On Wed, Sep 22, 2021 at 02:10:36PM -0600, Alex Williamson wrote: > But why would we create vfio device interface files at all if they > can't work? I'm not really on board with creating a try-and-fail > interface for a mechanism that cannot work for a given device. The > existence of the device interface should indicate that it's supported. I'm a little worried about adding a struct device to vfio_device and then making it optional.. That is a really weird situation. I suppose you could create the sysfs presence in the struct device but not create a cdev. However, if we ever want to use the device fd for something else, like querying the device driver capabilities or mode, (ie clean the driver_api thing wrongly placed in mdev sysfs for instance), we are blocked as the uAPI will be cdev == must support iommufd.. Jason
