On Mon, Oct 25, 2021 at 07:47:29PM +0100, Dr. David Alan Gilbert wrote: > It may need some further refinement; for example in that quiesed state > do counters still tick? will a NIC still respond to packets that don't > get forwarded to the host? At least for the mlx5 NIC the two states are 'able to issue outbound DMA' and 'all internal memories and state are frozen and unchanging'. The later means it should not respond/count/etc to network packets either. Roughly it is 'able to mutate external state' / 'able to mutate internal state' The invariant should be that successive calls to serialize the internal state while frozen should return the same serialization. We may find that migratable PCI functions must have some limited functionality. Ie anything with a realtime compoment - for instance a sync-ethernet clock synchronization control loop, may become challenging to migrate without creating a serious functional distortion. Jason
