From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vincent JARDIN Subject: Re: VFIO no-iommu Date: Fri, 11 Dec 2015 23:12:32 +0100 Message-ID: <566B4A50.9090607@6wind.com> References: <60420822.AbcfvjLZCk@xps13> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit To: dev@dpdk.org, Alex Williamson Return-path: Received: from mail-wm0-f45.google.com (mail-wm0-f45.google.com [74.125.82.45]) by dpdk.org (Postfix) with ESMTP id 480008E7B for ; Fri, 11 Dec 2015 23:12:34 +0100 (CET) Received: by mail-wm0-f45.google.com with SMTP id c201so91090777wme.0 for ; Fri, 11 Dec 2015 14:12:34 -0800 (PST) In-Reply-To: <60420822.AbcfvjLZCk@xps13> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Thanks Thomas for putting back this topic. Alex, I'd like to hear more about the impacts of "unsupported": https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=033291eccbdb1b70ffc02641edae19ac825dc75d Use of this mode, specifically binding a device without a native IOMMU group to a VFIO bus driver will taint the kernel and should therefore not be considered supported. It means that we get ride of uio; so it is a nice code cleanup: but why would VFIO/NO IOMMU be better if the bottomline is "unsupported"? Thank you, Vincent On 11/12/2015 17:28, Thomas Monjalon wrote: > Recently there were some discussions to have an upstream replacement > for our igb_uio module. > Several solutions were discussed (new uio driver, uio_pci_generic, vfio): > https://lkml.org/lkml/2015/10/16/700 > > Alex Williamson (maintainer of VFIO driver), submitted a solution > and was waiting some feedback. Unfortunately, nobody caught it and > he has reverted his work: > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ae5515d > > It is an important challenge to remove our out-of-tree modules and > especially igb_uio. It is a long way to have a standard solution integrated > in every distributions. > The current cooking Linux kernel is 4.4 and will have a long term maintenance: > https://kernel.org/releases.html > So it is a pity to miss this opportunity. > > Stephen has fixed a bug to use the IOMMU group zero: > http://dpdk.org/browse/dpdk/commit/?id=22215f141b1 > > Is there someone interested to work on VFIO no-iommu and provide > some feedbacks? > We also need to prepare a documentation patch to explain its usage > compared to the standard VFIO mode. > > Thanks >