C-2 Vol. 3D

VMX BASIC EXIT REASONS

24

VMRESUME. Guest software attempted to execute VMRESUME.

25

VMWRITE. Guest software attempted to execute VMWRITE.

26

VMXOFF. Guest software attempted to execute VMXOFF.

27

VMXON. Guest software attempted to execute VMXON.

28

Control-register accesses. Guest software attempted to access CR0, CR3, CR4, or CR8 using CLTS, LMSW, or 

MOV CR and the VM-execution control fields indicate that a VM exit should occur (see Section 25.1 for details). This 

basic exit reason is not used for trap-like VM exits following executions of the MOV to CR8 instruction when the “use 

TPR shadow” VM-execution control is 1.

29

MOV DR. Guest software attempted a MOV to or from a debug register and the “MOV-DR exiting” VM-execution 

control was 1.

30

I/O instruction. Guest software attempted to execute an I/O instruction and either:
1: The “use I/O bitmaps” VM-execution control was 0 and the “unconditional I/O exiting” VM-execution control was 1.

2: The “use I/O bitmaps” VM-execution control was 1 and a bit in the I/O bitmap associated with one of the ports 

accessed by the I/O instruction was 1.

31

RDMSR. Guest software attempted to execute RDMSR and either:
1: The “use MSR bitmaps” VM-execution control was 0.

2: The value of RCX is neither in the range 00000000H – 00001FFFH nor in the range C0000000H – C0001FFFH.

3: The value of RCX was in the range 00000000H – 00001FFFH and the n

th

 bit in read bitmap for low MSRs is 1, 

where n was the value of RCX.

4: The value of RCX is in the range C0000000H – C0001FFFH and the n

th

 bit in read bitmap for high MSRs is 1, where 

n is the value of RCX & 00001FFFH.

32

WRMSR. Guest software attempted to execute WRMSR and either:
1: The “use MSR bitmaps” VM-execution control was 0.

2: The value of RCX is neither in the range 00000000H – 00001FFFH nor in the range C0000000H – C0001FFFH.

3: The value of RCX was in the range 00000000H – 00001FFFH and the n

th

 bit in write bitmap for low MSRs is 1, 

where n was the value of RCX.

4: The value of RCX is in the range C0000000H – C0001FFFH and the n

th

 bit in write bitmap for high MSRs is 1, 

where n is the value of RCX & 00001FFFH.

33

VM-entry failure due to invalid guest state. A VM entry failed one of the checks identified in Section 26.3.1.

34

VM-entry failure due to MSR loading. A VM entry failed in an attempt to load MSRs. See Section 26.4.

36

MWAIT. Guest software attempted to execute MWAIT and the “MWAIT exiting” VM-execution control was 1.

37

Monitor trap flag. A VM entry occurred due to the 1-setting of the “monitor trap flag” VM-execution control and 

injection of an MTF VM exit as part of VM entry. See Section 25.5.2.

39

MONITOR. Guest software attempted to execute MONITOR and the “MONITOR exiting” VM-execution control was 1.

40

PAUSE. Either guest software attempted to execute PAUSE and the “PAUSE exiting” VM-execution control was 1 or 

the “PAUSE-loop exiting” VM-execution control was 1 and guest software executed a PAUSE loop with execution 

time exceeding PLE_Window (see Section 25.1.3).

41

VM-entry failure due to machine-check event. A machine-check event occurred during VM entry (see Section 

26.8).

43

TPR below threshold. The logical processor determined that the value of bits 7:4 of the byte at offset 080H on the 

virtual-APIC page was below that of the TPR threshold VM-execution control field while the “use TPR shadow” VM-

execution control was 1 either as part of TPR virtualization (Section 29.1.2) or VM entry (Section 26.6.7).

44

APIC access. Guest software attempted to access memory at a physical address on the APIC-access page and the 

“virtualize APIC accesses” VM-execution control was 1 (see Section 29.4).

45

Virtualized EOI. EOI virtualization was performed for a virtual interrupt whose vector indexed a bit set in the EOI-

exit bitmap.

Table C-1.  Basic Exit Reasons  (Contd.)

Basic Exit 

Reason

Description