From: "Michael S. Tsirkin" <mst@redhat•com>
To: Siwei Liu <loseweigh@gmail•com>
Cc: Sridhar Samudrala <sridhar.samudrala@intel•com>,
Stephen Hemminger <stephen@networkplumber•org>,
David Miller <davem@davemloft•net>,
Netdev <netdev@vger•kernel.org>, Jiri Pirko <jiri@resnulli•us>,
virtio-dev@lists•oasis-open.org, "Brandeburg,
Jesse" <jesse.brandeburg@intel•com>,
Alexander Duyck <alexander.h.duyck@intel•com>,
Jakub Kicinski <kubakici@wp•pl>
Subject: Re: [PATCH v4 2/2] virtio_net: Extend virtio to use VF datapath when available
Date: Fri, 2 Mar 2018 23:36:10 +0200 [thread overview]
Message-ID: <20180302233443-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CADGSJ23tForX9HSvYpC-1wV9v_u15-mzeg8jY7nOO2gaVdjgMw@mail.gmail.com>
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.samudrala@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.samudrala@intel•com>
> > Signed-off-by: Alexander Duyck <alexander.h.duyck@intel•com>
> > Reviewed-by: Jesse Brandeburg <jesse.brandeburg@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
next prev parent reply other threads:[~2018-03-02 21:36 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-01 20:08 [PATCH v4 0/2] Enable virtio_net to act as a backup for a passthru device Sridhar Samudrala
2018-03-01 20:08 ` [PATCH v4 1/2] virtio_net: Introduce VIRTIO_NET_F_BACKUP feature bit Sridhar Samudrala
2018-03-01 20:08 ` [PATCH v4 2/2] virtio_net: Extend virtio to use VF datapath when available Sridhar Samudrala
2018-03-02 8:36 ` Jiri Pirko
2018-03-02 15:26 ` Alexander Duyck
2018-03-02 16:20 ` Jiri Pirko
2018-03-02 16:37 ` Samudrala, Sridhar
2018-03-02 17:06 ` Alexander Duyck
2018-03-02 19:42 ` Michael S. Tsirkin
2018-03-02 20:49 ` Siwei Liu
2018-03-03 11:31 ` Jiri Pirko
2018-03-03 18:04 ` Alexander Duyck
2018-03-03 21:25 ` Jiri Pirko
2018-03-04 0:26 ` Alexander Duyck
2018-03-04 7:13 ` Jiri Pirko
2018-03-04 18:24 ` Alexander Duyck
2018-03-04 18:50 ` Jiri Pirko
2018-03-04 21:54 ` Samudrala, Sridhar
2018-03-04 21:58 ` Alexander Duyck
2018-03-05 9:21 ` Jiri Pirko
2018-03-05 16:11 ` Stephen Hemminger
2018-03-05 22:30 ` Jiri Pirko
2018-03-05 22:47 ` Alexander Duyck
2018-03-06 3:15 ` Stephen Hemminger
2018-03-06 19:08 ` Alexander Duyck
2018-03-06 22:59 ` Jiri Pirko
2018-03-06 23:27 ` Alexander Duyck
2018-03-07 2:38 ` Michael S. Tsirkin
2018-03-07 17:50 ` Alexander Duyck
2018-03-07 18:06 ` Stephen Hemminger
2018-03-07 18:55 ` Alexander Duyck
2018-03-07 20:11 ` Michael S. Tsirkin
2018-03-12 18:47 ` Samudrala, Sridhar
2018-03-02 19:41 ` Michael S. Tsirkin
2018-03-02 19:52 ` Samudrala, Sridhar
2018-03-02 20:10 ` Michael S. Tsirkin
2018-03-02 20:44 ` Siwei Liu
2018-03-02 20:56 ` Samudrala, Sridhar
2018-03-02 21:33 ` Michael S. Tsirkin
2018-03-02 21:31 ` Michael S. Tsirkin
2018-03-02 22:26 ` Siwei Liu
2018-03-04 4:00 ` Michael S. Tsirkin
2018-03-02 21:11 ` Siwei Liu
2018-03-02 21:36 ` Michael S. Tsirkin [this message]
2018-03-02 23:56 ` Siwei Liu
2018-03-04 4:04 ` Michael S. Tsirkin
2018-03-12 21:53 ` Siwei Liu
2018-03-02 23:12 ` Samudrala, Sridhar
2018-03-03 0:09 ` Siwei Liu
2018-03-12 20:12 ` Jiri Pirko
2018-03-12 20:58 ` Samudrala, Sridhar
2018-03-12 21:08 ` Jiri Pirko
2018-03-14 0:36 ` Samudrala, Sridhar
2018-03-14 0:54 ` Stephen Hemminger
2018-03-14 15:45 ` Jiri Pirko
2018-03-12 22:44 ` Siwei Liu
2018-03-14 0:28 ` Samudrala, Sridhar
2018-03-14 0:44 ` Michael S. Tsirkin
2018-03-14 4:50 ` Siwei Liu
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