Processor Configuration Registers
B/D/F/Type:
Address Offset:
Reset Value:
Access:
0/0/0/VC0PREMAP
8–Fh
00C9008020660262h
RO
64 bits
000h
Size:
BIOS Optimal Default
Reset
Value
RST/
PWR
Bit
Access
Description
Fault-recording Register offset (FRO)
This field specifies the location to the first fault recording register
relative to the register base address of this remapping hardware
unit.
If the register base address is X, and the value reported in this
field is Y, the address for the first fault recording register is
calculated as X+(16*Y).
33:24
RO
020h
Uncore
Uncore
Uncore
Isochrony (ISOCH)
0 = Remapping hardware unit has no critical isochronous
requesters in its scope.
1 = Remapping hardware unit has one or more critical
isochronous requesters in its scope. To ensure isochronous
performance, software must ensure invalidation operations
do not impact active DMA streams from such requesters.
This implies, when DMA is active, software performs page-
selective invalidations (and not coarser invalidations).
23
22
RO
RO
0b
Zero Length Read (ZLR)
0 = Indicates the remapping hardware unit blocks (and treats as
fault) zero length DMA read requests to write-only pages.
1 = Indicates the remapping hardware unit supports zero length
DMA read requests to write-only pages.
1b
DMA remapping hardware implementations are recommended to
report ZLR field as set.
Maximum Guest Address Width (MGAW)
This field indicates the maximum DMA virtual addressability
supported by remapping hardware. The Maximum Guest Address
Width (MGAW) is computed as (N+1), where N is the value
reported in this field. For example, a hardware implementation
supporting 48-bit MGAW reports a value of 47 (101111b) in this
field.
If the value in this field is X, untranslated and translated DMA
requests to addresses above 2^(x+1)-1 are always blocked by
hardware. Translations requests to address above 2^(x+1)-1
from allowed devices return a null Translation Completion Data
Entry with R=W=0.
21:16
RO
100110b
Uncore
Guest addressability for a given DMA request is limited to the
minimum of the value reported through this field and the
adjusted guest address width of the corresponding page-table
structure. (Adjusted guest address widths supported by
hardware are reported through the SAGAW field).
Implementations are recommended to support MGAW at least
equal to the physical addressability (host address width) of the
platform.
15:13
RO
0h
Reserved (RSVD)
312
Datasheet, Volume 2
INTEL [ INTEL ]
