Use of IB Drivers Co-resident with OPA¶

The Omni-Path hardware and drivers should operate correctly when co-resident with InfiniBand HCAs and their associated drivers. However, on Jessie (Debian 8.x), kmod-ifs-kernel-updates installs a version of ib_mad that includes jumbo MAD support. This version of ib_mad is required for OPA, and is incompatible with the InfiniBand drivers that are in-box with Jessie.

The behavior that will be experienced when loading an in-box InfiniBand driver co-resident with OPA is a report of "invalid parameters". Syslog will contain reports of "disagrees about version of symbol ib_unregister_mad_agent", etc. This is due to the fact that the updated ib_mad module has a different version of its ABI than what is expected by the in-box drivers.

In order to use the in-box InfiniBand drivers with the jumbo-mad enabled ib_mad module, they must be recompiled against the updated headers. This process is outlined below. The build system must have build-essentials installed. The build should be executed as a non-root user.

This process assumes that the mlx4 driver is to be included with kmod-ifs-kernel-updates. It should apply to other InfiniBand drivers.

# mkdir ifsbuild
# cd ifsbuild
# dget http://security.debian.org/debian-security/pool/updates/main/l/linux/linux_3.16.43-2+deb8u3.dsc
# cp ../IntelOPA-IFS.DEBIAN8-x86_64.10.4.2.0.7-2/packages/ifs-kernel-updates*{orig,debian}* .
# tar xf ifs-kernel-updates_3.16.0-616.orig.tar.gz
# cd ifs-kernel-updates-3.10.0_327.el7.x86_64
# QUILT_PATCHES=“debian/patches" quilt push -a
# cp -r ../linux-3.16.43/drivers/infiniband/hw/mlx4/ .
# cd mlx4
# mv Makefile Makefile.org

mlx4/Makefile must now be created. The source below will work for the current version of the driver (Jessie 8.9). You may examine Makefile.org to determine the correct statements for obj-$(CONFIG_MLX4_INFINIBAND) and mlx4_ib-y.

#
# mlx4 module
#
#
# Called from the kernel module build system.
#
ifneq ($(KERNELRELEASE),)
#kbuild part of makefile

ccflags-y := -I$(src)/../include

obj-$(CONFIG_MLX4_INFINIBAND)   += mlx4_ib.o

mlx4_ib-y :=    ah.o cq.o doorbell.o mad.o main.o mr.o qp.o srq.o mcg.o cm.o alias_GUID.o sysfs.o

else
#normal makefile
KDIR ?= /lib/modules/`uname -r`/build

default:
    $(MAKE) -C $(KDIR) M=$$PWD NOSTDINC_FLAGS=-I$$PWD

clean:
    $(MAKE) -C $(KDIR) M=$$PWD clean

install:
    $(MAKE) INSTALL_MOD_DIR=updates -C $(KDIR) M=$$PWD modules_install

endif

Now, the top-level Makefile should be edited to include mlx4 in the build. Add mlx4/ to the end of the obj-y directive. The trailing slash is necessary.

obj-y := rdmavt/ ib_uverbs/ hfi1/ ib_mad/ opa_compat/ \
        ib_umad/ ib_sa/ ib_cm/ ib_ucm/ rdma_cm/ rdma_ucm/ ib_srpt/ ib_ipoib/ mlx4/

Now, build the package via the command:

# debuild -us -uc -b

The build should complete without errors, although lintian may complain about a few things. The package may now be installed with:

# sudo dpkg -i ../kmod-ifs-kernel-updates_3.16.0-616-1ifs_amd64.deb
# depmod -a

The system should now have a recompiled driver installed to /lib/modules/3.16.0-4-amd64/updates/ifs-kernel-updates/mlx4/mlx4_ib.ko and modprobe mlx4_ib should execute without errors. ibstat should include information for the mlx4_0 device.

The system will also need the libmlx4 package installed in order to provide user-space ibverbs access. User-space packages should not require recompilation.