Re: [PATCH V2 3/3] virtio-net: synchronize operstate with admin state on up/down

Jason Wang
2024-06-25T01:27:53Z

On Mon, Jun 24, 2024 at 6:07 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Mon, Jun 24, 2024 at 10:45:23AM +0800, Jason Wang wrote:
> > This patch synchronize operstate with admin state per RFC2863.
> >
> > This is done by trying to toggle the carrier upon open/close and
> > synchronize with the config change work. This allows propagate status
> > correctly to stacked devices like:
> >
> > ip link add link enp0s3 macvlan0 type macvlan
> > ip link set link enp0s3 down
> > ip link show
> >
> > Before this patch:
> >
> > 3: enp0s3: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
> > link/ether 00:00:05:00:00:09 brd ff:ff:ff:ff:ff:ff
> > ......
> > 5: macvlan0@enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
> > link/ether b2:a9:c5:04:da:53 brd ff:ff:ff:ff:ff:ff
> >
> > After this patch:
> >
> > 3: enp0s3: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
> > link/ether 00:00:05:00:00:09 brd ff:ff:ff:ff:ff:ff
> > ...
> > 5: macvlan0@enp0s3: <NO-CARRIER,BROADCAST,MULTICAST,UP,M-DOWN> mtu 1500 qdisc noqueue state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
> > link/ether b2:a9:c5:04:da:53 brd ff:ff:ff:ff:ff:ff
> >
> > Cc: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
> > Cc: Gia-Khanh Nguyen <gia-khanh.nguyen@oracle.com>
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> > drivers/net/virtio_net.c | 72 +++++++++++++++++++++++-----------------
> > 1 file changed, 42 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index b1f8b720733e..eff3ad3d6bcc 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -2468,6 +2468,25 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
> > return err;
> > }
> >
> > +static void virtnet_update_settings(struct virtnet_info *vi)
> > +{
> > + u32 speed;
> > + u8 duplex;
> > +
> > + if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_SPEED_DUPLEX))
> > + return;
> > +
> > + virtio_cread_le(vi->vdev, struct virtio_net_config, speed, &speed);
> > +
> > + if (ethtool_validate_speed(speed))
> > + vi->speed = speed;
> > +
> > + virtio_cread_le(vi->vdev, struct virtio_net_config, duplex, &duplex);
> > +
> > + if (ethtool_validate_duplex(duplex))
> > + vi->duplex = duplex;
> > +}
> > +
> > static int virtnet_open(struct net_device *dev)
> > {
> > struct virtnet_info *vi = netdev_priv(dev);
> > @@ -2486,6 +2505,22 @@ static int virtnet_open(struct net_device *dev)
> > goto err_enable_qp;
> > }
> >
> > + /* Assume link up if device can't report link status,
> > + otherwise get link status from config. */
> > + netif_carrier_off(dev);
> > + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > + virtio_config_enable(vi->vdev);
> > + /* We are not sure if config interrupt is disabled by
> > + * core or not, so we can't schedule config_work by
> > + * ourselves.
> > + */
>
> This comment confuses more than it explains.
> You seem to be arguing about some alternative design
> you had in mind, but readers don't have it in mind.
>
>
> Please just explain what this does and why.
> For what: something like "Trigger re-read of config - same
> as we'd do if config changed".
>
> Now, please do what you don't do here: explain the why:
>
>
> why do we want all these VM
> exits on each open/close as opposed to once on probe and later on
> config changed interrupt.

Fine, the main reason is that a config interrupt might be pending
during ifdown and core may disable configure interrupt due to several
reasons.

Thanks

>
>
> > + virtio_config_changed(vi->vdev);
> > + } else {
> > + vi->status = VIRTIO_NET_S_LINK_UP;
> > + virtnet_update_settings(vi);
> > + netif_carrier_on(dev);
> > + }
> > +
> > return 0;
> >
> > err_enable_qp:
> > @@ -2928,12 +2963,19 @@ static int virtnet_close(struct net_device *dev)
> > disable_delayed_refill(vi);
> > /* Make sure refill_work doesn't re-enable napi! */
> > cancel_delayed_work_sync(&vi->refill);
> > + /* Make sure config notification doesn't schedule config work */
> > + virtio_config_disable(vi->vdev);
> > + /* Make sure status updating is cancelled */
> > + cancel_work_sync(&vi->config_work);
> >
> > for (i = 0; i < vi->max_queue_pairs; i++) {
> > virtnet_disable_queue_pair(vi, i);
> > cancel_work_sync(&vi->rq[i].dim.work);
> > }
> >
> > + vi->status &= ~VIRTIO_NET_S_LINK_UP;
> > + netif_carrier_off(dev);
> > +
> > return 0;
> > }
> >
> > @@ -4632,25 +4674,6 @@ static void virtnet_init_settings(struct net_device *dev)
> > vi->duplex = DUPLEX_UNKNOWN;
> > }
> >
> > -static void virtnet_update_settings(struct virtnet_info *vi)
> > -{
> > - u32 speed;
> > - u8 duplex;
> > -
> > - if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_SPEED_DUPLEX))
> > - return;
> > -
> > - virtio_cread_le(vi->vdev, struct virtio_net_config, speed, &speed);
> > -
> > - if (ethtool_validate_speed(speed))
> > - vi->speed = speed;
> > -
> > - virtio_cread_le(vi->vdev, struct virtio_net_config, duplex, &duplex);
> > -
> > - if (ethtool_validate_duplex(duplex))
> > - vi->duplex = duplex;
> > -}
> > -
> > static u32 virtnet_get_rxfh_key_size(struct net_device *dev)
> > {
> > return ((struct virtnet_info *)netdev_priv(dev))->rss_key_size;
> > @@ -5958,17 +5981,6 @@ static int virtnet_probe(struct virtio_device *vdev)
> > goto free_unregister_netdev;
> > }
> >
> > - /* Assume link up if device can't report link status,
> > - otherwise get link status from config. */
> > - netif_carrier_off(dev);
> > - if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > - schedule_work(&vi->config_work);
> > - } else {
> > - vi->status = VIRTIO_NET_S_LINK_UP;
> > - virtnet_update_settings(vi);
> > - netif_carrier_on(dev);
> > - }
> > -
> > for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
> > if (virtio_has_feature(vi->vdev, guest_offloads[i]))
> > set_bit(guest_offloads[i], &vi->guest_offloads);
> > --
> > 2.31.1
>