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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 C8F16C4321A for ; Fri, 28 Jun 2019 09:07:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6FFA205ED for ; Fri, 28 Jun 2019 09:07:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726542AbfF1JG7 (ORCPT ); Fri, 28 Jun 2019 05:06:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42372 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726431AbfF1JG7 (ORCPT ); Fri, 28 Jun 2019 05:06:59 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5806D308339F; Fri, 28 Jun 2019 09:06:59 +0000 (UTC) Received: from gondolin (dhcp-192-222.str.redhat.com [10.33.192.222]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0319760600; Fri, 28 Jun 2019 09:06:50 +0000 (UTC) Date: Fri, 28 Jun 2019 11:06:48 +0200 From: Cornelia Huck To: Alex Williamson Cc: Matthew Rosato , "kvm@vger.kernel.org" , Libvirt Devel , Kirti Wankhede , Erik Skultety , Pavel Hrdina , "Daniel P. =?UTF-8?B?QmVycmFuZ8Op?=" , Sylvain Bauza , Christophe de Dinechin , Tony Krowiak Subject: Re: mdevctl: A shoestring mediated device management and persistence utility Message-ID: <20190628110648.40e0607d.cohuck@redhat.com> In-Reply-To: <20190627195704.66be88c8@x1.home> References: <20190523172001.41f386d8@x1.home> <20190625165251.609f6266@x1.home> <20190626115806.3435c45c.cohuck@redhat.com> <20190626083720.42a2b5d4@x1.home> <20190626195350.2e9c81d3@x1.home> <20190627142626.415138da.cohuck@redhat.com> <06114b39-69c2-3fa0-d0b3-aa96a44ae2ce@linux.ibm.com> <20190627093832.064a346f@x1.home> <20190627151502.2ae5314f@x1.home> <20190627195704.66be88c8@x1.home> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Fri, 28 Jun 2019 09:06:59 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, 27 Jun 2019 19:57:04 -0600 Alex Williamson wrote: > On Thu, 27 Jun 2019 15:15:02 -0600 > Alex Williamson wrote: > > > On Thu, 27 Jun 2019 09:38:32 -0600 > > Alex Williamson wrote: > > > > On 6/27/19 8:26 AM, Cornelia Huck wrote: > > > > > > > > > > { > > > > > "foo": "1", > > > > > "bar": "42", > > > > > "baz": { > > > > > "depends": ["foo", "bar"], > > > > > "value": "plahh" > > > > > } > > > > > } > > > > > > > > > > Something like that? > > > > > > I'm not sure yet. I think we need to look at what's feasible (and > > > easy) with jq. Thanks, > > > > I think it's not too much trouble to remove and insert into arrays, so > > what if we were to define the config as: > > > > { > > "mdev_type":"vendor-type", > > "start":"auto", > > "attrs": [ > > {"attrX":["Xvalue1","Xvalue2"]}, > > {"dir/attrY": "Yvalue1"}, > > {"attrX": "Xvalue3"} > > ] > > } > > > > "attr" here would define sysfs attributes under the device. The array > > would be processed in order, so in the above example we'd do the > > following: > > > > 1. echo Xvalue1 > attrX > > 2. echo Xvalue2 > attrX > > 3. echo Yvalue1 > dir/attrY > > 4. echo Xvalue3 > attrX > > > > When starting the device mdevctl would simply walk the array, if the > > attribute key exists write the value(s). If a write fails or the > > attribute doesn't exist, remove the device and report error. Yes, I think it makes sense to fail the startup of a device where we cannot set all attributes to the requested values. > > > > I think it's easiest with jq to manipulate arrays by removing and > > inserting by index. Also if we end up with something like above, it's > > ambiguous if we reference the "attrX" key. So perhaps we add the > > following options to the modify command: > > > > --addattr=ATTRIBUTE --delattr --index=INDEX --value=VALUE1[,VALUE2] > > > > We could handle it like a stack, so if --index is not supplied, add to > > the end or remove from the end. If --index is provided, delete that > > index or add the attribute at that index. So if you had the above and > > wanted to remove Xvalue1 but keep the ordering, you'd do: > > > > --delattr --index=0 > > --addattr --index=0 --value=Xvalue2 > > > > Which should results in: > > > > "attrs": [ > > {"attrX": "Xvalue2"}, > > {"dir/attrY": "Yvalue1"}, > > {"attrX": "Xvalue3"} > > ] Modifying by index looks reasonable; I just sent a pull request to print the index of an attribute out as well, so it is easier to specify the right attribute to modify. > > > > If we want to modify a running device, I'm thinking we probably want a > > new command and options --attr=ATTRIBUTE --value=VALUE might suffice. > > > > Do we need to support something like this for the 'start' command or > > should we leave that for simple devices and require a sequence of: > > > > # mdevctl define ... > > # mdevctl modify --addattr... > > ... > > # mdevctl start > > # mdevctl undefine > > > > This is effectively the long way to get a transient device. Otherwise > > we'd need to figure out how to have --attr --value appear multiple > > times on the start command line. Thanks, What do you think of a way to specify JSON for the attributes directly on the command line? Or would it be better to just edit the config files directly? > > This is now implemented, and yes you can specify '--addattr remove > --value 1' and mdevctl will immediately remove the device after it's > created (more power to the admin). Listing defined devices also lists Fun ;) > any attributes defined for easy inspection. It is also possible to > override the conversion of comma separated values into an array by > encoding and escaping the comma. It's a little cumbersome, but > possible in case a driver isn't fully on board with the one attribute, > one value rule of sysfs. Does this work for vfio-ap? I also still I do not have ap devices to actually test this with; but defining a device and adding attributes seems to work. > need to check if this allows an NVIDIA vGPU mdev to be configured such > that the framerate limiter can be automatically controlled. Thanks, > > Alex