RE: [PATCH v3 15/15] vfio: Add struct device to vfio_device

Tian, Kevin
2022-09-20T22:55:47Z

> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Wednesday, September 21, 2022 4:27 AM
>
> On Fri, 9 Sep 2022 18:22:47 +0800
> Kevin Tian <kevin.tian@intel.com> wrote:
>
> > From: Yi Liu <yi.l.liu@intel.com>
> >
> > and replace kref. With it a 'vfio-dev/vfioX' node is created under the
> > sysfs path of the parent, indicating the device is bound to a vfio
> > driver, e.g.:
> >
> > /sys/devices/pci0000\:6f/0000\:6f\:01.0/vfio-dev/vfio0
> >
> > It is also a preparatory step toward adding cdev for supporting future
> > device-oriented uAPI.
> >
> > Add Documentation/ABI/testing/sysfs-devices-vfio-dev.
> >
> > Also take this chance to rename chardev 'vfio' to 'vfio-group' in
> > /proc/devices.
>
> What's the risk/reward here, is this just more aesthetically pleasing
> symmetry vs 'vfio-dev'? The char major number to name association in
> /proc/devices seems pretty obscure, but what due diligence have we done
> to make sure this doesn't break anyone? Thanks,
>

I'm not sure whether the content of /proc/devices is considered as ABI.

@Jason?

But to be safe I can remove this change in next version. If it's the right
thing to do such change after discussion then it can be done in a separate
patch after.