658
CPUID
Incorrectly
Reports
Large
Page
Support
in
L
2
Instruction
TLB
Description
The
CPUID
instruction
incorrectly
reports
the
number
of
entries
and
the
associativity
of
2
MB
, 4
MB
and
1
GB
TLB
entries
in
the
L
2
instruction
TLB
.
The
following
CPUID
fields
are
incorrectly
zero
:
•
CPUID
Fn
8000_0006_
EAX
[
L
2
ITlb
2
and
4
MSize
]
•
CPUID
Fn
8000_0006_
EAX
[
L
2
ITlb
2
and
4
MAssoc
]
•
CPUID
Fn
8000_0019_
EBX
[
L
2
ITlb
1
GSize
]
•
CPUID
Fn
8000_0019_
EBX
[
L
2
ITlb
1
GAssoc
]
Potential
Effect
on
System
None
expected
.
Suggested
Workaround
Software
may
substitute
the
following
values
to
determine
the
number
and
associativity
of
large
page
L
2
TLB
entries
:
•
CPUID
Fn
8000_0006_
EAX
[
L
2
ITlb
2
and
4
MSize
] = 1024
•
CPUID
Fn
8000_0006_
EAX
[
L
2
ITlb
2
and
4
MAssoc
] = 6
•
CPUID
Fn
8000_0019_
EBX
[
L
2
ITlb
1
GSize
] = 1024
•
CPUID
Fn
8000_0019_
EBX
[
L
2
ITlb
1
GAssoc
] = 6
This
workaround
should
only
be
implemented
after
checking
for
affected
silicon
family
and
model
(
CPUID
Fn
0000_0001_
EAX
[
Extended
Family
,
Family
,
Extended
Model
and
Model
]),
and
that
the
processor
reports
zero
for
these
fields
.
Fix
Planned
Yes
Revision
Guide
for
AMD
Family
15
h
Models
00
h-
0
Fh
Processors
48063
Rev
. 3.18
October
2012
50
Product
Errata