From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f173.google.com (mail-ua0-f173.google.com [209.85.217.173]) by dpdk.org (Postfix) with ESMTP id 3902C3B5 for ; Fri, 10 Feb 2017 11:08:16 +0100 (CET) Received: by mail-ua0-f173.google.com with SMTP id i68so24398763uad.0 for ; Fri, 10 Feb 2017 02:08:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netronome-com.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=Un0vXymWzreGD9r2Wyt8XgL4MZL4LVJca6bJ6HTvr5s=; b=KfeHuiAFdoDydZwQu91TABYiKKyShQtg1ATpMTSLcH/2l82/cY2XqaIqwnOvBXRiQU /QZW/yXOP0P9AFzzEzq/3VMOQ09Jz7Kego5k+KTkaDPRHJDna6yymOkq6x/bzeNwtS8j xssQ08gn/+kh9qOLJVBTIKDxtKzuSIEaPnPkjiFKpGD9WPhR4njcr9gFsbK2uieBh3Nb 2KpuO4rT5Txe3sspOpRbmqOoWZ+8b4/s4YOG6mNrDB7eC7+geQ1KYgNgRsB9Y4q/7gq9 U4wtPXMouxP6F45DQaHC/8tpCXu/DNHE8jFkHskdRXJ/6HIpw4qbgTky7n/wG1JkzPAe jQgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=Un0vXymWzreGD9r2Wyt8XgL4MZL4LVJca6bJ6HTvr5s=; b=SSwz4DnAsIfU3xmll/QT5zO9cZ4kfSZNwlzeBWSrjCOg+yrYRGDPo/sff2T3ZQ/b9o NWfOiBR9oyCvKfCkJhoe5rnTYv4bmvlkJ8UEiNIXtE0VNf6lnwKZV+UYwM1oNrbl2yVV Tv4UggUktC6nud7wwz8AtGgZ8yg/sQh+gd8B5JY23kxs9SKdTtXuCSYcyhqW/VdUoCvI zBzEdLxFgGO0ZABaKoMBLlaMz8+uXbABZ2exLQNwV4DzMpIdl6h4PJEJ/EtSeVC5mAJO B1m66b2VAwhJi3HT/VYBp1WlNLwPT/ZoFlpMsUS1taKhDFeJu1Py8Rlh0YQ0LP2RIpnX G+kw== X-Gm-Message-State: AMke39nNczrCn3y59k+i6iAn2VGJJzolH+baF7ma+dqjaNgTInhGzgEj8IYSkxQvZjv3vRQ3w4JyJjUtOak0bHV2 X-Received: by 10.176.4.22 with SMTP id 22mr4196792uav.16.1486721295494; Fri, 10 Feb 2017 02:08:15 -0800 (PST) MIME-Version: 1.0 Received: by 10.103.146.141 with HTTP; Fri, 10 Feb 2017 02:08:14 -0800 (PST) In-Reply-To: References: <1eca3907-39e6-2b09-a8fc-fe894988cc79@redhat.com> <2ce1bbcd-f3f2-bf8f-7b86-f04072139c4b@redhat.com> From: Alejandro Lucero Date: Fri, 10 Feb 2017 10:08:14 +0000 Message-ID: To: Tetsuya Mukawa Cc: echaudron@redhat.com, Eelco Chaudron , dev Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: Re: [dpdk-dev] Hotplug support for VFIO 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: Fri, 10 Feb 2017 10:08:16 -0000 On Thu, Feb 9, 2017 at 3:16 AM, Tetsuya Mukawa wrote: > 2017-02-09 0:48 GMT+09:00 Alejandro Lucero >: > > I just wanted to clarify the hotplug VFIO is not the problem, as I can > see > > it, but the unplug. When attaching a device the current VFIO code will be > > used, but there is no code for doing the IOMMU unmapping when unplugging. > > > > On Wed, Feb 8, 2017 at 3:43 PM, Alejandro Lucero > > wrote: > >> > >> Hi Eelco, > >> > >> On Wed, Feb 8, 2017 at 9:41 AM, Eelco Chaudron > >> wrote: > >>> > >>> Hi Anatoly, > >>> > >>> This will be great... If you want I can do some testing on (early) > >>> patches if required. > >>> > >>> Also do you know why it is currently not supported, i.e. what are the > >>> limitations? > >>> > >>> Thanks, > >> > >> > >> I assume your reply was to my previous email and not to Anatoly's one. > My > >> apologies if this assumption is wrong. > >> By the way, you did not reply to the list, but I'm doing to do so > because > >> this could be interesting to other people. Also, I'm CCing hotplug UIO > >> developer, Tetsuya Mukawa, since there is no a specific maintainer for > this > >> functionality. > > Hi, > > Sorry for late reply. > Honestly, I am not so familiar with VFIO, so I may be wrong. > But please check my below comments. > > >> > >> I think the main problem for supporting VFIO hotplug is to deal with > what > >> VFIO does, this is IOMMU mappings. > >> There is no code for doing so, and although the implementation would use > >> most of the code already there for UIO hotplug, which is basically > related > >> to unmapping PCI resources, and the interrupt part will be likely quite > >> similar, the IOMMU unmapping requires more work. > >> > >> I dare to say this is the main reason for not having VFIO hotplug > support > >> right now. Maybe Tetsuya can confirm this or give us other reasons. > > Yes, this is the main reason. > When I implement hot plugging, I also needed to implement UIO detaching > code. > And at the time, I also tried to implement VFIO code as well, but I > gave up with below reasons. > - Patch will be bigger and more difficult to be merged in mainline code. > - I don't have enough time to check actually what kind of code is > needed to detach it. > > I'm quite familiar with the VFIO code so I know what it requires. At least the main part. You know there are details not so trivial to see initially until you start doing the work. > So above were not technical reasons. > > One thing I am not clear is whether we may need to do something > special for multi process case. > For example, if primary process is died suddenly, what kind of error > will be happen to slave process, and what is good way to handle it. > > I do no think this is a problem specific to the hotplug mechanism, but thanks for the heads up. I will start working on this. Hopefully it could be part of the 17.05 release. Thank you > Thanks, > Tetsuya > > >> > >>> > >>> > >>> Eelco > >>> > >>> > >>> > >>> On 07/02/17 10:29, Alejandro Lucero wrote: > >>> > >>> It seems none is working on this VFIO support. > >>> > >>> I will work on this if there is no reply to this thread saying the > >>> opposite the next days. > >>> > >>> On Thu, Feb 2, 2017 at 12:58 PM, Eelco Chaudron > >>> wrote: > >>>> > >>>> On 02/02/17 13:05, Burakov, Anatoly wrote: > >>>>> > >>>>> Hi Eelco, > >>>>> > >>>>> Please forgive me my ignorance on this matter, but doesn't it work at > >>>>> the moment? I would assume that if regular PCI hotplug works (with > igb_uio), > >>>>> then so would hotplug with VFIO, as it basically utilizes the same > PCI > >>>>> infrastructure igb_uio does. That said, I'm not aware of any patches > >>>>> submitted that had to do with VFIO and hotplug, so I guess the > answer is, > >>>>> not at the moment. > >>>>> > >>>>> Thanks, > >>>>> Anatoly > >>>> > >>>> I was asking as the documentation explicitly mentions its not > supported. > >>>> > >>>> http://dpdk.org/doc/guides/prog_guide/port_hotplug_ > framework.html#hotplug > >>>> > >>>> - "To detach a port, the port should be backed by a device that > igb_uio > >>>> manages. VFIO is not supported." > >>>> > >>>> I could not find any specific reason why it's not supported, so if > some > >>>> one can explain this it would help also... > >>>> > >>>> Cheers, > >>>> > >>>> Eelco > >>>> > >>>> > >>> > >>> > >> > > >