Re: [Qemu-devel] [PATCH v7 00/13] basic channel IO passthrough infrastructure based on vfio

[Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>]

* Cornelia Huck <cornelia.huck@de.ibm.com> [2017-05-05 14:22:34 +0200]:

> On Fri,  5 May 2017 04:03:39 +0200
> Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> wrote:
> 
> > The patch series introduce a basic channel I/O passthrough
> > infrastructure based on vfio.
> > - Focus on supporting dasd-eckd(cu_type/dev_type = 0x3990/0x3390) as
> >   the target device. 
> > - Support new qemu parameters in the style of:
> >     -machine s390-ccw-virtio(,s390-squash-mcss=on|off) \
> >     -device vfio-ccw,sysfsdev=$MDEV_PATH
> >   We want to support real (i.e. not virtual) channel devices even for
> >   guests that do not support MCSS-E (where guests may see devices from
> >   any channel subsystem image at once). As all virtio-ccw devices are in
> >   css 0xfe (and show up in the default css 0 for guests not activating
> >   MCSS-E), we need an option to squash e.g. passed-through channel devices
> >   from their real css (0-3, or 0 for hosts not activating MCSS-E) into
> >   the default css, that is what the new machine option s390-squash-css is
> >   added.
> 
> Basically looks good, some small nitpicking and the virtual vs. virtio
> issue I noticed.
Thanks for the review! I replied in the coressponding threads.

> 
> Let's wait if others have more comments. Hopefully, the 3270 changes
> will by then be in master and you can rebase on top of them :)
Roger!

-- 
Dong Jia Shi