3 files changed, 10 insertions, 0 deletions

diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index bab6a1ad806e..1c602ad4bda8 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -21,6 +21,7 @@
 #define HYPERV_CPUID_FEATURES                   0x40000003
 #define HYPERV_CPUID_ENLIGHTMENT_INFO           0x40000004
 #define HYPERV_CPUID_IMPLEMENT_LIMITS           0x40000005
+#define HYPERV_CPUID_NESTED_FEATURES            0x4000000A
 
 #define HYPERV_HYPERVISOR_PRESENT_BIT           0x80000000
 #define HYPERV_CPUID_MIN                        0x40000005
@@ -339,6 +340,9 @@ struct hv_tsc_emulation_status {
 #define HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_MASK  \
                 (~((1ull << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) - 1))
 
+/* Hyper-V Enlightened VMCS version mask in nested features CPUID */
+#define HV_X64_ENLIGHTENED_VMCS_VERSION         0xff
+
 #define HV_X64_MSR_TSC_REFERENCE_ENABLE         0x00000001
 #define HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT  12
 
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 3f162353f180..57c65315b60b 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -13,6 +13,7 @@ struct ms_hyperv_info {
         u32 features;
         u32 misc_features;
         u32 hints;
+        u32 nested_features;
         u32 max_vp_index;
         u32 max_lp_index;
 };
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 0dfc568c110c..1afc0a453bba 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -208,6 +208,11 @@ static void __init ms_hyperv_init_platform(void)
                 x86_platform.calibrate_cpu = hv_get_tsc_khz;
         }
 
+        if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
+                ms_hyperv.nested_features =
+                        cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
+        }
+
 #ifdef CONFIG_X86_LOCAL_APIC
         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {