Messages in this thread | | | Date | Fri, 28 Oct 2016 00:38:54 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v7 6/6] x86/arch_prctl: Add ARCH_[GET|SET]_CPUID |
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On Thu, 27 Oct 2016, Andy Lutomirski wrote: > On Thu, Oct 27, 2016 at 4:15 AM, Thomas Gleixner <tglx@linutronix.de> wrote: > Let's just do this right from day one: > > static void set_cpuid_faulting(bool on) > { > u64 msrval; > > DEBUG_LOCKS_WARN_ON(!irqs_disabled()); > > msrval = this_cpu_read(msr_misc_features_enables_shadow); > msrval &= CPUID_FAULT_ENABLE; > msrval |= (on << CPUID_FAULT_ENABLE_BIT); > this_cpu_write(msr_misc_features_enables_shadow, msrval); > wrmsrl(MSR_MISC_FEATURES_ENABLES, msrval); > } > > RDMSR may be considerably faster than WRMSR, but that doesn't mean it's *fast*.
Good point!
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