Errata
Intel
®
Core™2 Extreme Quad-Core Processor QX6000
Δ
Sequence and
51
Intel
®
Core™2 Quad Processor Q6000
Δ
Sequence
Specification Update
AK88.
Microcode Updates Performed During VMX Non-root Operation Could
Result in Unexpected Behavior
Problem:
When Intel
®
Virtualization Technology is enabled microcode updates are
allowed only during VMX root operations. Attempts to apply microcode
updates while in VMX non-root operation should be silently ignored. Due to
this erratum, the processor may allow microcode updates during VMX non-
root operations if not explicitly prevented by the host software.
Implication:
Microcode updates performed in non-root operation may result in unexpected
system behavior.
Workaround:
Host software should intercept and prevent loads to IA32_BIOS_UPDT_TRIG
MSR (79H) during VMX non-root operations. There are two mechanism that
can be used (1) Enabling MSR access protection in the VM-execution controls
or (2) Enabling selective MSR protection of IA32_BIOS_UPDT_TRIG MSR.
Status:
For the steppings affected, see the Summary Tables of Changes.
AK89.
INVLPG Operation for Large (2M/4M) Pages May be Incomplete
under Certain Conditions
Problem:
The INVLPG instruction may not completely invalidate Translation Look-aside
Buffer (TLB) entries for large pages (2M/4M) when both of the following
conditions exist:
•
Address range of the page being invalidated spans several Memory Type Range
Registers (MTRRs) with different memory types specified
•
INVLPG operation is preceded by a Page Assist Event (Page Fault (#PF) or an
access that results in either A or D bits being set in a Page Table Entry (PTE))
Implication:
Stale translations may remain valid in TLB after a PTE update resulting in
unpredictable system behavior. Intel has not observed this erratum with any
commercially available software.
Workaround:
Software should ensure that the memory type specified in the MTRRs is the
same for the entire address range of the large page.
Status:
For the steppings affected, see the Summary Tables of Changes.
AK90.
Page Access Bit May be Set Prior to Signaling a Code Segment Limit
Fault
Problem:
If code segment limit is set close to the end of a code page, then due to this
erratum the memory page Access bit (A bit) may be set for the subsequent
page prior to general protection fault on code segment limit.
Implication:
When this erratum occurs, a non-accessed page present in memory following
a page that contains the code segment limit may be tagged as accessed.
Workaround:
Non-present or non-executable page can be placed after the limit of the code
segment to prevent this erratum.
Status:
For the steppings affected, see the Summary Tables of Changes.
