From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752261AbdK2T0k (ORCPT ); Wed, 29 Nov 2017 14:26:40 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:25382 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751660AbdK2T0j (ORCPT ); Wed, 29 Nov 2017 14:26:39 -0500 Date: Wed, 29 Nov 2017 14:26:30 -0500 From: Konrad Rzeszutek Wilk To: Jan Beulich Cc: xen-devel@lists.xenproject.org, Boris Ostrovsky , Govinda Tatti , Juergen Gross , linux-kernel@vger.kernel.org Subject: Re: [Xen-devel] [PATCH] Xen/pciback: Implement PCI slot or bus reset with 'do_flr' SysFS attribute Message-ID: <20171129192630.GS31092@char.us.oracle.com> References: <20171106174842.20276-1-Govinda.Tatti@Oracle.COM> <5A01D3F3020000780018CE86@prv-mh.provo.novell.com> <8940b38d-715c-9fcb-cc74-46574d416703@oracle.com> <5A041FB9020000780018D6E8@prv-mh.provo.novell.com> <5A1EE1D50200007800193318@prv-mh.provo.novell.com> <20171129162907.GO31092@char.us.oracle.com> <5A1EF1040200007800193425@prv-mh.provo.novell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5A1EF1040200007800193425@prv-mh.provo.novell.com> User-Agent: Mutt/1.8.3 (2017-05-23) X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 29, 2017 at 09:40:20AM -0700, Jan Beulich wrote: > >>> On 29.11.17 at 17:29, wrote: > > On Wed, Nov 29, 2017 at 08:35:33AM -0700, Jan Beulich wrote: > >> >>> On 29.11.17 at 16:08, wrote: > >> > On 11/9/2017 2:28 AM, Jan Beulich wrote: > >> >>>>> On 08.11.17 at 16:44, wrote: > >> >>> On 11/7/2017 8:40 AM, Jan Beulich wrote: > >> >>>>>>> On 06.11.17 at 18:48, wrote: > >> >>>>> --- a/Documentation/ABI/testing/sysfs-driver-pciback > >> >>>>> +++ b/Documentation/ABI/testing/sysfs-driver-pciback > >> >>>>> @@ -11,3 +11,15 @@ Description: > >> >>>>> #echo 00:19.0-E0:2:FF > > > /sys/bus/pci/drivers/pciback/quirks > >> >>>>> will allow the guest to read and write to the > > configuration > >> >>>>> register 0x0E. > >> >>>>> + > >> >>>>> +What: /sys/bus/pci/drivers/pciback/do_flr > >> >>>>> +Date: Nov 2017 > >> >>>>> +KernelVersion: 4.15 > >> >>>>> +Contact: xen-devel@lists.xenproject.org > >> >>>>> +Description: > >> >>>>> + An option to perform a slot or bus reset when a PCI device > >> >>>>> + is owned by Xen PCI backend. Writing a string of DDDD:BB:DD.F > >> >>>>> + will cause the pciback driver to perform a slot or bus reset > >> >>>>> + if the device supports it. It also checks to make sure that > >> >>>>> + all of the devices under the bridge are owned by Xen PCI > >> >>>>> + backend. > >> >>>> Why do you name this "do_flr" when you don't even try FLR, but > >> >>>> go to slot or then bus reset right away. > >> >>> Yes, I agree but xen toolstack has already been modified to > >> >>> consume"do_flr" attribute. Hence, we are using the > >> >>> function that matches with sysfs attribute. > >> >> That's not a valid reason imo: Right now the driver doesn't expose > >> >> such an attribute, so if the tool stack was trying to use it, it would > >> >> not do what is intended at present anyway (i.e. the code could at > >> >> best be called dead). > >> > Sure, we can consider renaming "do_flr" attribute to "pci reset" or "bus > >> > reset". > >> > Please let me knowyour preference. > >> > >> Well, that's more a question to Konrad as the maintainer. > >> Personally I'd prefer just "reset", as "pci" is redundant and "bus" > > > > Can't do 'reset'. > > Why? B/c I forgot that this attribute is not per device, but on the module sub-directory: /sys/bus/pci/drivers/pciback/do_flr It can be indeed called 'reset'. > > >> doesn't cover the slot variant. > > > > 'bus_reset' sounds lovely? > > Lovely sounding or not, it may end up misleading, and even more so > if - like asked for - FLR would be tried first. Fair enough. Reset should work then.