On Fri, 24 May 2019 12:11:06 +0200 Cornelia Huck <cohuck@xxxxxxxxxx> wrote: > On Thu, 23 May 2019 17:20:01 -0600 > Alex Williamson <alex.williamson@xxxxxxxxxx> wrote: > > > Hi, > > > > Currently mediated device management, much like SR-IOV VF management, > > is largely left as an exercise for the user. This is an attempt to > > provide something and see where it goes. I doubt we'll solve > > everyone's needs on the first pass, but maybe we'll solve enough and > > provide helpers for the rest. Without further ado, I'll point to what > > I have so far: > > > > https://github.com/awilliam/mdevctl > > > > This is inspired by driverctl, which is also a bash utility. mdevctl > > uses udev and systemd to record and recreate mdev devices for > > persistence and provides a command line utility for querying, listing, > > starting, stopping, adding, and removing mdev devices. Currently, for > > better or worse, it considers anything created to be persistent. I can > > imagine a global configuration option that might disable this and > > perhaps an autostart flag per mdev device, such that mdevctl might > > simply "know" about some mdevs but not attempt to create them > > automatically. Clearly command line usage help, man pages, and > > packaging are lacking as well, release early, release often, plus this > > is a discussion starter to see if perhaps this is sufficient to meet > > some needs. > > > > Originally I thought about making a utility to manage both mdev and > > SR-IOV VFs all in one, but it seemed more natural to start here > > (besides, I couldn't think of a good name for the combined utility). > > If this seems useful, maybe I'll start on a vfctl for SR-IOV and we'll > > see whether they have enough synergy to become one. > > > > It would be really useful if s390 folks could help me understand > > whether it's possible to glean all the information necessary to > > recreate a ccw or ap mdev device from sysfs. I expect the file where > > we currently only store the mdev_type to evolve into something that > > includes more information to facilitate more complicated devices. For > > now I make no claims to maintaining compatibility of recorded mdev > > devices, it will absolutely change, but I didn't want to get bogged > > down in making sure I don't accidentally source a root kit hidden in an > > mdev config file. > > I played a bit with it on my LPAR, and it is at least not obviously > broken with vfio-ccw :) I don't have any ap devices to play with, > though. Awesome, that's a good start. Thanks for testing! > > I'm also curious how or if libvirt or openstack might use this. If > > nothing else, it makes libvirt hook scripts easier to write, especially > > if we add an option not to autostart mdevs, or if users don't mind > > persistent mdevs, maybe there's nothing more to do. > > > > BTW, feel free to clean up by bash, I'm a brute force and ignorance > > shell coder ;) > > Not that I'm a good shell coder, but I sent you a pull req at least > adding a basic help text ;) > > I have not yet looked at most of the code, though. Pulled, thanks again! I'll continue to try to fill in some of the gaps. I also forgot to mention that the integration with systemd means that mdevs that mdevctl knows about can be started and stopped with systemctl, ie: # systemctl {start|stop} mdev@$UUID.service You'll see that sbin/mdevctl start/stop-mdev is effectively just an alias to this. Thanks, Alex
