On Thu, Feb 23, 2023 at 09:03:14AM +0000, Tian, Kevin wrote: > > 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); yes > 2) immediate_attach=false when adding hwpt_alloc() uAPI and VT-d > support; yes > 3) fix domain_alloc() to take struct device so the SMMU drivers can > decide the domain info w/o relying on attach; Yes, this is where Robin's patches are going. > 4) remove immediate_attach and enable hwpt_alloc() on SMMU. Sort of, the domain_alloc_user already takes in the device so SMMU can be fixed for that API immediately, in theory, but it looks like some amount of work to get there. Jason
