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NTB_HW_INTEL(4)		 BSD Kernel Interfaces Manual	       NTB_HW_INTEL(4)

NAME
     ntb_hw_intel -- Intel(R) Non-Transparent Bridge driver

SYNOPSIS
     To	compile	this driver into your kernel, place the	following lines	in
     your kernel configuration file:

	   device ntb
	   device ntb_hw_intel

     Or, to load the driver as a module	at boot, place the following line in
     loader.conf(5):

	   ntb_hw_intel_load="YES"

DESCRIPTION
     The ntb_hw_intel driver provides support for the Non-Transparent Bridge
     (NTB) hardware in Intel Xeon E3/E5	and S1200 processor families, which
     allow one of their	PCIe ports to be switched from transparent to non-
     transparent bridge	mode.  In this mode bridge looks not as	a PCI bridge,
     but as PCI	endpoint device.  The driver hides hardware details, exposing
     memory windows, scratchpads and doorbells of the other side via hardware
     independent KPI to	ntb(4) subsystem.

     The hardware provides 2 or	3 memory windows to the	other system's memory,
     16	scratchpad registers and 14 or 34 doorbells to interrupt the other
     system.  On Xeon processors one of	memory windows is typically consumed
     by	the driver itself to workaround	multiple hardware erratas.

CONFIGURATION
     The NTB configuration should be set by BIOS.  It includes enabling	NTB,
     choosing between NTB-to-NTB (back-to-back)	or NTB-to-Root Port mode, en-
     abling split BAR mode (one	of two 64-bit BARs can be split	into two
     32-bit ones) and configuring BAR sizes in bits (from 12 to	29/39) for
     both NTB sides.

     The recommended configuration is NTB-to-NTB mode, split bar is enabled
     and all BAR sizes are set to 20 (1	MiB).  This needs to be	done on	both
     systems.

SEE ALSO
     if_ntb(4),	ntb_transport(4), ntb(4),

AUTHORS
     The ntb_hw_intel driver was developed by Intel and	originally written by
     Carl Delsey <carl@FreeBSD.org>.  Later improvements were done by Conrad
     E.	Meyer <cem@FreeBSD.org>	and Alexander Motin <mav@FreeBSD.org>.

BUGS
     NTB-to-Root Port mode is not yet supported, but it	doesn't	look very use-
     ful.

     On	Xeon v2/v3/v4 processors split BAR mode	should be enabled to allow
     SB01BASE_LOCKUP errata workaround to be applied by	the driver.

     There is no way to	protect	your system from malicious behavior on the
     other system once the link	is brought up.	Anyone with root or kernel ac-
     cess on the other system can read or write	to any location	on your	sys-
     tem.  In other words, only	connect	two systems that completely trust each
     other.

BSD				August 30, 2017				   BSD

NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION | SEE ALSO | AUTHORS | BUGS

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