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 <vkuznets@xxxxxxxxxx>
---
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..6f60b58 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_AVAILABELE (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..250f432 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_AVAILABELE) {
/*
* Get the APIC frequency.
*/
--
2.9.4
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