And then you could have a pointer to that inside the mm_struct instead > of just the naked pasid. > > > +static __maybe_unused struct iommu_domain * > > Why maybe unused? > > > +iommu_sva_get_domain(struct device *dev, struct mm_struct *mm) > > +{ > > + struct iommu_domain *domain; > > + ioasid_t pasid = mm->pasid; > > + > > + if (pasid == INVALID_IOASID) > > + return NULL; > > + > > + domain = xa_load(&sva_domain_array, pasid); > > + if (!domain) > > + return iommu_sva_alloc_domain(dev, mm); > > + iommu_sva_domain_get_user(domain); > > 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? > > 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? Thanks Kevin _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
