Processor Configuration Registers
126
Datasheet, Volume 2
2.7.5
VC0RCTL—VC0 Resource Control Register
This register controls the resources associated with PCI Express Virtual Channel 0.
B/D/F/Type:
0/1/0–2/MMR
Address Offset:
114–117h
Reset Value:
800000FFh
Access:
RO, RW
Size:
32 bits
BIOS Optimal Default
000h
Bit
Attr
Reset
Value
RST/
PWR
Description
31
RO
1b
Uncore
VC0 Enable (VC0E)
For VC0, this is hardwired to 1 and read only as VC0 can never be
disabled.
30:27
RO
0h
Reserved
26:24
RO
000b
Uncore
VC0 ID (VC0ID)
Assigns a VC ID to the VC resource. For VC0, this is hardwired to 0
and read only.
23:20
RO
0h
Reserved
19:17
RW
000b
Uncore
Port Arbitration Select (PAS)
This field configures the VC resource to provide a particular Port
Arbitration service. This field is valid for RCRBs, Root Ports that
support peer-to-peer traffic, and Switch Ports, but not for PCI
Express Endpoint devices or Root Ports that do not support peer-
to-peer traffic.
The permissible value of this field is a number corresponding to
one of the asserted bits in the Port Arbitration Capability field of
the VC resource.
This field does not affect the root port behavior.
16:16
RO
0h
Reserved
15:8
RW
00h
Uncore
TC High VC0 Map (TCHVC0M)
Allow usage of high order TCs.
BIOS should keep this field zeroed to allow usage of the reserved
TC[3] for other purposes.
7:1
RW
7Fh
Uncore
TC/VC0 Map (TCVC0M)
Indicates the TCs (Traffic Classes) that are mapped to the VC
resource. Bit locations within this field correspond to TC values. For
example, when bit 7 is set in this field, TC7 is mapped to this VC
resource. When more than one bit in this field is set, it indicates
that multiple TCs are mapped to the VC resource. To remove one
or more TCs from the TC/VC Map of an enabled VC, software must
ensure that no new or outstanding transactions with the TC labels
are targeted at the given Link.
0
RO
1b
Uncore
TC0/VC0 Map (TC0VC0M)
Traffic Class 0 is always routed to VC0.