USB Modem, mapped from host to VM - slow upload

[Davyd]

I have USB modem (Huawei E3372h), connected to host. On host it works well, shows 30/30 megabits on upload and download.
When I map it to linux VM (virtual router), its upload speed dramatically goes down - only 1 megabit on upload. But download is Ok - same 30 megabit, as on host.
I was check it several times and got same results.
What can I do to fix it?

 

[Davyd]

fixed by vm kernel update.
Was - debian 8 standart 3.16. Now - 4.6.0 from backports.