From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F957C433F4 for ; Tue, 18 Sep 2018 07:15:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C0FB12083A for ; Tue, 18 Sep 2018 07:15:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C0FB12083A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=iki.fi Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729049AbeIRMqk (ORCPT ); Tue, 18 Sep 2018 08:46:40 -0400 Received: from emh04.mail.saunalahti.fi ([62.142.5.110]:50968 "EHLO emh04.mail.saunalahti.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727140AbeIRMqk (ORCPT ); Tue, 18 Sep 2018 08:46:40 -0400 Received: from ydin.reaktio.net (reaktio.net [85.76.255.15]) by emh04.mail.saunalahti.fi (Postfix) with ESMTP id 55B0330066; Tue, 18 Sep 2018 10:15:19 +0300 (EEST) Received: by ydin.reaktio.net (Postfix, from userid 1001) id 5405F36C0F8; Tue, 18 Sep 2018 10:15:19 +0300 (EEST) Date: Tue, 18 Sep 2018 10:15:19 +0300 From: Pasi =?iso-8859-1?Q?K=E4rkk=E4inen?= To: Boris Ostrovsky Cc: Jan Beulich , Juergen Gross , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, bhelgaas@google.com, xen-devel@lists.xenproject.org, roger.pau@citrix.com, Konrad Rzeszutek Wilk , George Dunlap Subject: Re: [Xen-devel] [PATCH V3 2/2] Xen/PCIback: Implement PCI flr/slot/bus reset with 'reset' SysFS attribute Message-ID: <20180918071519.GG18222@reaktio.net> References: <20171207222145.9769-1-Govinda.Tatti@Oracle.COM> <20171207222145.9769-3-Govinda.Tatti@Oracle.COM> <5A2A6AB10200007800195D4F@prv-mh.provo.novell.com> <8a3bc517-1255-4547-d244-5c400e44cc77@Oracle.COM> <5A377E020200007800197FFA@prv-mh.provo.novell.com> <559ffd12-b541-8a69-60bd-fbe10e3dc159@oracle.com> <20180916114306.GF18222@reaktio.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, Sep 17, 2018 at 02:06:02PM -0400, Boris Ostrovsky wrote: > On 9/16/18 7:43 AM, Pasi Kärkkäinen wrote: > > Hi, > > > > On Mon, Dec 18, 2017 at 12:32:11PM -0500, Boris Ostrovsky wrote: > >> On 12/18/2017 02:36 AM, Jan Beulich wrote: > >>>>>> On 15.12.17 at 20:52, wrote: > >>>>>>> +static int pcistub_device_reset(struct pci_dev *dev) > >>>>>>> +{ > >>>>>>> + struct xen_pcibk_dev_data *dev_data; > >>>>>>> + bool slot = false, bus = false; > >>>>>>> + struct pcistub_args arg = {}; > >>>>>>> + > >>>>>>> + if (!dev) > >>>>>>> + return -EINVAL; > >>>>>>> + > >>>>>>> + dev_dbg(&dev->dev, "[%s]\n", __func__); > >>>>>>> + > >>>>>>> + /* First check and try FLR */ > >>>>>>> + if (pcie_has_flr(dev)) { > >>>>>>> + dev_dbg(&dev->dev, "resetting %s device using FLR\n", > >>>>>>> + pci_name(dev)); > >>>>>>> + pcie_flr(dev); > >>>>>> The lack of error check here puzzled me, but I see the function > >>>>>> indeed returns void right now. I think the prereq patch should > >>>>>> change this along with exporting the function - you really don't > >>>>>> want the device to be handed to a guest when the FLR timed > >>>>>> out. > >>>>> We will change pcie_flr() to return error code. I will make this change > >>>>> in the next version of this patch. > >>>> I exchanged some emails with Bjorn/Christoph and it looks like Christoph > >>>> as some planto restructure pcie flr specific functions but I don't know > >>>> the exact time-frame. For now,I am planning to use existing pcie_flr() > >>>> after checking FLR capability. We will switchto revised pcie_flr() once > >>>> it is available. > >>>> > >>>> I hope you are fine with this approach. Please let me know. Thanks. > >>> I've seen that other discussion. I don't think the change here > >>> should be done prior to the error reporting being put in place, > >>> for security reasons. But in the end it'll be Konrad as the > >>> maintainer to judge. > >>> > >>> Or wait, looks like there's some confusion in ./MAINTAINERS: > >>> Konrad is listed as maintainer for "XEN PCI SUBSYSTEM", but the > >>> list of files doesn't include pciback. So it would instead be Boris > >>> or Jürgen to give you a final word. > >> > >> This is now 4.16 material so we can at least wait until closer to > >> opening of the merge window when we may have the PCI updates. (And I > >> just noticed that you responded to Christoph.) > >> > >> Besides, we don't want to make kernel changes until the interface is > >> settled (i.e the toolstack changes are accepted). > >> > > It seems Govinda's email address is giving an error, so I assume someone else needs to pick up this pciback 'reset' feature. > > Is it likely someone else from Oracle can/will pick up and refresh this patch, with the review comments addressed? > > > Govinda is no longer at Oracle. > Yep, thought so. Removed from CC list. > What about the toolstack changes? Have they been accepted? I vaguely > recall there was a discussion about those changes but don't remember how > it ended. > I don't think toolstack/libxl patch has been applied yet either. "[PATCH V1 0/1] Xen/Tools: PCI reset using 'reset' SysFS attribute": https://lists.xen.org/archives/html/xen-devel/2017-12/msg00664.html "[PATCH V1 1/1] Xen/libxl: Perform PCI reset using 'reset' SysFS attribute": https://lists.xen.org/archives/html/xen-devel/2017-12/msg00663.html George asked for some clarifications: https://lists.xen.org/archives/html/xen-devel/2017-12/msg01044.html https://lists.xen.org/archives/html/xen-devel/2017-12/msg01116.html > > -boris > Thanks, -- Pasi > > > > > > > Meanwhile the pcie_has_flr() has been exported in upstream Linux kernel, so that's already available for use now. > > > > "PCI: Export pcie_has_flr()": > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2d2917f7747805a1f4188672f308d82a8ba01700 > > > > > > >