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

[Andreas Färber]

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

> 
> 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) {
>>>>
>>>
>>
> 


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