Specification Update

Errata
Intel
®
Xeon
®
Processor E7 v2 Product Family 37
Specification Update January 2015
CF71 #GP on Segment Selector Descriptor That Straddles Canonical
Boundary May Not Provide Correct Exception Error Code
Problem: During a #GP (General Protection Exception), the processor pushes an error code on to
the exception handler’s stack. If the segment selector descriptor straddles the
canonical boundary, the error code pushed onto the stack may be incorrect.
Implication: An incorrect error code may be pushed onto the stack. Intel has not observed this
erratum with any commercially available software.
Workaround: None identified.
Status: For the affected steppings, see the “Summary Table of Changes”.
CF72 APIC Error “Received Illegal Vector” May Be Lost
Problem: APIC (Advanced Programmable Interrupt Controller) may not update the ESR (Error
Status Register) flag Received Illegal Vector bit [6] properly when an illegal vector error
is received on the same internal clock that the ESR is being written (as part of the
write-read ESR access flow). The corresponding error interrupt will also not be
generated for this case.
Implication: Due to this erratum, an incoming illegal vector error may not be logged into ESR
properly and may not generate an error interrupt.
Workaround: None identified.
Status: For the affected steppings, see the “Summary Table of Changes”.
CF73 Changing the Memory Type for an In-Use Page Translation May Lead
to Memory-Ordering Violations
Problem: Under complex microarchitectural conditions, if software changes the memory type for
data being actively used and shared by multiple threads without the use of semaphores
or barriers, software may see load operations execute out of order.
Implication: Memory ordering may be violated. Intel has not observed this erratum with any
commercially available software.
Workaround: Software should ensure pages are not being actively used before requesting their
memory type be changed.
Status: For the affected steppings, see the “Summary Table of Changes”.
CF74 Reported Memory Type May Not be Used to Access the VMCS and
Referenced Data Structures
Problem: Bits 53:50 of the IA32_VMX_BASIC MSR report the memory type that the processor
uses to access the VMCS and data structures referenced by pointers in the VMCS. Due
to this erratum, a VMX access to the VMCS or referenced data structures will instead
use the memory type that the MTRRs (memory-type range registers) specify for the
physical address of the access.
Implication: Bits 53:50 of the IA32_VMX_BASIC MSR report that the WB (write-back) memory type
will be used but the processor may use a different memory type.
Workaround: Software should ensure that the VMCS and referenced data structures are located at
physical addresses that are mapped to WB memory type by the MTRRs.
Status: For the affected steppings, see the “Summary Table of Changes”.
CF75 LBR, BTM or BTS Records May have Incorrect Branch From
Information After an Enhanced Intel SpeedStep® Technology/T-
state/S-state/C1E Transition or Adaptive Thermal Throttling
Problem: The “From” address associated with the LBR (Last Branch Record), BTM (Branch Trace
Message) or BTS (Branch Trace Store) may be incorrect for the first branch after a
transition of: