IA32 EFER
MSR 0xc0000080 – IA32_EFER
- If (CPUID.80000001H:EDX.[20] || CPUID.80000001H:EDX.[29])
| Bit | Name | Label | Ops | Description |
|---|---|---|---|---|
| 0 | SYSCALL Enable | IA32_EFER.SCE | R/W | Enables SYSCALL/SYSRET instructions in 64-bit mode. |
| 1 | Reserved | |||
| 2 | ||||
| 3 | ||||
| 4 | ||||
| 5 | ||||
| 6 | ||||
| 7 | ||||
| 8 | IA-32e Mode Enable | IA32_EFER.LME | R/W | Enables IA-32e mode operation. |
| 9 | Reserved | |||
| 10 | IA-32e Mode Active | IA32_EFER.LMA | R | Indicates IA-32e mode is active when set. |
| 11 | Execute Disable Bit Enable | IA32_EFER.NXE | R/W | |
From Intel SDM [1]