diff mbox series

[V4,net-next,3/3] virtio-net: synchronize operstate with admin state on up/down

Message ID 20240731025947.23157-4-jasowang@redhat.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series virtio-net: synchronize op/admin state | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 42 this patch: 42
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 9 of 9 maintainers
netdev/build_clang success Errors and warnings before: 43 this patch: 43
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 44 this patch: 44
netdev/checkpatch fail CHECK: Please don't use multiple blank lines ERROR: code indent should use tabs where possible WARNING: Block comments use * on subsequent lines WARNING: Block comments use a trailing */ on a separate line WARNING: please, no spaces at the start of a line
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-07-31--12-00 (tests: 707)

Commit Message

Jason Wang July 31, 2024, 2:59 a.m. UTC
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 | 84 ++++++++++++++++++++++++++--------------
 1 file changed, 54 insertions(+), 30 deletions(-)

Comments

Michael S. Tsirkin July 31, 2024, 9:25 p.m. UTC | #1
On Wed, Jul 31, 2024 at 10:59:47AM +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>

Changelog?

> ---
>  drivers/net/virtio_net.c | 84 ++++++++++++++++++++++++++--------------
>  1 file changed, 54 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 0383a3e136d6..0cb93261eba1 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2878,6 +2878,7 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
>  	return err;
>  }
>  
> +
>  static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
>  {
>  	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))

hmm

> @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
>  	net_dim_work_cancel(dim);
>  }
>  
> +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;
> +}
> +

I already commented on this approach.  This is now invoked on each open,
lots of extra VM exits. No bueno, people are working hard to keep setup
overhead under control. Handle this in the config change interrupt -
your new infrastructure is perfect for this.


>  static int virtnet_open(struct net_device *dev)
>  {
>  	struct virtnet_info *vi = netdev_priv(dev);
> @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
>  			goto err_enable_qp;
>  	}
>  
> +	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> +		if (vi->status & VIRTIO_NET_S_LINK_UP)
> +			netif_carrier_on(vi->dev);
> +		virtio_config_driver_enable(vi->vdev);
> +	} else {
> +		vi->status = VIRTIO_NET_S_LINK_UP;
> +		netif_carrier_on(dev);
> +		virtnet_update_settings(vi);
> +	}
> +
>  	return 0;
>  
>  err_enable_qp:
> @@ -3381,12 +3411,18 @@ 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 */

it's clear what this does even without a comment.
what you should comment on, and do not, is *why*.

> +	virtio_config_driver_disable(vi->vdev);
> +	/* Make sure status updating is cancelled */

same

also what "status updating"? confuses more than this clarifies.

> +	cancel_work_sync(&vi->config_work);
>  
>  	for (i = 0; i < vi->max_queue_pairs; i++) {
>  		virtnet_disable_queue_pair(vi, i);
>  		virtnet_cancel_dim(vi, &vi->rq[i].dim);
>  	}
>  
> +	netif_carrier_off(dev);
> +
>  	return 0;
>  }
>  
> @@ -5085,25 +5121,6 @@ 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;
> @@ -6514,6 +6531,11 @@ static int virtnet_probe(struct virtio_device *vdev)
>  		goto free_failover;
>  	}
>  
> +	/* Forbid config change notification until ndo_open. */

notifications

Disable, not forbid.

> +	virtio_config_driver_disable(vi->vdev);
> +	/* Make sure status updating work is done */



> +	cancel_work_sync(&vi->config_work);
> +
>  	virtio_device_ready(vdev);
>  
>  	virtnet_set_queues(vi, vi->curr_queue_pairs);
> @@ -6563,6 +6585,19 @@ static int virtnet_probe(struct virtio_device *vdev)
>  		vi->device_stats_cap = le64_to_cpu(v);
>  	}
>  
> +	/* 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)) {
> +		/* This is safe as config notification change has been

config change notification

> +		   disabled. */
> +                virtnet_config_changed_work(&vi->config_work);
> +        } else {
> +                vi->status = VIRTIO_NET_S_LINK_UP;
> +                virtnet_update_settings(vi);
> +                netif_carrier_on(dev);
> +        }
> +
>  	rtnl_unlock();
>  
>  	err = virtnet_cpu_notif_add(vi);
> @@ -6571,17 +6606,6 @@ 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
Jason Wang Aug. 1, 2024, 2:16 a.m. UTC | #2
On Thu, Aug 1, 2024 at 5:26 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Wed, Jul 31, 2024 at 10:59:47AM +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>
>
> Changelog?

In the cover letter actually.

>
> > ---
> >  drivers/net/virtio_net.c | 84 ++++++++++++++++++++++++++--------------
> >  1 file changed, 54 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index 0383a3e136d6..0cb93261eba1 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -2878,6 +2878,7 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
> >       return err;
> >  }
> >
> > +
> >  static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> >  {
> >       if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
>
> hmm
>
> > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> >       net_dim_work_cancel(dim);
> >  }
> >
> > +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;
> > +}
> > +
>
> I already commented on this approach.  This is now invoked on each open,
> lots of extra VM exits. No bueno, people are working hard to keep setup
> overhead under control. Handle this in the config change interrupt -
> your new infrastructure is perfect for this.

No, in this version it doesn't. Config space read only happens if
there's a pending config interrupt during ndo_open:

+       if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
+               if (vi->status & VIRTIO_NET_S_LINK_UP)
+                       netif_carrier_on(vi->dev);
+               virtio_config_driver_enable(vi->vdev);
+       } else {
+               vi->status = VIRTIO_NET_S_LINK_UP;
+               netif_carrier_on(dev);
+               virtnet_update_settings(vi);
+       }

>
>
> >  static int virtnet_open(struct net_device *dev)
> >  {
> >       struct virtnet_info *vi = netdev_priv(dev);
> > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> >                       goto err_enable_qp;
> >       }
> >
> > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > +                     netif_carrier_on(vi->dev);
> > +             virtio_config_driver_enable(vi->vdev);
> > +     } else {
> > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > +             netif_carrier_on(dev);
> > +             virtnet_update_settings(vi);
> > +     }
> > +
> >       return 0;
> >
> >  err_enable_qp:
> > @@ -3381,12 +3411,18 @@ 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 */
>
> it's clear what this does even without a comment.
> what you should comment on, and do not, is *why*.

Well, it just follows the existing style, for example the above said

"/* Make sure refill_work doesn't re-enable napi! */"

>
> > +     virtio_config_driver_disable(vi->vdev);
> > +     /* Make sure status updating is cancelled */
>
> same
>
> also what "status updating"? confuses more than this clarifies.

Does "Make sure the config changed work is cancelled" sounds better?

>
> > +     cancel_work_sync(&vi->config_work);
> >
> >       for (i = 0; i < vi->max_queue_pairs; i++) {
> >               virtnet_disable_queue_pair(vi, i);
> >               virtnet_cancel_dim(vi, &vi->rq[i].dim);
> >       }
> >
> > +     netif_carrier_off(dev);
> > +
> >       return 0;
> >  }
> >
> > @@ -5085,25 +5121,6 @@ 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;
> > @@ -6514,6 +6531,11 @@ static int virtnet_probe(struct virtio_device *vdev)
> >               goto free_failover;
> >       }
> >
> > +     /* Forbid config change notification until ndo_open. */
>
> notifications
>
> Disable, not forbid.

Ok.

>
> > +     virtio_config_driver_disable(vi->vdev);
> > +     /* Make sure status updating work is done */
>
>
>
> > +     cancel_work_sync(&vi->config_work);
> > +
> >       virtio_device_ready(vdev);
> >
> >       virtnet_set_queues(vi, vi->curr_queue_pairs);
> > @@ -6563,6 +6585,19 @@ static int virtnet_probe(struct virtio_device *vdev)
> >               vi->device_stats_cap = le64_to_cpu(v);
> >       }
> >
> > +     /* 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)) {
> > +             /* This is safe as config notification change has been
>
> config change notification
>
> > +                disabled. */
> > +                virtnet_config_changed_work(&vi->config_work);
> > +        } else {
> > +                vi->status = VIRTIO_NET_S_LINK_UP;
> > +                virtnet_update_settings(vi);
> > +                netif_carrier_on(dev);
> > +        }
> > +
> >       rtnl_unlock();
> >
> >       err = virtnet_cpu_notif_add(vi);
> > @@ -6571,17 +6606,6 @@ 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
>
Michael S. Tsirkin Aug. 1, 2024, 5:58 a.m. UTC | #3
On Thu, Aug 01, 2024 at 10:16:00AM +0800, Jason Wang wrote:
> > > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > >       net_dim_work_cancel(dim);
> > >  }
> > >
> > > +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;
> > > +}
> > > +
> >
> > I already commented on this approach.  This is now invoked on each open,
> > lots of extra VM exits. No bueno, people are working hard to keep setup
> > overhead under control. Handle this in the config change interrupt -
> > your new infrastructure is perfect for this.
> 
> No, in this version it doesn't. Config space read only happens if
> there's a pending config interrupt during ndo_open:
> 
> +       if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> +               if (vi->status & VIRTIO_NET_S_LINK_UP)
> +                       netif_carrier_on(vi->dev);
> +               virtio_config_driver_enable(vi->vdev);
> +       } else {
> +               vi->status = VIRTIO_NET_S_LINK_UP;
> +               netif_carrier_on(dev);
> +               virtnet_update_settings(vi);
> +       }

Sorry for being unclear, I was referring to !VIRTIO_NET_F_STATUS.
I do not see why do we need to bother re-reading settings in this case at all,
status is not there, nothing much changes.


> >
> >
> > >  static int virtnet_open(struct net_device *dev)
> > >  {
> > >       struct virtnet_info *vi = netdev_priv(dev);
> > > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> > >                       goto err_enable_qp;
> > >       }
> > >
> > > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > +                     netif_carrier_on(vi->dev);
> > > +             virtio_config_driver_enable(vi->vdev);
> > > +     } else {
> > > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > > +             netif_carrier_on(dev);
> > > +             virtnet_update_settings(vi);
> > > +     }
> > > +
> > >       return 0;
> > >
> > >  err_enable_qp:
> > > @@ -3381,12 +3411,18 @@ 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 */
> >
> > it's clear what this does even without a comment.
> > what you should comment on, and do not, is *why*.
> 
> Well, it just follows the existing style, for example the above said
> 
> "/* Make sure refill_work doesn't re-enable napi! */"

only at the grammar level.
you don't see the difference?

        /* Make sure refill_work doesn't re-enable napi! */
        cancel_delayed_work_sync(&vi->refill);

it explains why we cancel: to avoid re-enabling napi.

why do you cancel config callback and work?
comment should say that.



> >
> > > +     virtio_config_driver_disable(vi->vdev);
> > > +     /* Make sure status updating is cancelled */
> >
> > same
> >
> > also what "status updating"? confuses more than this clarifies.
> 
> Does "Make sure the config changed work is cancelled" sounds better?

no, this just repeats what code does.
explain why you cancel it.
Michael S. Tsirkin Aug. 1, 2024, 6:05 a.m. UTC | #4
On Wed, Jul 31, 2024 at 10:59:47AM +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 | 84 ++++++++++++++++++++++++++--------------
>  1 file changed, 54 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 0383a3e136d6..0cb93261eba1 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2878,6 +2878,7 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
>  	return err;
>  }
>  
> +
>  static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
>  {
>  	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
> @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
>  	net_dim_work_cancel(dim);
>  }
>  
> +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);
> @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
>  			goto err_enable_qp;
>  	}
>  
> +	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> +		if (vi->status & VIRTIO_NET_S_LINK_UP)
> +			netif_carrier_on(vi->dev);
> +		virtio_config_driver_enable(vi->vdev);
> +	} else {
> +		vi->status = VIRTIO_NET_S_LINK_UP;
> +		netif_carrier_on(dev);
> +		virtnet_update_settings(vi);
> +	}
> +
>  	return 0;
>  
>  err_enable_qp:
> @@ -3381,12 +3411,18 @@ 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_driver_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);
>  		virtnet_cancel_dim(vi, &vi->rq[i].dim);
>  	}
>  
> +	netif_carrier_off(dev);
> +
>  	return 0;
>  }
>  
> @@ -5085,25 +5121,6 @@ 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;
> @@ -6514,6 +6531,11 @@ static int virtnet_probe(struct virtio_device *vdev)
>  		goto free_failover;
>  	}
>  
> +	/* Forbid config change notification until ndo_open. */
> +	virtio_config_driver_disable(vi->vdev);
> +	/* Make sure status updating work is done */

Wait a second, how can anything run here, this is probe,
config change callbacks are never invoked at all.

> +	cancel_work_sync(&vi->config_work);
> +


this is pointless, too.

>  	virtio_device_ready(vdev);
>  
>  	virtnet_set_queues(vi, vi->curr_queue_pairs);
> @@ -6563,6 +6585,19 @@ static int virtnet_probe(struct virtio_device *vdev)
>  		vi->device_stats_cap = le64_to_cpu(v);
>  	}
>  
> +	/* 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)) {
> +		/* This is safe as config notification change has been
> +		   disabled. */

What "this"? pls explain what this does: get config data from
device.

Actually not because it was disabled. probe can poke at
config with impunity no change callbacks trigger during probe.

> +                virtnet_config_changed_work(&vi->config_work);




> +        } else {
> +                vi->status = VIRTIO_NET_S_LINK_UP;
> +                virtnet_update_settings(vi);
> +                netif_carrier_on(dev);
> +        }
> +
>  	rtnl_unlock();
>  
>  	err = virtnet_cpu_notif_add(vi);
> @@ -6571,17 +6606,6 @@ 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
Jason Wang Aug. 1, 2024, 6:13 a.m. UTC | #5
On Thu, Aug 1, 2024 at 1:58 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Thu, Aug 01, 2024 at 10:16:00AM +0800, Jason Wang wrote:
> > > > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > > >       net_dim_work_cancel(dim);
> > > >  }
> > > >
> > > > +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;
> > > > +}
> > > > +
> > >
> > > I already commented on this approach.  This is now invoked on each open,
> > > lots of extra VM exits. No bueno, people are working hard to keep setup
> > > overhead under control. Handle this in the config change interrupt -
> > > your new infrastructure is perfect for this.
> >
> > No, in this version it doesn't. Config space read only happens if
> > there's a pending config interrupt during ndo_open:
> >
> > +       if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > +               if (vi->status & VIRTIO_NET_S_LINK_UP)
> > +                       netif_carrier_on(vi->dev);
> > +               virtio_config_driver_enable(vi->vdev);
> > +       } else {
> > +               vi->status = VIRTIO_NET_S_LINK_UP;
> > +               netif_carrier_on(dev);
> > +               virtnet_update_settings(vi);
> > +       }
>
> Sorry for being unclear, I was referring to !VIRTIO_NET_F_STATUS.
> I do not see why do we need to bother re-reading settings in this case at all,
> status is not there, nothing much changes.

Ok, let me remove it from the next version.

>
>
> > >
> > >
> > > >  static int virtnet_open(struct net_device *dev)
> > > >  {
> > > >       struct virtnet_info *vi = netdev_priv(dev);
> > > > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> > > >                       goto err_enable_qp;
> > > >       }
> > > >
> > > > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > > +                     netif_carrier_on(vi->dev);
> > > > +             virtio_config_driver_enable(vi->vdev);
> > > > +     } else {
> > > > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > > > +             netif_carrier_on(dev);
> > > > +             virtnet_update_settings(vi);
> > > > +     }
> > > > +
> > > >       return 0;
> > > >
> > > >  err_enable_qp:
> > > > @@ -3381,12 +3411,18 @@ 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 */
> > >
> > > it's clear what this does even without a comment.
> > > what you should comment on, and do not, is *why*.
> >
> > Well, it just follows the existing style, for example the above said
> >
> > "/* Make sure refill_work doesn't re-enable napi! */"
>
> only at the grammar level.
> you don't see the difference?
>
>         /* Make sure refill_work doesn't re-enable napi! */
>         cancel_delayed_work_sync(&vi->refill);
>
> it explains why we cancel: to avoid re-enabling napi.
>
> why do you cancel config callback and work?
> comment should say that.

Something like "Prevent the config change callback from changing
carrier after close"?

>
>
>
> > >
> > > > +     virtio_config_driver_disable(vi->vdev);
> > > > +     /* Make sure status updating is cancelled */
> > >
> > > same
> > >
> > > also what "status updating"? confuses more than this clarifies.
> >
> > Does "Make sure the config changed work is cancelled" sounds better?
>
> no, this just repeats what code does.
> explain why you cancel it.

Does something like "Make sure carrier changes have been done by the
config change callback" works?

Thanks

>
>
>
> --
> MST
>
Jason Wang Aug. 1, 2024, 6:13 a.m. UTC | #6
On Thu, Aug 1, 2024 at 2:06 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Wed, Jul 31, 2024 at 10:59:47AM +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 | 84 ++++++++++++++++++++++++++--------------
> >  1 file changed, 54 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index 0383a3e136d6..0cb93261eba1 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -2878,6 +2878,7 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
> >       return err;
> >  }
> >
> > +
> >  static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> >  {
> >       if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
> > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> >       net_dim_work_cancel(dim);
> >  }
> >
> > +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);
> > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> >                       goto err_enable_qp;
> >       }
> >
> > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > +                     netif_carrier_on(vi->dev);
> > +             virtio_config_driver_enable(vi->vdev);
> > +     } else {
> > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > +             netif_carrier_on(dev);
> > +             virtnet_update_settings(vi);
> > +     }
> > +
> >       return 0;
> >
> >  err_enable_qp:
> > @@ -3381,12 +3411,18 @@ 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_driver_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);
> >               virtnet_cancel_dim(vi, &vi->rq[i].dim);
> >       }
> >
> > +     netif_carrier_off(dev);
> > +
> >       return 0;
> >  }
> >
> > @@ -5085,25 +5121,6 @@ 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;
> > @@ -6514,6 +6531,11 @@ static int virtnet_probe(struct virtio_device *vdev)
> >               goto free_failover;
> >       }
> >
> > +     /* Forbid config change notification until ndo_open. */
> > +     virtio_config_driver_disable(vi->vdev);
> > +     /* Make sure status updating work is done */
>
> Wait a second, how can anything run here, this is probe,
> config change callbacks are never invoked at all.

For buggy devices.

>
> > +     cancel_work_sync(&vi->config_work);
> > +
>
>
> this is pointless, too.
>
> >       virtio_device_ready(vdev);
> >
> >       virtnet_set_queues(vi, vi->curr_queue_pairs);
> > @@ -6563,6 +6585,19 @@ static int virtnet_probe(struct virtio_device *vdev)
> >               vi->device_stats_cap = le64_to_cpu(v);
> >       }
> >
> > +     /* 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)) {
> > +             /* This is safe as config notification change has been
> > +                disabled. */
>
> What "this"? pls explain what this does: get config data from
> device.
>
> Actually not because it was disabled. probe can poke at
> config with impunity no change callbacks trigger during probe.

Only if we have a good device.

>
> > +                virtnet_config_changed_work(&vi->config_work);
>
>
>

Thanks


>
> > +        } else {
> > +                vi->status = VIRTIO_NET_S_LINK_UP;
> > +                virtnet_update_settings(vi);
> > +                netif_carrier_on(dev);
> > +        }
> > +
> >       rtnl_unlock();
> >
> >       err = virtnet_cpu_notif_add(vi);
> > @@ -6571,17 +6606,6 @@ 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
>
Michael S. Tsirkin Aug. 1, 2024, 6:41 a.m. UTC | #7
On Thu, Aug 01, 2024 at 02:13:18PM +0800, Jason Wang wrote:
> On Thu, Aug 1, 2024 at 1:58 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Thu, Aug 01, 2024 at 10:16:00AM +0800, Jason Wang wrote:
> > > > > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > > > >       net_dim_work_cancel(dim);
> > > > >  }
> > > > >
> > > > > +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;
> > > > > +}
> > > > > +
> > > >
> > > > I already commented on this approach.  This is now invoked on each open,
> > > > lots of extra VM exits. No bueno, people are working hard to keep setup
> > > > overhead under control. Handle this in the config change interrupt -
> > > > your new infrastructure is perfect for this.
> > >
> > > No, in this version it doesn't. Config space read only happens if
> > > there's a pending config interrupt during ndo_open:
> > >
> > > +       if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > +               if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > +                       netif_carrier_on(vi->dev);
> > > +               virtio_config_driver_enable(vi->vdev);
> > > +       } else {
> > > +               vi->status = VIRTIO_NET_S_LINK_UP;
> > > +               netif_carrier_on(dev);
> > > +               virtnet_update_settings(vi);
> > > +       }
> >
> > Sorry for being unclear, I was referring to !VIRTIO_NET_F_STATUS.
> > I do not see why do we need to bother re-reading settings in this case at all,
> > status is not there, nothing much changes.
> 
> Ok, let me remove it from the next version.
> 
> >
> >
> > > >
> > > >
> > > > >  static int virtnet_open(struct net_device *dev)
> > > > >  {
> > > > >       struct virtnet_info *vi = netdev_priv(dev);
> > > > > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> > > > >                       goto err_enable_qp;
> > > > >       }
> > > > >
> > > > > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > > > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > > > +                     netif_carrier_on(vi->dev);
> > > > > +             virtio_config_driver_enable(vi->vdev);
> > > > > +     } else {
> > > > > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > > > > +             netif_carrier_on(dev);
> > > > > +             virtnet_update_settings(vi);
> > > > > +     }
> > > > > +
> > > > >       return 0;
> > > > >
> > > > >  err_enable_qp:
> > > > > @@ -3381,12 +3411,18 @@ 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 */
> > > >
> > > > it's clear what this does even without a comment.
> > > > what you should comment on, and do not, is *why*.
> > >
> > > Well, it just follows the existing style, for example the above said
> > >
> > > "/* Make sure refill_work doesn't re-enable napi! */"
> >
> > only at the grammar level.
> > you don't see the difference?
> >
> >         /* Make sure refill_work doesn't re-enable napi! */
> >         cancel_delayed_work_sync(&vi->refill);
> >
> > it explains why we cancel: to avoid re-enabling napi.
> >
> > why do you cancel config callback and work?
> > comment should say that.
> 
> Something like "Prevent the config change callback from changing
> carrier after close"?


sounds good.

> >
> >
> >
> > > >
> > > > > +     virtio_config_driver_disable(vi->vdev);
> > > > > +     /* Make sure status updating is cancelled */
> > > >
> > > > same
> > > >
> > > > also what "status updating"? confuses more than this clarifies.
> > >
> > > Does "Make sure the config changed work is cancelled" sounds better?
> >
> > no, this just repeats what code does.
> > explain why you cancel it.
> 
> Does something like "Make sure carrier changes have been done by the
> config change callback" works?
> 
> Thanks

I don't understand what this means.

> >
> >
> >
> > --
> > MST
> >
Michael S. Tsirkin Aug. 1, 2024, 6:42 a.m. UTC | #8
On Thu, Aug 01, 2024 at 02:13:49PM +0800, Jason Wang wrote:
> On Thu, Aug 1, 2024 at 2:06 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Wed, Jul 31, 2024 at 10:59:47AM +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 | 84 ++++++++++++++++++++++++++--------------
> > >  1 file changed, 54 insertions(+), 30 deletions(-)
> > >
> > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > > index 0383a3e136d6..0cb93261eba1 100644
> > > --- a/drivers/net/virtio_net.c
> > > +++ b/drivers/net/virtio_net.c
> > > @@ -2878,6 +2878,7 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
> > >       return err;
> > >  }
> > >
> > > +
> > >  static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > >  {
> > >       if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
> > > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > >       net_dim_work_cancel(dim);
> > >  }
> > >
> > > +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);
> > > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> > >                       goto err_enable_qp;
> > >       }
> > >
> > > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > +                     netif_carrier_on(vi->dev);
> > > +             virtio_config_driver_enable(vi->vdev);
> > > +     } else {
> > > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > > +             netif_carrier_on(dev);
> > > +             virtnet_update_settings(vi);
> > > +     }
> > > +
> > >       return 0;
> > >
> > >  err_enable_qp:
> > > @@ -3381,12 +3411,18 @@ 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_driver_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);
> > >               virtnet_cancel_dim(vi, &vi->rq[i].dim);
> > >       }
> > >
> > > +     netif_carrier_off(dev);
> > > +
> > >       return 0;
> > >  }
> > >
> > > @@ -5085,25 +5121,6 @@ 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;
> > > @@ -6514,6 +6531,11 @@ static int virtnet_probe(struct virtio_device *vdev)
> > >               goto free_failover;
> > >       }
> > >
> > > +     /* Forbid config change notification until ndo_open. */
> > > +     virtio_config_driver_disable(vi->vdev);
> > > +     /* Make sure status updating work is done */
> >
> > Wait a second, how can anything run here, this is probe,
> > config change callbacks are never invoked at all.
> 
> For buggy devices.

buggy or not, virtio core will not invoke callbacks until
after probe and scan.

> >
> > > +     cancel_work_sync(&vi->config_work);
> > > +
> >
> >
> > this is pointless, too.
> >
> > >       virtio_device_ready(vdev);
> > >
> > >       virtnet_set_queues(vi, vi->curr_queue_pairs);
> > > @@ -6563,6 +6585,19 @@ static int virtnet_probe(struct virtio_device *vdev)
> > >               vi->device_stats_cap = le64_to_cpu(v);
> > >       }
> > >
> > > +     /* 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)) {
> > > +             /* This is safe as config notification change has been
> > > +                disabled. */
> >
> > What "this"? pls explain what this does: get config data from
> > device.
> >
> > Actually not because it was disabled. probe can poke at
> > config with impunity no change callbacks trigger during probe.
> 
> Only if we have a good device.

not if you read the core code.

> >
> > > +                virtnet_config_changed_work(&vi->config_work);
> >
> >
> >
> 
> Thanks
> 
> 
> >
> > > +        } else {
> > > +                vi->status = VIRTIO_NET_S_LINK_UP;
> > > +                virtnet_update_settings(vi);
> > > +                netif_carrier_on(dev);
> > > +        }
> > > +
> > >       rtnl_unlock();
> > >
> > >       err = virtnet_cpu_notif_add(vi);
> > > @@ -6571,17 +6606,6 @@ 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
> >
Jason Wang Aug. 1, 2024, 6:55 a.m. UTC | #9
On Thu, Aug 1, 2024 at 2:42 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Thu, Aug 01, 2024 at 02:13:18PM +0800, Jason Wang wrote:
> > On Thu, Aug 1, 2024 at 1:58 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > >
> > > On Thu, Aug 01, 2024 at 10:16:00AM +0800, Jason Wang wrote:
> > > > > > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > > > > >       net_dim_work_cancel(dim);
> > > > > >  }
> > > > > >
> > > > > > +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;
> > > > > > +}
> > > > > > +
> > > > >
> > > > > I already commented on this approach.  This is now invoked on each open,
> > > > > lots of extra VM exits. No bueno, people are working hard to keep setup
> > > > > overhead under control. Handle this in the config change interrupt -
> > > > > your new infrastructure is perfect for this.
> > > >
> > > > No, in this version it doesn't. Config space read only happens if
> > > > there's a pending config interrupt during ndo_open:
> > > >
> > > > +       if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > > +               if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > > +                       netif_carrier_on(vi->dev);
> > > > +               virtio_config_driver_enable(vi->vdev);
> > > > +       } else {
> > > > +               vi->status = VIRTIO_NET_S_LINK_UP;
> > > > +               netif_carrier_on(dev);
> > > > +               virtnet_update_settings(vi);
> > > > +       }
> > >
> > > Sorry for being unclear, I was referring to !VIRTIO_NET_F_STATUS.
> > > I do not see why do we need to bother re-reading settings in this case at all,
> > > status is not there, nothing much changes.
> >
> > Ok, let me remove it from the next version.
> >
> > >
> > >
> > > > >
> > > > >
> > > > > >  static int virtnet_open(struct net_device *dev)
> > > > > >  {
> > > > > >       struct virtnet_info *vi = netdev_priv(dev);
> > > > > > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> > > > > >                       goto err_enable_qp;
> > > > > >       }
> > > > > >
> > > > > > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > > > > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > > > > +                     netif_carrier_on(vi->dev);
> > > > > > +             virtio_config_driver_enable(vi->vdev);
> > > > > > +     } else {
> > > > > > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > > > > > +             netif_carrier_on(dev);
> > > > > > +             virtnet_update_settings(vi);
> > > > > > +     }
> > > > > > +
> > > > > >       return 0;
> > > > > >
> > > > > >  err_enable_qp:
> > > > > > @@ -3381,12 +3411,18 @@ 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 */
> > > > >
> > > > > it's clear what this does even without a comment.
> > > > > what you should comment on, and do not, is *why*.
> > > >
> > > > Well, it just follows the existing style, for example the above said
> > > >
> > > > "/* Make sure refill_work doesn't re-enable napi! */"
> > >
> > > only at the grammar level.
> > > you don't see the difference?
> > >
> > >         /* Make sure refill_work doesn't re-enable napi! */
> > >         cancel_delayed_work_sync(&vi->refill);
> > >
> > > it explains why we cancel: to avoid re-enabling napi.
> > >
> > > why do you cancel config callback and work?
> > > comment should say that.
> >
> > Something like "Prevent the config change callback from changing
> > carrier after close"?
>
>
> sounds good.
>
> > >
> > >
> > >
> > > > >
> > > > > > +     virtio_config_driver_disable(vi->vdev);
> > > > > > +     /* Make sure status updating is cancelled */
> > > > >
> > > > > same
> > > > >
> > > > > also what "status updating"? confuses more than this clarifies.
> > > >
> > > > Does "Make sure the config changed work is cancelled" sounds better?
> > >
> > > no, this just repeats what code does.
> > > explain why you cancel it.
> >
> > Does something like "Make sure carrier changes have been done by the
> > config change callback" works?
> >
> > Thanks
>
> I don't understand what this means.

Maybe "Ensure the configuration change callback successfully modifies
the carrier status"?

Thanks

>
> > >
> > >
> > >
> > > --
> > > MST
> > >
>
Jason Wang Aug. 1, 2024, 6:55 a.m. UTC | #10
On Thu, Aug 1, 2024 at 2:43 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Thu, Aug 01, 2024 at 02:13:49PM +0800, Jason Wang wrote:
> > On Thu, Aug 1, 2024 at 2:06 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > >
> > > On Wed, Jul 31, 2024 at 10:59:47AM +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 | 84 ++++++++++++++++++++++++++--------------
> > > >  1 file changed, 54 insertions(+), 30 deletions(-)
> > > >
> > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > > > index 0383a3e136d6..0cb93261eba1 100644
> > > > --- a/drivers/net/virtio_net.c
> > > > +++ b/drivers/net/virtio_net.c
> > > > @@ -2878,6 +2878,7 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
> > > >       return err;
> > > >  }
> > > >
> > > > +
> > > >  static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > > >  {
> > > >       if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
> > > > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > > >       net_dim_work_cancel(dim);
> > > >  }
> > > >
> > > > +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);
> > > > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> > > >                       goto err_enable_qp;
> > > >       }
> > > >
> > > > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > > +                     netif_carrier_on(vi->dev);
> > > > +             virtio_config_driver_enable(vi->vdev);
> > > > +     } else {
> > > > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > > > +             netif_carrier_on(dev);
> > > > +             virtnet_update_settings(vi);
> > > > +     }
> > > > +
> > > >       return 0;
> > > >
> > > >  err_enable_qp:
> > > > @@ -3381,12 +3411,18 @@ 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_driver_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);
> > > >               virtnet_cancel_dim(vi, &vi->rq[i].dim);
> > > >       }
> > > >
> > > > +     netif_carrier_off(dev);
> > > > +
> > > >       return 0;
> > > >  }
> > > >
> > > > @@ -5085,25 +5121,6 @@ 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;
> > > > @@ -6514,6 +6531,11 @@ static int virtnet_probe(struct virtio_device *vdev)
> > > >               goto free_failover;
> > > >       }
> > > >
> > > > +     /* Forbid config change notification until ndo_open. */
> > > > +     virtio_config_driver_disable(vi->vdev);
> > > > +     /* Make sure status updating work is done */
> > >
> > > Wait a second, how can anything run here, this is probe,
> > > config change callbacks are never invoked at all.
> >
> > For buggy devices.
>
> buggy or not, virtio core will not invoke callbacks until
> after probe and scan.

I think you're right, but we still need the
virtio_config_driver_disable(). Otherwise the config change callback
might race with ndo_open().

>
> > >
> > > > +     cancel_work_sync(&vi->config_work);
> > > > +
> > >
> > >
> > > this is pointless, too.
> > >
> > > >       virtio_device_ready(vdev);
> > > >
> > > >       virtnet_set_queues(vi, vi->curr_queue_pairs);
> > > > @@ -6563,6 +6585,19 @@ static int virtnet_probe(struct virtio_device *vdev)
> > > >               vi->device_stats_cap = le64_to_cpu(v);
> > > >       }
> > > >
> > > > +     /* 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)) {
> > > > +             /* This is safe as config notification change has been
> > > > +                disabled. */
> > >
> > > What "this"? pls explain what this does: get config data from
> > > device.
> > >
> > > Actually not because it was disabled. probe can poke at
> > > config with impunity no change callbacks trigger during probe.
> >
> > Only if we have a good device.
>
> not if you read the core code.

Right after the device is ready the config notification might be
triggered by the device, but the callback will be blocked by the core.

Thanks


>
> > >
> > > > +                virtnet_config_changed_work(&vi->config_work);
> > >
> > >
> > >
> >
> > Thanks
> >
> >
> > >
> > > > +        } else {
> > > > +                vi->status = VIRTIO_NET_S_LINK_UP;
> > > > +                virtnet_update_settings(vi);
> > > > +                netif_carrier_on(dev);
> > > > +        }
> > > > +
> > > >       rtnl_unlock();
> > > >
> > > >       err = virtnet_cpu_notif_add(vi);
> > > > @@ -6571,17 +6606,6 @@ 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
> > >
>
Michael S. Tsirkin Aug. 1, 2024, 7 a.m. UTC | #11
On Thu, Aug 01, 2024 at 02:55:10PM +0800, Jason Wang wrote:
> On Thu, Aug 1, 2024 at 2:42 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Thu, Aug 01, 2024 at 02:13:18PM +0800, Jason Wang wrote:
> > > On Thu, Aug 1, 2024 at 1:58 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > > >
> > > > On Thu, Aug 01, 2024 at 10:16:00AM +0800, Jason Wang wrote:
> > > > > > > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > > > > > >       net_dim_work_cancel(dim);
> > > > > > >  }
> > > > > > >
> > > > > > > +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;
> > > > > > > +}
> > > > > > > +
> > > > > >
> > > > > > I already commented on this approach.  This is now invoked on each open,
> > > > > > lots of extra VM exits. No bueno, people are working hard to keep setup
> > > > > > overhead under control. Handle this in the config change interrupt -
> > > > > > your new infrastructure is perfect for this.
> > > > >
> > > > > No, in this version it doesn't. Config space read only happens if
> > > > > there's a pending config interrupt during ndo_open:
> > > > >
> > > > > +       if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > > > +               if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > > > +                       netif_carrier_on(vi->dev);
> > > > > +               virtio_config_driver_enable(vi->vdev);
> > > > > +       } else {
> > > > > +               vi->status = VIRTIO_NET_S_LINK_UP;
> > > > > +               netif_carrier_on(dev);
> > > > > +               virtnet_update_settings(vi);
> > > > > +       }
> > > >
> > > > Sorry for being unclear, I was referring to !VIRTIO_NET_F_STATUS.
> > > > I do not see why do we need to bother re-reading settings in this case at all,
> > > > status is not there, nothing much changes.
> > >
> > > Ok, let me remove it from the next version.
> > >
> > > >
> > > >
> > > > > >
> > > > > >
> > > > > > >  static int virtnet_open(struct net_device *dev)
> > > > > > >  {
> > > > > > >       struct virtnet_info *vi = netdev_priv(dev);
> > > > > > > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> > > > > > >                       goto err_enable_qp;
> > > > > > >       }
> > > > > > >
> > > > > > > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > > > > > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > > > > > +                     netif_carrier_on(vi->dev);
> > > > > > > +             virtio_config_driver_enable(vi->vdev);
> > > > > > > +     } else {
> > > > > > > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > > > > > > +             netif_carrier_on(dev);
> > > > > > > +             virtnet_update_settings(vi);
> > > > > > > +     }
> > > > > > > +
> > > > > > >       return 0;
> > > > > > >
> > > > > > >  err_enable_qp:
> > > > > > > @@ -3381,12 +3411,18 @@ 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 */
> > > > > >
> > > > > > it's clear what this does even without a comment.
> > > > > > what you should comment on, and do not, is *why*.
> > > > >
> > > > > Well, it just follows the existing style, for example the above said
> > > > >
> > > > > "/* Make sure refill_work doesn't re-enable napi! */"
> > > >
> > > > only at the grammar level.
> > > > you don't see the difference?
> > > >
> > > >         /* Make sure refill_work doesn't re-enable napi! */
> > > >         cancel_delayed_work_sync(&vi->refill);
> > > >
> > > > it explains why we cancel: to avoid re-enabling napi.
> > > >
> > > > why do you cancel config callback and work?
> > > > comment should say that.
> > >
> > > Something like "Prevent the config change callback from changing
> > > carrier after close"?
> >
> >
> > sounds good.
> >
> > > >
> > > >
> > > >
> > > > > >
> > > > > > > +     virtio_config_driver_disable(vi->vdev);
> > > > > > > +     /* Make sure status updating is cancelled */
> > > > > >
> > > > > > same
> > > > > >
> > > > > > also what "status updating"? confuses more than this clarifies.
> > > > >
> > > > > Does "Make sure the config changed work is cancelled" sounds better?
> > > >
> > > > no, this just repeats what code does.
> > > > explain why you cancel it.
> > >
> > > Does something like "Make sure carrier changes have been done by the
> > > config change callback" works?
> > >
> > > Thanks
> >
> > I don't understand what this means.
> 
> Maybe "Ensure the configuration change callback successfully modifies
> the carrier status"?
> 
> Thanks

I don't know what this means either.
Do you mean:

/* Stop getting status/speed updates: we don't care until next open */


> >
> > > >
> > > >
> > > >
> > > > --
> > > > MST
> > > >
> >
Jason Wang Aug. 2, 2024, 2:47 a.m. UTC | #12
On Thu, Aug 1, 2024 at 3:00 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Thu, Aug 01, 2024 at 02:55:10PM +0800, Jason Wang wrote:
> > On Thu, Aug 1, 2024 at 2:42 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > >
> > > On Thu, Aug 01, 2024 at 02:13:18PM +0800, Jason Wang wrote:
> > > > On Thu, Aug 1, 2024 at 1:58 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> > > > >
> > > > > On Thu, Aug 01, 2024 at 10:16:00AM +0800, Jason Wang wrote:
> > > > > > > > @@ -2885,6 +2886,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
> > > > > > > >       net_dim_work_cancel(dim);
> > > > > > > >  }
> > > > > > > >
> > > > > > > > +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;
> > > > > > > > +}
> > > > > > > > +
> > > > > > >
> > > > > > > I already commented on this approach.  This is now invoked on each open,
> > > > > > > lots of extra VM exits. No bueno, people are working hard to keep setup
> > > > > > > overhead under control. Handle this in the config change interrupt -
> > > > > > > your new infrastructure is perfect for this.
> > > > > >
> > > > > > No, in this version it doesn't. Config space read only happens if
> > > > > > there's a pending config interrupt during ndo_open:
> > > > > >
> > > > > > +       if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > > > > +               if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > > > > +                       netif_carrier_on(vi->dev);
> > > > > > +               virtio_config_driver_enable(vi->vdev);
> > > > > > +       } else {
> > > > > > +               vi->status = VIRTIO_NET_S_LINK_UP;
> > > > > > +               netif_carrier_on(dev);
> > > > > > +               virtnet_update_settings(vi);
> > > > > > +       }
> > > > >
> > > > > Sorry for being unclear, I was referring to !VIRTIO_NET_F_STATUS.
> > > > > I do not see why do we need to bother re-reading settings in this case at all,
> > > > > status is not there, nothing much changes.
> > > >
> > > > Ok, let me remove it from the next version.
> > > >
> > > > >
> > > > >
> > > > > > >
> > > > > > >
> > > > > > > >  static int virtnet_open(struct net_device *dev)
> > > > > > > >  {
> > > > > > > >       struct virtnet_info *vi = netdev_priv(dev);
> > > > > > > > @@ -2903,6 +2923,16 @@ static int virtnet_open(struct net_device *dev)
> > > > > > > >                       goto err_enable_qp;
> > > > > > > >       }
> > > > > > > >
> > > > > > > > +     if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> > > > > > > > +             if (vi->status & VIRTIO_NET_S_LINK_UP)
> > > > > > > > +                     netif_carrier_on(vi->dev);
> > > > > > > > +             virtio_config_driver_enable(vi->vdev);
> > > > > > > > +     } else {
> > > > > > > > +             vi->status = VIRTIO_NET_S_LINK_UP;
> > > > > > > > +             netif_carrier_on(dev);
> > > > > > > > +             virtnet_update_settings(vi);
> > > > > > > > +     }
> > > > > > > > +
> > > > > > > >       return 0;
> > > > > > > >
> > > > > > > >  err_enable_qp:
> > > > > > > > @@ -3381,12 +3411,18 @@ 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 */
> > > > > > >
> > > > > > > it's clear what this does even without a comment.
> > > > > > > what you should comment on, and do not, is *why*.
> > > > > >
> > > > > > Well, it just follows the existing style, for example the above said
> > > > > >
> > > > > > "/* Make sure refill_work doesn't re-enable napi! */"
> > > > >
> > > > > only at the grammar level.
> > > > > you don't see the difference?
> > > > >
> > > > >         /* Make sure refill_work doesn't re-enable napi! */
> > > > >         cancel_delayed_work_sync(&vi->refill);
> > > > >
> > > > > it explains why we cancel: to avoid re-enabling napi.
> > > > >
> > > > > why do you cancel config callback and work?
> > > > > comment should say that.
> > > >
> > > > Something like "Prevent the config change callback from changing
> > > > carrier after close"?
> > >
> > >
> > > sounds good.
> > >
> > > > >
> > > > >
> > > > >
> > > > > > >
> > > > > > > > +     virtio_config_driver_disable(vi->vdev);
> > > > > > > > +     /* Make sure status updating is cancelled */
> > > > > > >
> > > > > > > same
> > > > > > >
> > > > > > > also what "status updating"? confuses more than this clarifies.
> > > > > >
> > > > > > Does "Make sure the config changed work is cancelled" sounds better?
> > > > >
> > > > > no, this just repeats what code does.
> > > > > explain why you cancel it.
> > > >
> > > > Does something like "Make sure carrier changes have been done by the
> > > > config change callback" works?
> > > >
> > > > Thanks
> > >
> > > I don't understand what this means.
> >
> > Maybe "Ensure the configuration change callback successfully modifies
> > the carrier status"?
> >
> > Thanks
>
> I don't know what this means either.
> Do you mean:
>
> /* Stop getting status/speed updates: we don't care until next open */

Somehow yes.

Thanks

>
>
> > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > > MST
> > > > >
> > >
>
diff mbox series

Patch

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 0383a3e136d6..0cb93261eba1 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2878,6 +2878,7 @@  static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
 	return err;
 }
 
+
 static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
 {
 	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
@@ -2885,6 +2886,25 @@  static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
 	net_dim_work_cancel(dim);
 }
 
+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);
@@ -2903,6 +2923,16 @@  static int virtnet_open(struct net_device *dev)
 			goto err_enable_qp;
 	}
 
+	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
+		if (vi->status & VIRTIO_NET_S_LINK_UP)
+			netif_carrier_on(vi->dev);
+		virtio_config_driver_enable(vi->vdev);
+	} else {
+		vi->status = VIRTIO_NET_S_LINK_UP;
+		netif_carrier_on(dev);
+		virtnet_update_settings(vi);
+	}
+
 	return 0;
 
 err_enable_qp:
@@ -3381,12 +3411,18 @@  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_driver_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);
 		virtnet_cancel_dim(vi, &vi->rq[i].dim);
 	}
 
+	netif_carrier_off(dev);
+
 	return 0;
 }
 
@@ -5085,25 +5121,6 @@  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;
@@ -6514,6 +6531,11 @@  static int virtnet_probe(struct virtio_device *vdev)
 		goto free_failover;
 	}
 
+	/* Forbid config change notification until ndo_open. */
+	virtio_config_driver_disable(vi->vdev);
+	/* Make sure status updating work is done */
+	cancel_work_sync(&vi->config_work);
+
 	virtio_device_ready(vdev);
 
 	virtnet_set_queues(vi, vi->curr_queue_pairs);
@@ -6563,6 +6585,19 @@  static int virtnet_probe(struct virtio_device *vdev)
 		vi->device_stats_cap = le64_to_cpu(v);
 	}
 
+	/* 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)) {
+		/* This is safe as config notification change has been
+		   disabled. */
+                virtnet_config_changed_work(&vi->config_work);
+        } else {
+                vi->status = VIRTIO_NET_S_LINK_UP;
+                virtnet_update_settings(vi);
+                netif_carrier_on(dev);
+        }
+
 	rtnl_unlock();
 
 	err = virtnet_cpu_notif_add(vi);
@@ -6571,17 +6606,6 @@  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);