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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-03 14:09:32 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-03 14:09:32 -0700 |
| commit | e1449007e83f18db4470194232812ae524d64d79 (patch) | |
| tree | 63e7b9ecd3b3b87a71eacf32894bb67c3e44de4a /arch/x86/kernel | |
| parent | e6529f6f58a293fff59fa809ce67cfa063219d73 (diff) | |
| parent | 71c2a2d0a81f096a2932fccb39a500116fece554 (diff) | |
| download | linux-e1449007e83f18db4470194232812ae524d64d79.tar.bz2 | |
Merge branch 'x86-hyperv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 hyperv updates from Ingo Molnar:
"Avoid boot time TSC calibration on Hyper-V hosts, to improve
calibration robustness. (Vitaly Kuznetsov)"
* 'x86-hyperv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/hyperv: Read TSC frequency from a synthetic MSR
x86/hyperv: Check frequency MSRs presence according to the specification
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 04cb8d34ccb8..70e717fccdd6 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -161,6 +161,15 @@ static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) } #endif +static unsigned long hv_get_tsc_khz(void) +{ + unsigned long freq; + + rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); + + return freq / 1000; +} + static void __init ms_hyperv_init_platform(void) { int hv_host_info_eax; @@ -193,8 +202,15 @@ static void __init ms_hyperv_init_platform(void) hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); } + if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && + ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { + x86_platform.calibrate_tsc = hv_get_tsc_khz; + x86_platform.calibrate_cpu = hv_get_tsc_khz; + } + #ifdef CONFIG_X86_LOCAL_APIC - if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) { + if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && + ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { /* * Get the APIC frequency. */ |