Re: [Qemu-devel] [PULL 25/26] block: Remove deprecated -drive option serial

[Christian Borntraeger]

On 06/22/2018 02:55 PM, Kevin Wolf wrote:
> Am 22.06.2018 um 13:38 hat Christian Borntraeger geschrieben:
>>
>> On 06/15/2018 04:21 PM, Kevin Wolf wrote:
>>> The -drive option serial was deprecated in QEMU 2.10. It's time to
>>> remove it.
>>>
>>> Tests need to be updated to set the serial number with -global instead
>>> of using the -drive option.
>>
>> libvirt 4.5 still creates those (at least on s390x)
>>
>>     <disk type='file' device='disk'>
>>       <driver name='qemu' type='qcow2' cache='none' io='native' 
>> iothread='1'/>
>>       <source file='/var/lib/libvirt/qemu/image.zhyp137'/>
>>       <target dev='hda' bus='virtio'/>
>>       <serial>skel</serial>
>>       <boot order='1'/>
>>       <address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0000'/>
>>     </disk>
>>
>>
>> -> 
>> [...]
>> -drive 
>> file=/var/lib/libvirt/qemu/image.zhyp137,format=qcow2,if=none,id=drive-virtio-disk0,serial=skel,cache=none,aio=native
>>  -device 
>> virtio-blk-ccw,iothread=iothread1,scsi=off,devno=fe.0.0000,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1,write-cache=on
>>  
>> [...]
>>
>> 2018-06-22T11:25:20.946024Z qemu-system-s390x: -drive 
>> file=/var/lib/libvirt/qemu/image.zhyp137,format=qcow2,if=none,id=drive-virtio-disk0,serial=skel,cache=none,aio=native:
>>  Block format 'qcow2' does not support the option 'serial'
>> 2018-06-22 11:25:21.098+0000: shutting down, reason=failed
>>
>> So it seems that this breaks s390x.

To me it seems that this is also broken on x86.
> 
> Thanks for bringing this up. libvirt should fix this before QEMU 3.0 is
> released.

I think this is definitely too short notice. We should not break existing
setups just by insisting that users have to update libvirt when they update
QEMU. Yes, this might be our policy, but doing so "just because we can"
is certainly a very bad attitude. I see no fundamental technical reason why
we should not revert this change.


> 
> Sadly, it also shows that deprecation warnings in log files go
> unnoticed.

In fact whoever added the deprication notice should have followed up
with the libvirt team to implement that change. no?