> > As you indicate, the vendor driver is responsible for checking version > > information embedded within the migration stream. Therefore a > > migration should fail early if the devices are incompatible. Is it > but as I know, currently in VFIO migration protocol, we have no way to > get vendor specific compatibility checking string in migration setup stage > (i.e. .save_setup stage) before the device is set to _SAVING state. > In this way, for devices who does not save device data in precopy stage, > the migration compatibility checking is as late as in stop-and-copy > stage, which is too late. > do you think we need to add the getting/checking of vendor specific > compatibility string early in save_setup stage? > hi Alex, after an offline discussion with Kevin, I realized that it may not be a problem if migration compatibility check in vendor driver occurs late in stop-and-copy phase for some devices, because if we report device compatibility attributes clearly in an interface, the chances for libvirt/openstack to make a wrong decision is little. so, do you think we are now arriving at an agreement that we'll give up the read-and-test scheme and start to defining one interface (perhaps in json format), from which libvirt/openstack is able to parse and find out compatibility list of a source mdev/physical device? Thanks Yan
