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

[Hans de Goede]

Hi,

On 03/01/2013 11:02 AM, Fabio Fantoni wrote:
> 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.
> >
> > I'm confused about usb configuration.
> >
> > Looking at what virt-manager does, it seems that you set the usbredirection in 
> > channels like this:
> > -chardev spicevmc,id=charredir0,name=usbredir -device 
> > usb-redir,chardev=charredir0,id=redir0
> >
> > At the moment I'm defining the physical usb devices like this:
> > -readconfig /etc/qemu/ich9-ehci-uhci.cfg
> >
> > 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 does not matter the multifunction bit needs to set only on 0x5.0x0.

> besides I can't understand how many physical ports are defined.

6, the same as with the "-readconfig /etc/qemu/ich9-ehci-uhci.cf" directive.

> 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.

Hmm, that would be a libvirt bug you should be able to add only 6
usb-redir channels, unless you add a second usb controller ...

Possibly libvirt is also adding a hub? That would work sort-of, it
would make channels 6-9 be usb-1 only, since we don't emulate
usb-2 hubs.

> > Can you omit physical addresses?

In most cases yes, then qemu will pick one itself.

> > I searched the web but I can't find detailed informations about it. Can someone 
> > explain in detail how you are supposed to configure usb physical ports? I want 
> > to enable both usb redirection and usb passthrough in a dynamic and concise 
> > manner.

The easiest way to do is probably to create the setup you want using
virt-manager and then run the vm once, after that the xml file
should contain fixed addresses for all devices.

> > 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?

No.

Regards,

Hans