> From: Jason Gunthorpe <jgg@xxxxxxxxxx> > Sent: Thursday, February 23, 2023 5:03 AM > > The HWPT is always linked to an IOAS and once a HWPT exists its domain > should be fully mapped. This ended up being split up into device.c during > a two phase creation that was a bit confusing. > > Move the iopt_table_add_domain() into iommufd_hw_pagetable_alloc() by > having it call back to device.c to complete the domain attach in the > required order. > > Calling iommufd_hw_pagetable_alloc() with immediate_attach = false will > work on most drivers, but notably the SMMU drivers will fail because they > can't decide what kind of domain to create until they are attached. This > will be fixed when the domain_alloc function can take in a struct device. > Is below understanding correct on how to retire immediate_attach? 1) immediate_attach=true in auto domain path for back compat (what this patch does); 2) immediate_attach=false when adding hwpt_alloc() uAPI and VT-d support; 3) fix domain_alloc() to take struct device so the SMMU drivers can decide the domain info w/o relying on attach; 4) remove immediate_attach and enable hwpt_alloc() on SMMU. Of course 3) doesn't need to wait. If it happens before 2) is merged then 2/4) can come together.
