From 2eb7c526b9291d6c2ce8f00d58c010c8932ee19d Mon Sep 17 00:00:00 2001 From: Tone Zhang Date: Wed, 26 Sep 2018 13:08:47 +0800 Subject: [PATCH] doc: clarify IOMMU disabling for uio_pci_generic If the devices used for DPDK are bound to the "uio_pci_generic" kernel module, the IOMMU should be disabled in order not to break the IO transmission because of the virtual / physical address mapping. The patch clarifies the IOMMU configurations on both x86_64 and arm64 systems. Signed-off-by: Tone Zhang Reviewed-by: Honnappa Nagarahalli Reviewed-by: Stephen Hemminger Reviewed-by: Rami Rosen Acked-by: Gavin Hu Acked-by: Bruce Richardson Acked-by: Luca Boccassi --- doc/guides/linux_gsg/linux_drivers.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/doc/guides/linux_gsg/linux_drivers.rst b/doc/guides/linux_gsg/linux_drivers.rst index 371a817ff9..8da6a31bed 100644 --- a/doc/guides/linux_gsg/linux_drivers.rst +++ b/doc/guides/linux_gsg/linux_drivers.rst @@ -48,6 +48,13 @@ be loaded as shown below: ``vfio-pci`` kernel module rather than ``igb_uio`` or ``uio_pci_generic``. For more details see :ref:`linux_gsg_binding_kernel` below. +.. note:: + + If the devices used for DPDK are bound to the ``uio_pci_generic`` kernel module, + please make sure that the IOMMU is disabled or passthrough. One can add + ``intel_iommu=off`` or ``amd_iommu=off`` or ``intel_iommu=on iommu=pt``in GRUB + command line on x86_64 systems, or add ``iommu.passthrough=1`` on arm64 system. + Since DPDK release 1.7 onward provides VFIO support, use of UIO is optional for platforms that support using VFIO. -- 2.20.1