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, > > [..] > > > > 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. > Sorry for being late... I guess for vfio-ccw one needs to make sure that the ccw device is bound to the vfio-ccw driver first, and only after that can one use create-mdev to create the mdev on top of the subchannel. So to make this work persistently (survive a reboot) one would need to take care of the subchannel getting bound to the right vfio_ccw driver before mdevctl is called. Right? BTW how does this concurrence situation between the drivers io_subchannel and vfio_ccw work? Especially if both are build in? > > > > 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. > > +1 @Alex: I'm curious what is the big management picture for non-auto looks like. Regards, Halil [..]
