答复: [PATCH] [RFC] kvm: x86: emulate APERF/MPERF registers

Commit Message

Li,Rongqing April 26, 2020, 8:30 a.m. UTC

> 
> But then here you only emulate it for VMX, which then results in SVM guests
> going wobbly.
> 
> Also, on Intel, the moment you advertise APERFMPERF, we'll try and read
> MSR_PLATFORM_INFO / MSR_TURBO_RATIO_LIMIT*, I don't suppose you're
> passing those through as well?
> 

init_freq_invariance(void) is trying read MSR_PLATFORM_INFO / MSR_TURBO_RATIO_LIMIT*,
should we add a check of turbo status in init_freq_invariance, to avoid the reading?

It is unnecessary to call intel_set_max_freq_ratio  If turbo is disabled

-Li

Patch

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index fe3ab9632f3b..54fb88323293 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -2009,6 +2009,9 @@  static void init_freq_invariance(void)
        if (smp_processor_id() != 0 || !boot_cpu_has(X86_FEATURE_APERFMPERF))
                return;
 
+       if (turbo_disabled())
+               return;
+
        if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
                ret = intel_set_max_freq_ratio();