IA32 EFER: Difference between revisions
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MSR <code>0xc0000080</code> – <code>IA32_EFER</code> | MSR <code>0xc0000080</code> – <code>IA32_EFER</code> | ||
: | : Usable if (CPUID.80000001H:EDX.[20] || CPUID.80000001H:EDX.[29]) | ||
{| class="wikitable" | {| class="wikitable" | ||
Latest revision as of 22:36, 20 February 2025
MSR 0xc0000080 – IA32_EFER
- Usable 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 | |
| ⋮ | Reserved | |||
From Intel SDM [1]