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x86/tsc: Use X86_FEATURE_TSC_ADJUST in detect_art()

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The art detection uses rdmsrl_safe() to detect the availablity of the
TSC_ADJUST MSR.

That's pointless because we have a feature bit for this. Use it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20161119134017.483561692@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2016-11-19 13:47:33 +00:00
parent 984fecebda
commit 7b3d2f6e08
1 changed files with 8 additions and 6 deletions
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14
arch/x86/kernel/tsc.c
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@ -1057,17 +1057,19 @@ static void detect_art(void)
if (boot_cpu_data.cpuid_level < ART_CPUID_LEAF)
return;
/* Don't enable ART in a VM, non-stop TSC and TSC_ADJUST required */
if (boot_cpu_has(X86_FEATURE_HYPERVISOR) ||
!boot_cpu_has(X86_FEATURE_NONSTOP_TSC) ||
!boot_cpu_has(X86_FEATURE_TSC_ADJUST))
return;
cpuid(ART_CPUID_LEAF, &art_to_tsc_denominator,
&art_to_tsc_numerator, unused, unused+1);
/* Don't enable ART in a VM, non-stop TSC required */
if (boot_cpu_has(X86_FEATURE_HYPERVISOR) ||
!boot_cpu_has(X86_FEATURE_NONSTOP_TSC) ||
art_to_tsc_denominator < ART_MIN_DENOMINATOR)
if (art_to_tsc_denominator < ART_MIN_DENOMINATOR)
return;
if (rdmsrl_safe(MSR_IA32_TSC_ADJUST, &art_to_tsc_offset))
return;
rdmsrl(MSR_IA32_TSC_ADJUST, art_to_tsc_offset);
/* Make this sticky over multiple CPU init calls */
setup_force_cpu_cap(X86_FEATURE_ART);