Re: [Qemu-devel] [PATCH] qdev: Assign a default device ID when none is provided.

[Paolo Bonzini]

Il 09/01/2014 19:18, Hani Benhabiles ha scritto:
> On Wed, Jan 08, 2014 at 06:34:01PM +0100, Paolo Bonzini wrote:
>> Il 08/01/2014 18:17, Hani Benhabiles ha scritto:
>>> For this reason, the loop in assign_device_name() specifically check that 
>>> the ID
>>> doesn't exist already and uses the next value if it does.
>>>
>>> How would something like:
>>> (qemu) device_add virtio-net-pci
>>> ==> ID: virtio-net-pci.0
>>>
>>> Be more problematic than:
>>> (qemu) device_add virtio-net-pci,id=virtio-net-pci.0
>>
>> (qemu) device_add virtio-net-pci
>> (qemu) device_add virtio-net-pci,id=virtio-net-pci.0
>>
>> works without your patches, fails with them (IIUC).
> 
> It would fail with a clear and descriptive message (Duplicate ID) which is no
> different than when a user uses tries to do so manually.

It would still be a regression.

> Without the patch, how does a user unplug a device for which he didn't specify
> an ID (eg. forgotten, added quickly...)

He doesn't. :)

> It is even more confusing with other commands like info networks.
> 
> (qemu) device_add virtio-net-pci
> (qemu) device_add virtio-net-pci,id=foo
> (qemu) info network 
> virtio-net-pci.0: 
> index=0,type=nic,model=virtio-net-pci,macaddr=52:54:00:12:34:56
> foo: index=0,type=nic,model=virtio-net-pci,macaddr=52:54:00:12:34:57
> (qemu) device_del foo
> (qemu) device_del virtio-net-pci.0
> Device 'virtio-net-pci.0' not found

This could be considered a bug in "info network" too.  You might use a
different template such as "unnamed virtio-net-pci #1" in net/net.c's
assign_name.

Paolo

> If the naming scheme is an issue, could something like starting it with one or
> two underscores better suited ?
> 
> Cheers,
> 
> Hani.
> 
>