Specification Update

Errata
Intel
®
Xeon
®
Processor E7 v2 Product Family 43
Specification Update January 2015
CF95 The Corrected Error Count Overflow Bit in IA32_ MC0_STATUS is Not
Updated After a UC Error is Logged
Problem: When a UC (uncorrected) error is logged in the IA32_MC0_STATUS MSR (401H),
corrected errors will continue to update the lower 14 bits (bits 51:38) of the Corrected
Error Count. Due to this erratum, the sticky count overflow bit (bit 52) of the Corrected
Error Count will not get updated after a UC error is logged.
Implication: The Corrected Error Count Overflow indication will be lost if the overflow occurs after an
uncorrectable error has been logged.
Workaround: None identified.
Status: For the affected steppings, see the “Summary Table of Changes”.
CF96 IA32_VMX_VMCS_ENUM MSR (48AH) Does Not Properly Report the
Highest Index Value Used for VMCS Encoding
Problem: IA32_VMX_VMCS_ENUM MSR (48AH) bits 9:1 report the highest index value used for
any VMCS encoding. Due to this erratum, the value 21 is returned in bits 9:1 although
there is a VMCS field whose encoding uses the index value 23.
Implication: Software that uses the value reported in IA32_VMX_VMCS_ENUM[9:1] to read and
write all VMCS fields may omit one field.
Workaround: None identified.
Status: For the affected steppings, see the “Summary Table of Changes”.
CF97 The Upper 32 Bits of CR3 May be Incorrectly Used With 32-Bit Paging
Problem: When 32-bit paging is in use, the processor should use a page directory located at the
32-bit physical address specified in bits 31:12 of CR3; the upper 32 bits of CR3 should
be ignored. Due to this erratum, the processor will use a page directory located at the
64-bit physical address specified in bits 63:12 of CR3.
Implication: The processor may use an unexpected page directory or, if EPT (Extended Page Tables)
is in use, cause an unexpected EPT violation. This erratum applies only if software
enters 64-bit mode, loads CR3 with a 64-bit value, and then returns to 32-bit paging
without changing CR3. Intel has not observed this erratum with any commercially
available software.
Workaround: Software that has executed in 64-bit mode should reload CR3 with a 32-bit value
before returning to 32-bit paging.
Status: For the affected steppings, see the “Summary Table of Changes”.
CF98 EPT Violations May Report Bits 11:0 of Guest Linear Address
Incorrectly
Problem: If a memory access to a linear address requires the processor to update an accessed or
dirty flag in a paging-structure entry and if that update causes an EPT violation, the
processor should store the linear address into the “guest linear address” field in the
VMCS. Due to this erratum, the processor may store an incorrect value into bits 11:0 of
this field. (The processor correctly stores the guest-physical address of the paging-
structure entry into the “guest-physical address” field in the VMCS.)
Implication: Software may not be easily able to determine the page offset of the original memory
access that caused the EPT violation. Intel has not observed this erratum to impact the
operation of any commercially available software.
Workaround: Software requiring the page offset of the original memory access address can derive it
by simulating the effective address computation of the instruction that caused the EPT
violation.
Status: For the affected steppings, see the “Summary Table of Changes”.