Re: [libvirt] libvirt mdev migration, mdevctl integration

On 11/25/19 6:14 PM, Cornelia Huck wrote: > Also, I'm wondering if we need special care for vfio-ap, although I'm > not sure if it is feasible to add migration support for it all. We > currently have a matrix device (always same parent) defined by the > UUID, and adapters/domains configured for this matrix device (which is > handled as extra parameters in the mdevctl device config). I'm not sure > how different adapters/domains translate between systems we want to > migrate between. Not sure how much sense it makes to dwell on this at Aside from the card preparation with the appropriate masterkeys the adapter/domain configuration (including the card types) for an mdev needs to remain the same since there is no virtualization of adapter/domain addresses in the current vfio-ap driver implementation. As a result a currently possible migration scenario is cross-CEC.

From libvirts perspective: Assuming that mdevs on the source and target system exist, would a matching UUID be enough assurance that these two host resources match for a migration? If not, is a check performed on the configuration of the two mdevs? What is in that case considered migration save? Where are these checks implemented? Does the checking for migratablity go beyond the configuration data of mdev devices, e.g. vfio-ap: check for existence of masterkeys, card type equivalency or as Connie mentioned before on vfio-ccw the equivalency of the child ccw device of the subchannels.