Hi morganyang1982,
Thank you for contacting Intel.
On Linux Kernel version 3.8.x and above, VF can be destroyed or disabled by writing the value 0 to the sriov_numvfs parameter via sysfs interface.
#echo 0 > /sys/class/net/device name/device/sriov_numvfs
You can find the above-mentioned settings and other information on this Technical Brief.
Refer to page 12.
I hope this is helpful. Feel free to reply to us if you have further questions.
Sincerely,
Sandy