Re: [PATCH net] Revert "drivers/net: Disable UFO through virtio" in macvtap and tun

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Nov 11, 2014 at 05:12:58PM +0000, Ben Hutchings wrote:
> This reverts commit 88e0e0e5aa722b193c8758c8b45d041de5316924 for
> the tap drivers, but leaves UFO disabled in virtio_net.
> 
> libvirt at least assumes that tap features will never be dropped
> in new kernel versions, and doing so prevents migration of VMs to
> the never kernel version while they are running with virtio net
> devices.
> 
> Fixes: 88e0e0e5aa7a ("drivers/net: Disable UFO through virtio")
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

I did some light testing with IPv4, and this seems to migrate fine now.
So let's apply, please

Acked-by: Michael S. Tsirkin <mst@redhat.com>


> ---
> Compile-tested only.
> 
> Ben.
> 
>  drivers/net/macvtap.c | 13 ++++++++-----
>  drivers/net/tun.c     | 19 ++++++++-----------
>  2 files changed, 16 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
> index 6f226de..aeaeb6d 100644
> --- a/drivers/net/macvtap.c
> +++ b/drivers/net/macvtap.c
> @@ -66,7 +66,7 @@ static struct cdev macvtap_cdev;
>  static const struct proto_ops macvtap_socket_ops;
>  
>  #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
> -		      NETIF_F_TSO6)
> +		      NETIF_F_TSO6 | NETIF_F_UFO)
>  #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
>  #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG)
>  
> @@ -570,8 +570,6 @@ static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb,
>  			gso_type = SKB_GSO_TCPV6;
>  			break;
>  		case VIRTIO_NET_HDR_GSO_UDP:
> -			pr_warn_once("macvtap: %s: using disabled UFO feature; please fix this program\n",
> -				     current->comm);
>  			gso_type = SKB_GSO_UDP;
>  			if (skb->protocol == htons(ETH_P_IPV6))
>  				ipv6_proxy_select_ident(skb);
> @@ -619,6 +617,8 @@ static void macvtap_skb_to_vnet_hdr(const struct sk_buff *skb,
>  			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
>  		else if (sinfo->gso_type & SKB_GSO_TCPV6)
>  			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
> +		else if (sinfo->gso_type & SKB_GSO_UDP)
> +			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
>  		else
>  			BUG();
>  		if (sinfo->gso_type & SKB_GSO_TCP_ECN)
> @@ -953,6 +953,9 @@ static int set_offload(struct macvtap_queue *q, unsigned long arg)
>  			if (arg & TUN_F_TSO6)
>  				feature_mask |= NETIF_F_TSO6;
>  		}
> +
> +		if (arg & TUN_F_UFO)
> +			feature_mask |= NETIF_F_UFO;
>  	}
>  
>  	/* tun/tap driver inverts the usage for TSO offloads, where
> @@ -963,7 +966,7 @@ static int set_offload(struct macvtap_queue *q, unsigned long arg)
>  	 * When user space turns off TSO, we turn off GSO/LRO so that
>  	 * user-space will not receive TSO frames.
>  	 */
> -	if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6))
> +	if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
>  		features |= RX_OFFLOADS;
>  	else
>  		features &= ~RX_OFFLOADS;
> @@ -1064,7 +1067,7 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd,
>  	case TUNSETOFFLOAD:
>  		/* let the user check for future flags */
>  		if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
> -			    TUN_F_TSO_ECN))
> +			    TUN_F_TSO_ECN | TUN_F_UFO))
>  			return -EINVAL;
>  
>  		rtnl_lock();
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 7302398..a0987d1 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -175,7 +175,7 @@ struct tun_struct {
>  	struct net_device	*dev;
>  	netdev_features_t	set_features;
>  #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
> -			  NETIF_F_TSO6)
> +			  NETIF_F_TSO6|NETIF_F_UFO)
>  
>  	int			vnet_hdr_sz;
>  	int			sndbuf;
> @@ -1152,20 +1152,10 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
>  			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
>  			break;
>  		case VIRTIO_NET_HDR_GSO_UDP:
> -		{
> -			static bool warned;
> -
> -			if (!warned) {
> -				warned = true;
> -				netdev_warn(tun->dev,
> -					    "%s: using disabled UFO feature; please fix this program\n",
> -					    current->comm);
> -			}
>  			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
>  			if (skb->protocol == htons(ETH_P_IPV6))
>  				ipv6_proxy_select_ident(skb);
>  			break;
> -		}
>  		default:
>  			tun->dev->stats.rx_frame_errors++;
>  			kfree_skb(skb);
> @@ -1265,6 +1255,8 @@ static ssize_t tun_put_user(struct tun_struct *tun,
>  				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
>  			else if (sinfo->gso_type & SKB_GSO_TCPV6)
>  				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
> +			else if (sinfo->gso_type & SKB_GSO_UDP)
> +				gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
>  			else {
>  				pr_err("unexpected GSO type: "
>  				       "0x%x, gso_size %d, hdr_len %d\n",
> @@ -1774,6 +1766,11 @@ static int set_offload(struct tun_struct *tun, unsigned long arg)
>  				features |= NETIF_F_TSO6;
>  			arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
>  		}
> +
> +		if (arg & TUN_F_UFO) {
> +			features |= NETIF_F_UFO;
> +			arg &= ~TUN_F_UFO;
> +		}
>  	}
>  
>  	/* This gives the user a way to test for new features in future by
> 
> 
> -- 
> Ben Hutchings
> Experience is directly proportional to the value of equipment destroyed.
>                                                          - Carolyn Scheppner