Re: [RFC 00/13] x86/mm: PCID and INVPCID

From	Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups	linux.kernel
Subject	Re: [RFC 00/13] x86/mm: PCID and INVPCID
Date	2016-01-09 00:50 +0100
Message-ID	<qOOX8-5wC-11@gated-at.bofh.it> (permalink)
References	<qOOu6-5ka-5@gated-at.bofh.it> <qOONs-5sr-5@gated-at.bofh.it> <qOONs-5sr-9@gated-at.bofh.it>
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On Fri, Jan 8, 2016 at 3:36 PM, Andy Lutomirski <luto@amacapital.net> wrote:
>>
>> Either things have changed (newer hardware with more pcids perhaps?)
>> or you did a better job at it.
>
> On my Skylake laptop, all of the PCID bits appear to have at least
> some effect.  Whether this means it gets hashed or whether this means
> that all of the bits are real, I don't know.

They have always gotten hashed, and no the bits aren't real - hardware
doesn't actually have as many bits in the pcid as there are in cr3.

              Linus

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[RFC 00/13] x86/mm: PCID and INVPCID Andy Lutomirski <luto@kernel.org> - 2016-01-09 00:20 +0100
  Re: [RFC 00/13] x86/mm: PCID and INVPCID Linus Torvalds <torvalds@linux-foundation.org> - 2016-01-09 00:40 +0100
    Re: [RFC 00/13] x86/mm: PCID and INVPCID Andy Lutomirski <luto@amacapital.net> - 2016-01-09 00:40 +0100
      Re: [RFC 00/13] x86/mm: PCID and INVPCID Linus Torvalds <torvalds@linux-foundation.org> - 2016-01-09 00:50 +0100

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