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

Table Of Contents
Vol. 3 21-11
VMX NON-ROOT OPERATION
implies that the “virtualize APIC accesses” VM-execution control is 1 at this
time.)
Software did not execute the INVEPT instruction, either with the all-context
INVEPT type or with the single-context INVEPT type and X as the INVEPT
descriptor, between times t
1
and t
2
.
In any of the above cases, the guest-physical access at time t
2
might or might not an
APIC-access VM exit. If it does not, the access operates on memory on the APIC-
access page.
Software can avoid this situation through appropriate use of the INVEPT instruction;
see Section 24.3.3.4.
21.2.2.2 Priority of APIC-Access VM Exits Caused by Guest-Physical
Accesses
The following items specify the priority relative to other events of APIC-access
VM exits caused by guest-physical accesses.
The priority of an APIC-access VM exit caused by a guest-physical access to
memory is below that of any EPT violation that that access may incur. That is, a
guest-physical access does not cause an APIC-access VM exit if it would cause an
EPT violation.
With respect to all other events, any APIC-access VM exit caused by a guest-
physical access has the same priority as any EPT violation that the guest-physical
access could cause.
21.2.3 Physical Accesses to the APIC-Access Page
An access to the APIC-access page is called a physical access if (1) either (a) the
“enable EPT” VM-execution control is 0;
1
or (b) the access’s physical address is not
the result of a translation through the EPT paging structures; and (2) either (a) the
access is not generated by a linear address; or (b) the access’s physical address is
not the translation of its linear address.
Physical accesses include the following:
If the “enable EPT” VM-execution control is 0:
Reads from the paging structures when translating a linear address.
Loads of the page-directory-pointer-table entries by MOV to CR when the
logical processor is using (or that causes the logical processor to use) PAE
paging.
2
1. Note that “enable EPT” is a secondary processor-based VM-execution control. If bit 31 of the pri-
mary processor-based VM-execution controls is 0, VMX non-root operation functions as if the
“enable EPT” VM-execution control were 0. See Section 20.6.2.