Intel CORE 2 DUO E4000 - SPECIFICATION UPDATE 3-2008 Specification page 54

Implication: When this erratum occurs, the processor may live lock causing a system
hang.
Workaround: Do not perform unaligned accesses on paging structure entries.
For the steppings affected, see the Summary Tables of Changes.
Status:
AI88. Microcode Updates Performed During VMX Non-root Operation Could
Result in Unexpected Behavior
When Intel
Problem:
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.
For the steppings affected, see the Summary Tables of Changes.
Status:
AI89. INVLPG Operation for Large (2M/4M) Pages May be Incomplete
under Certain Conditions
The INVLPG instruction may not completely invalidate Translation Look-aside
Problem:
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.
For the steppings affected, see the Summary Tables of Changes.
Status:
AI90. Page Access Bit May be Set Prior to Signaling a Code Segment Limit
Fault
If code segment limit is set close to the end of a code page, then due to this
Problem:
erratum the memory page Access bit (A bit) may be set for the subsequent
page prior to general protection fault on code segment limit.
54
®
Virtualization Technology is enabled, microcode updates are
Intel® Core™2 Duo Desktop Processor E6000 and E4000 Sequence
®
Intel Core™2 Extreme Processor X6800 and
Errata
Specification Update