L1d Cache Flushing On Context Switch Trying Again But More Conservative In 2021

Coming out in early 2020 were patches by an Amazon engineer to implement flushing the L1 data cache on context switching in the name of security given the various data sampling vulnerabilities. That work so far has been rejected from the mainline kernel but today was updated and makes it harder to enable and thus moving forward could stand chances to finally see the opt-in functionality merged to mainline...