From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id A4961677E for ; Wed, 11 May 2016 19:24:41 +0200 (CEST) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP; 11 May 2016 10:24:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,608,1455004800"; d="scan'208";a="700587084" Received: from fyigit-mobl1.ger.corp.intel.com (HELO [10.237.220.154]) ([10.237.220.154]) by FMSMGA003.fm.intel.com with ESMTP; 11 May 2016 10:24:39 -0700 To: Alejandro Lucero , Stephen Hemminger References: <1462879301-13570-1-git-send-email-zhe.tao@intel.com> <20160510085915.529b4af5@xeon-e3> Cc: Zhe Tao , dev From: Ferruh Yigit Message-ID: <57336AD6.1050809@intel.com> Date: Wed, 11 May 2016 18:24:38 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [dpdk-dev] [PATCH v1] igu_uio: fix IOMMU domain issue X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 11 May 2016 17:24:42 -0000 On 5/11/2016 8:35 AM, Alejandro Lucero wrote: > On Tue, May 10, 2016 at 4:59 PM, Stephen Hemminger < > stephen@networkplumber.org> wrote: > >> On Tue, 10 May 2016 19:21:41 +0800 >> Zhe Tao wrote: >> >>> Problem: >>> The following operations will cause the igb_uio based DPDK >>> operation failed. >>> --Any device assignment through the kvm_assign_device interface, >>> this can be the pci-assign method in QEMU >>> --VFIO group attachment operation(attach to the container) >>> this can happens in vfio-pci assignment in QEMU >> >> >> If you have an IOMMU why not use VFIO instead, it is better. >> > > It is not about VFIO against UIO but about how iommu domains are created > and destroyed by the (old) kernel when iommu=pt. So even with VFIO you can > have problems. Problem is in IOMMU driver but we are adding a workaround to igb_uio, if using VFIO solves the issue, I believe that is better workaround. 1) Is there any case IOMMU supported but VFIO is not supported? Is there anything forces to use igb_uio? 2) Does using VFIO solves the issue defined in problem statement? > > We have had problems like this and other due to our device (NFP) just > mapping up to 40 bits of address space. Old kernels used in LTS > distributions like Ubuntu are iommu buggy and you need to do things like > this mapping inside the driver for solving problems. By the way, using > SRIOV just adds more problems. It is not safe to use iommu=pt with 3.13.x > Ubuntu kernels. > > It would be a good thing for the original patch to identify those kernels > where the problem was detected. Of course, there could be more kernels with > the same problem but that is more work to do. > Thanks, ferruh