确定虚拟机是Xen还是KVM

最近整个了阿里云，一直以为是基于kvm的，今天用代码测试了下，原来是Xen的 

#include
#include
#include
#define SIGNATURE 0x40000000
static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
         unsigned int *ecx, unsigned int *edx)
{
     asm volatile("cpuid"
             : "=a" (*eax),
             "=b" (*ebx),
             "=c" (*ecx),
             "=d" (*edx)
             : "0" (*eax), "2" (*ecx));
}

void cpuid(unsigned int op,
        unsigned int *eax, unsigned int *ebx,
        unsigned int *ecx, unsigned int *edx)
{
    *eax = op;
    *ecx = 0;
    __cpuid(eax, ebx, ecx, edx);
}

int main(int argc,char *argv[])
{
        unsigned int eax, ebx, ecx, edx;
        char signature[13];

        cpuid(SIGNATURE, &eax, &ebx, &ecx, &edx);
        memcpy(signature + 0, &ebx, 4);
        memcpy(signature + 4, &ecx, 4);
        memcpy(signature + 8, &edx, 4);
        signature[12] = 0;

       if (strncmp(signature, "KVMKVMKVM",9) == 0)
                printf("kvm\n");
        else if(strncmp(signature,"XenVMMXenVMM",12) == 0)
                printf("XEN\n");
        else if(strncmp(signature,"VMwareVMware",12) == 0)
                printf("VMware\n");
        else
                printf("%s\n",signature);
    
       return   0;
}