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

Table Of Contents
23-24 Vol. 3
VM EXITS
For VM exits due to attempts to execute INVEPT or INVVPID, the field has the
format is given in Table 23-13.
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).
31:28 Reg2 (same encoding as Reg1 above)
Table 23-13. Format of the VM-Exit Instruction-Information Field as Used for INVEPT
and INVVPID
Bit Position(s) Content
1:0 Scaling:
0: no scaling
1: scale by 2
2: scale by 4
3: scale by 8 (used only on processors that support Intel 64 architecture)
Undefined for instructions with no index register (bit 22 is set).
6:2 Undefined.
Table 23-12. Format of the VM-Exit Instruction-Information Field as Used for
VMREAD and VMWRITE (Contd.)
Bit Position(s) Content