Intel 64 and IA-32 Architectures Software Developers Manual Volume 2B, Instruction Set Reference, N-Z

5-2 Vol. 2B
VMX INSTRUCTION REFERENCE
• VMXON — This instruction takes a single 64-bit source operand that is in
memory. It causes a logical processor to enter VMX root operation and to use the
memory referenced by the operand to support VMX operation.
Only VMCALL can be executed in compatibility mode (causing a VM exit). The other
VMX instructions generate invalid-opcode exceptions if executed in compatibility
mode.
5.2 CONVENTIONS
The operation sections for the VMX instructions in Section 5.3 use the pseudo-func-
tion VMexit, which indicates that the logical processor performs a VM exit.
The operation sections also use the pseudo-functions VMsucceed, VMfail,
VMfailInvalid, and VMfailValid. These pseudo-functions signal instruction success or
failure by setting or clearing bits in RFLAGS and, in some cases, by writing the
VM-instruction error field. The following pseudocode fragments detail these func-
tions:
VMsucceed:
CF ← 0;
PF ← 0;
AF ← 0;
ZF ← 0;
SF ← 0;
OF ← 0;
VMfail(ErrorNumber):
IF VMCS pointer is valid
THEN VMfailValid(ErrorNumber);
ELSE VMfailInvalid;
FI;
VMfailInvalid:
CF ← 1;
PF ← 0;
AF ← 0;
ZF ← 0;
SF ← 0;
OF ← 0;