On Thu, Oct 02, 2025 at 10:49:21AM -0700, John Hubbard wrote: > > Forgot to add: But I think Zhi explained that this is not necessary and can > > be > > controlled by the VFIO driver, i.e. the PCI driver that binds to the VF > > itself. > > Yes, this is the direction that I originally (3 whole days ago, haha) had in > mind, > after talking with Zhi and a few others: nova-core handles PFs, and the VFIO > driver > handles the VFs, and use the "is virtual" logic to sort them out.
To be clear, no matter what the VFIO driver bound to the VF should not become entangled with any aux devices. The VFIO VF driver uses pci_iov_get_pf_drvdata() to reach into the PF to request the PF's help. Eg for live migration or things of that nature. My point here is that generally we don't put profiling code in the VFIO driver and then use pci_iov_get_pf_drvdata() to access the PF do actually do the profiling. The VF cannot/should not control profiling of itself - that would be a security problem once it is assigned to a VM. So the profiling resides entirely inside the PF world and should operate without VFIO. As I've said this design is compatible with VFs for containers and so on. So it is the strongly preferred design pattern. Jason
