[PATCH v13 0/8] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction

From	Kyle Huey <me@kylehuey.com>
Newsgroups	linux.kernel
Subject	[PATCH v13 0/8] x86/arch_prctl Add ARCH_[GET\|SET]_CPUID for controlling the CPUID instruction
Date	2016-11-28 04:10 +0100
Message-ID	<sIkul-4M5-5@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

Show all headers | View raw

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.

Newer Intel CPUs (Ivy Bridge and later) can fault when CPUID is executed at
CPL > 0. Expose this capability to userspace as a new pair of arch_prctls,
ARCH_GET_CPUID and ARCH_SET_CPUID.

Since v12:
Patch 4: x86/syscalls/32: Wire up arch_prctl on x86-32
- compat_sys_arch_prctl prototype has argument names.

Patch 5: x86/cpufeature: Detect CPUID faulting support
- s/init_intel_misc_features_enables/init_intel_misc_features/.
- Added Reviewed-by Borislav.

Patch 6: x86/arch_prctl: Add ARCH_[GET|SET]_CPUID
- Selftest was split out into Patch 7.
- s/msr_misc_features_enables_shadow/msr_misc_features_shadow/.
- ARCH_GET_CPUID now returns its value directly, not in an outparam.
- ARCH_SET_CPUID now takes a simple 0/1 value, ARCH_CPUID_ENABLE and
  ARCH_CPUID_SIGSEGV are gone.
- ARCH_[GET|SET]_CPUID now operate on the enabledness of the CPUID
  instruction, not the CPUID faulting bit. Thus the default return
  value of ARCH_GET_CPUID is 1, and calling ARCH_SET_CPUID with 0
  activates CPUID faulting (and thus disabling the CPUID instruction).

Patch 7: x86/arch_prctl: Selftest for ARCH_[GET|SET]_CPUID
- The self test was updated for the API changes.

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

Thread

[PATCH v13 0/8] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction Kyle Huey <me@kylehuey.com> - 2016-11-28 04:10 +0100
  [PATCH v13 8/8] KVM: x86: virtualize cpuid faulting Kyle Huey <me@kylehuey.com> - 2016-11-28 04:10 +0100
  [PATCH v13 7/8] x86/arch_prctl: Selftest for ARCH_[GET|SET]_CPUID Kyle Huey <me@kylehuey.com> - 2016-11-28 04:10 +0100
  [PATCH v13 4/8] x86/syscalls/32: Wire up arch_prctl on x86-32 Kyle Huey <me@kylehuey.com> - 2016-11-28 04:10 +0100
  [PATCH v13 2/8] x86/arch_prctl/64: Rename do_arch_prctl to do_arch_prctl_64 Kyle Huey <me@kylehuey.com> - 2016-11-28 04:10 +0100
  [PATCH v13 5/8] x86/cpufeature: Detect CPUID faulting support Kyle Huey <me@kylehuey.com> - 2016-11-28 04:10 +0100
  [PATCH v13 1/8] x86/arch_prctl/64: Use SYSCALL_DEFINE2 to define sys_arch_prctl Kyle Huey <me@kylehuey.com> - 2016-11-28 04:10 +0100
  [PATCH v13 6/8] x86/arch_prctl: Add ARCH_[GET|SET]_CPUID Kyle Huey <me@kylehuey.com> - 2016-11-28 04:10 +0100
    Re: [PATCH v13 6/8] x86/arch_prctl: Add ARCH_[GET|SET]_CPUID Thomas Gleixner <tglx@linutronix.de> - 2016-11-28 15:20 +0100
      Re: [PATCH v13 6/8] x86/arch_prctl: Add ARCH_[GET|SET]_CPUID Kyle Huey <me@kylehuey.com> - 2016-11-28 17:20 +0100
  Re: [PATCH v13 0/8] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for  controlling the CPUID instruction Ingo Molnar <mingo@kernel.org> - 2016-12-02 11:30 +0100
    Re: [PATCH v13 0/8] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for  controlling the CPUID instruction Kyle Huey <me@kylehuey.com> - 2016-12-03 17:00 +0100

csiph-web