On Tue, Jul 27, 2021 at 08:09:41PM -0300, Jason Gunthorpe wrote: > On Tue, Jul 27, 2021 at 03:54:40PM -0600, Alex Williamson wrote: > > > I'm still not happy with how this is likely to break users and even > > downstreams when upgrading to a Kconfig with this change. > > I've never heard of Kconfig as stable ABI. Christoph/Arnd, have you > heard of any cases where we want to keep it stable? It isn't an ABI, but we really do try to avoid breaking if we can and I rember Linus shouting at people if they did that for common options. However lately for example the completely silly s/THUNDERBOLT/USB4/ change did slip through and did break my test setup with a vfio passed through external nvme drive :( > Which might reasonably be from an old kernel. 'make oldconfig' prompts: > > VFIO Non-Privileged userspace driver framework (VFIO) [Y/n/m/?] y > VFIO No-IOMMU support (VFIO_NOIOMMU) [Y/n/?] y > VFIO support for PCI devices (VFIO_PCI_CORE) [N/m/y/?] (NEW) > > Which is completely fine, IMHO. Why do we need to have VFIO_PCI_CORE as a user visible option? I'd just select it.