Re: [libvirt] <interface type='hostdev'>vf configuration cleanup when VM is delete

On 12/13/2015 10:51 AM, Moshe Levi wrote: What libvirt does is to restore the MAC address to whatever it was before we set it up for use with a guest. Although there are some sriov net drivers that (for some unfathomable reason) think it's cool to assign a random MAC address to each VF at boot time, the "normal" thing is for the VFs to have a MAC address of all 0's to start with. So libvirt should be saving 00:00:00:00:00:00 (it will be in the file /var/run/libvirt/hostdevmgr/$ifname_vf$vfnum) then setting the MAC to use; when done, libvirt will read the 00:00:00:00:00:00 and use netlink to set the MAC address, but this is apparently failing. I checked on my Fedora 22 system with the igb driver, and found that if the MAC address was originally set to something other than 0's, it was restored properly by libvirt, but if it was set to all 0's originally, the attempt to set it back to 0 would fail. I then tried doing the same thing with the "ip" utility: # ip link set dev p4p2 vf 0 mac 00:00:00:00:00:00 and I get the following response: RTNETLINK answers: Invalid argument So it appears that either the kernel or the NIC driver is refusing to set the MAC address to all 0's. I'm reasonably certain this is a regression in the kernel, although I can't say how long it's been there, as I don't normally pay attention to this (and as I said, many SRIOV NIC drivers don't default their VFs to 0 MAC addresses) What distro and kernel are you using for your tests? F15