From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id 032511041 for ; Wed, 19 Sep 2018 13:34:35 +0200 (CEST) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Sep 2018 04:34:34 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,393,1531810800"; d="scan'208";a="71223973" Received: from bricha3-mobl.ger.corp.intel.com ([10.237.221.107]) by fmsmga007.fm.intel.com with SMTP; 19 Sep 2018 04:33:44 -0700 Received: by (sSMTP sendmail emulation); Wed, 19 Sep 2018 12:33:43 +0100 Date: Wed, 19 Sep 2018 12:33:43 +0100 From: Bruce Richardson To: "Tone Zhang (Arm Technology China)" Cc: "dev@dpdk.org" , "Gavin Hu (Arm Technology China)" , "bluca@debian.org" , "roszenrami@gmail.com" , Stephen Hemminger , nd Message-ID: <20180919113342.GA16956@bricha3-MOBL.ger.corp.intel.com> References: <1536122382-26525-1-git-send-email-tone.zhang@arm.com> <1536124655-27163-1-git-send-email-tone.zhang@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Research and Development Ireland Ltd. User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [dpdk-dev] [PATCH v3] doc: Clarify IOMMU usage with "uio_pci_generic" kernel module X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Sep 2018 11:34:36 -0000 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 On Behalf Of tone.zhang > Sent: Wednesday, September 5, 2018 1:18 PM > To: dev@dpdk.org > Cc: Gavin Hu (Arm Technology China) ; bruce.richardson@intel.com; bluca@debian.org; roszenrami@gmail.com; nd > 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 > --- > 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