diff mbox series

[v2] doc: Clarify IOMMU usage with "uio_pci_generic" kernel module

Message ID 1536122382-26525-1-git-send-email-tone.zhang@arm.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers
Series [v2] doc: Clarify IOMMU usage with "uio_pci_generic" kernel module |

Checks

Context Check Description
ci/checkpatch warning coding style issues
ci/Intel-compilation success Compilation OK

Commit Message

tone.zhang Sept. 5, 2018, 4:39 a.m. UTC 
  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 mbox series

Patch

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.