From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f44.google.com (mail-wm0-f44.google.com [74.125.82.44]) by dpdk.org (Postfix) with ESMTP id EA27B8D3A for ; Thu, 17 Dec 2015 11:10:39 +0100 (CET) Received: by mail-wm0-f44.google.com with SMTP id p187so15933340wmp.0 for ; Thu, 17 Dec 2015 02:10:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:organization:user-agent :in-reply-to:references:mime-version:content-transfer-encoding :content-type; bh=LGmGiDlRtmAYTeElfmHQU/JbGDuR2X66SfZ7XS9rrqQ=; b=ZcvkNs3x2qoeS3iOYXuuwdPUzPcAhM3Lbgp9vk76mdZ/MR2LBjXeHZAZB+caoVlD7t xz6LKpqtNU6vhVlTf0QU1r2MsvadhiR6+wUYKCcl3gaSwUqLUM8tKAue0vNa8lgHEoJL r0W/WfMg0J8rbDAvxGr6QwhNdRmecmltLUTgEZa+6XqMLicgtQNv5UWRnE0CjbduB0w5 uO0LRe0imgVessDFUfPOla8kFG8sEIqdCA0MW9N6IMRBNc85yDF3QwfiogJ0ezY3vErJ PPpijdfNkK/gpwMNpPBE/IMlX2GFQb/Imh2nnRd/AoLV3BDrNAjWpty7nWPjqX4bnzhV f+Jw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:organization :user-agent:in-reply-to:references:mime-version :content-transfer-encoding:content-type; bh=LGmGiDlRtmAYTeElfmHQU/JbGDuR2X66SfZ7XS9rrqQ=; b=cJB8y7ZWwHt75DO9/M7I/cgQYkh1lacystRUysKl7sE/s5HCz8ydXd+nF1CHSTGdk6 5pWc8TQ3aJeNpBkDo3UeA9eyeH7uOSl23O3XOlWykBKxWatRW850X/S5VLQE6Tvp2ONO 189fJAJm9tCKA8gp8bb7sUvTy94UhGAQsimguX9JkjQeV0sk3BiZqSj1NNnLNVHMDJ/g PU5T7sQEd9Hs+A4OT8w4b2nRfn8KI2BK0SR67QxTefbyQCZpko96BB2rG38traku66L2 OBw1yExIQXYpvPraOdv34yjT+RvVL7XFwH46MRmQCTtB7LdkLAJI7LKUEdt3tmtXD3VM HVaA== X-Gm-Message-State: ALoCoQnkAUB4DPfm0f0FpaFOdZGLeeovHB/v985JOdQA20K3cAsb4GVjfv3gzCE6MR8aYNgBF5B6YJREyrM/ucRbzkuueY2LQA== X-Received: by 10.194.11.66 with SMTP id o2mr30337492wjb.103.1450347039787; Thu, 17 Dec 2015 02:10:39 -0800 (PST) Received: from xps13.localnet (guy78-3-82-239-227-177.fbx.proxad.net. [82.239.227.177]) by smtp.gmail.com with ESMTPSA id n129sm1625733wmb.1.2015.12.17.02.10.38 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 17 Dec 2015 02:10:39 -0800 (PST) From: Thomas Monjalon To: "Burakov, Anatoly" Date: Thu, 17 Dec 2015 11:09:23 +0100 Message-ID: <2580440.9rYeIQLTBH@xps13> Organization: 6WIND User-Agent: KMail/4.14.10 (Linux/4.1.6-1-ARCH; KDE/4.14.11; x86_64; ; ) In-Reply-To: References: <60420822.AbcfvjLZCk@xps13> <17700135.Qc9aIsHGGP@xps13> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Cc: dev@dpdk.org Subject: Re: [dpdk-dev] VFIO no-iommu 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: Thu, 17 Dec 2015 10:10:40 -0000 Hi, 2015-12-17 09:52, Burakov, Anatoly: > > > > > On Tue, Dec 15, 2015 at 09:53:18AM -0700, Alex Williamson wrote: > > > > > So it works. Is it acceptable? Useful? Sufficiently complete? > > > > > Does it imply deprecating the uio interface? I believe the > > > > > feature that started this discussion was support for MSI/X > > > > > interrupts so that VFs can support some kind of interrupt (uio > > > > > only supports INTx since it doesn't allow DMA). Implementing that > > > > > would be the ultimate test of whether this provides dpdk with not > > > > > only a more consistent interface, but the feature dpdk wants > > > > > that's missing in uio. Thanks, > > > > > > Ferruh has done a great job so far testing Alex's patch, very few changes > > from DPDK side seem to be required as far as existing functionality goes (not > > sure about VF interrupts mentioned by Alex). However, one thing that > > concerns me is usability. While it is true that no-IOMMU mode in VFIO would > > mean uio interfaces could be deprecated in time, the no-iommu mode is way > > more hassle than using igb_uio/uio_pci_generic because it will require a > > kernel recompile as opposed to simply compiling and insmod'ding an out-of- > > tree driver. So, in essence, if you don't want an IOMMU, it's becoming that > > much harder to use DPDK. Would that be something DPDK is willing to live > > with in the absence of uio interfaces? > > > > Excuse me if I missed something obvious. > > Why a kernel compilation is needed? > > Well, not really full kernel compilation, but in the default configuration, VFIO driver would not support NOIOMMU mode. I.e. it's not compiled by default. Support for no-iommu should be enabled in kernel config and compiled in. So, whoever is going to use DPDK with VFIO-no-iommu will have to download kernel tree and recompile the VFIO module and install it. That's obviously way more hassle than simply compiling an out-of-tree driver that's already included and works with an out-of-the-box kernel. The "out-of-the-box kernel" is configured by your distribution. So we don't know yet what will be their choice. If the distribution supports DPDK, it should be enabled.