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PCID Speculation

Posted: 2018/01/13 19:36:57
by dcrdev
With the performance hit hitting KPTI patched systems and the apparent mitigation of this performance decrease with systems that have PCID support.

Would anyone care to speculate whether or not Redhat will backport PCID support to the kernel in the current 7.x series of releases?

I'm thinking they've got to, otherwise people will start flooding to Orace with their 'Unbreakable' kernel which has support for this...

Re: PCID Speculation

Posted: 2018/01/13 22:05:05
by avij
I don't know if there's a need for speculation (clever pun, btw), because the current kernel changelog says:

Code: Select all

- [x86] mm/kaiser: use PCID feature to make user and kernel switches faster (Josh Poimboeuf) [1519800 1519801] {CVE-2017-5754}
.. so the support is already included.