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Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled

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From Andy Lutomirski <luto@amacapital.net>
Newsgroups linux.kernel
Subject Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled
Date Tue, 29 Sep 2015 20:30:02 +0200
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On Tue, Sep 29, 2015 at 11:18 AM, H. Peter Anvin <hpa@zytor.com> wrote:
> SGDT would be easy to use, and it is logical that it is faster since it reads an internal register.  SIDT does too but unlike the GDT has a secondary limit (it can never be larger than 4096 bytes) and so all limits in the range 4095-65535 are exactly equivalent.
>

Using the IDT limit would have been a great ideal if Intel hadn't
decided to clobber it on every VM exit.

--Andy
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[PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled Denys Vlasenko <dvlasenk@redhat.com> - 2015-09-26 20:10 +0200
  Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled "H. Peter Anvin" <hpa@zytor.com> - 2015-09-26 22:00 +0200
    Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled Denys Vlasenko <dvlasenk@redhat.com> - 2015-09-26 22:40 +0200
      Re: [PATCH] x86: Use entire page for the per-cpu GDT only if  paravirt-enabled Ingo Molnar <mingo@kernel.org> - 2015-09-28 10:00 +0200
        Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled Denys Vlasenko <dvlasenk@redhat.com> - 2015-09-28 14:50 +0200
          Re: [PATCH] x86: Use entire page for the per-cpu GDT only if  paravirt-enabled Ingo Molnar <mingo@kernel.org> - 2015-09-29 11:10 +0200
            Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled Andy Lutomirski <luto@amacapital.net> - 2015-09-29 19:40 +0200
              Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled Linus Torvalds <torvalds@linux-foundation.org> - 2015-09-29 20:00 +0200
                Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled Andy Lutomirski <luto@amacapital.net> - 2015-09-29 20:10 +0200
                Re: [PATCH] x86: Use entire page for the per-cpu GDT only if  paravirt-enabled "H. Peter Anvin" <hpa@zytor.com> - 2015-09-29 22:40 +0200
                Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled ebiederm@xmission.com (Eric W. Biederman) - 2015-09-30 03:30 +0200
                Re: [PATCH] x86: Use entire page for the per-cpu GDT only if  paravirt-enabled "H. Peter Anvin" <hpa@zytor.com> - 2015-09-30 03:40 +0200
                Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled ebiederm@xmission.com (Eric W. Biederman) - 2015-09-30 04:20 +0200
                Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled "H. Peter Anvin" <hpa@zytor.com> - 2015-09-30 04:30 +0200
              Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled "H. Peter Anvin" <hpa@zytor.com> - 2015-09-29 20:30 +0200
                Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled "H. Peter Anvin" <hpa@zytor.com> - 2015-09-29 20:30 +0200
                Re: [PATCH] x86: Use entire page for the per-cpu GDT only if paravirt-enabled Andy Lutomirski <luto@amacapital.net> - 2015-09-29 20:30 +0200

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