System Address Map
3.4.1
Memory Re-claim Background
The following are examples of Memory Mapped IO devices are typically located below
4 GB:
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High BIOS
HSEG
TSEG
GFXstolen
XAPIC
Local APIC
FSB Interrupts
Mbase/Mlimit
Memory Mapped I/O space that supports only 32B addressing
The GMCH provides the capability to re-claim the physical memory overlapped by the
Memory Mapped I/O logical address space. The GMCH re-maps physical memory from
the Top of Low Memory (TOLUD) boundary up to the 4 GB boundary to an equivalent
sized logical address range located just below the Manageability Engine's stolen
memory.
3.4.2
Memory Reclaiming
An incoming address (referred to as a logical address) is checked to see if it falls in
the memory re-map window. The bottom of the re-map window is defined by the
value in the RECLAIMBASE register. The top of the re-map window is defined by the
value in the RECLAIMLIMIT register. An address that falls within this window is
reclaimed to the physical memory starting at the address defined by the TOLUD
register. The TOLUD register must be 64M aligned when RECLAIM is enabled, but can
be 1M aligned when reclaim is disabled.
3.5
PCI Express* Configuration Address Space
There is a device 0 register, PCIEXBAR, that defines the base address for the
configuration space associated with all devices and functions that are potentially a
part of the PCI Express root complex hierarchy. The size of this range is
programmable for GMCH. BIOS must assign this address range such that it will not
conflict with any other address ranges.
See the configuration portion of this document for more details.
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Datasheet
INTEL [ INTEL ]
