Datasheet

Datasheet, Volume 2 267
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Processor Integrated I/O (IIO) Configuration Registers
3.3.8.49 VTD1_CTXCMD—Context Command Register
VTD1_CTXCMD
Bus: 0 Device: 5 Function: 0 MMIO BAR: VTBAR
Offset: 1028
Bit Attr
Reset
Value
Description
63 RW 0b
Invalidate Context Entry Cache
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.
62:61 RW 0b
Context Invalidation Request Granularity
When requesting hardware to invalidate the context-entry cache (by setting the
ICC field), software writes the requested invalidation granularity through this field.
Following are the encoding for the 2-bit IRG field.
00 = Reserved. Hardware ignores the invalidation request and reports
invalidation complete by clearing the ICC field and reporting 00 in the CAIG
field.
01 = Global Invalidation request. The processor supports this.
10 = Domain-selective invalidation request. The target domain-id must be
specified in the DID field. The processor supports this.
11 = Device-selective invalidation request. The target SID must be specified in
the SID field, and the domain-id (programmed in the context-entry for this
device) must be provided in the DID field. The processor aliases the
hardware behavior for this command to the ’Domain-selective invalidation
request’.
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.
60:59 RO 0b
Context Actual Invalidation Granularity
Hardware reports the granularity at which an invalidation request was processed
through the CAIG field at the time of reporting invalidation completion (by clearing
the ICC field). The following are the encoding for the 2-bit CAIG field.
00 = Reserved. This is the value on reset.
01 = Global Invalidation performed. The processor sets this in response to a
global invalidation request.
10 = Domain-selective invalidation performed using the domain-id that was
specified by software in the DID field. The processor set this in response to
a domain-selective or device-selective invalidation request.
11 = Device-selective invalidation. The processor never sets this encoding.
58:34 RV 0h Reserved
33:32 RW 00b
fm
Used by the processor when performing device selective invalidation.
31:16 RW 0h
Source ID
Used by the processor when performing device selective context cache
invalidation.
15:0 RW 0h
Domain ID
Indicates the id of the domain whose context-entries needs to be selectively
invalidated. S/W needs to program this for both domain and device selective
invalidates. The processor ignores bits 15:8 since it supports only a 8 bit Domain
ID.