On Wed, Mar 22, 2023 at 08:17:54AM +0000, Liu, Yi L wrote: > Could you elaborate what is required with _INFO before libvirt can > use a FD pass? Make a new _INFO that returns an array of dev_ids within the cdev's iommufd_ctx that are part of the reset group, eg the devset. qemu will call this for each dev_id after it opens the cdev to generate the groupings. > > But for the current qemu setup it will open cdev directly and it will > > know the BDF so it can still use the current _INFO. > > > > Though it would be nice if qemu didn't need two implementations so Yi > > I'd rather see a new info in this series as well and qemu can just > > consistently use dev_id and never bdf in iommufd mode. > > I have one concern here. iommufd dev_id is not a static info as much as > bdf. It is generated when bound to iommufd. So if there are devices that > are affected but not bound to iommufd yet at the time of invoking _INFO, > then the _INFO ioctl just gets a subset of the affected devices. Is it enough? I'd probably use similar logic as the reset path, if one of reset group devices is open and on a different iommufd_ctx then fail the IOCTL with EPERM. Jason
