Commit-ID: 2cf0284223a40773bd0ec76a409a7cbf0607ca28 Gitweb: http://git.kernel.org/tip/2cf0284223a40773bd0ec76a409a7cbf0607ca28 Author: Vitaly Kuznetsov <vkuzn...@redhat.com> AuthorDate: Thu, 22 Jun 2017 18:07:29 +0800 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Thu, 22 Jun 2017 15:35:11 +0200
x86/hyperv: Check frequency MSRs presence according to the specification Hyper-V TLFS specifies two bits which should be checked before accessing frequency MSRs: - AccessFrequencyMsrs (BIT(11) in EAX) which indicates if we have access to frequency MSRs. - FrequencyMsrsAvailable (BIT(8) in EDX) which indicates is these MSRs are present. Rename and specify these bits accordingly. Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: Stephen Hemminger <sthem...@microsoft.com> Cc: Haiyang Zhang <haiya...@microsoft.com> Cc: Ladi Prosek <lpro...@redhat.com> Cc: Jork Loeser <jloe...@microsoft.com> Cc: de...@linuxdriverproject.org Cc: "K. Y. Srinivasan" <k...@microsoft.com> Link: http://lkml.kernel.org/r/20170622100730.18112-2-vkuzn...@redhat.com --- arch/x86/include/uapi/asm/hyperv.h | 15 ++++++--------- arch/x86/kernel/cpu/mshyperv.c | 3 ++- 2 files changed, 8 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h index 432df4b..f4fef5a 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 04cb8d3..3563c8e 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -194,7 +194,8 @@ static void __init ms_hyperv_init_platform(void) } #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. */
