Datasheet

System Address Map
Intel
®
Xeon
®
Processor C5500/C3500 Series
Datasheet, Volume 1 February 2010
326 Order Number: 323103-001
6.1.6.4 HPET/Others
This region covers the High performance event timers in the PCH. All inbound/peer-to-
peer accesses to this region are completer aborted by the IIO.
Outbound non-locked Intel
®
QPI accesses (that is, accesses that happen when Intel
®
QPI quiescence is not established) to the FED4_0xxx region are converted by IIO
before forwarding to legacy DMI port. All outbound Intel
®
QPI accesses (that is,
accesses that happen after Intel
®
QPI quiescence has been established) to FED4_0xxx
range are aborted by non-IIO. Also IIO aborts all locked Intel
®
QPI accesses to the
FED4_0xxx range. Other outbound Intel
®
QPI accesses in the FEDx_xxxx range, but
outside of the FED4_0xxx range are forwarded to legacy DMI port by virtue of
subtractive decoding.
6.1.6.5 Local XAPIC
The local XAPIC space is used to deliver interrupts to the CPU(s). Message Signaled
Interrupts (MSI) from PCIe devices that target this address are forwarded as SpcInt
messages to the CPU. See Chapter 7.0, “Interrupts,” for details of interrupt routing by
IIO.
The processors may also use this region to send inter-processor interrupts (IPI) from
one processor to another. But, the IIO is never a recipient of such an interrupt. Inbound
reads to this address are considered errors and are completer aborted by IIO.
Outbound accesses to this address range should never occur, but IIO does not explicitly
check for this error condition but simply forwards the transaction subtractively to its
subtractive decode port, if one exists downstream.
6.1.6.6 Firmware
This ranges starts at FF00_0000 and ends at FFFF_FFFF. It is used for BIOS/Firmware.
Outbound accesses within this range are forwarded to the firmware hub devices. During
boot initialization, IIO with firmware connected south of it will communicate this on the
Intel
®
QPI ports so that CPU hardware can configure the path to firmware. The IIO
does not support accesses to this address range inbound that is, those inbound
transactions are aborted and a completer abort response is sent back.
Address Region From To
HPET/Others FED0_0000 FEDF_FFFF
Address Region From To
Local XAPIC FEE0_0000 FEEF_FFFF
Address Region From To
HIGHBIO FF00_0000 FFFF_FFFF