Intel E7-8891 v2 CM8063601377422 User Manual

Product codes
CM8063601377422
Page of 504
Registers Overview and Configuration Process
80
Intel
®
 Xeon
® 
Processor E7-2800/4800/8800 v2 Product Family
Datasheet Volume Two: Functional Description, February 2014
RW_LB
Read/Write Lock Bypass: Similar to RW_L, these bits can be read and written by software. 
HW can make these bits “Read Only” via a separate configuration bit or other logic. However, 
RW_LB is a special case where the locking is controlled by the lock-bypass capability that is 
controlled by the lock-bypass enable bits. Each lock-bypass enable bit enables a set of configure 
request sources that can bypass the lock. The requests sourced from the corresponding bypass 
enable bits will be lock-bypassed (i.e. RW) while requests sourced from other sources are under 
lock control (RO). The lock bit and bypass enable bit are generally defined with RW_O attributes. 
Sticky can be used with this attribute (RWS_LB). 
RW_LV
Read / Write Lock - Variant: These bits can be read and written by software. In addition, 
hardware can modify the value. Hardware can make these bits ‘Read Only’ via a separate 
configuration bit or other logic.
RW_LBV
Read / Write Lock Bypass - Variant: Similar to RW_LB. In addition, hardware can modify the 
value. 
RW_V 
Read/Write - Variant: These bits are readable or writable by software. In addition, hardware 
can modify the value.
RW1C
Read / Write 1 to Clear: These bits can be read and cleared by software. Writing a ‘1’ to a bit 
clears it, while writing a ‘0’ to a bit has no effect. 
RW1CS
Read / Write 1 Clear Sticky: These bits can be read and cleared by software. Writing a ‘1’ to a 
bit clears it, while writing a ‘0’ to a bit has no effect. These bits are only reinitialized to their 
default value by a PWRGOOD reset. 
RWS
Read / Write Sticky: These bits can be read and written by software. These bits are only 
reinitialized to their default value by a PWRGOOD reset. 
RWS_L 
Read / Write Sticky Lock: These bits can be read and written by software. These bits are only 
reinitialized to their default value by a PWRGOOD reset. Hardware can make these bits ‘Read 
Only’ via a separate configuration bit or other logic. 
RWS_O 
Read/Write Sticky Once: If a register is both sticky and “once” then the sticky value applies to 
both the register value and the “once” characteristic. Only a PWRGOOD reset will reset both the 
value and the “once” so that the register can be written to again. 
RWS_V 
Read / Write Sticky - Variant: These bits can be read and written by software. In addition, 
hardware can modify the value. These bits are only reinitialized to their default value by a 
PWRGOOD reset.
RWS_LB
Read/Write Lock with selective lock-Bypass Sticky: Similar to RW_LB except that the 
register is Sticky. These bits are only reinitialized to their default value by a PWRGOOD reset. 
Note that the lock bits may not be sticky. In order to maintain the locked behavior through hard-
reset, software/firmware/BIOS must write the write-once lock bits after reset in order to prevent 
the lock bit being changed by others.
RV
Reserved: These bits are reserved for future expansion and their value must not be modified by 
software. When writing these bits, software must preserve the value read.
Table 12-3. Register attribute definitions  (Sheet 2 of 2)
Attribute
Description
downloadlike
ArtboardArtboardArtboard
Report Bug