Intel Xeon L3406 CM80616005010AA User Manual

Product codes
CM80616005010AA
Page of 302
System Address Map
282
Datasheet, Volume 2
The VGA memory address range can also be mapped to system memory in SMM. IIO is 
totally transparent to the workings of this region in the SMM mode. All outbound and 
inbound accesses to this address range are always forwarded to the VGA device by the 
IIO. Refer to 
 for further details of inbound and outbound VGA 
decoding.
5.2.3.2
C/D/E/F Segments
The E/F region is used for BIOS flash in the early stages of the boot flow and could be 
mapped to any firmware hub port in IA32 system. E/F could also be used to address 
DRAM from an I/O device (processors have registers to select between addressing 
BIOS flash and DRAM). IIO does not explicitly decode the E/F region in the outbound 
direction and relies on subtractive decoding to forward accesses to this region to the 
legacy PCH through DMI. IIO does not explicitly decode inbound accesses to the E/F 
address region. It is expected that the DRAM low range that IIO decodes will be setup 
to cover the E/F address range. By virtue of that, IIO will forward inbound accesses to 
the E/F segment to system DRAM.
 
If it is necessary to block inbound access to these 
ranges, a Generic Memory Protection Ranges could be used.
C/D region is used in system DRAM memory for BIOS and option ROM shadowing. IIO 
does not explicitly decode these regions for inbound accesses. Software must program 
one of the system DRAM memory decode ranges that IIO uses (for inbound system 
memory decoding) to include these ranges. If it is necessary to block inbound access to 
these ranges, the Generic Memory Protection Ranges could be used.
All outbound accesses to the C-F regions are first positively decoded against all valid 
targets’ address ranges and if none match, these address are forwarded to the 
subtractive decode port of the IIO.
IIO will complete locks to this range, but cannot guarantee atomicity when writes and 
reads are mapped to separate destinations.
 
5.2.4
Address Region between 1 MB and TOLM
Note:
The ME stolen memory space must be located below Top Of Low Memory 
(TOLM) (or TOHM ifit needs to be above 4 GB). 
This region is always allocated to system DRAM memory. Software must set up one of 
the coarse memory decode ranges that IIO uses (for inbound system memory 
decoding) to include this address range. By virtue of that, IIO will forward inbound 
accesses to this region to system memory (unless any of these access addresses fall 
within a protected DRAM range as described in 
). It would be an error for 
IIO to receive outbound accesses to an address in this region, other than snoop 
requests, from Intel QuickPath Interconnect, but IIO does not explicitly check for this 
error condition but would rather forward such accesses to the subtractive decode port 
by virtue of subtractive decoding.
Any inbound access that decodes to be within one of the two coarse memory decode 
windows but has no real DRAM populated for that address, will result in a master abort 
response on PCI Express.