HP A2Y15AV ユーザーズマニュアル

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Processor Configuration Registers
154
Datasheet, Volume 2
2.8.10
GTTMMADR—Graphics Translation Table, Memory  
Mapped Range Address Register
This register requests allocation for the combined Graphics Translation Table 
Modification Range and Memory Mapped Range. The range requires 4 MB combined for 
MMIO and Global GTT aperture, with 2 MB of that used by MMIO and 2 MB used by GTT. 
GTTADR will begin at (GTTMMADR + 2 MB) while the MMIO base address will be the 
same as GTTMMADR.
For the Global GTT, this range is defined as a memory BAR in graphics device 
configuration space. It is an alias into which software is required to write Page Table 
Entry values (PTEs). Software may read PTE values from the global Graphics 
Translation Table (GTT). PTEs cannot be written directly into the global GTT memory 
area.
The device snoops writes to this region in order to invalidate any cached translations 
within the various TLBs implemented on-chip.
The allocation is for 4 MB and the base address is defined by bits 38:22.
B/D/F/Type:
0/2/0/PCI
Address Offset:
10–17h
Reset Value:
0000000000000004h
Access:
RO, RW
Size:
64 bits
Bit
Access
Reset 
Value
RST/
PWR
Description
63:39
RW
0000000h
FLR, 
Uncore
Reserved for Memory Base Address (RSVDRW) 
Must be set to 0 since addressing above 512 GB is not supported.
38:22
RW
00000h
FLR, 
Uncore
Memory Base Address (MBA) 
set by the operating system, these bits correspond to address 
signals 38:22. 4 MB combined for MMIO and Global GTT table 
aperture (2 MB for MMIO and 2 MB for GTT).
21:4
RO
00000h
Uncore
Address Mask (ADM) 
Hardwired to 0s to indicate at least 4 MB address range.
3
RO
0b
Uncore
Prefetchable Memory (PREFMEM) 
Hardwired to 0 to prevent prefetching.
2:1
RO
10b
Uncore
Memory Type (MEMTYP) 
00 = To indicate 32 bit base address
01 = Reserved
10 = To indicate 64 bit base address
11 = Reserved
0
RO
0b
Uncore
Memory/IO Space (MIOS) 
Hardwired to 0 to indicate memory space.