18 Nov
2018
18 Nov
'18
11:56 p.m.
Linus Torvalds torvalds@linux-foundation.org writes:
On Sun, Nov 18, 2018 at 2:17 PM Jiri Kosina jikos@kernel.org wrote:
Which gets us back to Tim's fixup patch. Do you still prefer the revert, given the existence of that?
I don't think the code needs to be reverted, but the *behavior* of just unconditionally enabling STIBP needs to be reverted.
Actually I think it should be reverted. Yes of course opt-in is needed.
But also when you opt-in it doesn't make sense to set STIBP when the sibling is running the same security context, which is actually a common case. So to even use it properly you would need some scheduler support to detect these cases and only enable it then with opt-in. These patches didn't even try to tackle this problem.
-Andi