> From: Jason Gunthorpe <jgg@xxxxxxxxxx> > Sent: Friday, October 13, 2023 10:06 PM > > On Fri, Oct 13, 2023 at 07:13:34AM +0000, Tian, Kevin wrote: > > > From: Jason Gunthorpe <jgg@xxxxxxxxxx> > > > Sent: Friday, October 13, 2023 3:10 AM > > > > > > Also, we probably should feed enforce_cache_coherency through the > > > alloc_hwpt uapi and not try to autodetect it.. > > > > > > > In the past we had a long discussion about this with the conclusion > > that user opt is the ideal model but it's fine to stay with autodetect > > and existing vfio/kvm contract for coherency detection until we > > see a real demand for user opt. > > > > Is there anything new which changes your mind to have user opt now? > > I guess, I was just looking at the complexity it brings to keep that > working. > vfio_file_enforced_coherent() currently just looks at device_iommu_capable() and can be called before attach, assuming an autodetect model. moving away from autodetect would need a new contract which I hesitate to bother with at this point.
