hvinfo

hvinfo dumps the HyperV feature support bits as documented in the HyperV Top Level Functional Specifications.

If you don't know what any of this does mean, you don't need hvinfo :)

hvinfo is (C) 2019 Red Hat Inc and licensed under the MIT license.

compile

Cross compile on linux for windows:

GOOS=windows GOARCH=amd64 go build -o binaries/hvinfo.exe hvinfo.go

Should you need to compile for linux (negative test?):

go build -o binaries/hvinfo hvinfo.go

usage

hvinfo takes no arguments and just emits JSON outputs. hvinfo does NOT require admin privileges to run. Being a commandline tool, is hard to give a "screenshot", so we will just show a sample output.

Windows PowerShell
Copyright (C) Microsoft Corporation. All rights reserved.

PS C:\Users\admin> .\hvinfo.exe
{
  "HyperVsupport": true,
  "VendorId": "Microsoft Hv",
  "Features": {
    "GuestDebugging": false,
    "PerformanceMonitor": false,
    "PCPUDynamicPartitioningEvents": true,
    "HypercallInputParamsXMM": false,
    "VirtualGuestIdleState": false,
    "HypervisorSleepState": false,
    "NUMADistanceQuery": false,
    "TimerFrequenciesQuery": false,
    "SytheticMCEInjection": false,
    "GuestCrashMSR": false,
    "DebugMSR": false,
    "NPIEP": false,
    "DisableHypervisorAvailable": false,
    "ExtendedGvaRangesForFlushVirtualAddressList": false,
    "HypercallOutputReturnXMM": false,
    "SintPollingMode": false,
    "HypercallMsrLock": false,
    "UseDirectSyntheticTimers": false
  },
  "Privileges": {
    "AccessVpRunTimeReg": false,
    "AccessPartitionReferenceCounter": true,
    "AccessSynicRegs": false,
    "AccessSyntheticTimerRegs": false,
    "AccessIntrCtrlRegs": true,
    "AccessHypercallMsrs": true,
    "AccessVpIndex": false,
    "AccessResetReg": false,
    "AccessStatsReg": false,
    "AccessPartitionReferenceTsc": true,
    "AccessGuestIdleReg": false,
    "AccessFrequencyRegs": false,
    "AccessDebugRegs": false,
    "AccessReenlightenmentControls": false,
    "CreatePartitions": false,
    "AccessPartitionId": false,
    "AccessMemoryPool": false,
    "PostMessages": false,
    "SignalEvents": false,
    "CreatePort": false,
    "ConnectPort": false,
    "AccessStats": false,
    "Debugging": false,
    "CpuManagement": false,
    "AccessVSM": false,
    "AccessVpRegisters": false,
    "EnableExtendedHypercalls": false,
    "StartVirtualProcessor": false
  },
  "Recommendations": {
    "HypercallAddressSpaceSwitch": false,
    "HypercallLocalTLBFlush": false,
    "HypercallRemoteTLBFlush": false,
    "MSRAPICRegisters": true,
    "MSRSystemReset": false,
    "RelaxedTiming": true,
    "DMARemapping": false,
    "InterruptRemapping": false,
    "X2APICMSR": false,
    "DeprecatingAutoEOI": false,
    "SyntheticClusterIPI": false,
    "ExProcessorMasks": false,
    "Nested": false,
    "INTForMBECSyscalls": false,
    "NestedEVMCS": false,
    "SyncedTimeline": false,
    "DirectLocalFlushEntire": false,
    "NoNonArchitecturalCoreSharing": false,
    "SpinlockRetries": 8191
  }
}

mapping between libvirt domain XML and hvinfo output

libvirt XML	hvinfo JSON	Notes
features.hyperv.relaxed	Recommendations.RelaxedTiming
features.hyperv.vapic	Recommendations.MSRAPICRegisters	needs confirmation
features.hyperv.spinlocks retries=X	Recommendations.SpinlockRetries=X
features.hyperv.vpindex	Privileges.AccessVpIndex
features.hyperv.runtime	Privileges.AccessVpRunTimeReg
features.hyperv.crash	Features.GuestCrashMSR
features.hyperv.time	Privileges.AccessPartitionReferenceCounter
features.hyperv.synic	Privileges.AccessSynicRegs
features.hyperv.stimer	Privileges.AccessSyntheticTimerRegs
features.hyperv.reset	Recommendations.MSRSystemReset
features.hyperv.vendor_id value=V	VendorId
features.hyperv.frequencies	Privileges.AccessFrequencyRegs
features.hyperv.reenlightenment	NestedInfo.Features.MSRAccessReenlighenmentCtrls
features.hyperv.tlbflush	Recommendations.HypercallRemoteTLBFlush
features.hyperv.ipi	Recommendations.SyntheticClusterIPI	needs confirmation
features.hyperv.evmcs	Recommendations.NestedEVMCS

bugs

Trivial bugs and typos in the otherwise simple but repetitive implementation of hvinfo may end up in incorrect reporting. Please send bugs to fromani at redhat dot com. Always include:

• the version (git commit hash from which the tool is compiled)
• the output of the tool
• the errors: what you should see and you don't, or the other way around