On Fri, Mar 02, 2018 at 01:11:56PM -0800, Siwei Liu wrote: > On Thu, Mar 1, 2018 at 12:08 PM, Sridhar Samudrala > <sridhar.samudr...@intel.com> wrote: > > This patch enables virtio_net to switch over to a VF datapath when a VF > > netdev is present with the same MAC address. It allows live migration > > of a VM with a direct attached VF without the need to setup a bond/team > > between a VF and virtio net device in the guest. > > > > The hypervisor needs to enable only one datapath at any time so that > > packets don't get looped back to the VM over the other datapath. When a VF > > is plugged, the virtio datapath link state can be marked as down. The > > hypervisor needs to unplug the VF device from the guest on the source host > > and reset the MAC filter of the VF to initiate failover of datapath to > > virtio before starting the migration. After the migration is completed, > > the destination hypervisor sets the MAC filter on the VF and plugs it back > > to the guest to switch over to VF datapath. > > > > When BACKUP feature is enabled, an additional netdev(bypass netdev) is > > created that acts as a master device and tracks the state of the 2 lower > > netdevs. The original virtio_net netdev is marked as 'backup' netdev and a > > passthru device with the same MAC is registered as 'active' netdev. > > > > This patch is based on the discussion initiated by Jesse on this thread. > > https://marc.info/?l=linux-virtualization&m=151189725224231&w=2 > > > > Signed-off-by: Sridhar Samudrala <sridhar.samudr...@intel.com> > > Signed-off-by: Alexander Duyck <alexander.h.du...@intel.com> > > Reviewed-by: Jesse Brandeburg <jesse.brandeb...@intel.com> > > --- > > drivers/net/virtio_net.c | 683 > > ++++++++++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 682 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index bcd13fe906ca..f2860d86c952 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -30,6 +30,8 @@ > > #include <linux/cpu.h> > > #include <linux/average.h> > > #include <linux/filter.h> > > +#include <linux/netdevice.h> > > +#include <linux/pci.h> > > #include <net/route.h> > > #include <net/xdp.h> > > > > @@ -206,6 +208,9 @@ struct virtnet_info { > > u32 speed; > > > > unsigned long guest_offloads; > > + > > + /* upper netdev created when BACKUP feature enabled */ > > + struct net_device *bypass_netdev; > > }; > > > > struct padded_vnet_hdr { > > @@ -2236,6 +2241,22 @@ static int virtnet_xdp(struct net_device *dev, > > struct netdev_bpf *xdp) > > } > > } > > > > +static int virtnet_get_phys_port_name(struct net_device *dev, char *buf, > > + size_t len) > > +{ > > + struct virtnet_info *vi = netdev_priv(dev); > > + int ret; > > + > > + if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_BACKUP)) > > + return -EOPNOTSUPP; > > + > > + ret = snprintf(buf, len, "_bkup"); > > + if (ret >= len) > > + return -EOPNOTSUPP; > > + > > + return 0; > > +} > > + > > What if the systemd/udevd is not new enough to enforce the > n<phys_port_name> naming? Would virtio_bypass get a different name > than the original virtio_net?
You mean people using ethX names? Any hardware config change breaks these, I don't think that can be helped. > Should we detect this earlier and fall > back to legacy mode without creating the bypass netdev and ensalving > the VF? I don't think we can do this with existing kernel/userspace APIs. -- MST
