(C++) VMCPUID by 一半人生

Created the Friday 19 May 2023. Updated 11 months ago.

Description:

This C++ program uses the Windows and Intel intrinsic headers to check if it's running in a Microsoft Hyper-V virtual environment. It defines a union called CpuFeaturesEcx, which is used to map out the CPU features reported by the cpuid instruction, specifically the contents of the ECX register. These include various instruction sets, such as SSE3, SMX, and AESNI.

The function IsHyperV() uses the __cpuid function intrinsic to get the processor features and checks for the existence of Hyper-V by examining the hypervisor brand identification reported by cpuid with the leaf parameter 0x40000001. If the returned value is more than or equal to 4000, it indicates the presence of Hyper-V.

In the main() function, it calls the IsHyperV() function and outputs whether the current environment is a Hyper-V or not. If IsHyperV() returns true, it prints "Hyper-V True"; otherwise, it prints "Hyper-V False".

Code

            #include <Windows.h>
#include <iostream>
#include <intrin.h>

/// See: Feature Information Returned in the ECX Register
union CpuFeaturesEcx {
    ULONG32 all;
    struct {
        ULONG32 sse3 : 1;       //!< [0] Streaming SIMD Extensions 3 (SSE3)
        ULONG32 pclmulqdq : 1;  //!< [1] PCLMULQDQ
        ULONG32 dtes64 : 1;     //!< [2] 64-bit DS Area
        ULONG32 monitor : 1;    //!< [3] MONITOR/WAIT
        ULONG32 ds_cpl : 1;     //!< [4] CPL qualified Debug Store
        ULONG32 vmx : 1;        //!< [5] Virtual Machine Technology
        ULONG32 smx : 1;        //!< [6] Safer Mode Extensions
        ULONG32 est : 1;        //!< [7] Enhanced Intel Speedstep Technology
        ULONG32 tm2 : 1;        //!< [8] Thermal monitor 2
        ULONG32 ssse3 : 1;      //!< [9] Supplemental Streaming SIMD Extensions 3
        ULONG32 cid : 1;        //!< [10] L1 context ID
        ULONG32 sdbg : 1;       //!< [11] IA32_DEBUG_INTERFACE MSR
        ULONG32 fma : 1;        //!< [12] FMA extensions using YMM state
        ULONG32 cx16 : 1;       //!< [13] CMPXCHG16B
        ULONG32 xtpr : 1;       //!< [14] xTPR Update Control
        ULONG32 pdcm : 1;       //!< [15] Performance/Debug capability MSR
        ULONG32 reserved : 1;   //!< [16] Reserved
        ULONG32 pcid : 1;       //!< [17] Process-context identifiers
        ULONG32 dca : 1;        //!< [18] prefetch from a memory mapped device
        ULONG32 sse4_1 : 1;     //!< [19] SSE4.1
        ULONG32 sse4_2 : 1;     //!< [20] SSE4.2
        ULONG32 x2_apic : 1;    //!< [21] x2APIC feature
        ULONG32 movbe : 1;      //!< [22] MOVBE instruction
        ULONG32 popcnt : 1;     //!< [23] POPCNT instruction
        ULONG32 reserved3 : 1;  //!< [24] one-shot operation using a TSC deadline
        ULONG32 aes : 1;        //!< [25] AESNI instruction
        ULONG32 xsave : 1;      //!< [26] XSAVE/XRSTOR feature
        ULONG32 osxsave : 1;    //!< [27] enable XSETBV/XGETBV instructions
        ULONG32 avx : 1;        //!< [28] AVX instruction extensions
        ULONG32 f16c : 1;       //!< [29] 16-bit floating-point conversion
        ULONG32 rdrand : 1;     //!< [30] RDRAND instruction
        ULONG32 not_used : 1;   //!< [31] Always 0 (a.k.a. HypervisorPresent)
    } fields;
};
static_assert(sizeof(CpuFeaturesEcx) == 4, "Size check");

const bool IsHyperV()
{
	int cpu_info[4] = {};
	__cpuid(cpu_info, 1);
	const CpuFeaturesEcx cpu_features = { static_cast<ULONG_PTR>(cpu_info[2]) };
    __cpuid(cpu_info, 0x40000001);
    DWORD vid = 0;
    vid = (DWORD)cpu_info[0];
    return (vid >= 4000);
}

int main()
{
    if (IsHyperV()) {
        std::cout << "Hyper-v Ture" << std::endl;
    }
    else {
        std::cout << "Hyper-v Flase" << std::endl;
    }
    return 0;
}

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