diff options
| -rw-r--r-- | arch/x86/include/uapi/asm/hyperv.h | 19 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 24 |
2 files changed, 43 insertions, 0 deletions
diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h index b80420bcd09..b8f1c0176cb 100644 --- a/arch/x86/include/uapi/asm/hyperv.h +++ b/arch/x86/include/uapi/asm/hyperv.h @@ -27,6 +27,19 @@ #define HV_X64_MSR_VP_RUNTIME_AVAILABLE (1 << 0) /* Partition Reference Counter (HV_X64_MSR_TIME_REF_COUNT) available*/ #define HV_X64_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1) + +/* + * 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. + */ + +/* 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) + /* * Basic SynIC MSRs (HV_X64_MSR_SCONTROL through HV_X64_MSR_EOM * and HV_X64_MSR_SINT0 through HV_X64_MSR_SINT15) available @@ -136,6 +149,12 @@ /* MSR used to read the per-partition time reference counter */ #define HV_X64_MSR_TIME_REF_COUNT 0x40000020 +/* MSR used to retrieve the TSC frequency */ +#define HV_X64_MSR_TSC_FREQUENCY 0x40000022 + +/* MSR used to retrieve the local APIC timer frequency */ +#define HV_X64_MSR_APIC_FREQUENCY 0x40000023 + /* Define the virtual APIC registers */ #define HV_X64_MSR_EOI 0x40000070 #define HV_X64_MSR_ICR 0x40000071 diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 71a39f3621b..0a490ca278e 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -15,6 +15,7 @@ #include <linux/clocksource.h> #include <linux/module.h> #include <linux/hardirq.h> +#include <linux/efi.h> #include <linux/interrupt.h> #include <asm/processor.h> #include <asm/hypervisor.h> @@ -23,6 +24,7 @@ #include <asm/desc.h> #include <asm/idle.h> #include <asm/irq_regs.h> +#include <asm/i8259.h> struct ms_hyperv_info ms_hyperv; EXPORT_SYMBOL_GPL(ms_hyperv); @@ -67,6 +69,8 @@ static struct clocksource hyperv_cs = { static void __init ms_hyperv_init_platform(void) { + u64 hv_lapic_frequency; + /* * Extract the features and hints */ @@ -76,6 +80,26 @@ static void __init ms_hyperv_init_platform(void) printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n", ms_hyperv.features, ms_hyperv.hints); + if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) { + /* + * Get the APIC frequency. + */ + rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); + hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); + lapic_timer_frequency = hv_lapic_frequency; + printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n", + lapic_timer_frequency); + + /* + * On Hyper-V, when we are booting off an EFI firmware stack, + * we do not have many legacy devices including PIC, PIT etc. + */ + if (efi_enabled(EFI_BOOT)) { + printk(KERN_INFO "HyperV: Using null_legacy_pic\n"); + legacy_pic = &null_legacy_pic; + } + } + if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); } |