[dpdk-dev] [PATCH v3] doc: Clarify IOMMU usage with "uio_pci_generic" kernel module
Gavin Hu (Arm Technology China)
Gavin.Hu at arm.com
Wed Sep 5 07:23:20 CEST 2018
> -----Original Message-----
> From: tone.zhang <tone.zhang at arm.com>
> Sent: Wednesday, September 5, 2018 1:18 PM
> To: dev at dpdk.org
> Cc: Gavin Hu (Arm Technology China) <Gavin.Hu at arm.com>;
> bruce.richardson at intel.com; bluca at debian.org; roszenrami at gmail.com; nd
> <nd at arm.com>
> Subject: [PATCH v3] doc: Clarify IOMMU usage with "uio_pci_generic" kernel
> module
>
> 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 <tone.zhang at arm.com>
Acked-by: Gavin Hu <gavin.hu at arm.com>
> ---
> 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 371a817..b46fc6a 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. One can add
> ``intel_iommu=off`` or
> + ``intel_iommu=pt`` or ``amd_iommu=off`` 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.
>
> --
> 2.7.4
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