Re: [Qemu-devel] [PATCH v4 06/16] net: Remove vlan qdev property

[Zhi Yong Wu]

On Tue, Jun 12, 2012 at 4:05 AM, Luiz Capitulino <address@hidden> wrote:
> On Mon, 11 Jun 2012 22:15:55 +0800
> Zhi Yong Wu <address@hidden> wrote:
>
>> On Mon, Jun 11, 2012 at 2:28 PM, Paolo Bonzini <address@hidden> wrote:
>> > Il 09/06/2012 05:04, Zhi Yong Wu ha scritto:
>> >>>>> This commit looks suspicious because it removes a user-visible qdev
>> >>>>> property but we're trying to preserve backward compatibility.  This
>> >>>>> command-line will break:
>> >>>>>
>> >>>>> x86_64-softmmu/qemu-system-x86_64 -net user,vlan=1 -device 
>> >>>>> virtio-net-pci,vlan=1
>> >>>>>
>> >>>>> Instead of dropping the qdev_prop_vlan completely the
>> >>>>> hw/qdev-properties.c code needs to call net/hub.h external functions
>> >>>>> to implement equivalent functionality:
>> >>>>>
>> >>>>> 1. Setting the vlan=<id> property looks up the hub port and assigns
>> >>>>> the NICConf->peer field.
>> >>>>> 2. Getting the vlan property looks up the hub id (i.e. vlan id) given
>> >>>>> the peer.  If the peer is not a hub port the result is -1.
>> >>>>>
>> >>>>> When I wrote this patch I missed the big picture and forgot about
>> >>>>> backwards compatibility :(.
>> >>>>>
>> >> To be honest, i am concerned if anyone uses this syntax. Since the
>> >> feature will finally be discarded, i suggest that we don't support
>> >> this now. If someone complains this later, we can fix it. If nobody
>> >> complains, that is what we hope.
>> >
>> > I think you're missing the big picture of this series, which is exactly
>> > _not_ to discard the VLAN feature, but just to rewrite it in a better way.
>> Yeah, i know that this series are rewriting VLAN feature in one better way.
>>
>> What i mean was that luiz and other some guys think that the -net
>> syntax should be completely removed.
>
> One of the motivations for having the hub feature is to preserve the vlan
> functionality, in that case we shouldn't break cmd-line backwards 
> compatibility.
 OK, thanks.



-- 
Regards,

Zhi Yong Wu