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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 | |
| parent | Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff) | |
| parent | x86/hyperv: Read TSC frequency from a synthetic MSR (diff) | |
| download | linux-dev-e1449007e83f18db4470194232812ae524d64d79.tar.xz linux-dev-e1449007e83f18db4470194232812ae524d64d79.zip | |
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')
| -rw-r--r-- | arch/x86/include/uapi/asm/hyperv.h | 15 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 18 |
2 files changed, 23 insertions, 10 deletions
diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h index 432df4b1baec..f4fef5a24ebd 100644 --- a/arch/x86/include/uapi/asm/hyperv.h +++ b/arch/x86/include/uapi/asm/hyperv.h @@ -34,16 +34,10 @@ #define HV_X64_MSR_REFERENCE_TSC 0x40000021 /* - * There is a single feature flag that signifies the presence of the MSR - * that can be used to retrieve both the local APIC Timer frequency as - * well as the TSC frequency. + * There is a single feature flag that signifies if the partition has access + * to MSRs with local APIC and TSC frequencies. */ - -/* Local APIC timer frequency MSR (HV_X64_MSR_APIC_FREQUENCY) is available */ -#define HV_X64_MSR_APIC_FREQUENCY_AVAILABLE (1 << 11) - -/* TSC frequency MSR (HV_X64_MSR_TSC_FREQUENCY) is available */ -#define HV_X64_MSR_TSC_FREQUENCY_AVAILABLE (1 << 11) +#define HV_X64_ACCESS_FREQUENCY_MSRS (1 << 11) /* * Basic SynIC MSRs (HV_X64_MSR_SCONTROL through HV_X64_MSR_EOM @@ -73,6 +67,9 @@ */ #define HV_X64_MSR_STAT_PAGES_AVAILABLE (1 << 8) +/* Frequency MSRs available */ +#define HV_FEATURE_FREQUENCY_MSRS_AVAILABLE (1 << 8) + /* Crash MSR available */ #define HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE (1 << 10) 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. */ |