AC82G41SLGQ3 Datasheet, PDF (504/604 Pages) Intel Corporation – Intel® 4 Series Chipset Family

Intel^® Virtualization Technology for Directed I/O Registers (D0:F0) (Intel^® 82Q45 GMCH Only)
12.3.7
CCMD_REG—Context Command Register
B/D/F/Type:
Address Offset:
Default Value:
Access:
Size:
0/2/0/GFXVTBAR
28-2Fh
0800000000000000h
R/W, RO, WO
64 bits
This register is used to manage context-entry cache. The act of writing the uppermost
byte of the CCMD_REG with ICC field set causes the hardware to perform the context-
cache invalidation.
Bit
Access
63
R/W
62:61
R/W
Default
Value
0
00b
RST/PWR
Description
Core
Core
Invalidate Context-entry Cache (ICC): Software
requests invalidation of context-cache by setting this field.
Software must also set the requested invalidation
granularity by programming the CIRG field.
Software must read back and check the ICC field to be
clear to confirm the invalidation is complete. Software
must 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 must not
submit another invalidation request through this register
while the ICC field is set.
Software must submit a context cache invalidation request
through this field only when there are no invalidation
requests pending at this DMA-remapping hardware unit.
Since information from the context-cache may be used by
hardware to tag IOTLB entries, software must 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) must
implicitly perform a write buffer flushing before reporting
invalidation complete to software through the ICC field.
Context-cache Invalidation Request Granularity
(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 must be specified in the DID field.
11 = Device-selective invalidation request. The target
source-ID(s) must be specified through the SID and
FM fields, and the domain-ID (that was programmed
in the context-entry for these device(s)) must 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.
504
Datasheet