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 F3C071BE0 for ; Tue, 4 Sep 2018 12:06:37 +0200 (CEST) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Sep 2018 03:06:36 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,329,1531810800"; d="scan'208";a="71444249" Received: from bricha3-mobl.ger.corp.intel.com ([10.237.221.107]) by orsmga006.jf.intel.com with SMTP; 04 Sep 2018 03:06:27 -0700 Received: by (sSMTP sendmail emulation); Tue, 04 Sep 2018 11:06:27 +0100 Date: Tue, 4 Sep 2018 11:06:26 +0100 From: Bruce Richardson To: "tone.zhang" Cc: dev@dpdk.org, nd@arm.com Message-ID: <20180904100626.GA19424@bricha3-MOBL.ger.corp.intel.com> References: <1536051547-8797-1-git-send-email-tone.zhang@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1536051547-8797-1-git-send-email-tone.zhang@arm.com> Organization: Intel Research and Development Ireland Ltd. User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [dpdk-dev] [PATCH] doc: Clarify IOMMU usage with "uio-pci" 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: Tue, 04 Sep 2018 10:06:38 -0000 On Tue, Sep 04, 2018 at 04:59:07PM +0800, tone.zhang wrote: > 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 > --- > 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. > + I think passthrough mode should work on x86 too. I remember running with iommu=pt setting in the kernel in the past. /Bruce