Messages in this thread | | | From | Tim Chen <> | Subject | Re: [PATCH v5 2/2] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation | Date | Tue, 11 Sep 2018 10:32:34 -0700 |
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On 09/10/2018 04:46 AM, Jiri Kosina wrote: > On Mon, 10 Sep 2018, Jiri Kosina wrote: > >>> That looks much more palatable. One missing piece is the sysfs >>> mitigation file for spectre v2. That should reflect STIPB state as well. >> >> FWIW, we're missing a bit more in that area, namely RSB stuffing on >> context switch, IBRS (even through only around fw) and IBPB; those are >> only signalled in dmesg during bootup. > > Nah, IBPB is actuall there, sorry. So I'll add reporting of STIBP + fixup > the missing reporting of RSB_CTXSW for v6. >
I anticipate that STIBP could affect workloads with a lot of indirect branches (see previous discussion with Andrea). We should have a knob for people to opt in or opt out of STIBP.
Thanks.
Tim
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