Speakers
Description
Data that is serialized and preserved through a live update may have formatting differences between two kernels. This can affect the compatibility between two kernels when trying to perform a Live Update. Current efforts have been to use compatibility strings with implicit version numbers, like "memfd-v2" to help provide compatibility data. Changes to the formatting of the preserved data may not affect the compatibility if the new kernel understands the format of the old version. For example, an optional feature may be available on a new kernel that is not strictly needed. If the old kernel does not support that feature and the new kernel does, we still want to allow a Live Update between these versions.
This discussion is for a proposed method of serializing all supported versions of a component and having the new kernel negotiate the version to deserialize. The current proposal uses file handlers as the first user of this scheme, but this will apply to any component that needs to preserve and restore serialized data.