Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754234AbaLDNQv (ORCPT ); Thu, 4 Dec 2014 08:16:51 -0500 Received: from vserver.eikelenboom.it ([84.200.39.61]:38685 "EHLO smtp.eikelenboom.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751322AbaLDNQt (ORCPT ); Thu, 4 Dec 2014 08:16:49 -0500 X-Greylist: delayed 350 seconds by postgrey-1.27 at vger.kernel.org; Thu, 04 Dec 2014 08:16:49 EST Date: Thu, 4 Dec 2014 14:10:54 +0100 From: Sander Eikelenboom Organization: Eikelenboom IT services X-Priority: 3 (Normal) Message-ID: <1107877503.20141204141054@eikelenboom.it> To: David Vrabel CC: Konrad Rzeszutek Wilk , bhelgaas@google.com, , Boris Ostrovsky , , Subject: Re: [Xen-devel] [PATCH v5 9/9] xen/pciback: Implement PCI reset slot or bus with 'do_flr' SysFS attribute In-Reply-To: <5480528F.8010106@citrix.com> References: <201412041206.sB4C6XVQ009497@userz7022.oracle.com> <5480528F.8010106@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thursday, December 4, 2014, 1:24:47 PM, you wrote: > On 04/12/14 12:06, Konrad Rzeszutek Wilk wrote: >> >> On Dec 4, 2014 6:30 AM, David Vrabel wrote: >>> >>> On 03/12/14 21:40, Konrad Rzeszutek Wilk wrote: >>>> >>>> Instead of doing all this complex dance, we depend on the toolstack >>>> doing the right thing. As such implement the 'do_flr' SysFS attribute >>>> which 'xl' uses when a device is detached or attached from/to a guest. >>>> It bypasses the need to worry about the PCI lock. >>> >>> No. Get pciback to add its own "reset" sysfs file (as I have repeatedly >>> proposed). >>> >> >> Which does not work as the kobj will complain (as there is already an 'reset' associated with the PCI device). > It is only needed if the core won't provide one. > +static int pcistub_try_create_reset_file(struct pci_dev *pci) > +{ > + struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(pci); > + struct device *dev = &pci->dev; > + int ret; > + > + /* Already have a per-function reset? */ > + if (pci_probe_reset_function(pci) == 0) > + return 0; > + > + ret = device_create_file(dev, &dev_attr_reset); > + if (ret < 0) > + return ret; + dev_data->>created_reset_file = true; > + return 0; > +} Wouldn't the "core-reset-sysfs-file" be still wired to the end up calling "pci.c:__pci_dev_reset" ? The problem with that function is that from my testing it seems that the first option "pci_dev_specific_reset" always seems to return succes, so all the other options are skipped (flr, pm, slot, bus). However the device it self is not properly reset enough (perhaps the pci_dev_specific_reset is good enough for none virtualization purposes and it's probably the least intrusive. For virtualization however it would be nice to be sure it resets properly, or have a way to force a specific reset routine.) So it's the ordering and skipping of the other resets that seems to make this workaround necessary in the first place. > David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/