Re: [Qemu-devel] [PATCH] qdev: Fix device_add bus assumptions

[KONRAD Frédéric]

On 22/04/2013 15:27, Andreas Färber wrote:
> Hi,
>
> Am 22.04.2013 13:51, schrieb Libaiqing:
> >    When I use the config below,an error occurs.Is there anything wrong?
> >
> >    Qemu-kvm -enable-kvm -name win7 -M pc-0.15 -m 1024 -smp 2 -boot c  -device 
> > virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x4 -chardev 
> > spicevmc,id=charchannel0,name=vdagent -device 
> > virtserialport,bus=virtio-serial0.0,chardev=charchannel0,id=channel0,name=com.redhat.spice.0
> >   -drive file=/home/img/win7.qed,if=virtio,index=0,format=qed  -monitor stdio   
> > -vga qxl  -vnc :1
> >
> > Error output:
> >      -device 
> > virtserialport,bus=virtio-serial0.0,chardev=charchannel0,id=channel0,name=com.redhat.spice.0:
> >  Bus 'virtio-serial0.0' is full
> >      -device 
> > virtserialport,bus=virtio-serial0.0,chardev=charchannel0,id=channel0,name=com.redhat.spice.0:
> >  Bus 'virtio-serial0.0' not found
> >
> > Any feedback are appliciated.
> This does not sound related to this patch at all...
>
> Instead it sounds as if the virtio refactorings had some effect not only
> on virtio-net but also on virtio-serial. Fred?
>
> Andreas
Hi,

Yes, sounds like the same issue as virtio-net:

    bus: pci.0
      type PCI
      dev: virtio-serial-pci, id "virtio-serial0"
        ioeventfd = off
        vectors = 2
        class = 0x780
        indirect_desc = on
        event_idx = on
        max_ports = 31
        addr = 04.0
        romfile = <null>
        rombar = 1
        multifunction = off
        command_serr_enable = on
        class Class 0780, addr 00:04.0, pci id 1af4:1003 (sub 1af4:0003)
        bar 0: i/o at 0xc040 [0xc05f]
        bar 1: mem at 0xfebf1000 [0xfebf1fff]
        bus: virtio-serial0.0
          type virtio-pci-bus
          dev: virtio-serial-device, id ""
            max_ports = 31
            bus: virtio-serial-bus.0
              type virtio-serial-bus

The autogenerated bus name "deviceid.n" (virtio-serial0.0) became a 
virtio-bus...

virtio-serial-bus.0 is the right bus to connect virtserialport.

Any idea how to fix that?

Sorry for that,
Fred

> > -----Original Message-----
> > From: address@hidden [mailto:address@hidden On Behalf Of Igor Mammedov
> > Sent: Thursday, April 18, 2013 5:02 PM
> > To: Igor Mammedov
> > Cc: address@hidden; address@hidden; address@hidden; address@hidden; 
> > address@hidden; address@hidden; Andreas Färber
> > Subject: Re: [Qemu-devel] [PATCH] qdev: Fix device_add bus assumptions
> >
> > On Thu, 18 Apr 2013 10:41:56 +0200
> > Igor Mammedov <address@hidden> wrote:
> >
> > [...]
> > > > -    if (!bus) {
> > > > -        bus = sysbus_get_default();
> > > > -    }
> > > > -
> > > I've checked all direct childs of TYPE_DEVICE and they all set k->bus_type,
> > > with only one exception of TYPE_CPU. So it should be safe to remove fallback
> > > from qdev_device_add POV.
> > > However  TYPE_CPU breaks assumption that device always has parent_bus set
> > > to not NULL in qdev_unplug() and qdev_print()
> > Err, qdev_print() is safe since it's called on bus children only, so it has
> > parent_bus.
> >
> > > It would be better to add something like this:
> > > // untested
> > >
> > > diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> > > index 4eb0134..45009ba 100644
> > > --- a/hw/core/qdev.c
> > > +++ b/hw/core/qdev.c
> > > @@ -207,7 +207,7 @@ void qdev_unplug(DeviceState *dev, Error **errp)
> > >   {
> > >       DeviceClass *dc = DEVICE_GET_CLASS(dev);
> > >   
> > > -    if (!dev->parent_bus->allow_hotplug) {
> > > +    if (dev->parent_bus && !dev->parent_bus->allow_hotplug) {
> > >           error_set(errp, QERR_BUS_NO_HOTPLUG, dev->parent_bus->name);
> > >           return;
> > >       }
> > > diff --git a/qdev-monitor.c b/qdev-monitor.c
> > > index 9a78ccf..2476e4e 100644
> > > --- a/qdev-monitor.c
> > > +++ b/qdev-monitor.c
> > > @@ -557,7 +557,9 @@ static void qdev_print(Monitor *mon, DeviceState *dev,
> > > int indent) qdev_print_props(mon, dev, DEVICE_CLASS(class)->props, indent);
> > >           class = object_class_get_parent(class);
> > >       } while (class != object_class_by_name(TYPE_DEVICE));
> > > -    bus_print_dev(dev->parent_bus, mon, dev, indent);
> > > +    if (dev->parent_bus) {
> > > +        bus_print_dev(dev->parent_bus, mon, dev, indent);
> > > +    }
> > >       QLIST_FOREACH(child, &dev->child_bus, sibling) {
> > >           qbus_print(mon, child, indent);
> > >       }
> > >
> > > >       /* create device, set properties */
> > > >       qdev = DEVICE(object_new(driver));
> > > > -    qdev_set_parent_bus(qdev, bus);
> > > > +
> > > > +    if (bus) {
> > > > +        qdev_set_parent_bus(qdev, bus);
> > > > +    }
> > > >   
> > > >       id = qemu_opts_id(opts);
> > > >       if (id) {