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

[Stefan Priebe - Profihost AG]

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?

Greets,
Stefan

> Thanks,
> 
> Paolo
>