Messages in this thread | | | Date | Thu, 29 Oct 2020 17:51:32 +1100 | Subject | [PATCH 0/1] x86/speculation: Allow IBPB to be conditionally enabled on CPUs with always-on STIBP | From | Anand K Mistry <> |
| |
When attempting to do some performance testing of IBPB on and AMD platform, I noticed the IBPB instruction was never being issued, even though it was conditionally on and various seccomp protected processes were force enabling it. Turns out, on those AMD CPUs, STIBP is set to always-on and this was causing an early-out on the prctl() which turns off IB speculation. Here is my attempt to fix it.
I'm hoping someone that understands this better than me can explain why I'm wrong.
Anand K Mistry (1): x86/speculation: Allow IBPB to be conditionally enabled on CPUs with always-on STIBP
arch/x86/kernel/cpu/bugs.c | 41 +++++++++++++++++++++----------------- 1 file changed, 23 insertions(+), 18 deletions(-)
-- 2.29.1.341.ge80a0c044ae-goog
| |