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".
#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;
}
