Re: [Qemu-devel] kvm: virtio-net: saved image requires TUN_F_UFO support

[Paolo Bonzini]

On 06/11/2017 12:09, Stefan Priebe - Profihost AG wrote:
> HI Paolo,
> 
> could this patchset be related?

Uh oh, yes it should.  Jason, any ways to fix it?  I suppose we need to
disable UFO in the newest machine types, but do we also have to do
(software) UFO in vhost-net and QEMU for migration compatibility?

Thanks,

Paolo

> Greets,
> Stefan
> 
> Am 06.11.2017 um 10:52 schrieb Stefan Priebe - Profihost AG:
>> Hi Paolo,
>>
>> Am 06.11.2017 um 10:49 schrieb Paolo Bonzini:
>>> On 06/11/2017 10:48, Stefan Priebe - Profihost AG wrote:
>>>> Hi Paolo,
>>>>
>>>> Am 06.11.2017 um 10:40 schrieb Paolo Bonzini:
>>>>> On 06/11/2017 10:38, Stefan Priebe - Profihost AG wrote:
>>>>>> Hello,
>>>>>>
>>>>>> i've upgraded some servers from kernel 4.4 to 4.12 - both running Qemu
>>>>>> 2.9.1.
>>>>>>
>>>>>> If i migrate a VM from a host running kernel 4.4 to a host running 4.12
>>>>>> i get:
>>>>>>
>>>>>> kvm: virtio-net: saved image requires TUN_F_UFO support
>>>>>> kvm: Failed to load virtio-net-device:tmp
>>>>>> kvm: Failed to load virtio-net:virtio
>>>>>> kvm: error while loading state for instance 0x0 of device
>>>>>> '0000:00:12.0/virtio-net'
>>>>>> kvm: load of migration failed: Invalid argument
>>>>>>
>>>>>>
>>>>>> while migrating from 4.12 to 4.4 works fine.
>>>>>>
>>>>>> Can anybody help? Is this expected?
>>>>>
>>>>> Can you check why peer_has_ufo failed (in hw/net/virtio-net.c)?
>>>>
>>>> May be - how can i archieve this? Patching the code is not a problem if
>>>> you can give me a hint.
>>>>
>>>>> Also, did this ioctl fail when the tap device was set up on the 4.12 
>>>>> destination?
>>>>> int tap_probe_has_ufo(int fd)
>>>>> {
>>>>>     unsigned offload;
>>>>>
>>>>>     offload = TUN_F_CSUM | TUN_F_UFO;
>>>>>
>>>>>     if (ioctl(fd, TUNSETOFFLOAD, offload) < 0)
>>>>>         return 0;
>>>>>
>>>>>     return 1;
>>>>> }
>>>>
>>>> Should there be any kernel output or how can i detect / check it?
>>>
>>> For both, the simplest answer is probably just using printf.
>>
>> arg i missed an important part. The kernel is an opensuse SLE15 one.
>>
>> I've seen it contains the following patchset:
>> https://www.spinics.net/lists/netdev/msg443821.html
>>
>> Greets,
>> Stefan
>>