> The mitigation locks the entire memory bus before updating the staging buffer and only unlocks it after clearing its content.

Entire memory bus as in entire access to any kind of shared memory (shared CPU caches, RAM, ...)? If yes, wow, that's a pretty desperate mitigation. Doesn't that starve large parts of the whole CPU whenever an affected, but mitigated instruction is executed, as all other cores can't interact with memory anymore for the duration of this execution? Doesn't that also open the ability to "DoS" CPUs by constantly executing such instructions?