__arch_hweight8
ret += __arch_hweight8(cpu_data[0].guest.kscratch_mask);
unsigned int __arch_hweight8(unsigned int w);
unsigned int __arch_hweight8(unsigned int w);
#define hweight8(w) (__builtin_constant_p(w) ? __const_hweight8(w) : __arch_hweight8(w))
#define hweight8(w) (__builtin_constant_p(w) ? __const_hweight8(w) : __arch_hweight8(w))