On Wed, Sep 19, 2018 at 07:44:36AM +0000, Tone Zhang (Arm Technology China) wrote: > Hello Bruce, Luca, Rami and Stephen, > > Could you please help to review the change? > > Any comments are welcome. > > Thanks a lot! > > Br, > Tone > > -----Original Message----- > From: dev <dev-boun...@dpdk.org> On Behalf Of tone.zhang > Sent: Wednesday, September 5, 2018 1:18 PM > To: dev@dpdk.org > Cc: Gavin Hu (Arm Technology China) <gavin...@arm.com>; > bruce.richard...@intel.com; bl...@debian.org; roszenr...@gmail.com; nd > <n...@arm.com> > Subject: [dpdk-dev] [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.zh...@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. > +
I'm not really an expert in these IOMMU commands, but for the passthrough option on my systems, I've always used "intel_iommu=on iommu=pt", rather than "intel_iommu=pt". Can someone confirm that the latter works ok, as documented here? /Bruce
