From mboxrd@z Thu Jan  1 00:00:00 1970
From: Luca Boccassi <bluca@debian.org>
Subject: Re: [PATCH v3] doc: Clarify IOMMU usage with
 "uio_pci_generic" kernel module
Date: Wed, 19 Sep 2018 11:42:14 +0100
Message-ID: <1537353734.10481.21.camel@debian.org>
References: <1536122382-26525-1-git-send-email-tone.zhang@arm.com>
 <1536124655-27163-1-git-send-email-tone.zhang@arm.com>
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Cc: gavin.hu@arm.com, bruce.richardson@intel.com, roszenrami@gmail.com,
 nd@arm.com
To: "tone.zhang" <tone.zhang@arm.com>, dev@dpdk.org
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On Wed, 2018-09-05 at 13:17 +0800, tone.zhang wrote:
> 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.
>=20
> The patch clarifies the IOMMU configurations on both x86_64 and arm64
> systems.
>=20
> Signed-off-by: tone.zhang <tone.zhang@arm.com>
> ---
> =C2=A0doc/guides/linux_gsg/linux_drivers.rst | 7 +++++++
> =C2=A01 file changed, 7 insertions(+)
>=20
> 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:
> =C2=A0=C2=A0=C2=A0=C2=A0``vfio-pci`` kernel module rather than ``igb_uio`=
` or
> ``uio_pci_generic``.
> =C2=A0=C2=A0=C2=A0=C2=A0For more details see :ref:`linux_gsg_binding_kern=
el` below.
> =C2=A0
> +.. note::
> +
> +=C2=A0=C2=A0=C2=A0If the devices used for DPDK are bound to the ``uio_pc=
i_generic``
> kernel module,
> +=C2=A0=C2=A0=C2=A0please make sure that the IOMMU is disabled. One can a=
dd
> ``intel_iommu=3Doff`` or
> +=C2=A0=C2=A0=C2=A0``intel_iommu=3Dpt`` or ``amd_iommu=3Doff`` in GRUB co=
mmand line on
> x86_64 systems,
> +=C2=A0=C2=A0=C2=A0or add ``iommu.passthrough=3D1`` on arm64 system.
> +
> =C2=A0Since DPDK release 1.7 onward provides VFIO support, use of UIO is
> optional
> =C2=A0for platforms that support using VFIO.
> =C2=A0

Acked-by: Luca Boccassi <bluca@debian.org>

--=20
Kind regards,
Luca Boccassi