in nacl_cpuid.c (line 378):

The function “NaClArchSupported” returns the following:

return (Bool) (features.f_cpuid_supported && features.f_cpu_supported);

f_cpu_supported is only set on two lines: 372 & 374

  if (strncmp(cpuversionid, Intel_CPUID0, kCPUID0Length) == 0) {
    features->f_cpu_supported = 1;
  } else if (strncmp(cpuversionid, AMD_CPUID0, kCPUID0Length) == 0) {
    features->f_cpu_supported = 1;
  }

This means that only CPUs with the vendor string of “GenuineIntel” and “AuthenticAMD” can run NaCl.

A CPU vendor string is not a CPU feature and there is no reason to validate against it.

Please star this bug on the NACL bug tracker and help us get vendor strings out of the CPU features check!