CPUID_LEAF_MWAIT
cpuid(CPUID_LEAF_MWAIT, &eax, &ebx, &ecx, &edx);
if (!cpu_cstate_entry || c->cpuid_level < CPUID_LEAF_MWAIT)
{ X86_FEATURE_MWAIT, CPUID_LEAF_MWAIT },
cpuid(CPUID_LEAF_MWAIT, &eax, &ebx, &ecx, &mwait_substates);
cpuid(CPUID_LEAF_MWAIT, &eax, &ebx, &ecx, &edx);
case CPUID_LEAF_MWAIT:
ax = CPUID_LEAF_MWAIT;
cpuid(CPUID_LEAF_MWAIT, &eax, &ebx, &ecx, &edx);
cpuid(CPUID_LEAF_MWAIT, &eax, &ebx, &ecx, &mwait_substates);