Datasheet

Processor Configuration Registers
290 Datasheet, Volume 2
2.18.28 IVA_REG—Invalidate Address Register
This register provides the DMA address whose corresponding IOTLB entry needs to be
invalidated through the corresponding IOTLB Invalidate register. This register is a
write-only register.
B/D/F/Type: 0/0/0/GFXVTBAR
Address Offset: 100–107h
Reset Value: 0000000000000000h
Access: RW
Size: 64 bits
BIOS Optimal Default 00000000h
Bit Access
Reset
Value
RST/
PWR
Description
63:39 RO 0h Reserved (RSVD)
38:12 RW 0000000h Uncore
Address (ADDR)
Software provides the DMA address that needs to be page-
selectively invalidated. To make a page-selective invalidation
request to hardware, software must first write the appropriate
fields in this register, and then issue the appropriate page-
selective invalidate command through the IOTLB_REG. Hardware
ignores bits 63: N, where N is the maximum guest address width
(MGAW) supported.
11:7 RO 0h Reserved (RSVD)
6RW 0hUncore
Invalidation Hint (IH)
The field provides hint to hardware about preserving or flushing
the non-leaf (page-directory) entries that may be cached in
hardware:
0 = Software may have modified both leaf and non-leaf page-
table entries corresponding to mappings specified in the
ADDR and AM fields. On a page-selective invalidation
request, hardware must flush both the cached leaf and non-
leaf page-table entries corresponding to the mappings
specified by ADDR and AM fields.
1 = Software has not modified any non-leaf page-table entries
corresponding to mappings specified in the ADDR and AM
fields. On a page-selective invalidation request, hardware
may preserve the cached non-leaf page-table entries
corresponding to mappings specified by ADDR and AM fields.
5:0 RW 00h Uncore
Address Mask (AM)
The value in this field specifies the number of low order bits of
the ADDR field that must be masked for the invalidation
operation. This field enables software to request invalidation of
contiguous mappings for size-aligned regions. For example:
Mask ADDR bits Pages
Value masked invalidated
0 None 1
1 12 2
2 13:12 4
3 14:12 8
4 15:12 16
When invalidating mappings for super-pages, software must
specify the appropriate mask value. For example, when
invalidating mapping for a 2 MB page, software must specify an
address mask value of at least 9.
Hardware implementations report the maximum supported mask
value through the Capability register.