Intel G645 BX80623G645 User Manual

Datasheet, Volume 2

251

58:57

RO-V

1h

Uncore

IOTLB Actual Invalidation Granularity (IAIG)
Hardware reports the granularity at which an invalidation request 

was processed through this field when reporting invalidation 

completion (by clearing the IVT field).
The following are the encodings for this field.
00 = Reserved. This indicates hardware detected an incorrect 

invalidation request and ignored the request. Examples of 

incorrect invalidation requests include detecting an 

unsupported address mask value in Invalidate Address 

register for page-selective invalidation requests.

01 = Global Invalidation performed. This could be in response to a 

global, domain-selective, or page-selective invalidation 

request.

10 = Domain-selective invalidation performed using the domain-id 

specified by software in the DID field. This could be in 

response to a domain-selective or a page-selective 

invalidation request.

11 = Domain-page-selective invalidation performed using the 

address, mask and hint specified by software in the 

Invalidate Address register and domain-id specified in DID 

field. This can be in response to a page-selective invalidation 

request. 

56:50

RO

0h

Reserved 

49

RW

0b

Uncore

Drain Reads (DR)
This field is ignored by hardware if the DRD field is reported as 

clear in the Capability register. When the DRD field is reported as 

set in the Capability register, the following encodings are supported 

for this bit:
0 = Hardware may complete the IOTLB invalidation without 

draining any translated DMA read requests.

1 = Hardware must drain DMA read requests.

48

RW

0b

Uncore

Drain Writes (DW)
This bit is ignored by hardware if the DWD field is reported as clear 

in the Capability register. When the DWD field is reported as set in 

the Capability register, the following encodings are supported for 

this bit:
0 = Hardware may complete the IOTLB invalidation without 

draining DMA write requests.

1 = Hardware must drain relevant translated DMA write requests.

47:40

RO

0h

Reserved 

39:32

RW

00h

Uncore

Domain-ID (DID)
This field indicates the ID of the domain whose IOTLB entries need 

to be selectively invalidated. This field must be programmed by 

software for domain-selective and page-selective invalidation 

requests.
The Capability register reports the domain-id width supported by 

hardware. Software must ensure that the value written to this field 

is within this limit. Hardware ignores and does not implement bits 

47:(32+N), where N is the supported domain-id width reported in 

the Capability register. 

31:0

RO

0h

Reserved