Specification Sheet

Datasheet, Volume 2 of 2 297
GFXVTBAR Registers
8.31 IOTLB Invalidate Register (IOTLB)—Offset 508h
Register to invalidate IOTLB. The act of writing the upper byte of the IOTLB_REG with
IVT field Set causes the hardware to perform the IOTLB invalidation.
Access Method
Default: 200000000000000h
Type: MEM
(Size: 64 bits)
Offset: [B:0, D:0, F:0] + 508h
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 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
IVT
RSVD
IIRG
RSVD
IAIG
RSVD
DR
DW
RSVD
DID
RSVD
Bit
Range
Default &
Access
Field Name (ID): Description
63
0h
RW_V
IVT: Software requests IOTLB invalidation by setting this field. Software should also
set the requested invalidation granularity by programming the IIRG field.
Hardware clears the IVT field to indicate the invalidation request is complete.
Hardware also indicates the granularity at which the invalidation operation was
performed through the IAIG field. Software should not submit another invalidation
request through this register while the IVT field is Set, nor update the associated
Invalidate Address register.
Software should not submit IOTLB invalidation requests when there is a context-cache
invalidation request pending at this remapping hardware unit.
Hardware implementations reporting write-buffer flushing requirement (RWBF=1 in
Capability register) should implicitly perform a write buffer flushing before invalidating
the IOTLB.
62
0h
RO
Reserved (RSVD): Reserved.
61:60
0h
RW
IIRG: When requesting hardware to invalidate the IOTLB (by setting the IVT field),
software writes the requested invalidation granularity through this field. The following
are the encodings for the field.
00: Reserved.
01: Global invalidation request.
10: Domain-selective invalidation request. The target domain-id should be specified in
the DID field.
11: Page-selective invalidation request. The target address, mask and invalidation hint
should be specified in the Invalidate Address register, and the domain-id 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 IVT field. At this time, the granularity at which
actual invalidation was performed is reported through the IAIG field
59
0h
RO
Reserved (RSVD): Reserved.