Specification Sheet

GFXVTBAR Registers
274 Datasheet, Volume 2 of 2
8.7 Context Command Register (CCMD)—Offset 28h
Register to manage context cache. The act of writing the uppermost byte of the
CCMD_REG with the ICC field Set causes the hardware to perform the context-cache
invalidation.
Access Method
Default: 800000000000000h
Type: MEM
(Size: 64 bits)
Offset: [B:0, D:0, F:0] + 28h
6
3
6
0
5
6
5
2
4
8
4
4
4
0
3
6
3
2
2
8
2
4
2
0
1
6
1
2
8 4 0
0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ICC
CIRG
CAIG
RSVD
FM
SID
RSVD
DID
Bit
Range
Default &
Access
Field Name (ID): Description
63
0h
RW_V
ICC: Software requests invalidation of context-cache by setting this field. Software
should also set the requested invalidation granularity by programming the CIRG field.
Software should read back and check the ICC field is Clear to confirm the invalidation
is complete. Software should not update this register when this field is set.
Hardware clears the ICC field to indicate the invalidation request is complete.
Hardware also indicates the granularity at which the invalidation operation was
performed through the CAIG field.
Software should submit a context-cache invalidation request through this field only
when there are no invalidation requests pending at this remapping hardware unit.
Since information from the context-cache may be used by hardware to tag IOTLB
entries, software should perform domain-selective (or global) invalidation of IOTLB
after the context cache invalidation has completed.
Hardware implementations reporting write-buffer flushing requirement (RWBF=1 in
Capability register) should implicitly perform a write buffer flush before invalidating
the context cache.
62:61
0h
RW
CIRG: Software provides the requested invalidation granularity through this field
when setting the ICC field:
00: Reserved.
01: Global Invalidation request.
10: Domain-selective invalidation request. The target domain-id should be specified in
the DID field.
11: Device-selective invalidation request. The target source-id(s) should be specified
through the SID and FM fields, and the domain-id (that was programmed in the
context-entry for these device(s)) should be provided in the DID field.
Hardware implementations may process an invalidation request by performing
invalidation at a coarser granularity than requested. Hardware indicates completion of
the invalidation request by clearing the ICC field. At this time, hardware also indicates
the granularity at which the actual invalidation was performed through the CAIG field.