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

Table Of Contents
22-32 Vol. 3
VM ENTRIES
22.6.9 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.
22.7 VM-ENTRY FAILURES DURING OR AFTER LOADING
GUEST STATE
VM-entry failures due to the checks identified in Section 22.3.1 and failures during
the MSR loading identified in Section 22.4 are treated differently from those that
occur earlier in VM entry. In these cases, the following steps take place:
1. Information about the VM-entry failure is recorded in the VM-exit information
fields:
—Exit reason.
Bits 15:0 of this field contain the basic exit reason. It is loaded with a
number indicating the general cause of the VM-entry failure. The
following numbers are used:
33.VM-entry failure due to invalid guest state. A VM entry failed one of
the checks identified in Section 22.3.1.
34.VM-entry failure due to MSR loading. A VM entry failed in an attempt
to load MSRs (see Section 22.4).
41.VM-entry failure due to machine check. A machine check occurred
during VM entry (see Section 22.8).
Bit 31 is set to 1 to indicate a VM-entry failure.
The remainder of the field (bits 30:16) is cleared.
Exit qualification. This field is set based on the exit reason.
VM-entry failure due to invalid guest state. In most cases, the exit quali-
fication is cleared to 0. The following non-zero values are used in the
cases indicated:
1. Not used.
2. Failure was due to a problem loading the PDPTEs (see Section
22.3.1.6).
3. Failure was due to an attempt to inject a non-maskable interrupt
(NMI) into a guest that is blocking events through the STI blocking bit
in the interruptibility-state field. Such failures are implementation-
specific (see Section 22.3.1.5).
4.Failure was due to an invalid VMCS link pointer (see Section 22.3.1.5).
VM-entry checks on guest-state fields may be performed in any order.
Thus, an indication by exit qualification of one cause does not imply that