user/test/x86/vmexit.c

   1
   2 #include "libcflat.h"
   3
   4 static inline unsigned long long rdtsc()
   5 {
   6         long long r;
   7
   8 #ifdef __x86_64__
   9         unsigned a, d;
  10
  11         asm volatile ("rdtsc" : "=a"(a), "=d"(d));
  12         r = a | ((long long)d << 32);
  13 #else
  14         asm volatile ("rdtsc" : "=A"(r));
  15 #endif
  16         return r;
  17 }
  18
  19 #define N (1 << 22)
  20
  21 #ifdef __x86_64__
  22 #  define R "r"
  23 #else
  24 #  define R "e"
  25 #endif
  26
  27 int main()
  28 {
  29         int i;
  30         unsigned long long t1, t2;
  31
  32         t1 = rdtsc();
  33         for (i = 0; i < N; ++i)
  34                 asm volatile ("push %%"R "bx; cpuid; pop %%"R "bx"
  35                               : : : "eax", "ecx", "edx");
  36         t2 = rdtsc();
  37         printf("vmexit latency: %d\n", (int)((t2 - t1) / N));
  38         return 0;
  39 }