Embedded Page Table Configuration Register (Eptcfg) - IBM A2 User Manual

User's Manual
A2 Processor

6.17.25 Embedded Page Table Configuration Register (EPTCFG)

The EPTCFG register is a read-only register that can be read into a GPR using mfspr. EPTCFG is used to
provide additional implementation-specific parameters regarding the supported TLB indirect entry page sizes
and sub-page sizes to the operating system. This processor supports only two combinations of page and sub-
page sizes for the TLB IND = 1 entries; hence, the architected fields PS2 and SPS2 are treated as reserved
in this implementation. This processor supports only power of 4  1 K page and sub-page sizes for the TLB
indirect entries, but the architecture defines this register based on power of 2  1 K sizes.
Register Short Name:
Decimal SPR Number:
Initial Value:
Slow SPR:
Guest Supervisor Mapping:
Bits Field Name
32:43 ///
44:48 PS1
49:53 SPS1
54:58 PS0
59:63 SPS0
Memory Management
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EPTCFG
350
0x0000000000091942
Y
Initial
Value
0x0 Reserved
0x12 Page Size 1
Indicates whether an indirect entry with page size 2
size indicated by SPS1 is supported by the TLB. (The A2 supports an indirect page size of
256 MB with a sub-page size of 64 KB.)
0x6 Sub-Page Size 1
Indicates whether an indirect entry with sub-page size 2
size indicated by PS1 is supported by the TLB. (The A2 supports an indirect page size of
256 MB with a sub-page size of 64 KB.)
0xA Page Size 0
Indicates whether an indirect entry with page size 2
size indicated by SPS0 is supported by the TLB. (The A2 supports an indirect page size of
1 MB with a sub-page size of 4 KB.)
0x2 Sub-Page Size 0
Indicates whether an indirect entry with sub-page size 2
indicated by PS0 is supported by the TLB. (The A2 supports an indirect page size of 1 MB
with a sub-page size of 4 KB.)
Read Access:
Write Access:
Duplicated for Multithread:
Notes:
Scan Ring:
Description
PS1
PS0
Hypv
None
N
HM
func
KB combined with the sub-page
SPS1
KB combined with the page
KB combined with the sub-page
SPS0
KB combined with page size
Version 1.3
October 23, 2012