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

[KONRAD Frédéric]

On 22/04/2013 16:02, Andreas Färber wrote:
> Hi Fred,
>
> Am 22.04.2013 15:54, schrieb KONRAD Frédéric:
> > On 22/04/2013 15:27, Andreas Färber wrote:
> > > 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?
> > 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?
> The only idea I can come up with right now is to overwrite the bus name
> on realize/qdev-init of the containing (virtio-serial-pci) device.
>
> Whether we want that is another question... :) It would fix command line
> backwards compatibility but would be inconsistent then; I guess the
> former is more important here.
>
> Regards,
> Andreas
I'm not sure that only overwriting the bus name will fix the issue.

virtio-serial-device's bus still won't have the right name?

Here with the command line, we expect virtio-serial-pci,id=id0 to create 
a virtio-serial-bus called id0.0 is that right?

Thanks,
Fred

> > 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) {