On Tue, Jun 26, 2018 at 5:29 PM, Michael S. Tsirkin <m...@redhat.com> wrote: > On Tue, Jun 26, 2018 at 04:38:26PM -0700, Siwei Liu wrote: >> On Mon, Jun 25, 2018 at 6:50 PM, Michael S. Tsirkin <m...@redhat.com> wrote: >> > On Mon, Jun 25, 2018 at 10:54:09AM -0700, Samudrala, Sridhar wrote: >> >> > > > > Might not neccessarily be something wrong, but it's very limited >> >> > > > > to >> >> > > > > prohibit the MAC of VF from changing when enslaved by failover. >> >> > > > You mean guest changing MAC? I'm not sure why we prohibit that. >> >> > > I think Sridhar and Jiri might be better person to answer it. My >> >> > > impression was that sync'ing the MAC address change between all 3 >> >> > > devices is challenging, as the failover driver uses MAC address to >> >> > > match net_device internally. >> >> >> >> Yes. The MAC address is assigned by the hypervisor and it needs to manage >> >> the movement >> >> of the MAC between the PF and VF. Allowing the guest to change the MAC >> >> will require >> >> synchronization between the hypervisor and the PF/VF drivers. Most of the >> >> VF drivers >> >> don't allow changing guest MAC unless it is a trusted VF. >> > >> > OK but it's a policy thing. Maybe it's a trusted VF. Who knows? >> > For example I can see host just >> > failing VIRTIO_NET_CTRL_MAC_ADDR_SET if it wants to block it. >> > I'm not sure why VIRTIO_NET_F_STANDBY has to block it in the guest. >> >> That's why I think pairing using MAC is fragile IMHO. When VF's MAC >> got changed before virtio attempts to match and pair the device, it >> ends up with no pairing found out at all. > > Guest seems to match on the hardware mac and ignore whatever > is set by user. Makes sense to me and should not be fragile. Host can change the hardware mac for VF any time.
-Siwei > > >> UUID is better. >> >> -Siwei >> >> > >> > -- >> > MST
