thr3ads.net - Virtualization - [RFC PATCH v2 0/5] TUN/VirtioNet USO features support. [May 2022]

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Andrew Melnychenko

2022-May-12 11:23 UTC

[RFC PATCH v2 0/5] TUN/VirtioNet USO features support.

Added new offloads for TUN devices TUN_F_USO4 and TUN_F_USO6.
Technically they enable NETIF_F_GSO_UDP_L4
(and only if USO4 & USO6 are set simultaneously).
It allows to transmission of large UDP packets.

Different features USO4 and USO6 are required for qemu where Windows guests can
enable disable USO receives for IPv4 and IPv6 separately.
On the other side, Linux can't really differentiate USO4 and USO6, for now.
For now, to enable USO for TUN it requires enabling USO4 and USO6 together.
In the future, there would be a mechanism to control UDP_L4 GSO separately.

Test it WIP Qemu https://github.com/daynix/qemu/tree/Dev_USOv2

New types for VirtioNet already on mailing:
https://lists.oasis-open.org/archives/virtio-comment/202110/msg00010.html

Also, there is a known issue with transmitting packages between two guests.
Without hacks with skb's GSO - packages are still segmented on the
host's postrouting.

Andrew (5):
  uapi/linux/if_tun.h: Added new offload types for USO4/6.
  driver/net/tun: Added features for USO.
  uapi/linux/virtio_net.h: Added USO types.
  linux/virtio_net.h: Support USO offload in vnet header.
  drivers/net/virtio_net.c: Added USO support.

 drivers/net/tap.c               | 10 ++++++++--
 drivers/net/tun.c               |  8 +++++++-
 drivers/net/virtio_net.c        | 19 +++++++++++++++----
 include/linux/virtio_net.h      |  9 +++++++++
 include/uapi/linux/if_tun.h     |  2 ++
 include/uapi/linux/virtio_net.h |  4 ++++
 6 files changed, 45 insertions(+), 7 deletions(-)

-- 
2.35.1

Andrew Melnychenko

2022-May-12 11:23 UTC

head link

[RFC PATCH v2 1/5] uapi/linux/if_tun.h: Added new offload types for USO4/6.

Added 2 additional offlloads for USO(IPv4 & IPv6).
Separate offloads are required for Windows VM guests,
g.e. Windows may set USO rx only for IPv4.

Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
---
 include/uapi/linux/if_tun.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h
index 454ae31b93c7..e147dcb46d5c 100644
--- a/include/uapi/linux/if_tun.h
+++ b/include/uapi/linux/if_tun.h
@@ -88,6 +88,8 @@
 #define TUN_F_TSO6	0x04	/* I can handle TSO for IPv6 packets */
 #define TUN_F_TSO_ECN	0x08	/* I can handle TSO with ECN bits. */
 #define TUN_F_UFO	0x10	/* I can handle UFO packets */
+#define TUN_F_USO4	0x20	/* I can handle USO for IPv4 packets */
+#define TUN_F_USO6	0x40	/* I can handle USO for IPv6 packets */
 
 /* Protocol info prepended to the packets (when IFF_NO_PI is not set) */
 #define TUN_PKT_STRIP	0x0001
-- 
2.35.1

Andrew Melnychenko

2022-May-12 11:23 UTC

head link

[RFC PATCH v2 2/5] driver/net/tun: Added features for USO.

Added support for USO4 and USO6.
For now, to "enable" USO, it's required to set both USO4 and USO6
simultaneously.
USO enables NETIF_F_GSO_UDP_L4.

Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
---
 drivers/net/tap.c | 10 ++++++++--
 drivers/net/tun.c |  8 +++++++-
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index c3d42062559d..eae7c2c13713 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -955,6 +955,10 @@ static int set_offload(struct tap_queue *q, unsigned long
arg)
 			if (arg & TUN_F_TSO6)
 				feature_mask |= NETIF_F_TSO6;
 		}
+
+		/* TODO: for now USO4 and USO6 should work simultaneously */
+		if ((arg & (TUN_F_USO4 | TUN_F_USO6)) == (TUN_F_USO4 | TUN_F_USO6))
+			features |= NETIF_F_GSO_UDP_L4;
 	}
 
 	/* tun/tap driver inverts the usage for TSO offloads, where
@@ -965,7 +969,8 @@ static int set_offload(struct tap_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) ||
+	    (feature_mask & (TUN_F_USO4 | TUN_F_USO6)) == (TUN_F_USO4 |
TUN_F_USO6))
 		features |= RX_OFFLOADS;
 	else
 		features &= ~RX_OFFLOADS;
@@ -1089,7 +1094,8 @@ static long tap_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_UFO))
+			    TUN_F_TSO_ECN | TUN_F_UFO |
+			    TUN_F_USO4 | TUN_F_USO6))
 			return -EINVAL;
 
 		rtnl_lock();
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index dbe4c0a4be2c..ecad1bdee717 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -185,7 +185,7 @@ 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_GSO_UDP_L4)
 
 	int			align;
 	int			vnet_hdr_sz;
@@ -2861,6 +2861,12 @@ static int set_offload(struct tun_struct *tun, unsigned
long arg)
 		}
 
 		arg &= ~TUN_F_UFO;
+
+		/* TODO: for now USO4 and USO6 should work simultaneously */
+		if (arg & TUN_F_USO4 && arg & TUN_F_USO6) {
+			features |= NETIF_F_GSO_UDP_L4;
+			arg &= ~(TUN_F_USO4 | TUN_F_USO6);
+		}
 	}
 
 	/* This gives the user a way to test for new features in future by
-- 
2.35.1

Andrew Melnychenko

2022-May-12 11:23 UTC

head link

[RFC PATCH v2 3/5] uapi/linux/virtio_net.h: Added USO types.

Added new GSO type for USO: VIRTIO_NET_HDR_GSO_UDP_L4.
Feature VIRTIO_NET_F_HOST_USO allows to enable NETIF_F_GSO_UDP_L4.
Separated VIRTIO_NET_F_GUEST_USO4 & VIRTIO_NET_F_GUEST_USO6 features
required for Windows guests.

Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
---
 include/uapi/linux/virtio_net.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 3f55a4215f11..c654feb1ed9b 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -56,6 +56,9 @@
 #define VIRTIO_NET_F_MQ	22	/* Device supports Receive Flow
 					 * Steering */
 #define VIRTIO_NET_F_CTRL_MAC_ADDR 23	/* Set MAC address */
+#define VIRTIO_NET_F_GUEST_USO4	54	/* Guest can handle USOv4 in. */
+#define VIRTIO_NET_F_GUEST_USO6	55	/* Guest can handle USOv6 in. */
+#define VIRTIO_NET_F_HOST_USO	56	/* Host can handle USO in. */
 
 #define VIRTIO_NET_F_HASH_REPORT  57	/* Supports hash report */
 #define VIRTIO_NET_F_RSS	  60	/* Supports RSS RX steering */
@@ -130,6 +133,7 @@ struct virtio_net_hdr_v1 {
 #define VIRTIO_NET_HDR_GSO_TCPV4	1	/* GSO frame, IPv4 TCP (TSO) */
 #define VIRTIO_NET_HDR_GSO_UDP		3	/* GSO frame, IPv4 UDP (UFO) */
 #define VIRTIO_NET_HDR_GSO_TCPV6	4	/* GSO frame, IPv6 TCP */
+#define VIRTIO_NET_HDR_GSO_UDP_L4	5	/* GSO frame, IPv4& IPv6 UDP (USO) */
 #define VIRTIO_NET_HDR_GSO_ECN		0x80	/* TCP has ECN set */
 	__u8 gso_type;
 	__virtio16 hdr_len;	/* Ethernet + IP + tcp/udp hdrs */
-- 
2.35.1

Andrew Melnychenko

2022-May-12 11:23 UTC

head link

[RFC PATCH v2 4/5] linux/virtio_net.h: Support USO offload in vnet header.

Now, it's possible to convert USO vnet packets from/to skb.
Added support for GSO_UDP_L4 offload.

Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
---
 include/linux/virtio_net.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index a960de68ac69..bdf8de2cdd93 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -15,6 +15,7 @@ static inline bool virtio_net_hdr_match_proto(__be16 protocol,
__u8 gso_type)
 	case VIRTIO_NET_HDR_GSO_TCPV6:
 		return protocol == cpu_to_be16(ETH_P_IPV6);
 	case VIRTIO_NET_HDR_GSO_UDP:
+	case VIRTIO_NET_HDR_GSO_UDP_L4:
 		return protocol == cpu_to_be16(ETH_P_IP) ||
 		       protocol == cpu_to_be16(ETH_P_IPV6);
 	default:
@@ -31,6 +32,7 @@ static inline int virtio_net_hdr_set_proto(struct sk_buff
*skb,
 	switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 	case VIRTIO_NET_HDR_GSO_TCPV4:
 	case VIRTIO_NET_HDR_GSO_UDP:
+	case VIRTIO_NET_HDR_GSO_UDP_L4:
 		skb->protocol = cpu_to_be16(ETH_P_IP);
 		break;
 	case VIRTIO_NET_HDR_GSO_TCPV6:
@@ -69,6 +71,11 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
 			ip_proto = IPPROTO_UDP;
 			thlen = sizeof(struct udphdr);
 			break;
+		case VIRTIO_NET_HDR_GSO_UDP_L4:
+			gso_type = SKB_GSO_UDP_L4;
+			ip_proto = IPPROTO_UDP;
+			thlen = sizeof(struct udphdr);
+			break;
 		default:
 			return -EINVAL;
 		}
@@ -182,6 +189,8 @@ static inline int virtio_net_hdr_from_skb(const struct
sk_buff *skb,
 			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 		else if (sinfo->gso_type & SKB_GSO_TCPV6)
 			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+		else if (sinfo->gso_type & SKB_GSO_UDP_L4)
+			hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP_L4;
 		else
 			return -EINVAL;
 		if (sinfo->gso_type & SKB_GSO_TCP_ECN)
-- 
2.35.1

Andrew Melnychenko

2022-May-12 11:23 UTC

head link

[RFC PATCH v2 5/5] drivers/net/virtio_net.c: Added USO support.

Now, it possible to enable GSO_UDP_L4("tx-udp-segmentation") for
VirtioNet.

Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
---
 drivers/net/virtio_net.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index cbba9d2e8f32..17fb8be7e4f7 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -60,13 +60,17 @@ static const unsigned long guest_offloads[] = {
 	VIRTIO_NET_F_GUEST_TSO6,
 	VIRTIO_NET_F_GUEST_ECN,
 	VIRTIO_NET_F_GUEST_UFO,
-	VIRTIO_NET_F_GUEST_CSUM
+	VIRTIO_NET_F_GUEST_CSUM,
+	VIRTIO_NET_F_GUEST_USO4,
+	VIRTIO_NET_F_GUEST_USO6
 };
 
 #define GUEST_OFFLOAD_GRO_HW_MASK ((1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
 				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
 				(1ULL << VIRTIO_NET_F_GUEST_ECN)  | \
-				(1ULL << VIRTIO_NET_F_GUEST_UFO))
+				(1ULL << VIRTIO_NET_F_GUEST_UFO)  | \
+				(1ULL << VIRTIO_NET_F_GUEST_USO4) | \
+				(1ULL << VIRTIO_NET_F_GUEST_USO6))
 
 struct virtnet_stat_desc {
 	char desc[ETH_GSTRING_LEN];
@@ -2867,7 +2871,9 @@ static int virtnet_xdp_set(struct net_device *dev, struct
bpf_prog *prog,
 	        virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6) ||
 	        virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) ||
 		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO) ||
-		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM))) {
+		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM) ||
+		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_USO4) ||
+		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_USO6))) {
 		NL_SET_ERR_MSG_MOD(extack, "Can't set XDP while host is implementing
GRO_HW/CSUM, disable GRO_HW/CSUM first");
 		return -EOPNOTSUPP;
 	}
@@ -3507,6 +3513,8 @@ static int virtnet_probe(struct virtio_device *vdev)
 			dev->hw_features |= NETIF_F_TSO6;
 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 			dev->hw_features |= NETIF_F_TSO_ECN;
+		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_USO))
+			dev->hw_features |= NETIF_F_GSO_UDP_L4;
 
 		dev->features |= NETIF_F_GSO_ROBUST;
 
@@ -3552,7 +3560,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
-	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
+	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO) ||
+	    (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_USO4) &&
+	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_USO6)))
 		vi->big_packets = true;
 
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
@@ -3780,6 +3790,7 @@ static struct virtio_device_id id_table[] = {
 	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, \
 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, \
 	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO, \
+	VIRTIO_NET_F_HOST_USO, VIRTIO_NET_F_GUEST_USO4, VIRTIO_NET_F_GUEST_USO6, \
 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ, \
 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN, \
 	VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, \
-- 
2.35.1

Jason Wang

2022-May-17 06:32 UTC

head link

[RFC PATCH v2 0/5] TUN/VirtioNet USO features support.

On Thu, May 12, 2022 at 7:33 PM Andrew Melnychenko <andrew at daynix.com>
wrote:>
> Added new offloads for TUN devices TUN_F_USO4 and TUN_F_USO6.
> Technically they enable NETIF_F_GSO_UDP_L4
> (and only if USO4 & USO6 are set simultaneously).
> It allows to transmission of large UDP packets.
>
> Different features USO4 and USO6 are required for qemu where Windows guests
can
> enable disable USO receives for IPv4 and IPv6 separately.
> On the other side, Linux can't really differentiate USO4 and USO6, for
now.
> For now, to enable USO for TUN it requires enabling USO4 and USO6 together.
> In the future, there would be a mechanism to control UDP_L4 GSO separately.
>
> Test it WIP Qemu https://github.com/daynix/qemu/tree/Dev_USOv2
>
> New types for VirtioNet already on mailing:
> https://lists.oasis-open.org/archives/virtio-comment/202110/msg00010.html
>
> Also, there is a known issue with transmitting packages between two guests.
Could you explain this more? It looks like a bug. (Or any pointer to
the discussion)

Thanks
> Without hacks with skb's GSO - packages are still segmented on the
host's postrouting.
>
> Andrew (5):
>   uapi/linux/if_tun.h: Added new offload types for USO4/6.
>   driver/net/tun: Added features for USO.
>   uapi/linux/virtio_net.h: Added USO types.
>   linux/virtio_net.h: Support USO offload in vnet header.
>   drivers/net/virtio_net.c: Added USO support.
>
>  drivers/net/tap.c               | 10 ++++++++--
>  drivers/net/tun.c               |  8 +++++++-
>  drivers/net/virtio_net.c        | 19 +++++++++++++++----
>  include/linux/virtio_net.h      |  9 +++++++++
>  include/uapi/linux/if_tun.h     |  2 ++
>  include/uapi/linux/virtio_net.h |  4 ++++
>  6 files changed, 45 insertions(+), 7 deletions(-)
>
> --
> 2.35.1
>

Virtualization - May 2022 - [RFC PATCH v2 0/5] TUN/VirtioNet USO features support.

[RFC PATCH v2 0/5] TUN/VirtioNet USO features support.

[RFC PATCH v2 1/5] uapi/linux/if_tun.h: Added new offload types for USO4/6.

[RFC PATCH v2 2/5] driver/net/tun: Added features for USO.

[RFC PATCH v2 3/5] uapi/linux/virtio_net.h: Added USO types.

[RFC PATCH v2 4/5] linux/virtio_net.h: Support USO offload in vnet header.

[RFC PATCH v2 5/5] drivers/net/virtio_net.c: Added USO support.

[RFC PATCH v2 0/5] TUN/VirtioNet USO features support.