Messages in this thread Patch in this message |  | | Date | Sat, 19 Nov 2016 13:47:33 -0000 | From | Thomas Gleixner <> | Subject | [patch 1/8] 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> --- arch/x86/kernel/tsc.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
--- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1043,18 +1043,20 @@ static void detect_art(void) if (boot_cpu_data.cpuid_level < ART_CPUID_LEAF) 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 */ + /* 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) || - art_to_tsc_denominator < ART_MIN_DENOMINATOR) + !boot_cpu_has(X86_FEATURE_TSC_ADJUST)) return; - if (rdmsrl_safe(MSR_IA32_TSC_ADJUST, &art_to_tsc_offset)) + cpuid(ART_CPUID_LEAF, &art_to_tsc_denominator, + &art_to_tsc_numerator, unused, unused+1); + + if (art_to_tsc_denominator < ART_MIN_DENOMINATOR) 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); }
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