Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1481968

Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the CPUID instruction.

Show all headers | View raw

On Sep 12, 2016 10:57 AM, "Jann Horn" <jann@thejh.net> wrote:
>
> On Mon, Sep 12, 2016 at 09:56:11AM -0700, Andy Lutomirski wrote:
> > On Sep 11, 2016 5:29 PM, "Kyle Huey" <me@kylehuey.com> wrote:
> > >
> > > rr (http://rr-project.org/), a userspace record-and-replay reverse-
> > > execution debugger, would like to trap and emulate the CPUID instruction.
> > > This would allow us to a) mask away certain hardware features that rr does
> > > not support (e.g. RDRAND) and b) enable trace portability across machines
> > > by providing constant results.
> > >
> > > Intel supports faulting on the CPUID instruction in newer processors. Bit
> > > 31 of MSR_PLATFORM_INFO advertises support for this feature. It is
> > > documented in detail in Section 2.3.2 of
> > > http://www.intel.com/content/dam/www/public/us/en/documents/application-notes/virtualization-technology-flexmigration-application-note.pdf.
> [...]
> > If this bit is preserved on fork(), then no_new_privs must be checked
> > (or it must be cleared on "unsafe" exec, but that's nasty).
>
> I think you mean "preserved on execve()"?

Indeed.

So it should have defined and tested behavior on fork() and execve().
Maybe fork() should preserve the flag after all.

--Andy

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the CPUID instruction. Kyle Huey <me@kylehuey.com> - 2016-09-12 02:30 +0200
  Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Borislav Petkov <bp@suse.de> - 2016-09-12 11:10 +0200
    Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Kyle Huey <me@kylehuey.com> - 2016-09-12 16:20 +0200
      Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Borislav Petkov <bp@suse.de> - 2016-09-12 16:40 +0200
      Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Kyle Huey <me@kylehuey.com> - 2016-09-13 20:50 +0200
  Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Andy Lutomirski <luto@amacapital.net> - 2016-09-12 19:00 +0200
    Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Borislav Petkov <bp@suse.de> - 2016-09-12 19:20 +0200
    Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Jann Horn <jann@thejh.net> - 2016-09-12 20:00 +0200
      Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Andy Lutomirski <luto@amacapital.net> - 2016-09-12 23:10 +0200
    Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Kyle Huey <me@kylehuey.com> - 2016-09-14 08:20 +0200
      Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Andy Lutomirski <luto@amacapital.net> - 2016-09-14 21:00 +0200
        Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Andrew Cooper <andrew.cooper3@citrix.com> - 2016-09-14 21:30 +0200
          Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Andy Lutomirski <luto@amacapital.net> - 2016-09-14 21:40 +0200
            Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Andrew Cooper <andrew.cooper3@citrix.com> - 2016-09-14 21:50 +0200
        Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-09-14 21:30 +0200
        Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Andrew Cooper <andrew.cooper3@citrix.com> - 2016-09-14 21:40 +0200
  Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the CPUID instruction. Andi Kleen <andi@firstfloor.org> - 2016-09-12 19:40 +0200
    Re: [PATCH] prctl,x86 Add PR_[GET|SET]_CPUID for controlling the  CPUID instruction. Henrique de Moraes Holschuh <hmh@hmh.eng.br> - 2016-09-12 20:30 +0200

csiph-web