They are doing the same as the Intel microcode update presumably, offering kernel a bit to enable/disable indirect branch speculation. Usually it will be disabl

They are doing the same as the Intel microcode update presumably, offering kernel a bit to enable/disable indirect branch speculation. Usually it will be disabled on entry into kernel and reenabled on exit, so it helps the kernel, not necessary user programs spying on each other (retpoline for those) See here: https://lkml.org/lkml/2018/1/4/615 https://lkml.org/lkml/2018/1/4/615