On Wed, Feb 16, 2022 at 03:17:36AM +0000, Tian, Kevin wrote: > those requests don't rely on vCPUs but still take time to complete > (thus may break SLA) and are invisible to migration driver (directly > submitted by the guest thus cannot be estimated). So the only means > is for user to wait on a fd with a timeout (based on whatever SLA) and > if expires then aborts migration (may retry later). I think I explained in my other email how this can be implemented today with v2 for STOP_COPY without an event fd. Such a device might even be able to implement an abort.. Jason