On Tue, Jun 02, 2026 at 12:26:19PM +0300, Avihai Horon wrote: > According to VFIO uAPI, precopy initial_bytes is considered as critical > data that should be transferred and loaded prior to moving to STOP_COPY > state to ensure precopy phase would be effective. > > As currently defined, initial_bytes can only decrease as it's being read > from the data fd. However, there are cases where a new chunk of > initial_bytes should be transferred during precopy. > > The new VFIO_PRECOPY_INFO_REINIT feature addresses this and allows > reporting a new value for initial_bytes regardless of any previously > reported values. > > Implement VFIO_PRECOPY_INFO_REINIT feature: > 1. Opt-in for VFIO_DEVICE_FEATURE_MIG_PRECOPY_INFOv2 to make > VFIO_PRECOPY_INFO_REINIT available. > 2. Request a new switchover ACK if initial_bytes increases post of a > previous switchover ACK. This ensures the device is not moved to > STOP_COPY before initial_bytes has reached zero again. > > Signed-off-by: Avihai Horon <[email protected]>
Acked-by: Peter Xu <[email protected]> -- Peter Xu
