Re: [Qemu-devel] Advice on some configuration parameters

[Alon Levy <alevy@redhat.com>]

> Il 01/03/2013 13:45, Paolo Bonzini ha scritto:
> > Il 12/02/2013 14:05, Fabio Fantoni ha scritto:
> >> I'm making patches to enable some qemu upstream features in xen
> >> that are
> >> missing in libxl.
> >> I'm trying to do it just by giving arguments to qemu, and I want
> >> them to
> >> be dynamic (e.g. without physical addresses if possible) and
> >> concise.
> > They should use physical addresses, otherwise changing the VM
> > hardware
> > in trivial ways may cause a waterfall effect and cause Windows to
> > reactivate.
> >
> >> If I try to set up virt-manager so that it doesn't point to a
> >> file, it
> >> uses this configuration:
> >>
> >> -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x5.0x7
> >> -device
> >> ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x5
> >>
> >> -device
> >> ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x5.0x1
> >> -device
> >> ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x5.0x2
> >>
> >> This seems to differ from the configuration file, e.g. you have
> >> multifunzion=on only on the first uhci
> > That doesn't matter.
> >
> >> , besides I can't understand how many physical ports are defined.
> > There are 6 ports, controlled by either the EHCI for USB 2.0
> > devices
> > (the EHCI controls 6 ports) or by one of the three UHCI for USB 1.1
> > ports (one UHCI has 2 ports).
> >
> >> I tried setting 9 usbredirection
> >> channels in virt-manager but that configuration doesn't change and
> >> no
> >> errors are reported, but I doubt that physical ports are being
> >> define
> >> dynamically.
> > QEMU creates hubs automatically I think in that case.
> >
> >> About spice vdagent at the moment I'm using this configuration
> >> that
> >> seems to work:
> >> -device virtio-serial -chardev spicevmc,id=vdagent,name=vdagent
> >> -device
> >> virtserialport,chardev=vdagent,name=com.redhat.spice.0
> >>
> >> But I noticed that virt-manager use this slightly different one:
> >> -chardev pty,id=charserial0 -device
> >> isa-serial,chardev=charserial0,id=serial0 -chardev
> >> spicevmc,id=charchannel0,name=vdagent -device
> >> virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0
> >>
> >> Are there any problem with the more concise one I'm using?
> > It is the same.
> >
> > Paolo
> >
> >
> >
> Thanks for reply.
> I have another questions:
> What exactly does the -usb parameter that seems to be necessary for
> usb
> passthrough?

It is shorthand for the appropriate "-device" to create the usb host (i.e. uhci etc.)

> I mean usb devices passed through host (with -usbdevice).
> Is the number of such passthrough usb devices limiting the number of
> available channel for usb redirection devices?

AFAIR yes.

> 
> 
>