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

Table Of Contents
22-28 Vol. 3
VM ENTRIES
cycle that is normally generated when that activity state is entered from the
active state. If VM entry would end with the logical processor in the shutdown
state and the logical processor is in SMX operation,
1
an Intel
®
TXT shutdown
condition occurs. The error code used is 0000H, indicating “legacy shutdown.
See Intel
®
Trusted Execution Technology Preliminary Architecture Specification.
Some activity states unconditionally block certain events. The following blocking
is in effect after any VM entry that puts the processor in the indicated state:
The active state blocks start-up IPIs (SIPIs). SIPIs that arrive while a logical
processor is in the active state and in VMX non-root operation are discarded
and do not cause VM exits.
The HLT state blocks start-up IPIs (SIPIs). SIPIs that arrive while a logical
processor is in the HLT state and in VMX non-root operation are discarded and
do not cause VM exits.
The shutdown state blocks external interrupts and SIPIs. External interrupts
that arrive while a logical processor is in the shutdown state and in VMX non-
root operation do not cause VM exits even if the “external-interrupt exiting”
VM-execution control is 1. SIPIs that arrive while a logical processor is in the
shutdown state and in VMX non-root operation are discarded and do not
cause VM exits.
The wait-for-SIPI state blocks external interrupts, non-maskable interrupts
(NMIs), INIT signals, and system-management interrupts (SMIs). Such
events do not cause VM exits if they arrive while a logical processor is in the
wait-for-SIPI state and in VMX non-root operation do not cause VM exits
regardless of the settings of the pin-based VM-execution controls.
22.6.3 Delivery of Pending Debug Exceptions after VM Entry
The pending debug exceptions field in the guest-state area indicates whether there
are debug exceptions that have not yet been delivered (see Section 20.4.2). This
section describes how these are treated on VM entry.
There are no pending debug exceptions after VM entry if any of the following are
true:
The VM entry is vectoring with one of the following interruption types: external
interrupt, non-maskable interrupt (NMI), hardware exception, or privileged
software exception.
The interruptibility-state field does not indicate blocking by MOV SS and the
VM entry is vectoring with either of the following interruption type: software
interrupt or software exception.
1. A logical processor is in SMX operation if GETSEC[SEXIT] has not been executed since the last
execution of GETSEC[SENTER]. See Chapter 6, “Safer Mode Extensions Reference,” in Intel® 64
and IA-32 Architectures Software Developer’s Manual, Volume 2B.