[dpdk-dev] [PATCH] doc: Clarify IOMMU usage with "uio-pci" kernel module

[tone.zhang]

When binding the devices used by DPDK to the "uio-pci" 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 configuration on both x86_64 and arm64
systems.

Signed-off-by: tone.zhang <tone.zhang 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..8f9ec8f 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 for used DPDK bound to the ``uio-pci`` kernel module, please make
+   sure that the IOMMU is disabled. We can add ``intel_iommu=off`` or ``amd_iommu=off``
+   in ``GRUB_CMDLINE_LINUX`` in grub 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