[v4] doc: Clarify IOMMU usage with "uio_pci_generic" kernel module
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Commit Message
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@arm.com>
---
doc/guides/linux_gsg/linux_drivers.rst | 7 +++++++
1 file changed, 7 insertions(+)
Comments
On Fri, Sep 21, 2018 at 11:07:42AM +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.
>
> The patch clarifies the IOMMU configurations on both x86_64 and arm64
> systems.
>
> Signed-off-by: tone.zhang <tone.zhang@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..3304800 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 disabledi or passthrough. One can add
typo ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
> + ``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.
>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Hello Bruce,
Thanks for the comments.
I will update the change and issue v5 soon.
Thanks!
Br,
Tone
-----Original Message-----
From: Bruce Richardson <bruce.richardson@intel.com>
Sent: Friday, September 21, 2018 7:20 PM
To: Tone Zhang (Arm Technology China) <Tone.Zhang@arm.com>
Cc: dev@dpdk.org; Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>; bluca@debian.org; roszenrami@gmail.com; Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>; nd <nd@arm.com>
Subject: Re: [PATCH v4] doc: Clarify IOMMU usage with "uio_pci_generic" kernel module
On Fri, Sep 21, 2018 at 11:07:42AM +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.
>
> The patch clarifies the IOMMU configurations on both x86_64 and arm64
> systems.
>
> Signed-off-by: tone.zhang <tone.zhang@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..3304800 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 disabledi or passthrough. One
> + can add
typo ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
> + ``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.
>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
@@ -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 disabledi 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.