25-4 Vol. 3C

VMX NON-ROOT OPERATION

For purposes of these computations, time is measured based on a counter that runs at the same rate as 
the timestamp counter (TSC).

— CPL >  0.

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If the “PAUSE exiting” VM-execution control is 0, the PAUSE instruction executes normally.

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If the “PAUSE exiting” VM-execution control is 1, the PAUSE instruction causes a VM exit.

The “PAUSE-loop exiting” VM-execution control is ignored if CPL > 0.

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RDMSR. The RDMSR instruction causes a VM exit if any of the following are true:
— The “use MSR bitmaps” VM-execution control is 0.
— The value of ECX is not in the ranges 00000000H – 00001FFFH and C0000000H – C0001FFFH.
— The value of ECX is in the range 00000000H – 00001FFFH and bit n in read bitmap for low MSRs is 1, where 

n is the value of ECX.

— The value of ECX is in the range C0000000H – C0001FFFH and bit n in read bitmap for high MSRs is 1, 

where n is the value of ECX & 00001FFFH.

See Section 24.6.9 for details regarding how these bitmaps are identified.

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RDPMC. The RDPMC instruction causes a VM exit if the “RDPMC exiting” VM-execution control is 1.

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RDRAND. The RDRAND instruction causes a VM exit if the “RDRAND exiting” VM-execution control is 1.

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RDSEED. The RDSEED instruction causes a VM exit if the “RDSEED exiting” VM-execution control is 1.

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RDTSC. The RDTSC instruction causes a VM exit if the “RDTSC exiting” VM-execution control is 1.

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RDTSCP. The RDTSCP instruction causes a VM exit if the “RDTSC exiting” and “enable RDTSCP” VM-execution 
controls are both 1.

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RSM. The RSM instruction causes a VM exit if executed in system-management mode (SMM).

1

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VMREAD. The VMREAD instruction causes a VM exit if any of the following are true:
— The “VMCS shadowing” VM-execution control is 0.
— Bits 63:15 (bits 31:15 outside 64-bit mode) of the register source operand are not all 0.
— Bit n in VMREAD bitmap is 1, where n is the value of bits 14:0 of the register source operand. See Section 

24.6.15 for details regarding how the VMREAD bitmap is identified.

If the VMREAD instruction does not cause a VM exit, it reads from the VMCS referenced by the VMCS link
pointer. See Chapter 30, “VMREAD—Read Field from Virtual-Machine Control Structure” for details of the
operation of the VMREAD instruction.

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VMWRITE. The VMWRITE instruction causes a VM exit if any of the following are true:
— The “VMCS shadowing” VM-execution control is 0.
— Bits 63:15 (bits 31:15 outside 64-bit mode) of the register source operand are not all 0.
— Bit n in VMWRITE bitmap is 1, where n is the value of bits 14:0 of the register source operand. See Section 

24.6.15 for details regarding how the VMWRITE bitmap is identified.

If the VMWRITE instruction does not cause a VM exit, it writes to the VMCS referenced by the VMCS link
pointer. See Chapter 30, “VMWRITE—Write Field to Virtual-Machine Control Structure” for details of the
operation of the VMWRITE instruction.

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WBINVD. The WBINVD instruction causes a VM exit if the “WBINVD exiting” VM-execution control is 1.

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WRMSR. The WRMSR instruction causes a VM exit if any of the following are true:
— The “use MSR bitmaps” VM-execution control is 0.
— The value of ECX is not in the ranges 00000000H – 00001FFFH and C0000000H – C0001FFFH.
— The value of ECX is in the range 00000000H – 00001FFFH and bit n in write bitmap for low MSRs is 1, 

where n is the value of ECX.

1. Execution of the RSM instruction outside SMM causes an invalid-opcode exception regardless of whether the processor is in VMX 

operation. It also does so in VMX root operation in SMM; see Section 34.15.3.