PSL_AC
wrmsr(MSR_SF_MASK, PSL_NT | PSL_T | PSL_I | PSL_C | PSL_D | PSL_AC);
PGEX_P && (frame->tf_rflags & PSL_AC) == 0);
andq $~(PSL_D|PSL_AC),(%rsp)
if (cpl != 3 || (cr0 & CR0_AM) == 0 || (rf & PSL_AC) == 0)
| PSL_D | PSL_V | PSL_NT | PSL_RF | PSL_AC | PSL_ID)