On Wed, 2017-04-05 at 15:46 +0200, Corinna Vinschen wrote: > Before libvirt modifies the MAC address and vlan tag for an SRIOV > VF > for use by a virtual machine (either using vfio device assignment > or > macvtap passthru mode), it saves the current MAC address and vlan > tag > so that it can reset them to their original value when the guest is > done. Libvirt can't leave the VF MAC set to the value used by the > now-defunct guest since it may be started again later using a > different VF, but it certainly shouldn't just pick any random > value, > either. So it saves the state of everything prior to using the VF, > and > resets it to that. > > The igb driver initializes the MAC addresses of all VFs to > 00:00:00:00:00:00, and reports that when asked (via an RTM_GETLINK > netlink message, also visible in the list of VFs in the output of > "ip > link show"). But when libvirt attempts to restore the MAC address > back > to 00:00:00:00:00:00 (using an RTM_SETLINK netlink message) the > kernel > responds with "Invalid argument". > > Forbidding a reset back to the original value leaves the VF MAC at > the > value set for the now-defunct virtual machine. Especially on a > system > with NetworkManager enabled, this has very bad consequences, since > NetworkManager forces all interfacess to be IFF_UP all the time - > if > the same virtual machine is restarted using a different VF (or even > on > a different host), there will be multiple interfaces watching for > traffic with the same MAC address. > > To allow libvirt to revert to the original state, we need a way to > remove the administrative set MAC on a VF, to allow normal host > operation again, and to reset/overwrite the VF MAC via VF netdev. > > This patch implements the outlined scenario by allowing to set the > VF MAC to 00:00:00:00:00:00 via RTM_SETLINK on the PF. > igb_ndo_set_vf_mac resets the IGB_VF_FLAG_PF_SET_MAC flag to 0, > so it's possible to reset the VF MAC back to the original value via > the VF netdev. > > Note: Recent patches to libvirt allow for a workaround if the NIC > isn't capable of resetting the administrative MAC back to all 0, > but > in theory the NIC should allow resetting the MAC in the first > place. > > Signed-off-by: Corinna Vinschen <vinsc...@redhat.com> > --- > drivers/net/ethernet/intel/igb/igb_main.c | 42 > +++++++++++++++++++++++-------- > 1 file changed, 31 insertions(+), 11 deletions(-)
This patch does not apply (not even close). Please make sure to base you patch off my dev-queue branch of my next-queue tree on kernel.org.
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