Comment # 16 on bug 1163120 from Miroslav Bene��

I believe Boris provided exhaustive answers to your questions. Upstream
documentation provides all information about the current implementation of all
these mitigations. We try really hard to follow upstream here. If I recall
correctly, software mitigations were discussed in some cases, but they were not
implemented, because of another issues they have (performance, not reliable and
such).

Boris (or someone else) could add more specific info eventually if they like,
but I think we're done here.