On Mon, Apr 04, 2022 at 10:04:02AM +0200, Arnd Bergmann wrote: > The header is shared between kernel and other projects using virtio, such as > qemu and any boot loaders booting from virtio devices. It's not technically a > /kernel/ ABI, but it is an ABI and for practical reasons the kernel version is > maintained as the master copy if I understand it correctly. Besides that fact that as you correctly states these are not a UAPI at all, qemu and bootloades are not specific to Linux and can't require a specific kernel version. So the same thing we do for file system formats or network protocols applies here: just copy the damn header. And as stated above any reasonably portable userspace needs to have a copy anyway. If it is just as a "master copy" it can live in drivers/virtio/, just like we do for other formats.
