From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wes1-so2.wedos.net (wes1-so2.wedos.net [46.28.106.16]) by dpdk.org (Postfix) with ESMTP id 1CA0A8E7A for ; Sat, 12 Dec 2015 00:20:58 +0100 (CET) Received: from jvn (dynamic-109-81-211-44.ipv4.broadband.iol.cz [109.81.211.44]) by wes1-so2.wedos.net (Postfix) with ESMTPSA id 3pHSls4f9DzrH; Sat, 12 Dec 2015 00:20:57 +0100 (CET) Date: Sat, 12 Dec 2015 00:20:51 +0100 From: Jan Viktorin To: Thomas Monjalon Message-ID: <20151212002051.68708a38@jvn> In-Reply-To: <60420822.AbcfvjLZCk@xps13> References: <60420822.AbcfvjLZCk@xps13> Organization: RehiveTech X-Mailer: Claws Mail 3.13.0 (GTK+ 2.24.28; x86_64-unknown-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: dev@dpdk.org, Alex Williamson 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: Fri, 11 Dec 2015 23:20:58 -0000 Hello, I am not involved in the vfio very much, however, I was watching some vfio-related code in last few weeks. It looks promising to me and IMHO it seems to the best way to bring a support of integrated Ethernet MACs into DPDK (related to many SoCs). Unfortunately, the ARMv7 SoCs (I know) lacks of an IOMMU... The only protection there is the TrustZone technology but I have no idea of its support in the kernel. It's also far from being a replacement of an IOMMU. When using FPGAs, it is possible to put an IOMMU engine there (I've got such a prototype somewhere in my VHDL library) but nobody will probably do use because of saving on-chip resources. The X-Gene SoC (ARM 64) contains 2x 10 Gbps EMACs on the chip. I have no idea about IOMMUs there. Thus, this platform can probably benefit of such driver as well. The question is whether there is some interest to have this kind of support in DPDK. Thus, I'd like to have the vfio/no-iommu to support the ARMv7 (otherwise it would be effectively dead in DPDK). Unfortunately, it's not my primary job at the moment. Regards Jan Note: as far as I know, it is discouraged to refer to lkml.org as it is often very slow - my case today :). On Fri, 11 Dec 2015 17:28:43 +0100 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