Messages in this thread |  | | Subject | Re: [PATCH] x86/cpuid: Fix up "virtual" IBRS/IBPB/STIBP feature bits on Intel | From | David Woodhouse <> | Date | Tue, 30 Jan 2018 12:09:53 +0000 |
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On Tue, 2018-01-30 at 12:37 +0100, Thomas Gleixner wrote:
> In any case, if there is ucode mismatch between CPUs the whole thing is > hosed anyway no matter what. So can you please agree on a solution so we > can unbreak the current state of affairs?
If there is µcode mismatch between CPUs then the inconsistent bits should be filtered down to the lowest common denominator and we shouldn't use the features that are not consistently present. That much ought to work already with my patch.
Boris's version uses setup_force_cpu_cap() and forces the bit to be set even on secondary CPUs which don't really have it, and thus it won't get filtered out. We'll try to use it, and it will fault on the CPUs which don't have it.
That's the difference. [unhandled content-type:application/x-pkcs7-signature] |  |