Intel 64 and IA-32 Architectures Software Developers Manual Volume 3B, System Programming Guide Part 2

Table Of Contents
Vol. 3 23-21
VM EXITS
For VM exits due to attempts to execute VMCLEAR, VMPTRLD, VMPTRST, or
VMXON, the field has the format is given in Table 23-11.
9:7 Address size:
0: 16-bit
1: 32-bit
2: 64-bit (used only on processors that support Intel 64 architecture)
Other values not used. Undefined for register instructions (bit 10 is set).
10 Mem/Reg (0 = memory; 1 = register).
14:11 Undefined.
17:15 Segment register:
0: ES
1: CS
2: SS
3: DS
4: FS
5: GS
Other values not used. Undefined for register instructions (bit 10 is set).
21:18 IndexReg (encoded as Reg1 above)
Undefined for register instructions (bit 10 is set) and for memory instructions with
no index register (bit 10 is clear and bit 22 is set).
22 IndexReg invalid (0 = valid; 1 = invalid)
Undefined for register instructions (bit 10 is set).
26:23 BaseReg (encoded as Reg1 above)
Undefined for register instructions (bit 10 is set) and for memory instructions with
no base register (bit 10 is clear and bit 27 is set).
27 BaseReg invalid (0 = valid; 1 = invalid)
Undefined for register instructions (bit 10 is set).
29:28 Instruction identity:
0: SLDT
1: STR
2: LLDT
3: LTR
31:30 Undefined.
Table 23-10. Format of the VM-Exit Instruction-Information Field as Used for LLDT,
LTR, SLDT, and STR (Contd.)
Bit Position(s) Content