26-24 Vol. 3C

VM ENTRIES

The following items detail the treatment of these VM exits:

•

These VM exits follow event injection if such injection is specified for VM entry.

•

Debug-trap exceptions (see Section 26.6.3) and higher priority events take priority over VM exits caused by 
this control. VM exits caused by this control take priority over non-maskable interrupts (NMIs) and lower 
priority events. 

•

VM exits caused by this control wake the logical processor if it just entered either the HLT state or the shutdown 
state because of a VM entry (see Section 26.6.2). They do not occur if the logical processor just entered the 
wait-for-SIPI state.

26.6.7 

VM Exits Induced by the TPR Threshold

If the “use TPR shadow” and “virtualize APIC accesses” VM-execution controls are both 1 and the “virtual-interrupt 
delivery” VM-execution control is 0, a VM exit occurs immediately after VM entry if the value of bits 3:0 of the TPR 
threshold VM-execution control field is greater than the value of bits 7:4 of VTPR (see Section 29.1.1).

1

The following items detail the treatment of these VM exits:

•

The VM exits are not blocked if RFLAGS.IF = 0 or by the setting of bits in the interruptibility-state field in guest-
state area.

•

The VM exits follow event injection if such injection is specified for VM entry.

•

VM exits caused by this control take priority over system-management interrupts (SMIs), INIT signals, and 
lower priority events. They thus have priority over the VM exits described in Section 26.6.5, Section 26.6.6, 
and Section 26.6.8, as well as any interrupts or debug exceptions that may be pending at the time of VM entry.

•

These VM exits wake the logical processor if it just entered the HLT state as part of a VM entry (see Section 
26.6.2). They do not occur if the logical processor just entered the shutdown state or the wait-for-SIPI state.
If such a VM exit is suppressed because the processor just entered the shutdown state, it occurs after the
delivery of any event that cause the logical processor to leave the shutdown state while remaining in VMX
non-root operation (e.g., due to an NMI that occurs while the “NMI-exiting” VM-execution control is 0).

•

The basic exit reason is “TPR below threshold.”

26.6.8 

Pending MTF VM Exits

As noted in Section 26.5.2, VM entry may cause an MTF VM exit to be pending immediately after VM entry. The 
following items detail the treatment of these VM exits:

•

System-management interrupts (SMIs), INIT signals, and higher priority events take priority over these 
VM exits. These VM exits take priority over debug-trap exceptions and lower priority events. 

•

These VM exits wake the logical processor if it just entered the HLT state because of a VM entry (see Section 
26.6.2). They do not occur if the logical processor just entered the shutdown state or the wait-for-SIPI state.

26.6.9 

VM Entries and Advanced Debugging Features

VM entries are not logged with last-branch records, do not produce branch-trace messages, and do not update the 
branch-trace store.

1. “Virtualize APIC accesses” and “virtual-interrupt delivery” are secondary processor-based VM-execution controls. If bit 31 of the pri-

mary processor-based VM-execution controls is 0, VM entry functions as if these controls were 0. See Section 24.6.2.