On Tue, Nov 08, 2016 at 09:06:31PM +0100, Thomas Gleixner wrote:
> The upcoming ring3 mwait stuff can add its magic to tweak that MSR into
> this function.
>
> Stick the call at the end of init_scattered_cpuid_features() for now. I
> still need to figure out a proper place for it.
So Thomas and I discussed this more on IRC and I think we can get rid
of the MSR iterating in scattered.c and integrate both the R3 MWAIT and
CPUID faulting like this:
---
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index fcd484d2bb03..5c38a85af2e7 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -452,6 +457,39 @@ static void intel_bsp_resume(struct cpuinfo_x86 *c)
init_intel_energy_perf(c);
}
+static void init_misc_enables(struct cpuinfo_x86 *c)
+{
+ u64 val, misc_en;
+
+ if (rdmsrl_safe(MSR_MISC_FEATURES_ENABLES, &misc_en))
+ return;
+
+ misc_en &= ~MSR_MISC_ENABLES_CPUID_FAULT_ENABLE;
+
+ if (!rdmsrl_safe(MSR_PLATFORM_INFO, &val)) {
+ if (val & PLATINFO_CPUID_FAULT_BIT)
+ set_cpu_cap(c, X86_FEATURE_CPUID_FAULT);
+ }
+
+ wrmsrl(MSR_MISC_FEATURES_ENABLES, misc_en);
+ this_cpu_write(msr_misc_features_enables_shadow, misc_en);
+}
+
static void init_intel(struct cpuinfo_x86 *c)
{
unsigned int l2 = 0;
@@ -565,6 +603,8 @@ static void init_intel(struct cpuinfo_x86 *c)
detect_vmx_virtcap(c);
init_intel_energy_perf(c);
+
+ init_misc_enables(c);
}
#ifdef CONFIG_X86_32
---
Please redo your patchset and add the detection to init_intel() like above.
Also, let's call that MSR mask MSR_MISC_ENABLES_CPUID_FAULT_ENABLE like
the rest of the bits in msr-index.h
Thanks.
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284
(AG Nürnberg)
--
