Errata
58
Intel
®
Core™2 Extreme Quad-Core Processor QX6000
Δ
Sequence and Intel
®
Core™2 Quad Processor Q6000
Δ
Sequence
Specification Update
Status:
For the steppings affected, see the Summary Tables of Changes.
AK108.
Overlap of an Intel
®
VT APIC Access Page in a Guest with the DS Save
Area May Lead to Unpredictable Behavior
Problem:
Logging of a branch record or a PEBS (precise-event-based-sampling) record
to the DS (debug store) save area that overlaps with the APIC access page
may lead to unpredictable behavior.
Implication:
Guest software configured to log branch records or PEBS records
cannot specify the DS (debug store) save area within the APIC-access page.
Under any expected usage model this type of overlap is not expected to exist.
One should be aware of the fact that the specified DS address is of linear
form while the APIC access page is of a physical form. Any solution that
wishes to avoid this condition will need to comprehend the linear-to-physical
translation of the DS related address pointers with respect to the mapping of
the physical APIC access page to avoid such an overlap. Under normal
circumstances for correctly written software, such an overlap is not expected
to exist. Intel has not observed this erratum with any commercially available
software.
Workaround:
For a fully comprehensive workaround, the VMM should not allow the logging
of branch or PEBS records while guest software is running if the "virtualize
APIC accesses" VM-execution control is 1.
Status:
For the steppings affected, see the Summary Tables of Changes.
AK109.
CPUID Reports Certain Features/Parameters Incorrectly when HT
Technology is Disabled
Problem:
CPUID will report incorrect values for the following features/parameters
when Hyper-Threading Technology (HT Technology) is disabled:
•
Number of threads per physical processor (CPUID.01H:EBX [bits 23-16])
•
Multi-Threading extended feature information (CPUID.01H:EDX [bit 28])
•
Maximum number of processor cores in a physical package (CPUID.04H:EAX [bits
31-26])
•
Maximum number of threads sharing this cache in a physical package
(CPUID.04H:EAX [bits 25-14])
Implication:
If BIOS disables HT Technology, software executing CPUID will observe
incorrect values for the features/parameters listed above.
Workaround:
It is possible for BIOS to contain a workaround for this erratum.
Status:
For the steppings affected, see the Summary Tables of Changes.