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

Table Of Contents
22-6 Vol. 3
VM ENTRIES
22.2.1.2 VM-Exit Control Fields
VM entries perform the following checks on the VM-exit control fields.
Reserved bits in the VM-exit controls must be set properly. Software may consult
the VMX capability MSRs to determine the proper settings (see Appendix G.4).
If “activate VMX-preemption timer” VM-execution control is 0, the “save VMX-
preemption timer value” VM-exit control must also be 0.
The following checks are performed for the VM-exit MSR-store address if the
VM-exit MSR-store count field is non-zero:
The lower 4 bits of the VM-exit MSR-store address must be 0. On processors
that support Intel 64 architecture, the address should not set any bits beyond
the processor’s physical-address width.
1
On processors that do not support
Intel 64 architecture, the address should not set any bits in the range 63:32.
On processors that support Intel 64 architecture, the address of the last byte
in the VM-exit MSR-store area should not set any bits beyond the processors
physical-address width. On processors that do not support Intel 64 archi-
tecture, the address of the last byte in the VM-exit MSR-store area should not
set any bits in the range 63:32. The address of this last byte is VM-exit MSR-
store address + (MSR count * 16) 1. (The arithmetic used for the
computation uses more bits than the processors physical-address width.)
The following checks are performed for the VM-exit MSR-load address if the
VM-exit MSR-load count field is non-zero:
The lower 4 bits of the VM-exit MSR-load address must be 0. On processors
that support Intel 64 architecture, the address should not set any bits beyond
the processor’s physical-address width. On processors that do not support
Intel 64 architecture, the address should not set any bits in the range 63:32.
On processors that support Intel 64 architecture, the address of the last byte
in the VM-exit MSR-load area should not set any bits beyond the processor’s
physical-address width. On processors that do not support Intel 64 archi-
tecture, the address of the last byte in the VM-exit MSR-load area should not
set any bits in the range 63:32. The address of this last byte is VM-exit MSR-
load address + (MSR count * 16) – 1. (The arithmetic used for the
computation uses more bits than the processors physical-address width.)
22.2.1.3 VM-Entry Control Fields
VM entries perform the following checks on the VM-entry control fields.
Reserved bits in the VM-entry controls must be set properly. Software may
consult the VMX capability MSRs to determine the proper settings (see Appendix
G.5).
1. Software can determine a processor’s physical-address width by executing CPUID with
80000008H in EAX. The physical-address width is returned in bits 7:0 of EAX.