timing attack fundamentals for detecting a hypervisor,

/// timing attack functions
static inline long unsigned int rdtsc(void) /// simply gets the processor tick count since the machine was turned on
{                       /// it resets every 50 years, so im not too worried about it lol
    long unsigned int x;
    asm volatile ("rdtsc" : "=A" (x));
    return x;
}

static long unsigned int StartingTime, EndingTime;
void start_time(void)   /// get the start time and save the value
{
    StartingTime = rdtsc();
}

long unsigned int check_time(void)
{
    EndingTime = rdtsc();   /// get the endtime
    return (EndingTime - StartingTime); /// return the difference
}