Re: [PATCH 1/3] docs/s390x: document the virtual css

[Cornelia Huck]

On Fri, 15 May 2020 09:04:13 +0200
Thomas Huth <address@hidden> wrote:

> On 05/05/2020 15.50, Cornelia Huck wrote:

> > +Examples
> > +--------
> > +
> > +* a virtio-net device, cssid/ssid/devno automatically assigned::
> > +
> > +    -device virtio-net-ccw
> > +
> > +  In a Linux guest (without default devices and no other devices specified
> > +  prior to this one), this will show up as ``0.0.0000`` under subchannel
> > +  ``0.0.0000``.  
> 
> Maybe mention the QEMU side again, e.g. that when you run "info qtree"
> in the HMP monitor, you see the device with dev_id = "fe.0.0000".

Yes, that's a good idea.

> 
> > +* a virtio-rng device in subchannel set ``0``::
> > +
> > +    -device virtio-rng-ccw,devno=fe.0.0042
> > +
> > +  If added to the same Linux guest as above, it would show up as 
> > ``0.0.0042``
> > +  under subchannel ``0.0.0001``.  
> 
> Does "same" matter here? Otherwise, maybe just say "to a Linux guest" ?

I wanted to provide the subchannel number in my examples as well. As
QEMU always picks the first free one (and you cannot specify it
manually), I wanted to make the examples build upon each other.

> 
> > +* a virtio-gpu device in subchannel set ``2``::
> > +
> > +    -device virtio-gpu-ccw,devno=fe.2.1111
> > +
> > +  If added to the same Linux guest as above, it would show up as 
> > ``0.2.1111``
> > +  under subchannel ``0.2.0000``.  
> 
> Dito.

dito :)

> 
> > +* a virtio-mouse device in a non-standard channel subsystem::
> > +
> > +    -device virtio-mouse-ccw,devno=2.0.2222
> > +
> > +  This would not show up in a standard Linux guest.  
> 
> Ok ... and what happens if you use devno=0.0.1234 ? Will that then show
> up under fe.0.1234 in the guest??

That won't show up in the guest, either -- do you think I should add an
example for that as well?