[PATCH bpf-next v4 00/11] xsk: TX metadata

[PATCH bpf-next v4 00/11] xsk: TX metadata

[Stanislav Fomichev]

This series implements initial TX metadata (offloads) for AF_XDP.
See patch #2 for the main implementation and mlx5/stmmac ones for the
example on how to consume the metadata on the device side.

Starting with two types of offloads:
- request TX timestamp (and write it back into the metadata area)
- request TX checksum offload

Changes since v3:
- fix xsk_tx_metadata_ops kdoc (Song Yoong Siang)
- add missing xsk_tx_metadata_to_compl for XDP_SOCKETS=n (Vinicius Costa Gomes and Intel bots)
- add reference timestamps to the selftests + refactor existing ones (Jesper)

v3: https://lore.kernel.org/bpf/20231003200522.1914523-1-sdf@google.com/

Performance (mlx5):

I've implemented a small xskgen tool to try to saturate single tx queue:
https://github.com/fomichev/xskgen/tree/master

Here are the performance numbers with some analysis.

1. Baseline. Running with commit eb62e6aef940 ("Merge branch 'bpf:
Support bpf_get_func_ip helper in uprobes'"), nothing from this series:

- with 1400 bytes of payload: 98 gbps, 8 mpps
./xskgen -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 116960000000 bits, took 1.189130 sec, 98.357623 gbps 8.409509 mpps

- with 200 bytes of payload: 49 gbps, 23 mpps
./xskgen -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000064 packets 20960134144 bits, took 0.422235 sec, 49.640921 gbps 23.683645 mpps

2. Adding single commit that supports reserving tx_metadata_len
   changes nothing numbers-wise.

- baseline for 1400
./xskgen -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 116960000000 bits, took 1.189247 sec, 98.347946 gbps 8.408682 mpps

- baseline for 200
./xskgen -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 20960000000 bits, took 0.421248 sec, 49.756913 gbps 23.738985 mpps

3. Adding -M flag causes xskgen to reserve the metadata and fill it, but
   doesn't set XDP_TX_METADATA descriptor option.

- new baseline for 1400 (with only filling the metadata)
./xskgen -M -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 116960000000 bits, took 1.188767 sec, 98.387657 gbps 8.412077 mpps

- new baseline for 200 (with only filling the metadata)
./xskgen -M -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 20960000000 bits, took 0.410213 sec, 51.095407 gbps 24.377579 mpps
(the numbers go sligtly up here, not really sure why, maybe some cache-related
side-effects?

4. Next, I'm running the same test but with the commit that adds actual
   general infra to parse XDP_TX_METADATA (but no driver support).
   Essentially applying "xsk: add TX timestamp and TX checksum offload support"
   from this series. Numbers are the same.

- fill metadata for 1400
./xskgen -M -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 116960000000 bits, took 1.188430 sec, 98.415557 gbps 8.414463 mpps

- fill metadata for 200
./xskgen -M -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 20960000000 bits, took 0.411559 sec, 50.928299 gbps 24.297853 mpps

- request metadata for 1400
./xskgen -m -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 116960000000 bits, took 1.188723 sec, 98.391299 gbps 8.412389 mpps

- request metadata for 200
./xskgen -m -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000064 packets 20960134144 bits, took 0.411240 sec, 50.968131 gbps 24.316856 mpps

5. Now, for the most interesting part, I'm adding mlx5 driver support.
   The mpps for 200 bytes case goes down from 23 mpps to 19 mpps, but
   _only_ when I enable the metadata. This looks like a side effect
   of me pushing extra metadata pointer via mlx5e_xdpi_fifo_push.
   Hence, this part is wrapped into 'if (xp_tx_metadata_enabled)'
   to not affect the existing non-metadata use-cases. Since this is not
   regressing existing workloads, I'm not spending any time trying to
   optimize it more (and leaving it up to mlx owners to purse if
   they see any good way to do it).

- same baseline
./xskgen -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 116960000000 bits, took 1.189434 sec, 98.332484 gbps 8.407360 mpps

./xskgen -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000128 packets 20960268288 bits, took 0.425254 sec, 49.288821 gbps 23.515659 mpps

- fill metadata for 1400
./xskgen -M -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 116960000000 bits, took 1.189528 sec, 98.324714 gbps 8.406696 mpps

- fill metadata for 200
./xskgen -M -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000128 packets 20960268288 bits, took 0.519085 sec, 40.379260 gbps 19.264914 mpps

- request metadata for 1400
./xskgen -m -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000000 packets 116960000000 bits, took 1.189329 sec, 98.341165 gbps 8.408102 mpps

- request metadata for 200
./xskgen -m -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
sent 10000128 packets 20960268288 bits, took 0.519929 sec, 40.313713 gbps 19.233642 mpps

Song Yoong Siang (1):
  net: stmmac: Add Tx HWTS support to XDP ZC

Stanislav Fomichev (10):
  xsk: Support tx_metadata_len
  xsk: Add TX timestamp and TX checksum offload support
  tools: ynl: Print xsk-features from the sample
  net/mlx5e: Implement AF_XDP TX timestamp and checksum offload
  selftests/xsk: Support tx_metadata_len
  selftests/bpf: Add csum helpers
  selftests/bpf: Add TX side to xdp_metadata
  selftests/bpf: Convert xdp_hw_metadata to XDP_USE_NEED_WAKEUP
  selftests/bpf: Add TX side to xdp_hw_metadata
  xsk: Document tx_metadata_len layout

 Documentation/netlink/specs/netdev.yaml       |  19 ++
 Documentation/networking/index.rst            |   1 +
 Documentation/networking/xsk-tx-metadata.rst  |  77 ++++++
 drivers/net/ethernet/mellanox/mlx5/core/en.h  |   4 +-
 .../net/ethernet/mellanox/mlx5/core/en/xdp.c  |  72 +++++-
 .../net/ethernet/mellanox/mlx5/core/en/xdp.h  |  11 +-
 .../ethernet/mellanox/mlx5/core/en/xsk/tx.c   |  17 +-
 .../net/ethernet/mellanox/mlx5/core/en_main.c |   1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac.h  |  12 +
 .../net/ethernet/stmicro/stmmac/stmmac_main.c |  63 ++++-
 include/linux/netdevice.h                     |  27 ++
 include/linux/skbuff.h                        |  14 +-
 include/net/xdp_sock.h                        |  86 +++++++
 include/net/xdp_sock_drv.h                    |  13 +
 include/net/xsk_buff_pool.h                   |   7 +
 include/uapi/linux/if_xdp.h                   |  41 ++++
 include/uapi/linux/netdev.h                   |  16 ++
 net/core/netdev-genl.c                        |  12 +-
 net/xdp/xdp_umem.c                            |   4 +
 net/xdp/xsk.c                                 |  51 +++-
 net/xdp/xsk_buff_pool.c                       |   1 +
 net/xdp/xsk_queue.h                           |  19 +-
 tools/include/uapi/linux/if_xdp.h             |  55 ++++-
 tools/include/uapi/linux/netdev.h             |  16 ++
 tools/net/ynl/generated/netdev-user.c         |  19 ++
 tools/net/ynl/generated/netdev-user.h         |   3 +
 tools/net/ynl/samples/netdev.c                |   6 +
 tools/testing/selftests/bpf/network_helpers.h |  43 ++++
 .../selftests/bpf/prog_tests/xdp_metadata.c   |  31 ++-
 tools/testing/selftests/bpf/xdp_hw_metadata.c | 230 ++++++++++++++++--
 tools/testing/selftests/bpf/xsk.c             |   3 +
 tools/testing/selftests/bpf/xsk.h             |   1 +
 32 files changed, 914 insertions(+), 61 deletions(-)
 create mode 100644 Documentation/networking/xsk-tx-metadata.rst

-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 01/11] xsk: Support tx_metadata_len

[Stanislav Fomichev]

For zerocopy mode, tx_desc->addr can point to the arbitrary offset
and carry some TX metadata in the headroom. For copy mode, there
is no way currently to populate skb metadata.

Introduce new tx_metadata_len umem config option that indicates how many
bytes to treat as metadata. Metadata bytes come prior to tx_desc address
(same as in RX case).

The size of the metadata has the same constraints as XDP:
- less than 256 bytes
- 4-byte aligned
- non-zero

This data is not interpreted in any way right now.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 include/net/xdp_sock.h            |  1 +
 include/net/xsk_buff_pool.h       |  1 +
 include/uapi/linux/if_xdp.h       |  1 +
 net/xdp/xdp_umem.c                |  4 ++++
 net/xdp/xsk.c                     | 12 +++++++++++-
 net/xdp/xsk_buff_pool.c           |  1 +
 net/xdp/xsk_queue.h               | 17 ++++++++++-------
 tools/include/uapi/linux/if_xdp.h |  1 +
 8 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index 7dd0df2f6f8e..5ae88a00f34a 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -30,6 +30,7 @@ struct xdp_umem {
 	struct user_struct *user;
 	refcount_t users;
 	u8 flags;
+	u8 tx_metadata_len;
 	bool zc;
 	struct page **pgs;
 	int id;
diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index b0bdff26fc88..1985ffaf9b0c 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -77,6 +77,7 @@ struct xsk_buff_pool {
 	u32 chunk_size;
 	u32 chunk_shift;
 	u32 frame_len;
+	u8 tx_metadata_len; /* inherited from umem */
 	u8 cached_need_wakeup;
 	bool uses_need_wakeup;
 	bool dma_need_sync;
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index 8d48863472b9..2ecf79282c26 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -76,6 +76,7 @@ struct xdp_umem_reg {
 	__u32 chunk_size;
 	__u32 headroom;
 	__u32 flags;
+	__u32 tx_metadata_len;
 };
 
 struct xdp_statistics {
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 06cead2b8e34..333f3d53aad4 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -199,6 +199,9 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
 		return -EINVAL;
 
+	if (mr->tx_metadata_len > 256 || mr->tx_metadata_len % 4)
+		return -EINVAL;
+
 	umem->size = size;
 	umem->headroom = headroom;
 	umem->chunk_size = chunk_size;
@@ -207,6 +210,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	umem->pgs = NULL;
 	umem->user = NULL;
 	umem->flags = mr->flags;
+	umem->tx_metadata_len = mr->tx_metadata_len;
 
 	INIT_LIST_HEAD(&umem->xsk_dma_list);
 	refcount_set(&umem->users, 1);
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index ba070fd37d24..ba4c77a24a83 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -1265,6 +1265,14 @@ struct xdp_umem_reg_v1 {
 	__u32 headroom;
 };
 
+struct xdp_umem_reg_v2 {
+	__u64 addr; /* Start of packet data area */
+	__u64 len; /* Length of packet data area */
+	__u32 chunk_size;
+	__u32 headroom;
+	__u32 flags;
+};
+
 static int xsk_setsockopt(struct socket *sock, int level, int optname,
 			  sockptr_t optval, unsigned int optlen)
 {
@@ -1308,8 +1316,10 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname,
 
 		if (optlen < sizeof(struct xdp_umem_reg_v1))
 			return -EINVAL;
-		else if (optlen < sizeof(mr))
+		else if (optlen < sizeof(struct xdp_umem_reg_v2))
 			mr_size = sizeof(struct xdp_umem_reg_v1);
+		else if (optlen < sizeof(mr))
+			mr_size = sizeof(struct xdp_umem_reg_v2);
 
 		if (copy_from_sockptr(&mr, optval, mr_size))
 			return -EFAULT;
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 49cb9f9a09be..386eddcdf837 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -85,6 +85,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
 		XDP_PACKET_HEADROOM;
 	pool->umem = umem;
 	pool->addrs = umem->addrs;
+	pool->tx_metadata_len = umem->tx_metadata_len;
 	INIT_LIST_HEAD(&pool->free_list);
 	INIT_LIST_HEAD(&pool->xskb_list);
 	INIT_LIST_HEAD(&pool->xsk_tx_list);
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 13354a1e4280..c74a1372bcb9 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -143,15 +143,17 @@ static inline bool xp_unused_options_set(u32 options)
 static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
 					    struct xdp_desc *desc)
 {
-	u64 offset = desc->addr & (pool->chunk_size - 1);
+	u64 addr = desc->addr - pool->tx_metadata_len;
+	u64 len = desc->len + pool->tx_metadata_len;
+	u64 offset = addr & (pool->chunk_size - 1);
 
 	if (!desc->len)
 		return false;
 
-	if (offset + desc->len > pool->chunk_size)
+	if (offset + len > pool->chunk_size)
 		return false;
 
-	if (desc->addr >= pool->addrs_cnt)
+	if (addr >= pool->addrs_cnt)
 		return false;
 
 	if (xp_unused_options_set(desc->options))
@@ -162,16 +164,17 @@ static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
 static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool,
 					      struct xdp_desc *desc)
 {
-	u64 addr = xp_unaligned_add_offset_to_addr(desc->addr);
+	u64 addr = xp_unaligned_add_offset_to_addr(desc->addr) - pool->tx_metadata_len;
+	u64 len = desc->len + pool->tx_metadata_len;
 
 	if (!desc->len)
 		return false;
 
-	if (desc->len > pool->chunk_size)
+	if (len > pool->chunk_size)
 		return false;
 
-	if (addr >= pool->addrs_cnt || addr + desc->len > pool->addrs_cnt ||
-	    xp_desc_crosses_non_contig_pg(pool, addr, desc->len))
+	if (addr >= pool->addrs_cnt || addr + len > pool->addrs_cnt ||
+	    xp_desc_crosses_non_contig_pg(pool, addr, len))
 		return false;
 
 	if (xp_unused_options_set(desc->options))
diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
index 73a47da885dc..34411a2e5b6c 100644
--- a/tools/include/uapi/linux/if_xdp.h
+++ b/tools/include/uapi/linux/if_xdp.h
@@ -76,6 +76,7 @@ struct xdp_umem_reg {
 	__u32 chunk_size;
 	__u32 headroom;
 	__u32 flags;
+	__u32 tx_metadata_len;
 };
 
 struct xdp_statistics {
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 02/11] xsk: Add TX timestamp and TX checksum offload support

[Stanislav Fomichev]

This change actually defines the (initial) metadata layout
that should be used by AF_XDP userspace (xsk_tx_metadata).
The first field is flags which requests appropriate offloads,
followed by the offload-specific fields. The supported per-device
offloads are exported via netlink (new xsk-flags).

The offloads themselves are still implemented in a bit of a
framework-y fashion that's left from my initial kfunc attempt.
I'm introducing new xsk_tx_metadata_ops which drivers are
supposed to implement. The drivers are also supposed
to call xsk_tx_metadata_request/xsk_tx_metadata_complete in
the right places. Since xsk_tx_metadata_{request,_complete}
are static inline, we don't incur any extra overhead doing
indirect calls.

The benefit of this scheme is as follows:
- keeps all metadata layout parsing away from driver code
- makes it easy to grep and see which drivers implement what
- don't need any extra flags to maintain to keep track of what
  offloads are implemented; if the callback is implemented - the offload
  is supported (used by netlink reporting code)

Two offloads are defined right now:
1. XDP_TX_METADATA_CHECKSUM: skb-style csum_start+csum_offset
2. XDP_TX_METADATA_TIMESTAMP: writes TX timestamp back into metadata
   area upon completion (tx_timestamp field)

The offloads are also implemented for copy mode:
1. Extra XDP_TX_METADATA_CHECKSUM_SW to trigger skb_checksum_help; this
   might be useful as a reference implementation and for testing
2. XDP_TX_METADATA_TIMESTAMP writes SW timestamp from the skb
   destructor (note I'm reusing hwtstamps to pass metadata pointer)

The struct is forward-compatible and can be extended in the future
by appending more fields.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 Documentation/netlink/specs/netdev.yaml | 19 ++++++
 include/linux/netdevice.h               | 27 ++++++++
 include/linux/skbuff.h                  | 14 +++-
 include/net/xdp_sock.h                  | 85 +++++++++++++++++++++++++
 include/net/xdp_sock_drv.h              | 13 ++++
 include/net/xsk_buff_pool.h             |  6 ++
 include/uapi/linux/if_xdp.h             | 40 ++++++++++++
 include/uapi/linux/netdev.h             | 16 +++++
 net/core/netdev-genl.c                  | 12 +++-
 net/xdp/xsk.c                           | 39 ++++++++++++
 net/xdp/xsk_queue.h                     |  2 +-
 tools/include/uapi/linux/if_xdp.h       | 54 ++++++++++++++--
 tools/include/uapi/linux/netdev.h       | 16 +++++
 tools/net/ynl/generated/netdev-user.c   | 19 ++++++
 tools/net/ynl/generated/netdev-user.h   |  3 +
 15 files changed, 357 insertions(+), 8 deletions(-)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index 14511b13f305..22d2649a34ee 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -55,6 +55,19 @@ name: netdev
         name: hash
         doc:
           Device is capable of exposing receive packet hash via bpf_xdp_metadata_rx_hash().
+  -
+    type: flags
+    name: xsk-flags
+    render-max: true
+    entries:
+      -
+        name: tx-timestamp
+        doc:
+          HW timestamping egress packets is supported by the driver.
+      -
+        name: tx-checksum
+        doc:
+          L3 checksum HW offload is supported by the driver.
 
 attribute-sets:
   -
@@ -86,6 +99,11 @@ name: netdev
              See Documentation/networking/xdp-rx-metadata.rst for more details.
         type: u64
         enum: xdp-rx-metadata
+      -
+        name: xsk-features
+        doc: Bitmask of enabled AF_XDP features.
+        type: u64
+        enum: xsk-flags
 
 operations:
   list:
@@ -103,6 +121,7 @@ name: netdev
             - xdp-features
             - xdp-zc-max-segs
             - xdp-rx-metadata-features
+            - xsk-features
       dump:
         reply: *dev-all
     -
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 1c7681263d30..f0903a1ac791 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1643,6 +1643,31 @@ struct net_device_ops {
 						    struct netlink_ext_ack *extack);
 };
 
+/*
+ * This structure defines the AF_XDP TX metadata hooks for network devices.
+ * The following hooks can be defined; unless noted otherwise, they are
+ * optional and can be filled with a null pointer.
+ *
+ * void (*tmo_request_timestamp)(void *priv)
+ *     This function is called when AF_XDP frame requested egress timestamp.
+ *
+ * u64 (*tmo_fill_timestamp)(void *priv)
+ *     This function is called when AF_XDP frame, that had requested
+ *     egress timestamp, received a completion. The hook needs to return
+ *     the actual HW timestamp.
+ *
+ * void (*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv)
+ *     This function is called when AF_XDP frame requested HW checksum
+ *     offload. csum_start indicates position where checksumming should start.
+ *     csum_offset indicates position where checksum should be stored.
+ *
+ */
+struct xsk_tx_metadata_ops {
+	void	(*tmo_request_timestamp)(void *priv);
+	u64	(*tmo_fill_timestamp)(void *priv);
+	void	(*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv);
+};
+
 /**
  * enum netdev_priv_flags - &struct net_device priv_flags
  *
@@ -1831,6 +1856,7 @@ enum netdev_ml_priv_type {
  *	@netdev_ops:	Includes several pointers to callbacks,
  *			if one wants to override the ndo_*() functions
  *	@xdp_metadata_ops:	Includes pointers to XDP metadata callbacks.
+ *	@xsk_tx_metadata_ops:	Includes pointers to AF_XDP TX metadata callbacks.
  *	@ethtool_ops:	Management operations
  *	@l3mdev_ops:	Layer 3 master device operations
  *	@ndisc_ops:	Includes callbacks for different IPv6 neighbour
@@ -2090,6 +2116,7 @@ struct net_device {
 	unsigned long long	priv_flags;
 	const struct net_device_ops *netdev_ops;
 	const struct xdp_metadata_ops *xdp_metadata_ops;
+	const struct xsk_tx_metadata_ops *xsk_tx_metadata_ops;
 	int			ifindex;
 	unsigned short		gflags;
 	unsigned short		hard_header_len;
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 97bfef071255..5b79d7fe9f9c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -566,6 +566,15 @@ struct ubuf_info_msgzc {
 int mm_account_pinned_pages(struct mmpin *mmp, size_t size);
 void mm_unaccount_pinned_pages(struct mmpin *mmp);
 
+/* Preserve some data across TX submission and completion.
+ *
+ * Note, this state is stored in the driver. Extending the layout
+ * might need some special care.
+ */
+struct xsk_tx_metadata_compl {
+	__u64 *tx_timestamp;
+};
+
 /* This data is invariant across clones and lives at
  * the end of the header data, ie. at skb->end.
  */
@@ -578,7 +587,10 @@ struct skb_shared_info {
 	/* Warning: this field is not always filled in (UFO)! */
 	unsigned short	gso_segs;
 	struct sk_buff	*frag_list;
-	struct skb_shared_hwtstamps hwtstamps;
+	union {
+		struct skb_shared_hwtstamps hwtstamps;
+		struct xsk_tx_metadata_compl xsk_meta;
+	};
 	unsigned int	gso_type;
 	u32		tskey;
 
diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index 5ae88a00f34a..9f09ee47b434 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -92,6 +92,74 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp);
 int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp);
 void __xsk_map_flush(void);
 
+/**
+ *  xsk_tx_metadata_to_compl - Save enough relevant metadata information
+ *  to perform tx completion in the future.
+ *  @meta: pointer to AF_XDP metadata area
+ *  @compl: pointer to output struct xsk_tx_metadata_to_compl
+ *
+ *  This function should be called by the networking device when
+ *  it prepares AF_XDP egress packet. The value of @compl should be stored
+ *  and passed to xsk_tx_metadata_complete upon TX completion.
+ */
+static inline void xsk_tx_metadata_to_compl(struct xsk_tx_metadata *meta,
+					    struct xsk_tx_metadata_compl *compl)
+{
+	if (!meta)
+		return;
+
+	if (meta->flags & XDP_TX_METADATA_TIMESTAMP)
+		compl->tx_timestamp = &meta->completion.tx_timestamp;
+	else
+		compl->tx_timestamp = NULL;
+}
+
+/**
+ *  xsk_tx_metadata_request - Evaluate AF_XDP TX metadata at submission
+ *  and call appropriate xsk_tx_metadata_ops operation.
+ *  @meta: pointer to AF_XDP metadata area
+ *  @ops: pointer to struct xsk_tx_metadata_ops
+ *  @priv: pointer to driver-private aread
+ *
+ *  This function should be called by the networking device when
+ *  it prepares AF_XDP egress packet.
+ */
+static inline void xsk_tx_metadata_request(const struct xsk_tx_metadata *meta,
+					   const struct xsk_tx_metadata_ops *ops,
+					   void *priv)
+{
+	if (!meta)
+		return;
+
+	if (ops->tmo_request_timestamp)
+		if (meta->flags & XDP_TX_METADATA_TIMESTAMP)
+			ops->tmo_request_timestamp(priv);
+
+	if (ops->tmo_request_checksum)
+		if (meta->flags & XDP_TX_METADATA_CHECKSUM)
+			ops->tmo_request_checksum(meta->csum_start, meta->csum_offset, priv);
+}
+
+/**
+ *  xsk_tx_metadata_complete - Evaluate AF_XDP TX metadata at completion
+ *  and call appropriate xsk_tx_metadata_ops operation.
+ *  @compl: pointer to completion metadata produced from xsk_tx_metadata_to_compl
+ *  @ops: pointer to struct xsk_tx_metadata_ops
+ *  @priv: pointer to driver-private aread
+ *
+ *  This function should be called by the networking device upon
+ *  AF_XDP egress completion.
+ */
+static inline void xsk_tx_metadata_complete(struct xsk_tx_metadata_compl *compl,
+					    const struct xsk_tx_metadata_ops *ops,
+					    void *priv)
+{
+	if (!compl)
+		return;
+
+	*compl->tx_timestamp = ops->tmo_fill_timestamp(priv);
+}
+
 #else
 
 static inline int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
@@ -108,6 +176,23 @@ static inline void __xsk_map_flush(void)
 {
 }
 
+static inline void xsk_tx_metadata_to_compl(struct xsk_tx_metadata *meta,
+					    struct xsk_tx_metadata_compl *compl)
+{
+}
+
+static inline void xsk_tx_metadata_request(struct xsk_tx_metadata *meta,
+					   const struct xsk_tx_metadata_ops *ops,
+					   void *priv)
+{
+}
+
+static inline void xsk_tx_metadata_complete(struct xsk_tx_metadata_compl *compl,
+					    const struct xsk_tx_metadata_ops *ops,
+					    void *priv)
+{
+}
+
 #endif /* CONFIG_XDP_SOCKETS */
 
 #if defined(CONFIG_XDP_SOCKETS) && defined(CONFIG_DEBUG_NET)
diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h
index 1f6fc8c7a84c..e2558ac3e195 100644
--- a/include/net/xdp_sock_drv.h
+++ b/include/net/xdp_sock_drv.h
@@ -165,6 +165,14 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 	return xp_raw_get_data(pool, addr);
 }
 
+static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr)
+{
+	if (!pool->tx_metadata_len)
+		return NULL;
+
+	return xp_raw_get_data(pool, addr) - pool->tx_metadata_len;
+}
+
 static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool)
 {
 	struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);
@@ -324,6 +332,11 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 	return NULL;
 }
 
+static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr)
+{
+	return NULL;
+}
+
 static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool)
 {
 }
diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index 1985ffaf9b0c..97f5cc10d79e 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -33,6 +33,7 @@ struct xdp_buff_xsk {
 };
 
 #define XSK_CHECK_PRIV_TYPE(t) BUILD_BUG_ON(sizeof(t) > offsetofend(struct xdp_buff_xsk, cb))
+#define XSK_TX_COMPL_FITS(t) BUILD_BUG_ON(sizeof(struct xsk_tx_metadata_compl) > sizeof(t))
 
 struct xsk_dma_map {
 	dma_addr_t *dma_pages;
@@ -234,4 +235,9 @@ static inline u64 xp_get_handle(struct xdp_buff_xsk *xskb)
 	return xskb->orig_addr + (offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT);
 }
 
+static inline bool xp_tx_metadata_enabled(const struct xsk_buff_pool *pool)
+{
+	return pool->tx_metadata_len > 0;
+}
+
 #endif /* XSK_BUFF_POOL_H_ */
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index 2ecf79282c26..ecfd67988283 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -106,6 +106,43 @@ struct xdp_options {
 #define XSK_UNALIGNED_BUF_ADDR_MASK \
 	((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)
 
+/* Request transmit timestamp. Upon completion, put it into tx_timestamp
+ * field of struct xsk_tx_metadata.
+ */
+#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
+
+/* Request transmit checksum offload. Checksum start position and offset
+ * are communicated via csum_start and csum_offset fields of struct
+ * xsk_tx_metadata.
+ */
+#define XDP_TX_METADATA_CHECKSUM		(1 << 1)
+
+/* Force checksum calculation in software. Can be used for testing or
+ * working around potential HW issues. This option causes performance
+ * degradation and only works in XDP_COPY mode.
+ */
+#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)
+
+struct xsk_tx_metadata {
+	union {
+		struct {
+			__u32 flags;
+
+			/* XDP_TX_METADATA_CHECKSUM */
+
+			/* Offset from desc->addr where checksumming should start. */
+			__u16 csum_start;
+			/* Offset from csum_start where checksum should be stored. */
+			__u16 csum_offset;
+		};
+
+		struct {
+			/* XDP_TX_METADATA_TIMESTAMP */
+			__u64 tx_timestamp;
+		} completion;
+	};
+};
+
 /* Rx/Tx descriptor */
 struct xdp_desc {
 	__u64 addr;
@@ -122,4 +159,7 @@ struct xdp_desc {
  */
 #define XDP_PKT_CONTD (1 << 0)
 
+/* TX packet carries valid metadata. */
+#define XDP_TX_METADATA (1 << 1)
+
 #endif /* _LINUX_IF_XDP_H */
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index 2943a151d4f1..48d5477a668c 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -53,12 +53,28 @@ enum netdev_xdp_rx_metadata {
 	NETDEV_XDP_RX_METADATA_MASK = 3,
 };
 
+/**
+ * enum netdev_xsk_flags
+ * @NETDEV_XSK_FLAGS_TX_TIMESTAMP: HW timestamping egress packets is supported
+ *   by the driver.
+ * @NETDEV_XSK_FLAGS_TX_CHECKSUM: L3 checksum HW offload is supported by the
+ *   driver.
+ */
+enum netdev_xsk_flags {
+	NETDEV_XSK_FLAGS_TX_TIMESTAMP = 1,
+	NETDEV_XSK_FLAGS_TX_CHECKSUM = 2,
+
+	/* private: */
+	NETDEV_XSK_FLAGS_MASK = 3,
+};
+
 enum {
 	NETDEV_A_DEV_IFINDEX = 1,
 	NETDEV_A_DEV_PAD,
 	NETDEV_A_DEV_XDP_FEATURES,
 	NETDEV_A_DEV_XDP_ZC_MAX_SEGS,
 	NETDEV_A_DEV_XDP_RX_METADATA_FEATURES,
+	NETDEV_A_DEV_XSK_FEATURES,
 
 	__NETDEV_A_DEV_MAX,
 	NETDEV_A_DEV_MAX = (__NETDEV_A_DEV_MAX - 1)
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index fe61f85bcf33..5d889c2425fd 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -14,6 +14,7 @@ netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp,
 		   const struct genl_info *info)
 {
 	u64 xdp_rx_meta = 0;
+	u64 xsk_features = 0;
 	void *hdr;
 
 	hdr = genlmsg_iput(rsp, info);
@@ -26,11 +27,20 @@ netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp,
 XDP_METADATA_KFUNC_xxx
 #undef XDP_METADATA_KFUNC
 
+	if (netdev->xsk_tx_metadata_ops) {
+		if (netdev->xsk_tx_metadata_ops->tmo_fill_timestamp)
+			xsk_features |= NETDEV_XSK_FLAGS_TX_TIMESTAMP;
+		if (netdev->xsk_tx_metadata_ops->tmo_request_checksum)
+			xsk_features |= NETDEV_XSK_FLAGS_TX_CHECKSUM;
+	}
+
 	if (nla_put_u32(rsp, NETDEV_A_DEV_IFINDEX, netdev->ifindex) ||
 	    nla_put_u64_64bit(rsp, NETDEV_A_DEV_XDP_FEATURES,
 			      netdev->xdp_features, NETDEV_A_DEV_PAD) ||
 	    nla_put_u64_64bit(rsp, NETDEV_A_DEV_XDP_RX_METADATA_FEATURES,
-			      xdp_rx_meta, NETDEV_A_DEV_PAD)) {
+			      xdp_rx_meta, NETDEV_A_DEV_PAD) ||
+	    nla_put_u64_64bit(rsp, NETDEV_A_DEV_XSK_FEATURES,
+			      xsk_features, NETDEV_A_DEV_PAD)) {
 		genlmsg_cancel(rsp, hdr);
 		return -EINVAL;
 	}
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index ba4c77a24a83..c441a9eadbd5 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -553,6 +553,13 @@ static u32 xsk_get_num_desc(struct sk_buff *skb)
 
 static void xsk_destruct_skb(struct sk_buff *skb)
 {
+	struct xsk_tx_metadata_compl *compl = &skb_shinfo(skb)->xsk_meta;
+
+	if (compl->tx_timestamp) {
+		/* sw completion timestamp, not a real one */
+		*compl->tx_timestamp = ktime_get_tai_fast_ns();
+	}
+
 	xsk_cq_submit_locked(xdp_sk(skb->sk), xsk_get_num_desc(skb));
 	sock_wfree(skb);
 }
@@ -637,8 +644,10 @@ static struct sk_buff *xsk_build_skb_zerocopy(struct xdp_sock *xs,
 static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 				     struct xdp_desc *desc)
 {
+	struct xsk_tx_metadata *meta = NULL;
 	struct net_device *dev = xs->dev;
 	struct sk_buff *skb = xs->skb;
+	bool first_frag = false;
 	int err;
 
 	if (dev->priv_flags & IFF_TX_SKB_NO_LINEAR) {
@@ -669,6 +678,8 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 				kfree_skb(skb);
 				goto free_err;
 			}
+
+			first_frag = true;
 		} else {
 			int nr_frags = skb_shinfo(skb)->nr_frags;
 			struct page *page;
@@ -691,12 +702,40 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 
 			skb_add_rx_frag(skb, nr_frags, page, 0, len, 0);
 		}
+
+		if (first_frag && desc->options & XDP_TX_METADATA) {
+			if (unlikely(xs->pool->tx_metadata_len == 0)) {
+				err = -EINVAL;
+				goto free_err;
+			}
+
+			meta = buffer - xs->pool->tx_metadata_len;
+
+			if (meta->flags & XDP_TX_METADATA_CHECKSUM) {
+				if (unlikely(meta->csum_start + meta->csum_offset +
+					     sizeof(__sum16) > len)) {
+					err = -EINVAL;
+					goto free_err;
+				}
+
+				skb->csum_start = hr + meta->csum_start;
+				skb->csum_offset = meta->csum_offset;
+				skb->ip_summed = CHECKSUM_PARTIAL;
+
+				if (unlikely(meta->flags & XDP_TX_METADATA_CHECKSUM_SW)) {
+					err = skb_checksum_help(skb);
+					if (err)
+						goto free_err;
+				}
+			}
+		}
 	}
 
 	skb->dev = dev;
 	skb->priority = READ_ONCE(xs->sk.sk_priority);
 	skb->mark = READ_ONCE(xs->sk.sk_mark);
 	skb->destructor = xsk_destruct_skb;
+	xsk_tx_metadata_to_compl(meta, &skb_shinfo(skb)->xsk_meta);
 	xsk_set_destructor_arg(skb);
 
 	return skb;
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index c74a1372bcb9..6f2d1621c992 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -137,7 +137,7 @@ static inline bool xskq_cons_read_addr_unchecked(struct xsk_queue *q, u64 *addr)
 
 static inline bool xp_unused_options_set(u32 options)
 {
-	return options & ~XDP_PKT_CONTD;
+	return options & ~(XDP_PKT_CONTD | XDP_TX_METADATA);
 }
 
 static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
index 34411a2e5b6c..53ceaae10dd1 100644
--- a/tools/include/uapi/linux/if_xdp.h
+++ b/tools/include/uapi/linux/if_xdp.h
@@ -26,11 +26,11 @@
  */
 #define XDP_USE_NEED_WAKEUP (1 << 3)
 /* By setting this option, userspace application indicates that it can
- * handle multiple descriptors per packet thus enabling xsk core to split
+ * handle multiple descriptors per packet thus enabling AF_XDP to split
  * multi-buffer XDP frames into multiple Rx descriptors. Without this set
- * such frames will be dropped by xsk.
+ * such frames will be dropped.
  */
-#define XDP_USE_SG     (1 << 4)
+#define XDP_USE_SG	(1 << 4)
 
 /* Flags for xsk_umem_config flags */
 #define XDP_UMEM_UNALIGNED_CHUNK_FLAG (1 << 0)
@@ -106,6 +106,43 @@ struct xdp_options {
 #define XSK_UNALIGNED_BUF_ADDR_MASK \
 	((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)
 
+/* Request transmit timestamp. Upon completion, put it into tx_timestamp
+ * field of union xsk_tx_metadata.
+ */
+#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
+
+/* Request transmit checksum offload. Checksum start position and offset
+ * are communicated via csum_start and csum_offset fields of union
+ * xsk_tx_metadata.
+ */
+#define XDP_TX_METADATA_CHECKSUM		(1 << 1)
+
+/* Force checksum calculation in software. Can be used for testing or
+ * working around potential HW issues. This option causes performance
+ * degradation and only works in XDP_COPY mode.
+ */
+#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)
+
+struct xsk_tx_metadata {
+	union {
+		struct {
+			__u32 flags;
+
+			/* XDP_TX_METADATA_CHECKSUM */
+
+			/* Offset from desc->addr where checksumming should start. */
+			__u16 csum_start;
+			/* Offset from csum_start where checksum should be stored. */
+			__u16 csum_offset;
+		};
+
+		struct {
+			/* XDP_TX_METADATA_TIMESTAMP */
+			__u64 tx_timestamp;
+		} completion;
+	};
+};
+
 /* Rx/Tx descriptor */
 struct xdp_desc {
 	__u64 addr;
@@ -113,9 +150,16 @@ struct xdp_desc {
 	__u32 options;
 };
 
-/* Flag indicating packet constitutes of multiple buffers*/
+/* UMEM descriptor is __u64 */
+
+/* Flag indicating that the packet continues with the buffer pointed out by the
+ * next frame in the ring. The end of the packet is signalled by setting this
+ * bit to zero. For single buffer packets, every descriptor has 'options' set
+ * to 0 and this maintains backward compatibility.
+ */
 #define XDP_PKT_CONTD (1 << 0)
 
-/* UMEM descriptor is __u64 */
+/* TX packet carries valid metadata. */
+#define XDP_TX_METADATA (1 << 1)
 
 #endif /* _LINUX_IF_XDP_H */
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index 2943a151d4f1..48d5477a668c 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -53,12 +53,28 @@ enum netdev_xdp_rx_metadata {
 	NETDEV_XDP_RX_METADATA_MASK = 3,
 };
 
+/**
+ * enum netdev_xsk_flags
+ * @NETDEV_XSK_FLAGS_TX_TIMESTAMP: HW timestamping egress packets is supported
+ *   by the driver.
+ * @NETDEV_XSK_FLAGS_TX_CHECKSUM: L3 checksum HW offload is supported by the
+ *   driver.
+ */
+enum netdev_xsk_flags {
+	NETDEV_XSK_FLAGS_TX_TIMESTAMP = 1,
+	NETDEV_XSK_FLAGS_TX_CHECKSUM = 2,
+
+	/* private: */
+	NETDEV_XSK_FLAGS_MASK = 3,
+};
+
 enum {
 	NETDEV_A_DEV_IFINDEX = 1,
 	NETDEV_A_DEV_PAD,
 	NETDEV_A_DEV_XDP_FEATURES,
 	NETDEV_A_DEV_XDP_ZC_MAX_SEGS,
 	NETDEV_A_DEV_XDP_RX_METADATA_FEATURES,
+	NETDEV_A_DEV_XSK_FEATURES,
 
 	__NETDEV_A_DEV_MAX,
 	NETDEV_A_DEV_MAX = (__NETDEV_A_DEV_MAX - 1)
diff --git a/tools/net/ynl/generated/netdev-user.c b/tools/net/ynl/generated/netdev-user.c
index b5ffe8cd1144..6283d87dad37 100644
--- a/tools/net/ynl/generated/netdev-user.c
+++ b/tools/net/ynl/generated/netdev-user.c
@@ -58,6 +58,19 @@ const char *netdev_xdp_rx_metadata_str(enum netdev_xdp_rx_metadata value)
 	return netdev_xdp_rx_metadata_strmap[value];
 }
 
+static const char * const netdev_xsk_flags_strmap[] = {
+	[0] = "tx-timestamp",
+	[1] = "tx-checksum",
+};
+
+const char *netdev_xsk_flags_str(enum netdev_xsk_flags value)
+{
+	value = ffs(value) - 1;
+	if (value < 0 || value >= (int)MNL_ARRAY_SIZE(netdev_xsk_flags_strmap))
+		return NULL;
+	return netdev_xsk_flags_strmap[value];
+}
+
 /* Policies */
 struct ynl_policy_attr netdev_dev_policy[NETDEV_A_DEV_MAX + 1] = {
 	[NETDEV_A_DEV_IFINDEX] = { .name = "ifindex", .type = YNL_PT_U32, },
@@ -65,6 +78,7 @@ struct ynl_policy_attr netdev_dev_policy[NETDEV_A_DEV_MAX + 1] = {
 	[NETDEV_A_DEV_XDP_FEATURES] = { .name = "xdp-features", .type = YNL_PT_U64, },
 	[NETDEV_A_DEV_XDP_ZC_MAX_SEGS] = { .name = "xdp-zc-max-segs", .type = YNL_PT_U32, },
 	[NETDEV_A_DEV_XDP_RX_METADATA_FEATURES] = { .name = "xdp-rx-metadata-features", .type = YNL_PT_U64, },
+	[NETDEV_A_DEV_XSK_FEATURES] = { .name = "xsk-features", .type = YNL_PT_U64, },
 };
 
 struct ynl_policy_nest netdev_dev_nest = {
@@ -116,6 +130,11 @@ int netdev_dev_get_rsp_parse(const struct nlmsghdr *nlh, void *data)
 				return MNL_CB_ERROR;
 			dst->_present.xdp_rx_metadata_features = 1;
 			dst->xdp_rx_metadata_features = mnl_attr_get_u64(attr);
+		} else if (type == NETDEV_A_DEV_XSK_FEATURES) {
+			if (ynl_attr_validate(yarg, attr))
+				return MNL_CB_ERROR;
+			dst->_present.xsk_features = 1;
+			dst->xsk_features = mnl_attr_get_u64(attr);
 		}
 	}
 
diff --git a/tools/net/ynl/generated/netdev-user.h b/tools/net/ynl/generated/netdev-user.h
index b4351ff34595..bdbd1766ce46 100644
--- a/tools/net/ynl/generated/netdev-user.h
+++ b/tools/net/ynl/generated/netdev-user.h
@@ -19,6 +19,7 @@ extern const struct ynl_family ynl_netdev_family;
 const char *netdev_op_str(int op);
 const char *netdev_xdp_act_str(enum netdev_xdp_act value);
 const char *netdev_xdp_rx_metadata_str(enum netdev_xdp_rx_metadata value);
+const char *netdev_xsk_flags_str(enum netdev_xsk_flags value);
 
 /* Common nested types */
 /* ============== NETDEV_CMD_DEV_GET ============== */
@@ -50,12 +51,14 @@ struct netdev_dev_get_rsp {
 		__u32 xdp_features:1;
 		__u32 xdp_zc_max_segs:1;
 		__u32 xdp_rx_metadata_features:1;
+		__u32 xsk_features:1;
 	} _present;
 
 	__u32 ifindex;
 	__u64 xdp_features;
 	__u32 xdp_zc_max_segs;
 	__u64 xdp_rx_metadata_features;
+	__u64 xsk_features;
 };
 
 void netdev_dev_get_rsp_free(struct netdev_dev_get_rsp *rsp);
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 03/11] tools: ynl: Print xsk-features from the sample

[Stanislav Fomichev]

Regenerate the userspace specs and print xsk-features bitmask.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/net/ynl/samples/netdev.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/net/ynl/samples/netdev.c b/tools/net/ynl/samples/netdev.c
index b828225daad0..da7c2848f773 100644
--- a/tools/net/ynl/samples/netdev.c
+++ b/tools/net/ynl/samples/netdev.c
@@ -44,6 +44,12 @@ static void netdev_print_device(struct netdev_dev_get_rsp *d, unsigned int op)
 			printf(" %s", netdev_xdp_rx_metadata_str(1 << i));
 	}
 
+	printf(" xsk-features (%llx):", d->xsk_features);
+	for (int i = 0; d->xsk_features > 1U << i; i++) {
+		if (d->xsk_features & (1U << i))
+			printf(" %s", netdev_xsk_flags_str(1 << i));
+	}
+
 	printf(" xdp-zc-max-segs=%u", d->xdp_zc_max_segs);
 
 	name = netdev_op_str(op);
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 04/11] net/mlx5e: Implement AF_XDP TX timestamp and checksum offload

[Stanislav Fomichev]

TX timestamp:
- requires passing clock, not sure I'm passing the correct one (from
  cq->mdev), but the timestamp value looks convincing

TX checksum:
- looks like device does packet parsing (and doesn't accept custom
  start/offset), so I'm ignoring user offsets

Cc: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en.h  |  4 +-
 .../net/ethernet/mellanox/mlx5/core/en/xdp.c  | 72 ++++++++++++++++---
 .../net/ethernet/mellanox/mlx5/core/en/xdp.h  | 11 ++-
 .../ethernet/mellanox/mlx5/core/en/xsk/tx.c   | 17 ++++-
 .../net/ethernet/mellanox/mlx5/core/en_main.c |  1 +
 5 files changed, 89 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 2b3254e33fe5..695c609c4707 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -483,10 +483,12 @@ struct mlx5e_xdp_info_fifo {
 
 struct mlx5e_xdpsq;
 struct mlx5e_xmit_data;
+struct xsk_tx_metadata;
 typedef int (*mlx5e_fp_xmit_xdp_frame_check)(struct mlx5e_xdpsq *);
 typedef bool (*mlx5e_fp_xmit_xdp_frame)(struct mlx5e_xdpsq *,
 					struct mlx5e_xmit_data *,
-					int);
+					int,
+					struct xsk_tx_metadata *);
 
 struct mlx5e_xdpsq {
 	/* data path */
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
index cc3fcd24b36d..71df2f26812c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
@@ -103,7 +103,7 @@ mlx5e_xmit_xdp_buff(struct mlx5e_xdpsq *sq, struct mlx5e_rq *rq,
 		xdptxd->dma_addr = dma_addr;
 
 		if (unlikely(!INDIRECT_CALL_2(sq->xmit_xdp_frame, mlx5e_xmit_xdp_frame_mpwqe,
-					      mlx5e_xmit_xdp_frame, sq, xdptxd, 0)))
+					      mlx5e_xmit_xdp_frame, sq, xdptxd, 0, NULL)))
 			return false;
 
 		/* xmit_mode == MLX5E_XDP_XMIT_MODE_FRAME */
@@ -145,7 +145,7 @@ mlx5e_xmit_xdp_buff(struct mlx5e_xdpsq *sq, struct mlx5e_rq *rq,
 	xdptxd->dma_addr = dma_addr;
 
 	if (unlikely(!INDIRECT_CALL_2(sq->xmit_xdp_frame, mlx5e_xmit_xdp_frame_mpwqe,
-				      mlx5e_xmit_xdp_frame, sq, xdptxd, 0)))
+				      mlx5e_xmit_xdp_frame, sq, xdptxd, 0, NULL)))
 		return false;
 
 	/* xmit_mode == MLX5E_XDP_XMIT_MODE_PAGE */
@@ -261,6 +261,37 @@ const struct xdp_metadata_ops mlx5e_xdp_metadata_ops = {
 	.xmo_rx_hash			= mlx5e_xdp_rx_hash,
 };
 
+struct mlx5e_xsk_tx_complete {
+	struct mlx5_cqe64 *cqe;
+	struct mlx5e_cq *cq;
+};
+
+static u64 mlx5e_xsk_fill_timestamp(void *_priv)
+{
+	struct mlx5e_xsk_tx_complete *priv = _priv;
+	u64 ts;
+
+	ts = get_cqe_ts(priv->cqe);
+
+	if (mlx5_is_real_time_rq(priv->cq->mdev) || mlx5_is_real_time_sq(priv->cq->mdev))
+		return mlx5_real_time_cyc2time(&priv->cq->mdev->clock, ts);
+
+	return  mlx5_timecounter_cyc2time(&priv->cq->mdev->clock, ts);
+}
+
+static void mlx5e_xsk_request_checksum(u16 csum_start, u16 csum_offset, void *priv)
+{
+	struct mlx5_wqe_eth_seg *eseg = priv;
+
+	/* HW/FW is doing parsing, so offsets are largely ignored. */
+	eseg->cs_flags |= MLX5_ETH_WQE_L3_CSUM | MLX5_ETH_WQE_L4_CSUM;
+}
+
+const struct xsk_tx_metadata_ops mlx5e_xsk_tx_metadata_ops = {
+	.tmo_fill_timestamp		= mlx5e_xsk_fill_timestamp,
+	.tmo_request_checksum		= mlx5e_xsk_request_checksum,
+};
+
 /* returns true if packet was consumed by xdp */
 bool mlx5e_xdp_handle(struct mlx5e_rq *rq,
 		      struct bpf_prog *prog, struct mlx5e_xdp_buff *mxbuf)
@@ -398,11 +429,11 @@ INDIRECT_CALLABLE_SCOPE int mlx5e_xmit_xdp_frame_check_mpwqe(struct mlx5e_xdpsq
 
 INDIRECT_CALLABLE_SCOPE bool
 mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
-		     int check_result);
+		     int check_result, struct xsk_tx_metadata *meta);
 
 INDIRECT_CALLABLE_SCOPE bool
 mlx5e_xmit_xdp_frame_mpwqe(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
-			   int check_result)
+			   int check_result, struct xsk_tx_metadata *meta)
 {
 	struct mlx5e_tx_mpwqe *session = &sq->mpwqe;
 	struct mlx5e_xdpsq_stats *stats = sq->stats;
@@ -420,7 +451,7 @@ mlx5e_xmit_xdp_frame_mpwqe(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptx
 			 */
 			if (unlikely(sq->mpwqe.wqe))
 				mlx5e_xdp_mpwqe_complete(sq);
-			return mlx5e_xmit_xdp_frame(sq, xdptxd, 0);
+			return mlx5e_xmit_xdp_frame(sq, xdptxd, 0, meta);
 		}
 		if (!xdptxd->len) {
 			skb_frag_t *frag = &xdptxdf->sinfo->frags[0];
@@ -450,6 +481,7 @@ mlx5e_xmit_xdp_frame_mpwqe(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptx
 		 * and it's safe to complete it at any time.
 		 */
 		mlx5e_xdp_mpwqe_session_start(sq);
+		xsk_tx_metadata_request(meta, &mlx5e_xsk_tx_metadata_ops, &session->wqe->eth);
 	}
 
 	mlx5e_xdp_mpwqe_add_dseg(sq, p, stats);
@@ -480,7 +512,7 @@ INDIRECT_CALLABLE_SCOPE int mlx5e_xmit_xdp_frame_check(struct mlx5e_xdpsq *sq)
 
 INDIRECT_CALLABLE_SCOPE bool
 mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
-		     int check_result)
+		     int check_result, struct xsk_tx_metadata *meta)
 {
 	struct mlx5e_xmit_data_frags *xdptxdf =
 		container_of(xdptxd, struct mlx5e_xmit_data_frags, xd);
@@ -599,6 +631,8 @@ mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
 		sq->pc++;
 	}
 
+	xsk_tx_metadata_request(meta, &mlx5e_xsk_tx_metadata_ops, eseg);
+
 	sq->doorbell_cseg = cseg;
 
 	stats->xmit++;
@@ -608,7 +642,9 @@ mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd,
 static void mlx5e_free_xdpsq_desc(struct mlx5e_xdpsq *sq,
 				  struct mlx5e_xdp_wqe_info *wi,
 				  u32 *xsk_frames,
-				  struct xdp_frame_bulk *bq)
+				  struct xdp_frame_bulk *bq,
+				  struct mlx5e_cq *cq,
+				  struct mlx5_cqe64 *cqe)
 {
 	struct mlx5e_xdp_info_fifo *xdpi_fifo = &sq->db.xdpi_fifo;
 	u16 i;
@@ -668,10 +704,24 @@ static void mlx5e_free_xdpsq_desc(struct mlx5e_xdpsq *sq,
 
 			break;
 		}
-		case MLX5E_XDP_XMIT_MODE_XSK:
+		case MLX5E_XDP_XMIT_MODE_XSK: {
 			/* AF_XDP send */
+			struct xsk_tx_metadata_compl *compl = NULL;
+			struct mlx5e_xsk_tx_complete priv = {
+				.cqe = cqe,
+				.cq = cq,
+			};
+
+			if (xp_tx_metadata_enabled(sq->xsk_pool)) {
+				xdpi = mlx5e_xdpi_fifo_pop(xdpi_fifo);
+				compl = &xdpi.xsk_meta;
+
+				xsk_tx_metadata_complete(compl, &mlx5e_xsk_tx_metadata_ops, &priv);
+			}
+
 			(*xsk_frames)++;
 			break;
+		}
 		default:
 			WARN_ON_ONCE(true);
 		}
@@ -720,7 +770,7 @@ bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq)
 
 			sqcc += wi->num_wqebbs;
 
-			mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, &bq);
+			mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, &bq, cq, cqe);
 		} while (!last_wqe);
 
 		if (unlikely(get_cqe_opcode(cqe) != MLX5_CQE_REQ)) {
@@ -767,7 +817,7 @@ void mlx5e_free_xdpsq_descs(struct mlx5e_xdpsq *sq)
 
 		sq->cc += wi->num_wqebbs;
 
-		mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, &bq);
+		mlx5e_free_xdpsq_desc(sq, wi, &xsk_frames, &bq, NULL, NULL);
 	}
 
 	xdp_flush_frame_bulk(&bq);
@@ -840,7 +890,7 @@ int mlx5e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
 		}
 
 		ret = INDIRECT_CALL_2(sq->xmit_xdp_frame, mlx5e_xmit_xdp_frame_mpwqe,
-				      mlx5e_xmit_xdp_frame, sq, xdptxd, 0);
+				      mlx5e_xmit_xdp_frame, sq, xdptxd, 0, NULL);
 		if (unlikely(!ret)) {
 			int j;
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h
index ecfe93a479da..e054db1e10f8 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h
@@ -33,6 +33,7 @@
 #define __MLX5_EN_XDP_H__
 
 #include <linux/indirect_call_wrapper.h>
+#include <net/xdp_sock.h>
 
 #include "en.h"
 #include "en/txrx.h"
@@ -82,7 +83,7 @@ enum mlx5e_xdp_xmit_mode {
  *    num, page_1, page_2, ... , page_num.
  *
  * MLX5E_XDP_XMIT_MODE_XSK:
- *    none.
+ *    frame.xsk_meta.
  */
 #define MLX5E_XDP_FIFO_ENTRIES2DS_MAX_RATIO 4
 
@@ -97,6 +98,7 @@ union mlx5e_xdp_info {
 		u8 num;
 		struct page *page;
 	} page;
+	struct xsk_tx_metadata_compl xsk_meta;
 };
 
 struct mlx5e_xsk_param;
@@ -112,13 +114,16 @@ int mlx5e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
 		   u32 flags);
 
 extern const struct xdp_metadata_ops mlx5e_xdp_metadata_ops;
+extern const struct xsk_tx_metadata_ops mlx5e_xsk_tx_metadata_ops;
 
 INDIRECT_CALLABLE_DECLARE(bool mlx5e_xmit_xdp_frame_mpwqe(struct mlx5e_xdpsq *sq,
 							  struct mlx5e_xmit_data *xdptxd,
-							  int check_result));
+							  int check_result,
+							  struct xsk_tx_metadata *meta));
 INDIRECT_CALLABLE_DECLARE(bool mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq,
 						    struct mlx5e_xmit_data *xdptxd,
-						    int check_result));
+						    int check_result,
+						    struct xsk_tx_metadata *meta));
 INDIRECT_CALLABLE_DECLARE(int mlx5e_xmit_xdp_frame_check_mpwqe(struct mlx5e_xdpsq *sq));
 INDIRECT_CALLABLE_DECLARE(int mlx5e_xmit_xdp_frame_check(struct mlx5e_xdpsq *sq));
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c
index 597f319d4770..a59199ed590d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c
@@ -55,12 +55,16 @@ static void mlx5e_xsk_tx_post_err(struct mlx5e_xdpsq *sq,
 
 	nopwqe = mlx5e_post_nop(&sq->wq, sq->sqn, &sq->pc);
 	mlx5e_xdpi_fifo_push(&sq->db.xdpi_fifo, *xdpi);
+	if (xp_tx_metadata_enabled(sq->xsk_pool))
+		mlx5e_xdpi_fifo_push(&sq->db.xdpi_fifo,
+				     (union mlx5e_xdp_info) { .xsk_meta = {} });
 	sq->doorbell_cseg = &nopwqe->ctrl;
 }
 
 bool mlx5e_xsk_tx(struct mlx5e_xdpsq *sq, unsigned int budget)
 {
 	struct xsk_buff_pool *pool = sq->xsk_pool;
+	struct xsk_tx_metadata *meta = NULL;
 	union mlx5e_xdp_info xdpi;
 	bool work_done = true;
 	bool flush = false;
@@ -93,12 +97,13 @@ bool mlx5e_xsk_tx(struct mlx5e_xdpsq *sq, unsigned int budget)
 		xdptxd.dma_addr = xsk_buff_raw_get_dma(pool, desc.addr);
 		xdptxd.data = xsk_buff_raw_get_data(pool, desc.addr);
 		xdptxd.len = desc.len;
+		meta = xsk_buff_get_metadata(pool, desc.addr);
 
 		xsk_buff_raw_dma_sync_for_device(pool, xdptxd.dma_addr, xdptxd.len);
 
 		ret = INDIRECT_CALL_2(sq->xmit_xdp_frame, mlx5e_xmit_xdp_frame_mpwqe,
 				      mlx5e_xmit_xdp_frame, sq, &xdptxd,
-				      check_result);
+				      check_result, meta);
 		if (unlikely(!ret)) {
 			if (sq->mpwqe.wqe)
 				mlx5e_xdp_mpwqe_complete(sq);
@@ -106,6 +111,16 @@ bool mlx5e_xsk_tx(struct mlx5e_xdpsq *sq, unsigned int budget)
 			mlx5e_xsk_tx_post_err(sq, &xdpi);
 		} else {
 			mlx5e_xdpi_fifo_push(&sq->db.xdpi_fifo, xdpi);
+			if (xp_tx_metadata_enabled(sq->xsk_pool)) {
+				struct xsk_tx_metadata_compl compl;
+
+				xsk_tx_metadata_to_compl(meta, &compl);
+				XSK_TX_COMPL_FITS(void *);
+
+				mlx5e_xdpi_fifo_push(&sq->db.xdpi_fifo,
+						     (union mlx5e_xdp_info)
+						     { .xsk_meta = compl });
+			}
 		}
 
 		flush = true;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index afc3d488b8f6..70c7816c9177 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -5160,6 +5160,7 @@ static void mlx5e_build_nic_netdev(struct net_device *netdev)
 
 	netdev->netdev_ops = &mlx5e_netdev_ops;
 	netdev->xdp_metadata_ops = &mlx5e_xdp_metadata_ops;
+	netdev->xsk_tx_metadata_ops = &mlx5e_xsk_tx_metadata_ops;
 
 	mlx5e_dcbnl_build_netdev(netdev);
 
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 05/11] net: stmmac: Add Tx HWTS support to XDP ZC

[Stanislav Fomichev]

From: Song Yoong Siang <yoong.siang.song@intel.com>

This patch enables transmit hardware timestamp support to XDP zero copy
via XDP Tx metadata framework.

This patchset is tested with tools/testing/selftests/bpf/xdp_hw_metadata
on Intel Tiger Lake platform. Below are the test steps and results.

Command on DUT:
  sudo ./xdp_hw_metadata <interface name>
  sudo hwstamp_ctl -i <interface name> -t 1 -r 1

Command on Link Partner:
  echo -n xdp | nc -u -q1 <destination IPv4 addr> 9091

Result:
  xsk_ring_cons__peek: 1
  0x562e3313b6d0: rx_desc[3]->addr=8e100 addr=8e100 comp_addr=8e100
  No rx_hash err=-95
  rx_timestamp:  1677763849292380229 (sec:1677763849.2924)
  XDP RX-time:   1677763849292641940 (sec:1677763849.2926)
                 delta sec:0.0003 (261.711 usec)
  AF_XDP time:   1677763849292666175 (sec:1677763849.2927)
                 delta sec:0.0000 (24.235 usec)
  0x562e3313b6d0: ping-pong with csum=561c (want 08af)
                  csum_start=34 csum_offset=6
  0x562e3313b6d0: complete tx idx=3 addr=3008
  0x562e3313b6d0: tx_timestamp:  1677763849295700005 (sec:1677763849.2957)
  0x562e3313b6d0: complete rx idx=131 addr=8e100

Additionally, to double confirm the rx_timestamp and tx_timestamp are taken
from PTP Hardware Clock (PHC), we set the value of PHC to a specific value
using tools/testing/selftests/ptp/testptp. Below are the test steps and
results.

Command to set PHC to a specific value:
  sudo ./testptp -d /dev/ptp2 -T 123000000

Result:
  xsk_ring_cons__peek: 1
  0x562e3313b6d0: rx_desc[7]->addr=9e100 addr=9e100 comp_addr=9e100
  No rx_hash err=-95
  rx_timestamp:  123000002731730589 (sec:123000002.7317)
  XDP RX-time:   1677763869396644361 (sec:1677763869.3966)
                 delta sec:1554763866.6649 (1554763866664913.750 usec)
  AF_XDP time:   1677763869396671376 (sec:1677763869.3967)
                 delta sec:0.0000 (27.015 usec)
  0x562e3313b6d0: ping-pong with csum=561c (want d1bf)
                  csum_start=34 csum_offset=6
  0x562e3313b6d0: complete tx idx=7 addr=7008
  0x562e3313b6d0: tx_timestamp:  123000002735048790 (sec:123000002.7350)
  0x562e3313b6d0: complete rx idx=135 addr=9e100

Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h  | 12 ++++
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 63 ++++++++++++++++++-
 2 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index cd7a9768de5f..686c94c2e8a7 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -51,6 +51,7 @@ struct stmmac_tx_info {
 	bool last_segment;
 	bool is_jumbo;
 	enum stmmac_txbuf_type buf_type;
+	struct xsk_tx_metadata_compl xsk_meta;
 };
 
 #define STMMAC_TBS_AVAIL	BIT(0)
@@ -100,6 +101,17 @@ struct stmmac_xdp_buff {
 	struct dma_desc *ndesc;
 };
 
+struct stmmac_metadata_request {
+	struct stmmac_priv *priv;
+	struct dma_desc *tx_desc;
+	bool *set_ic;
+};
+
+struct stmmac_xsk_tx_complete {
+	struct stmmac_priv *priv;
+	struct dma_desc *desc;
+};
+
 struct stmmac_rx_queue {
 	u32 rx_count_frames;
 	u32 queue_index;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index bb1dbf4c9f6c..49fe2f20797e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2422,6 +2422,46 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv)
 	}
 }
 
+static void stmmac_xsk_request_timestamp(void *_priv)
+{
+	struct stmmac_metadata_request *meta_req = _priv;
+
+	stmmac_enable_tx_timestamp(meta_req->priv, meta_req->tx_desc);
+	*meta_req->set_ic = true;
+}
+
+static u64 stmmac_xsk_fill_timestamp(void *_priv)
+{
+	struct stmmac_xsk_tx_complete *tx_compl = _priv;
+	struct stmmac_priv *priv = tx_compl->priv;
+	struct dma_desc *desc = tx_compl->desc;
+	bool found = false;
+	u64 ns = 0;
+
+	if (!priv->hwts_tx_en)
+		return 0;
+
+	/* check tx tstamp status */
+	if (stmmac_get_tx_timestamp_status(priv, desc)) {
+		stmmac_get_timestamp(priv, desc, priv->adv_ts, &ns);
+		found = true;
+	} else if (!stmmac_get_mac_tx_timestamp(priv, priv->hw, &ns)) {
+		found = true;
+	}
+
+	if (found) {
+		ns -= priv->plat->cdc_error_adj;
+		return ns_to_ktime(ns);
+	}
+
+	return 0;
+}
+
+static const struct xsk_tx_metadata_ops stmmac_xsk_tx_metadata_ops = {
+	.tmo_request_timestamp		= stmmac_xsk_request_timestamp,
+	.tmo_fill_timestamp		= stmmac_xsk_fill_timestamp,
+};
+
 static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
 {
 	struct netdev_queue *nq = netdev_get_tx_queue(priv->dev, queue);
@@ -2441,6 +2481,8 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
 	budget = min(budget, stmmac_tx_avail(priv, queue));
 
 	while (budget-- > 0) {
+		struct stmmac_metadata_request meta_req;
+		struct xsk_tx_metadata *meta = NULL;
 		dma_addr_t dma_addr;
 		bool set_ic;
 
@@ -2464,6 +2506,7 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
 			tx_desc = tx_q->dma_tx + entry;
 
 		dma_addr = xsk_buff_raw_get_dma(pool, xdp_desc.addr);
+		meta = xsk_buff_get_metadata(pool, xdp_desc.addr);
 		xsk_buff_raw_dma_sync_for_device(pool, dma_addr, xdp_desc.len);
 
 		tx_q->tx_skbuff_dma[entry].buf_type = STMMAC_TXBUF_T_XSK_TX;
@@ -2491,6 +2534,11 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
 		else
 			set_ic = false;
 
+		meta_req.priv = priv;
+		meta_req.tx_desc = tx_desc;
+		meta_req.set_ic = &set_ic;
+		xsk_tx_metadata_request(meta, &stmmac_xsk_tx_metadata_ops, &meta_req);
+
 		if (set_ic) {
 			tx_q->tx_count_frames = 0;
 			stmmac_set_tx_ic(priv, tx_desc);
@@ -2503,6 +2551,8 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
 
 		stmmac_enable_dma_transmission(priv, priv->ioaddr);
 
+		xsk_tx_metadata_to_compl(meta, &tx_q->tx_skbuff_dma[entry].xsk_meta);
+
 		tx_q->cur_tx = STMMAC_GET_ENTRY(tx_q->cur_tx, priv->dma_conf.dma_tx_size);
 		entry = tx_q->cur_tx;
 	}
@@ -2608,8 +2658,18 @@ static int stmmac_tx_clean(struct stmmac_priv *priv, int budget, u32 queue)
 			} else {
 				tx_packets++;
 			}
-			if (skb)
+			if (skb) {
 				stmmac_get_tx_hwtstamp(priv, p, skb);
+			} else {
+				struct stmmac_xsk_tx_complete tx_compl = {
+					.priv = priv,
+					.desc = p,
+				};
+
+				xsk_tx_metadata_complete(&tx_q->tx_skbuff_dma[entry].xsk_meta,
+							 &stmmac_xsk_tx_metadata_ops,
+							 &tx_compl);
+			}
 		}
 
 		if (likely(tx_q->tx_skbuff_dma[entry].buf &&
@@ -7414,6 +7474,7 @@ int stmmac_dvr_probe(struct device *device,
 	ndev->netdev_ops = &stmmac_netdev_ops;
 
 	ndev->xdp_metadata_ops = &stmmac_xdp_metadata_ops;
+	ndev->xsk_tx_metadata_ops = &stmmac_xsk_tx_metadata_ops;
 
 	ndev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
 			    NETIF_F_RXCSUM;
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 06/11] selftests/xsk: Support tx_metadata_len

[Stanislav Fomichev]

Add new config field and propagate to umem registration setsockopt.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/testing/selftests/bpf/xsk.c | 3 +++
 tools/testing/selftests/bpf/xsk.h | 1 +
 2 files changed, 4 insertions(+)

diff --git a/tools/testing/selftests/bpf/xsk.c b/tools/testing/selftests/bpf/xsk.c
index e574711eeb84..25d568abf0f2 100644
--- a/tools/testing/selftests/bpf/xsk.c
+++ b/tools/testing/selftests/bpf/xsk.c
@@ -115,6 +115,7 @@ static void xsk_set_umem_config(struct xsk_umem_config *cfg,
 		cfg->frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE;
 		cfg->frame_headroom = XSK_UMEM__DEFAULT_FRAME_HEADROOM;
 		cfg->flags = XSK_UMEM__DEFAULT_FLAGS;
+		cfg->tx_metadata_len = 0;
 		return;
 	}
 
@@ -123,6 +124,7 @@ static void xsk_set_umem_config(struct xsk_umem_config *cfg,
 	cfg->frame_size = usr_cfg->frame_size;
 	cfg->frame_headroom = usr_cfg->frame_headroom;
 	cfg->flags = usr_cfg->flags;
+	cfg->tx_metadata_len = usr_cfg->tx_metadata_len;
 }
 
 static int xsk_set_xdp_socket_config(struct xsk_socket_config *cfg,
@@ -252,6 +254,7 @@ int xsk_umem__create(struct xsk_umem **umem_ptr, void *umem_area,
 	mr.chunk_size = umem->config.frame_size;
 	mr.headroom = umem->config.frame_headroom;
 	mr.flags = umem->config.flags;
+	mr.tx_metadata_len = umem->config.tx_metadata_len;
 
 	err = setsockopt(umem->fd, SOL_XDP, XDP_UMEM_REG, &mr, sizeof(mr));
 	if (err) {
diff --git a/tools/testing/selftests/bpf/xsk.h b/tools/testing/selftests/bpf/xsk.h
index 771570bc3731..93c2cc413cfc 100644
--- a/tools/testing/selftests/bpf/xsk.h
+++ b/tools/testing/selftests/bpf/xsk.h
@@ -200,6 +200,7 @@ struct xsk_umem_config {
 	__u32 frame_size;
 	__u32 frame_headroom;
 	__u32 flags;
+	__u32 tx_metadata_len;
 };
 
 int xsk_attach_xdp_program(struct bpf_program *prog, int ifindex, u32 xdp_flags);
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 07/11] selftests/bpf: Add csum helpers

[Stanislav Fomichev]

Checksum helpers will be used to calculate pseudo-header checksum in
AF_XDP metadata selftests.

The helpers are mirroring existing kernel ones:
- csum_tcpudp_magic : IPv4 pseudo header csum
- csum_ipv6_magic : IPv6 pseudo header csum
- csum_fold : fold csum and do one's complement

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/testing/selftests/bpf/network_helpers.h | 43 +++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index 34f1200a781b..94b9be24e39b 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -71,4 +71,47 @@ struct nstoken;
  */
 struct nstoken *open_netns(const char *name);
 void close_netns(struct nstoken *token);
+
+static __u16 csum_fold(__u32 csum)
+{
+	csum = (csum & 0xffff) + (csum >> 16);
+	csum = (csum & 0xffff) + (csum >> 16);
+
+	return (__u16)~csum;
+}
+
+static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
+					__u32 len, __u8 proto,
+					__wsum csum)
+{
+	__u64 s = csum;
+
+	s += (__u32)saddr;
+	s += (__u32)daddr;
+	s += htons(proto + len);
+	s = (s & 0xffffffff) + (s >> 32);
+	s = (s & 0xffffffff) + (s >> 32);
+
+	return csum_fold((__u32)s);
+}
+
+static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
+				      const struct in6_addr *daddr,
+					__u32 len, __u8 proto,
+					__wsum csum)
+{
+	__u64 s = csum;
+	int i;
+
+	for (i = 0; i < 4; i++)
+		s += (__u32)saddr->s6_addr32[i];
+	for (i = 0; i < 4; i++)
+		s += (__u32)daddr->s6_addr32[i];
+	s += htons(proto + len);
+	s = (s & 0xffffffff) + (s >> 32);
+	s = (s & 0xffffffff) + (s >> 32);
+
+	return csum_fold((__u32)s);
+}
+
 #endif
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 08/11] selftests/bpf: Add TX side to xdp_metadata

[Stanislav Fomichev]

Request TX timestamp and make sure it's not empty.
Request TX checksum offload (SW-only) and make sure it's resolved
to the correct one.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 .../selftests/bpf/prog_tests/xdp_metadata.c   | 31 +++++++++++++++++--
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
index 4439ba9392f8..79e043370923 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
@@ -57,6 +57,7 @@ static int open_xsk(int ifindex, struct xsk *xsk)
 		.comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS,
 		.frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE,
 		.flags = XDP_UMEM_UNALIGNED_CHUNK_FLAG,
+		.tx_metadata_len = sizeof(struct xsk_tx_metadata),
 	};
 	__u32 idx;
 	u64 addr;
@@ -138,6 +139,7 @@ static void ip_csum(struct iphdr *iph)
 
 static int generate_packet(struct xsk *xsk, __u16 dst_port)
 {
+	struct xsk_tx_metadata *meta;
 	struct xdp_desc *tx_desc;
 	struct udphdr *udph;
 	struct ethhdr *eth;
@@ -151,10 +153,14 @@ static int generate_packet(struct xsk *xsk, __u16 dst_port)
 		return -1;
 
 	tx_desc = xsk_ring_prod__tx_desc(&xsk->tx, idx);
-	tx_desc->addr = idx % (UMEM_NUM / 2) * UMEM_FRAME_SIZE;
+	tx_desc->addr = idx % (UMEM_NUM / 2) * UMEM_FRAME_SIZE + sizeof(struct xsk_tx_metadata);
 	printf("%p: tx_desc[%u]->addr=%llx\n", xsk, idx, tx_desc->addr);
 	data = xsk_umem__get_data(xsk->umem_area, tx_desc->addr);
 
+	meta = data - sizeof(struct xsk_tx_metadata);
+	memset(meta, 0, sizeof(*meta));
+	meta->flags = XDP_TX_METADATA_TIMESTAMP;
+
 	eth = data;
 	iph = (void *)(eth + 1);
 	udph = (void *)(iph + 1);
@@ -178,11 +184,17 @@ static int generate_packet(struct xsk *xsk, __u16 dst_port)
 	udph->source = htons(AF_XDP_SOURCE_PORT);
 	udph->dest = htons(dst_port);
 	udph->len = htons(sizeof(*udph) + UDP_PAYLOAD_BYTES);
-	udph->check = 0;
+	udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
+					 ntohs(udph->len), IPPROTO_UDP, 0);
 
 	memset(udph + 1, 0xAA, UDP_PAYLOAD_BYTES);
 
+	meta->flags |= XDP_TX_METADATA_CHECKSUM | XDP_TX_METADATA_CHECKSUM_SW;
+	meta->csum_start = sizeof(*eth) + sizeof(*iph);
+	meta->csum_offset = offsetof(struct udphdr, check);
+
 	tx_desc->len = sizeof(*eth) + sizeof(*iph) + sizeof(*udph) + UDP_PAYLOAD_BYTES;
+	tx_desc->options |= XDP_TX_METADATA;
 	xsk_ring_prod__submit(&xsk->tx, 1);
 
 	ret = sendto(xsk_socket__fd(xsk->socket), NULL, 0, MSG_DONTWAIT, NULL, 0);
@@ -194,13 +206,21 @@ static int generate_packet(struct xsk *xsk, __u16 dst_port)
 
 static void complete_tx(struct xsk *xsk)
 {
-	__u32 idx;
+	struct xsk_tx_metadata *meta;
 	__u64 addr;
+	void *data;
+	__u32 idx;
 
 	if (ASSERT_EQ(xsk_ring_cons__peek(&xsk->comp, 1, &idx), 1, "xsk_ring_cons__peek")) {
 		addr = *xsk_ring_cons__comp_addr(&xsk->comp, idx);
 
 		printf("%p: complete tx idx=%u addr=%llx\n", xsk, idx, addr);
+
+		data = xsk_umem__get_data(xsk->umem_area, addr);
+		meta = data - sizeof(struct xsk_tx_metadata);
+
+		ASSERT_NEQ(meta->completion.tx_timestamp, 0, "tx_timestamp");
+
 		xsk_ring_cons__release(&xsk->comp, 1);
 	}
 }
@@ -221,6 +241,7 @@ static int verify_xsk_metadata(struct xsk *xsk)
 	const struct xdp_desc *rx_desc;
 	struct pollfd fds = {};
 	struct xdp_meta *meta;
+	struct udphdr *udph;
 	struct ethhdr *eth;
 	struct iphdr *iph;
 	__u64 comp_addr;
@@ -257,6 +278,7 @@ static int verify_xsk_metadata(struct xsk *xsk)
 	ASSERT_EQ(eth->h_proto, htons(ETH_P_IP), "eth->h_proto");
 	iph = (void *)(eth + 1);
 	ASSERT_EQ((int)iph->version, 4, "iph->version");
+	udph = (void *)(iph + 1);
 
 	/* custom metadata */
 
@@ -270,6 +292,9 @@ static int verify_xsk_metadata(struct xsk *xsk)
 
 	ASSERT_EQ(meta->rx_hash_type, 0, "rx_hash_type");
 
+	/* checksum offload */
+	ASSERT_EQ(udph->check, 0x1c72, "csum");
+
 	xsk_ring_cons__release(&xsk->rx, 1);
 	refill_rx(xsk, comp_addr);
 
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 09/11] selftests/bpf: Convert xdp_hw_metadata to XDP_USE_NEED_WAKEUP

[Stanislav Fomichev]

This is the recommended way to run af_xdp, so let's use it in the test.

Also, come unrelated changes to now blow up the log too much:
- change default mode to zerocopy and add -c to use copy mode
- small fixes for the flags/sizes/prints
- add print_tstamp_delta to print timestamp + reference

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/testing/selftests/bpf/xdp_hw_metadata.c | 73 +++++++++++++------
 1 file changed, 49 insertions(+), 24 deletions(-)

diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
index 17c0f92ff160..057f7c145f62 100644
--- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
@@ -32,7 +32,7 @@
 
 #include "xdp_metadata.h"
 
-#define UMEM_NUM 16
+#define UMEM_NUM 256
 #define UMEM_FRAME_SIZE XSK_UMEM__DEFAULT_FRAME_SIZE
 #define UMEM_SIZE (UMEM_FRAME_SIZE * UMEM_NUM)
 #define XDP_FLAGS (XDP_FLAGS_DRV_MODE | XDP_FLAGS_REPLACE)
@@ -48,7 +48,7 @@ struct xsk {
 };
 
 struct xdp_hw_metadata *bpf_obj;
-__u16 bind_flags = XDP_COPY;
+__u16 bind_flags = XDP_USE_NEED_WAKEUP | XDP_ZEROCOPY;
 struct xsk *rx_xsk;
 const char *ifname;
 int ifindex;
@@ -68,7 +68,7 @@ static int open_xsk(int ifindex, struct xsk *xsk, __u32 queue_id)
 		.fill_size = XSK_RING_PROD__DEFAULT_NUM_DESCS,
 		.comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS,
 		.frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE,
-		.flags = XDP_UMEM_UNALIGNED_CHUNK_FLAG,
+		.flags = XSK_UMEM__DEFAULT_FLAGS,
 	};
 	__u32 idx;
 	u64 addr;
@@ -110,7 +110,7 @@ static int open_xsk(int ifindex, struct xsk *xsk, __u32 queue_id)
 	for (i = 0; i < UMEM_NUM / 2; i++) {
 		addr = (UMEM_NUM / 2 + i) * UMEM_FRAME_SIZE;
 		printf("%p: rx_desc[%d] -> %lx\n", xsk, i, addr);
-		*xsk_ring_prod__fill_addr(&xsk->fill, i) = addr;
+		*xsk_ring_prod__fill_addr(&xsk->fill, idx + i) = addr;
 	}
 	xsk_ring_prod__submit(&xsk->fill, ret);
 
@@ -131,12 +131,22 @@ static void refill_rx(struct xsk *xsk, __u64 addr)
 	__u32 idx;
 
 	if (xsk_ring_prod__reserve(&xsk->fill, 1, &idx) == 1) {
-		printf("%p: complete idx=%u addr=%llx\n", xsk, idx, addr);
+		printf("%p: complete rx idx=%u addr=%llx\n", xsk, idx, addr);
 		*xsk_ring_prod__fill_addr(&xsk->fill, idx) = addr;
 		xsk_ring_prod__submit(&xsk->fill, 1);
 	}
 }
 
+static int kick_tx(struct xsk *xsk)
+{
+	return sendto(xsk_socket__fd(xsk->socket), NULL, 0, MSG_DONTWAIT, NULL, 0);
+}
+
+static int kick_rx(struct xsk *xsk)
+{
+	return recvfrom(xsk_socket__fd(xsk->socket), NULL, 0, MSG_DONTWAIT, NULL, NULL);
+}
+
 #define NANOSEC_PER_SEC 1000000000 /* 10^9 */
 static __u64 gettime(clockid_t clock_id)
 {
@@ -152,6 +162,17 @@ static __u64 gettime(clockid_t clock_id)
 	return (__u64) t.tv_sec * NANOSEC_PER_SEC + t.tv_nsec;
 }
 
+static void print_tstamp_delta(const char *name, const char *refname,
+			       __u64 tstamp, __u64 reference)
+{
+	__s64 delta = (__s64)reference - (__s64)tstamp;
+
+	printf("%s:   %llu (sec:%0.4f) delta to %s sec:%0.4f (%0.3f usec)\n",
+	       name, tstamp, (double)tstamp / NANOSEC_PER_SEC, refname,
+	       (double)delta / NANOSEC_PER_SEC,
+	       (double)delta / 1000);
+}
+
 static void verify_xdp_metadata(void *data, clockid_t clock_id)
 {
 	struct xdp_meta *meta;
@@ -167,22 +188,13 @@ static void verify_xdp_metadata(void *data, clockid_t clock_id)
 	printf("rx_timestamp:  %llu (sec:%0.4f)\n", meta->rx_timestamp,
 	       (double)meta->rx_timestamp / NANOSEC_PER_SEC);
 	if (meta->rx_timestamp) {
-		__u64 usr_clock = gettime(clock_id);
-		__u64 xdp_clock = meta->xdp_timestamp;
-		__s64 delta_X = xdp_clock - meta->rx_timestamp;
-		__s64 delta_X2U = usr_clock - xdp_clock;
-
-		printf("XDP RX-time:   %llu (sec:%0.4f) delta sec:%0.4f (%0.3f usec)\n",
-		       xdp_clock, (double)xdp_clock / NANOSEC_PER_SEC,
-		       (double)delta_X / NANOSEC_PER_SEC,
-		       (double)delta_X / 1000);
-
-		printf("AF_XDP time:   %llu (sec:%0.4f) delta sec:%0.4f (%0.3f usec)\n",
-		       usr_clock, (double)usr_clock / NANOSEC_PER_SEC,
-		       (double)delta_X2U / NANOSEC_PER_SEC,
-		       (double)delta_X2U / 1000);
-	}
+		__u64 ref_tstamp = gettime(clock_id);
 
+		print_tstamp_delta("HW RX-time", "User RX-time",
+				   meta->rx_timestamp, ref_tstamp);
+		print_tstamp_delta("XDP RX-time", "User RX-time",
+				   meta->xdp_timestamp, ref_tstamp);
+	}
 }
 
 static void verify_skb_metadata(int fd)
@@ -252,6 +264,13 @@ static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t
 
 	while (true) {
 		errno = 0;
+
+		for (i = 0; i < rxq; i++) {
+			ret = kick_rx(&rx_xsk[i]);
+			if (ret)
+				printf("kick_rx ret=%d\n", ret);
+		}
+
 		ret = poll(fds, rxq + 1, 1000);
 		printf("poll: %d (%d) skip=%llu fail=%llu redir=%llu\n",
 		       ret, errno, bpf_obj->bss->pkts_skip,
@@ -420,8 +439,9 @@ static void print_usage(void)
 {
 	const char *usage =
 		"Usage: xdp_hw_metadata [OPTIONS] [IFNAME]\n"
-		"  -m    Enable multi-buffer XDP for larger MTU\n"
+		"  -c    Run in copy mode (zerocopy is default)\n"
 		"  -h    Display this help and exit\n\n"
+		"  -m    Enable multi-buffer XDP for larger MTU\n"
 		"Generate test packets on the other machine with:\n"
 		"  echo -n xdp | nc -u -q1 <dst_ip> 9091\n";
 
@@ -432,14 +452,19 @@ static void read_args(int argc, char *argv[])
 {
 	char opt;
 
-	while ((opt = getopt(argc, argv, "mh")) != -1) {
+	while ((opt = getopt(argc, argv, "chm")) != -1) {
 		switch (opt) {
-		case 'm':
-			bind_flags |= XDP_USE_SG;
+		case 'c':
+			bind_flags &= ~XDP_USE_NEED_WAKEUP;
+			bind_flags &= ~XDP_ZEROCOPY;
+			bind_flags |= XDP_COPY;
 			break;
 		case 'h':
 			print_usage();
 			exit(0);
+		case 'm':
+			bind_flags |= XDP_USE_SG;
+			break;
 		case '?':
 			if (isprint(optopt))
 				fprintf(stderr, "Unknown option: -%c\n", optopt);
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 10/11] selftests/bpf: Add TX side to xdp_hw_metadata

[Stanislav Fomichev]

When we get a packet on port 9091, we swap src/dst and send it out.
At this point we also request the timestamp and checksum offloads.

Checksum offload is verified by looking at the tcpdump on the other side.
The tool prints pseudo-header csum and the final one it expects.
The final checksum actually matches the incoming packets checksum
because we only flip the src/dst and don't change the payload.

Some other related changes:
- switched to zerocopy mode by default; new flag can be used to force
  old behavior
- request fixed tx_metadata_len headroom
- some other small fixes (umem size, fill idx+i, etc)

mvbz3:~# ./xdp_hw_metadata eth3
...
xsk_ring_cons__peek: 1
0x19546f8: rx_desc[0]->addr=80100 addr=80100 comp_addr=80100
rx_hash: 0x80B7EA8B with RSS type:0x2A
rx_timestamp:  1697580171852147395 (sec:1697580171.8521)
HW RX-time:   1697580171852147395 (sec:1697580171.8521), delta to User RX-time sec:0.2797 (279673.082 usec)
XDP RX-time:   1697580172131699047 (sec:1697580172.1317), delta to User RX-time sec:0.0001 (121.430 usec)
0x19546f8: ping-pong with csum=3b8e (want d862) csum_start=54 csum_offset=6
0x19546f8: complete tx idx=0 addr=8
tx_timestamp:  1697580172056756493 (sec:1697580172.0568)
HW TX-complete-time:   1697580172056756493 (sec:1697580172.0568), delta to User TX-complete-time sec:0.0852 (85175.537 usec)
XDP RX-time:   1697580172131699047 (sec:1697580172.1317), delta to User TX-complete-time sec:0.0102 (10232.983 usec)
HW RX-time:   1697580171852147395 (sec:1697580171.8521), delta to HW TX-complete-time sec:0.2046 (204609.098 usec)
0x19546f8: complete rx idx=128 addr=80100

mvbz4:~# nc  -Nu -q1 ${MVBZ3_LINK_LOCAL_IP}%eth3 9091

mvbz4:~# tcpdump -vvx -i eth3 udp
        tcpdump: listening on eth3, link-type EN10MB (Ethernet), snapshot length 262144 bytes
12:26:09.301074 IP6 (flowlabel 0x35fa5, hlim 127, next-header UDP (17) payload length: 11) fe80::1270:fdff:fe48:1087.55807 > fe80::1270:fdff:fe48:1077.9091: [bad udp cksum 0x3b8e -> 0xde7e!] UDP, length 3
        0x0000:  6003 5fa5 000b 117f fe80 0000 0000 0000
        0x0010:  1270 fdff fe48 1087 fe80 0000 0000 0000
        0x0020:  1270 fdff fe48 1077 d9ff 2383 000b 3b8e
        0x0030:  7864 70
12:26:09.301976 IP6 (flowlabel 0x35fa5, hlim 127, next-header UDP (17) payload length: 11) fe80::1270:fdff:fe48:1077.9091 > fe80::1270:fdff:fe48:1087.55807: [udp sum ok] UDP, length 3
        0x0000:  6003 5fa5 000b 117f fe80 0000 0000 0000
        0x0010:  1270 fdff fe48 1077 fe80 0000 0000 0000
        0x0020:  1270 fdff fe48 1087 2383 d9ff 000b de7e
        0x0030:  7864 70

This reverts commit c3c9abc1d0c989e0be21d78cccd99076cc94ec44.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/testing/selftests/bpf/xdp_hw_metadata.c | 159 +++++++++++++++++-
 1 file changed, 157 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
index 057f7c145f62..d9421c5889f8 100644
--- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
@@ -10,7 +10,9 @@
  *   - rx_hash
  *
  * TX:
- * - TBD
+ * - UDP 9091 packets trigger TX reply
+ * - TX HW timestamp is requested and reported back upon completion
+ * - TX checksum is requested
  */
 
 #include <test_progs.h>
@@ -24,11 +26,14 @@
 #include <linux/net_tstamp.h>
 #include <linux/udp.h>
 #include <linux/sockios.h>
+#include <linux/if_xdp.h>
 #include <sys/mman.h>
 #include <net/if.h>
 #include <ctype.h>
 #include <poll.h>
 #include <time.h>
+#include <unistd.h>
+#include <libgen.h>
 
 #include "xdp_metadata.h"
 
@@ -53,6 +58,9 @@ struct xsk *rx_xsk;
 const char *ifname;
 int ifindex;
 int rxq;
+bool skip_tx;
+__u64 last_hw_rx_timestamp;
+__u64 last_xdp_rx_timestamp;
 
 void test__fail(void) { /* for network_helpers.c */ }
 
@@ -69,6 +77,7 @@ static int open_xsk(int ifindex, struct xsk *xsk, __u32 queue_id)
 		.comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS,
 		.frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE,
 		.flags = XSK_UMEM__DEFAULT_FLAGS,
+		.tx_metadata_len = sizeof(struct xsk_tx_metadata),
 	};
 	__u32 idx;
 	u64 addr;
@@ -190,6 +199,10 @@ static void verify_xdp_metadata(void *data, clockid_t clock_id)
 	if (meta->rx_timestamp) {
 		__u64 ref_tstamp = gettime(clock_id);
 
+		/* store received timestamps to calculate a delta at tx */
+		last_hw_rx_timestamp = meta->rx_timestamp;
+		last_xdp_rx_timestamp = meta->xdp_timestamp;
+
 		print_tstamp_delta("HW RX-time", "User RX-time",
 				   meta->rx_timestamp, ref_tstamp);
 		print_tstamp_delta("XDP RX-time", "User RX-time",
@@ -242,6 +255,128 @@ static void verify_skb_metadata(int fd)
 	printf("skb hwtstamp is not found!\n");
 }
 
+static bool complete_tx(struct xsk *xsk, clockid_t clock_id)
+{
+	struct xsk_tx_metadata *meta;
+	__u64 addr;
+	void *data;
+	__u32 idx;
+
+	if (!xsk_ring_cons__peek(&xsk->comp, 1, &idx))
+		return false;
+
+	addr = *xsk_ring_cons__comp_addr(&xsk->comp, idx);
+	data = xsk_umem__get_data(xsk->umem_area, addr);
+	meta = data - sizeof(struct xsk_tx_metadata);
+
+	printf("%p: complete tx idx=%u addr=%llx\n", xsk, idx, addr);
+
+	printf("tx_timestamp:  %llu (sec:%0.4f)\n", meta->completion.tx_timestamp,
+	       (double)meta->completion.tx_timestamp / NANOSEC_PER_SEC);
+	if (meta->completion.tx_timestamp) {
+		__u64 ref_tstamp = gettime(clock_id);
+
+		print_tstamp_delta("HW TX-complete-time", "User TX-complete-time",
+				   meta->completion.tx_timestamp, ref_tstamp);
+		print_tstamp_delta("XDP RX-time", "User TX-complete-time",
+				   last_xdp_rx_timestamp, ref_tstamp);
+		print_tstamp_delta("HW RX-time", "HW TX-complete-time",
+				   last_hw_rx_timestamp, meta->completion.tx_timestamp);
+	}
+
+	xsk_ring_cons__release(&xsk->comp, 1);
+
+	return true;
+}
+
+#define swap(a, b, len) do { \
+	for (int i = 0; i < len; i++) { \
+		__u8 tmp = ((__u8 *)a)[i]; \
+		((__u8 *)a)[i] = ((__u8 *)b)[i]; \
+		((__u8 *)b)[i] = tmp; \
+	} \
+} while (0)
+
+static void ping_pong(struct xsk *xsk, void *rx_packet, clockid_t clock_id)
+{
+	struct xsk_tx_metadata *meta;
+	struct ipv6hdr *ip6h = NULL;
+	struct iphdr *iph = NULL;
+	struct xdp_desc *tx_desc;
+	struct udphdr *udph;
+	struct ethhdr *eth;
+	__sum16 want_csum;
+	void *data;
+	__u32 idx;
+	int ret;
+	int len;
+
+	ret = xsk_ring_prod__reserve(&xsk->tx, 1, &idx);
+	if (ret != 1) {
+		printf("%p: failed to reserve tx slot\n", xsk);
+		return;
+	}
+
+	tx_desc = xsk_ring_prod__tx_desc(&xsk->tx, idx);
+	tx_desc->addr = idx % (UMEM_NUM / 2) * UMEM_FRAME_SIZE + sizeof(struct xsk_tx_metadata);
+	data = xsk_umem__get_data(xsk->umem_area, tx_desc->addr);
+
+	meta = data - sizeof(struct xsk_tx_metadata);
+	memset(meta, 0, sizeof(*meta));
+	meta->flags = XDP_TX_METADATA_TIMESTAMP;
+
+	eth = rx_packet;
+
+	if (eth->h_proto == htons(ETH_P_IP)) {
+		iph = (void *)(eth + 1);
+		udph = (void *)(iph + 1);
+	} else if (eth->h_proto == htons(ETH_P_IPV6)) {
+		ip6h = (void *)(eth + 1);
+		udph = (void *)(ip6h + 1);
+	} else {
+		printf("%p: failed to detect IP version for ping pong %04x\n", xsk, eth->h_proto);
+		xsk_ring_prod__cancel(&xsk->tx, 1);
+		return;
+	}
+
+	len = ETH_HLEN;
+	if (ip6h)
+		len += sizeof(*ip6h) + ntohs(ip6h->payload_len);
+	if (iph)
+		len += ntohs(iph->tot_len);
+
+	swap(eth->h_dest, eth->h_source, ETH_ALEN);
+	if (iph)
+		swap(&iph->saddr, &iph->daddr, 4);
+	else
+		swap(&ip6h->saddr, &ip6h->daddr, 16);
+	swap(&udph->source, &udph->dest, 2);
+
+	want_csum = udph->check;
+	if (ip6h)
+		udph->check = ~csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+					       ntohs(udph->len), IPPROTO_UDP, 0);
+	else
+		udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
+						 ntohs(udph->len), IPPROTO_UDP, 0);
+
+	meta->flags |= XDP_TX_METADATA_CHECKSUM;
+	if (iph)
+		meta->csum_start = sizeof(*eth) + sizeof(*iph);
+	else
+		meta->csum_start = sizeof(*eth) + sizeof(*ip6h);
+	meta->csum_offset = offsetof(struct udphdr, check);
+
+	printf("%p: ping-pong with csum=%04x (want %04x) csum_start=%d csum_offset=%d\n",
+	       xsk, ntohs(udph->check), ntohs(want_csum), meta->csum_start, meta->csum_offset);
+
+	memcpy(data, rx_packet, len); /* don't share umem chunk for simplicity */
+	tx_desc->options |= XDP_TX_METADATA;
+	tx_desc->len = len;
+
+	xsk_ring_prod__submit(&xsk->tx, 1);
+}
+
 static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t clock_id)
 {
 	const struct xdp_desc *rx_desc;
@@ -307,6 +442,22 @@ static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t
 				verify_xdp_metadata(xsk_umem__get_data(xsk->umem_area, addr),
 						    clock_id);
 				first_seg = false;
+
+				if (!skip_tx) {
+					/* mirror first chunk back */
+					ping_pong(xsk, xsk_umem__get_data(xsk->umem_area, addr),
+						  clock_id);
+
+					ret = kick_tx(xsk);
+					if (ret)
+						printf("kick_tx ret=%d\n", ret);
+
+					for (int j = 0; j < 500; j++) {
+						if (complete_tx(xsk, clock_id))
+							break;
+						usleep(10*1000);
+					}
+				}
 			}
 
 			xsk_ring_cons__release(&xsk->rx, 1);
@@ -442,6 +593,7 @@ static void print_usage(void)
 		"  -c    Run in copy mode (zerocopy is default)\n"
 		"  -h    Display this help and exit\n\n"
 		"  -m    Enable multi-buffer XDP for larger MTU\n"
+		"  -r    Don't generate AF_XDP reply (rx metadata only)\n"
 		"Generate test packets on the other machine with:\n"
 		"  echo -n xdp | nc -u -q1 <dst_ip> 9091\n";
 
@@ -452,7 +604,7 @@ static void read_args(int argc, char *argv[])
 {
 	char opt;
 
-	while ((opt = getopt(argc, argv, "chm")) != -1) {
+	while ((opt = getopt(argc, argv, "chmr")) != -1) {
 		switch (opt) {
 		case 'c':
 			bind_flags &= ~XDP_USE_NEED_WAKEUP;
@@ -465,6 +617,9 @@ static void read_args(int argc, char *argv[])
 		case 'm':
 			bind_flags |= XDP_USE_SG;
 			break;
+		case 'r':
+			skip_tx = true;
+			break;
 		case '?':
 			if (isprint(optopt))
 				fprintf(stderr, "Unknown option: -%c\n", optopt);
-- 
2.42.0.655.g421f12c284-goog

[PATCH bpf-next v4 11/11] xsk: Document tx_metadata_len layout

[Stanislav Fomichev]

- how to use
- how to query features
- pointers to the examples

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 Documentation/networking/index.rst           |  1 +
 Documentation/networking/xsk-tx-metadata.rst | 77 ++++++++++++++++++++
 2 files changed, 78 insertions(+)
 create mode 100644 Documentation/networking/xsk-tx-metadata.rst

diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst
index 2ffc5ad10295..f3c2566d6cad 100644
--- a/Documentation/networking/index.rst
+++ b/Documentation/networking/index.rst
@@ -122,6 +122,7 @@ Refer to :ref:`netdev-FAQ` for a guide on netdev development process specifics.
    xfrm_sync
    xfrm_sysctl
    xdp-rx-metadata
+   xsk-tx-metadata
 
 .. only::  subproject and html
 
diff --git a/Documentation/networking/xsk-tx-metadata.rst b/Documentation/networking/xsk-tx-metadata.rst
new file mode 100644
index 000000000000..b7289f06745c
--- /dev/null
+++ b/Documentation/networking/xsk-tx-metadata.rst
@@ -0,0 +1,77 @@
+==================
+AF_XDP TX Metadata
+==================
+
+This document describes how to enable offloads when transmitting packets
+via :doc:`af_xdp`. Refer to :doc:`xdp-rx-metadata` on how to access similar
+metadata on the receive side.
+
+General Design
+==============
+
+The headroom for the metadata is reserved via ``tx_metadata_len`` in
+``struct xdp_umem_reg``. The metadata length is therefore the same for
+every socket that shares the same umem. The metadata layout is a fixed UAPI,
+refer to ``union xsk_tx_metadata`` in ``include/uapi/linux/if_xdp.h``.
+Thus, generally, the ``tx_metadata_len`` field above should contain
+``sizeof(union xsk_tx_metadata)``.
+
+The headroom and the metadata itself should be located right before
+``xdp_desc->addr`` in the umem frame. Within a frame, the metadata
+layout is as follows::
+
+           tx_metadata_len
+     /                         \
+    +-----------------+---------+----------------------------+
+    | xsk_tx_metadata | padding |          payload           |
+    +-----------------+---------+----------------------------+
+                                ^
+                                |
+                          xdp_desc->addr
+
+An AF_XDP application can request headrooms larger than ``sizeof(struct
+xsk_tx_metadata)``. The kernel will ignore the padding (and will still
+use ``xdp_desc->addr - tx_metadata_len`` to locate
+the ``xsk_tx_metadata``). For the frames that shouldn't carry
+any metadata (i.e., the ones that don't have ``XDP_TX_METADATA`` option),
+the metadata area is ignored by the kernel as well.
+
+The flags field enables the particular offload:
+
+- ``XDP_TX_METADATA_TIMESTAMP``: requests the device to put transmission
+  timestamp into ``tx_timestamp`` field of ``union xsk_tx_metadata``.
+- ``XDP_TX_METADATA_CHECKSUM``: requests the device to calculate L4
+  checksum. ``csum_start`` specifies byte offset of there the checksumming
+  should start and ``csum_offset`` specifies byte offset where the
+  device should store the computed checksum.
+- ``XDP_TX_METADATA_CHECKSUM_SW``: requests checksum calculation to
+  be done in software; this mode works only in ``XSK_COPY`` mode and
+  is mostly intended for testing. Do not enable this option, it
+  will negatively affect performance.
+
+Besides the flags above, in order to trigger the offloads, the first
+packet's ``struct xdp_desc`` descriptor should set ``XDP_TX_METADATA``
+bit in the ``options`` field. Also not that in a multi-buffer packet
+only the first chunk should carry the metadata.
+
+Querying Device Capabilities
+============================
+
+Every devices exports its offloads capabilities via netlink netdev family.
+Refer to ``xsk-flags`` features bitmask in
+``Documentation/netlink/specs/netdev.yaml``.
+
+- ``tx-timestamp``: device supports ``XDP_TX_METADATA_TIMESTAMP``
+- ``tx-checksum``: device supports ``XDP_TX_METADATA_CHECKSUM``
+
+Note that every devices supports ``XDP_TX_METADATA_CHECKSUM_SW`` when
+running in ``XSK_COPY`` mode.
+
+See ``tools/net/ynl/samples/netdev.c`` on how to query this information.
+
+Example
+=======
+
+See ``tools/testing/selftests/bpf/xdp_hw_metadata.c`` for an example
+program that handles TX metadata. Also see https://github.com/fomichev/xskgen
+for a more bare-bones example.
-- 
2.42.0.655.g421f12c284-goog

RE: [PATCH bpf-next v4 01/11] xsk: Support tx_metadata_len

[Song, Yoong Siang]

On Friday, October 20, 2023 1:50 AM Stanislav Fomichev <sdf@google.com> wrote:
>For zerocopy mode, tx_desc->addr can point to the arbitrary offset
>and carry some TX metadata in the headroom. For copy mode, there
>is no way currently to populate skb metadata.
>
>Introduce new tx_metadata_len umem config option that indicates how many
>bytes to treat as metadata. Metadata bytes come prior to tx_desc address
>(same as in RX case).
>
>The size of the metadata has the same constraints as XDP:
>- less than 256 bytes
>- 4-byte aligned
>- non-zero
>
>This data is not interpreted in any way right now.
>
>Signed-off-by: Stanislav Fomichev <sdf@google.com>

LGTM.
Reviewed-by: Song Yoong Siang <yoong.siang.song@intel.com>

>---
> include/net/xdp_sock.h            |  1 +
> include/net/xsk_buff_pool.h       |  1 +
> include/uapi/linux/if_xdp.h       |  1 +
> net/xdp/xdp_umem.c                |  4 ++++
> net/xdp/xsk.c                     | 12 +++++++++++-
> net/xdp/xsk_buff_pool.c           |  1 +
> net/xdp/xsk_queue.h               | 17 ++++++++++-------
> tools/include/uapi/linux/if_xdp.h |  1 +
> 8 files changed, 30 insertions(+), 8 deletions(-)
>
>diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
>index 7dd0df2f6f8e..5ae88a00f34a 100644
>--- a/include/net/xdp_sock.h
>+++ b/include/net/xdp_sock.h
>@@ -30,6 +30,7 @@ struct xdp_umem {
> 	struct user_struct *user;
> 	refcount_t users;
> 	u8 flags;
>+	u8 tx_metadata_len;
> 	bool zc;
> 	struct page **pgs;
> 	int id;
>diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
>index b0bdff26fc88..1985ffaf9b0c 100644
>--- a/include/net/xsk_buff_pool.h
>+++ b/include/net/xsk_buff_pool.h
>@@ -77,6 +77,7 @@ struct xsk_buff_pool {
> 	u32 chunk_size;
> 	u32 chunk_shift;
> 	u32 frame_len;
>+	u8 tx_metadata_len; /* inherited from umem */
> 	u8 cached_need_wakeup;
> 	bool uses_need_wakeup;
> 	bool dma_need_sync;
>diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
>index 8d48863472b9..2ecf79282c26 100644
>--- a/include/uapi/linux/if_xdp.h
>+++ b/include/uapi/linux/if_xdp.h
>@@ -76,6 +76,7 @@ struct xdp_umem_reg {
> 	__u32 chunk_size;
> 	__u32 headroom;
> 	__u32 flags;
>+	__u32 tx_metadata_len;
> };
>
> struct xdp_statistics {
>diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
>index 06cead2b8e34..333f3d53aad4 100644
>--- a/net/xdp/xdp_umem.c
>+++ b/net/xdp/xdp_umem.c
>@@ -199,6 +199,9 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct
>xdp_umem_reg *mr)
> 	if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
> 		return -EINVAL;
>
>+	if (mr->tx_metadata_len > 256 || mr->tx_metadata_len % 4)
>+		return -EINVAL;
>+
> 	umem->size = size;
> 	umem->headroom = headroom;
> 	umem->chunk_size = chunk_size;
>@@ -207,6 +210,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct
>xdp_umem_reg *mr)
> 	umem->pgs = NULL;
> 	umem->user = NULL;
> 	umem->flags = mr->flags;
>+	umem->tx_metadata_len = mr->tx_metadata_len;
>
> 	INIT_LIST_HEAD(&umem->xsk_dma_list);
> 	refcount_set(&umem->users, 1);
>diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
>index ba070fd37d24..ba4c77a24a83 100644
>--- a/net/xdp/xsk.c
>+++ b/net/xdp/xsk.c
>@@ -1265,6 +1265,14 @@ struct xdp_umem_reg_v1 {
> 	__u32 headroom;
> };
>
>+struct xdp_umem_reg_v2 {
>+	__u64 addr; /* Start of packet data area */
>+	__u64 len; /* Length of packet data area */
>+	__u32 chunk_size;
>+	__u32 headroom;
>+	__u32 flags;
>+};
>+
> static int xsk_setsockopt(struct socket *sock, int level, int optname,
> 			  sockptr_t optval, unsigned int optlen)
> {
>@@ -1308,8 +1316,10 @@ static int xsk_setsockopt(struct socket *sock, int level, int
>optname,
>
> 		if (optlen < sizeof(struct xdp_umem_reg_v1))
> 			return -EINVAL;
>-		else if (optlen < sizeof(mr))
>+		else if (optlen < sizeof(struct xdp_umem_reg_v2))
> 			mr_size = sizeof(struct xdp_umem_reg_v1);
>+		else if (optlen < sizeof(mr))
>+			mr_size = sizeof(struct xdp_umem_reg_v2);
>
> 		if (copy_from_sockptr(&mr, optval, mr_size))
> 			return -EFAULT;
>diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
>index 49cb9f9a09be..386eddcdf837 100644
>--- a/net/xdp/xsk_buff_pool.c
>+++ b/net/xdp/xsk_buff_pool.c
>@@ -85,6 +85,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct
>xdp_sock *xs,
> 		XDP_PACKET_HEADROOM;
> 	pool->umem = umem;
> 	pool->addrs = umem->addrs;
>+	pool->tx_metadata_len = umem->tx_metadata_len;
> 	INIT_LIST_HEAD(&pool->free_list);
> 	INIT_LIST_HEAD(&pool->xskb_list);
> 	INIT_LIST_HEAD(&pool->xsk_tx_list);
>diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
>index 13354a1e4280..c74a1372bcb9 100644
>--- a/net/xdp/xsk_queue.h
>+++ b/net/xdp/xsk_queue.h
>@@ -143,15 +143,17 @@ static inline bool xp_unused_options_set(u32 options)
> static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
> 					    struct xdp_desc *desc)
> {
>-	u64 offset = desc->addr & (pool->chunk_size - 1);
>+	u64 addr = desc->addr - pool->tx_metadata_len;
>+	u64 len = desc->len + pool->tx_metadata_len;
>+	u64 offset = addr & (pool->chunk_size - 1);
>
> 	if (!desc->len)
> 		return false;
>
>-	if (offset + desc->len > pool->chunk_size)
>+	if (offset + len > pool->chunk_size)
> 		return false;
>
>-	if (desc->addr >= pool->addrs_cnt)
>+	if (addr >= pool->addrs_cnt)
> 		return false;
>
> 	if (xp_unused_options_set(desc->options))
>@@ -162,16 +164,17 @@ static inline bool xp_aligned_validate_desc(struct
>xsk_buff_pool *pool,
> static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool,
> 					      struct xdp_desc *desc)
> {
>-	u64 addr = xp_unaligned_add_offset_to_addr(desc->addr);
>+	u64 addr = xp_unaligned_add_offset_to_addr(desc->addr) - pool-
>>tx_metadata_len;
>+	u64 len = desc->len + pool->tx_metadata_len;
>
> 	if (!desc->len)
> 		return false;
>
>-	if (desc->len > pool->chunk_size)
>+	if (len > pool->chunk_size)
> 		return false;
>
>-	if (addr >= pool->addrs_cnt || addr + desc->len > pool->addrs_cnt ||
>-	    xp_desc_crosses_non_contig_pg(pool, addr, desc->len))
>+	if (addr >= pool->addrs_cnt || addr + len > pool->addrs_cnt ||
>+	    xp_desc_crosses_non_contig_pg(pool, addr, len))
> 		return false;
>
> 	if (xp_unused_options_set(desc->options))
>diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
>index 73a47da885dc..34411a2e5b6c 100644
>--- a/tools/include/uapi/linux/if_xdp.h
>+++ b/tools/include/uapi/linux/if_xdp.h
>@@ -76,6 +76,7 @@ struct xdp_umem_reg {
> 	__u32 chunk_size;
> 	__u32 headroom;
> 	__u32 flags;
>+	__u32 tx_metadata_len;
> };
>
> struct xdp_statistics {
>--
>2.42.0.655.g421f12c284-goog

RE: [PATCH bpf-next v4 02/11] xsk: Add TX timestamp and TX checksum offload support

[Song, Yoong Siang]

On Friday, October 20, 2023 1:50 AM Stanislav Fomichev <sdf@google.com> wrote:
>This change actually defines the (initial) metadata layout
>that should be used by AF_XDP userspace (xsk_tx_metadata).
>The first field is flags which requests appropriate offloads,
>followed by the offload-specific fields. The supported per-device
>offloads are exported via netlink (new xsk-flags).
>
>The offloads themselves are still implemented in a bit of a
>framework-y fashion that's left from my initial kfunc attempt.
>I'm introducing new xsk_tx_metadata_ops which drivers are
>supposed to implement. The drivers are also supposed
>to call xsk_tx_metadata_request/xsk_tx_metadata_complete in
>the right places. Since xsk_tx_metadata_{request,_complete}
>are static inline, we don't incur any extra overhead doing
>indirect calls.
>
>The benefit of this scheme is as follows:
>- keeps all metadata layout parsing away from driver code
>- makes it easy to grep and see which drivers implement what
>- don't need any extra flags to maintain to keep track of what
>  offloads are implemented; if the callback is implemented - the offload
>  is supported (used by netlink reporting code)
>
>Two offloads are defined right now:
>1. XDP_TX_METADATA_CHECKSUM: skb-style csum_start+csum_offset
>2. XDP_TX_METADATA_TIMESTAMP: writes TX timestamp back into metadata
>   area upon completion (tx_timestamp field)
>
>The offloads are also implemented for copy mode:
>1. Extra XDP_TX_METADATA_CHECKSUM_SW to trigger skb_checksum_help; this
>   might be useful as a reference implementation and for testing
>2. XDP_TX_METADATA_TIMESTAMP writes SW timestamp from the skb
>   destructor (note I'm reusing hwtstamps to pass metadata pointer)
>
>The struct is forward-compatible and can be extended in the future
>by appending more fields.
>
>Signed-off-by: Stanislav Fomichev <sdf@google.com>

LGTM.
Reviewed-by: Song Yoong Siang <yoong.siang.song@intel.com>

>---
> Documentation/netlink/specs/netdev.yaml | 19 ++++++
> include/linux/netdevice.h               | 27 ++++++++
> include/linux/skbuff.h                  | 14 +++-
> include/net/xdp_sock.h                  | 85 +++++++++++++++++++++++++
> include/net/xdp_sock_drv.h              | 13 ++++
> include/net/xsk_buff_pool.h             |  6 ++
> include/uapi/linux/if_xdp.h             | 40 ++++++++++++
> include/uapi/linux/netdev.h             | 16 +++++
> net/core/netdev-genl.c                  | 12 +++-
> net/xdp/xsk.c                           | 39 ++++++++++++
> net/xdp/xsk_queue.h                     |  2 +-
> tools/include/uapi/linux/if_xdp.h       | 54 ++++++++++++++--
> tools/include/uapi/linux/netdev.h       | 16 +++++
> tools/net/ynl/generated/netdev-user.c   | 19 ++++++
> tools/net/ynl/generated/netdev-user.h   |  3 +
> 15 files changed, 357 insertions(+), 8 deletions(-)
>
>diff --git a/Documentation/netlink/specs/netdev.yaml
>b/Documentation/netlink/specs/netdev.yaml
>index 14511b13f305..22d2649a34ee 100644
>--- a/Documentation/netlink/specs/netdev.yaml
>+++ b/Documentation/netlink/specs/netdev.yaml
>@@ -55,6 +55,19 @@ name: netdev
>         name: hash
>         doc:
>           Device is capable of exposing receive packet hash via
>bpf_xdp_metadata_rx_hash().
>+  -
>+    type: flags
>+    name: xsk-flags
>+    render-max: true
>+    entries:
>+      -
>+        name: tx-timestamp
>+        doc:
>+          HW timestamping egress packets is supported by the driver.
>+      -
>+        name: tx-checksum
>+        doc:
>+          L3 checksum HW offload is supported by the driver.
>
> attribute-sets:
>   -
>@@ -86,6 +99,11 @@ name: netdev
>              See Documentation/networking/xdp-rx-metadata.rst for more details.
>         type: u64
>         enum: xdp-rx-metadata
>+      -
>+        name: xsk-features
>+        doc: Bitmask of enabled AF_XDP features.
>+        type: u64
>+        enum: xsk-flags
>
> operations:
>   list:
>@@ -103,6 +121,7 @@ name: netdev
>             - xdp-features
>             - xdp-zc-max-segs
>             - xdp-rx-metadata-features
>+            - xsk-features
>       dump:
>         reply: *dev-all
>     -
>diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>index 1c7681263d30..f0903a1ac791 100644
>--- a/include/linux/netdevice.h
>+++ b/include/linux/netdevice.h
>@@ -1643,6 +1643,31 @@ struct net_device_ops {
> 						    struct netlink_ext_ack *extack);
> };
>
>+/*
>+ * This structure defines the AF_XDP TX metadata hooks for network devices.
>+ * The following hooks can be defined; unless noted otherwise, they are
>+ * optional and can be filled with a null pointer.
>+ *
>+ * void (*tmo_request_timestamp)(void *priv)
>+ *     This function is called when AF_XDP frame requested egress timestamp.
>+ *
>+ * u64 (*tmo_fill_timestamp)(void *priv)
>+ *     This function is called when AF_XDP frame, that had requested
>+ *     egress timestamp, received a completion. The hook needs to return
>+ *     the actual HW timestamp.
>+ *
>+ * void (*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv)
>+ *     This function is called when AF_XDP frame requested HW checksum
>+ *     offload. csum_start indicates position where checksumming should start.
>+ *     csum_offset indicates position where checksum should be stored.
>+ *
>+ */
>+struct xsk_tx_metadata_ops {
>+	void	(*tmo_request_timestamp)(void *priv);
>+	u64	(*tmo_fill_timestamp)(void *priv);
>+	void	(*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void
>*priv);
>+};
>+
> /**
>  * enum netdev_priv_flags - &struct net_device priv_flags
>  *
>@@ -1831,6 +1856,7 @@ enum netdev_ml_priv_type {
>  *	@netdev_ops:	Includes several pointers to callbacks,
>  *			if one wants to override the ndo_*() functions
>  *	@xdp_metadata_ops:	Includes pointers to XDP metadata callbacks.
>+ *	@xsk_tx_metadata_ops:	Includes pointers to AF_XDP TX metadata
>callbacks.
>  *	@ethtool_ops:	Management operations
>  *	@l3mdev_ops:	Layer 3 master device operations
>  *	@ndisc_ops:	Includes callbacks for different IPv6 neighbour
>@@ -2090,6 +2116,7 @@ struct net_device {
> 	unsigned long long	priv_flags;
> 	const struct net_device_ops *netdev_ops;
> 	const struct xdp_metadata_ops *xdp_metadata_ops;
>+	const struct xsk_tx_metadata_ops *xsk_tx_metadata_ops;
> 	int			ifindex;
> 	unsigned short		gflags;
> 	unsigned short		hard_header_len;
>diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
>index 97bfef071255..5b79d7fe9f9c 100644
>--- a/include/linux/skbuff.h
>+++ b/include/linux/skbuff.h
>@@ -566,6 +566,15 @@ struct ubuf_info_msgzc {
> int mm_account_pinned_pages(struct mmpin *mmp, size_t size);
> void mm_unaccount_pinned_pages(struct mmpin *mmp);
>
>+/* Preserve some data across TX submission and completion.
>+ *
>+ * Note, this state is stored in the driver. Extending the layout
>+ * might need some special care.
>+ */
>+struct xsk_tx_metadata_compl {
>+	__u64 *tx_timestamp;
>+};
>+
> /* This data is invariant across clones and lives at
>  * the end of the header data, ie. at skb->end.
>  */
>@@ -578,7 +587,10 @@ struct skb_shared_info {
> 	/* Warning: this field is not always filled in (UFO)! */
> 	unsigned short	gso_segs;
> 	struct sk_buff	*frag_list;
>-	struct skb_shared_hwtstamps hwtstamps;
>+	union {
>+		struct skb_shared_hwtstamps hwtstamps;
>+		struct xsk_tx_metadata_compl xsk_meta;
>+	};
> 	unsigned int	gso_type;
> 	u32		tskey;
>
>diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
>index 5ae88a00f34a..9f09ee47b434 100644
>--- a/include/net/xdp_sock.h
>+++ b/include/net/xdp_sock.h
>@@ -92,6 +92,74 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp);
> int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp);
> void __xsk_map_flush(void);
>
>+/**
>+ *  xsk_tx_metadata_to_compl - Save enough relevant metadata information
>+ *  to perform tx completion in the future.
>+ *  @meta: pointer to AF_XDP metadata area
>+ *  @compl: pointer to output struct xsk_tx_metadata_to_compl
>+ *
>+ *  This function should be called by the networking device when
>+ *  it prepares AF_XDP egress packet. The value of @compl should be stored
>+ *  and passed to xsk_tx_metadata_complete upon TX completion.
>+ */
>+static inline void xsk_tx_metadata_to_compl(struct xsk_tx_metadata *meta,
>+					    struct xsk_tx_metadata_compl *compl)
>+{
>+	if (!meta)
>+		return;
>+
>+	if (meta->flags & XDP_TX_METADATA_TIMESTAMP)
>+		compl->tx_timestamp = &meta->completion.tx_timestamp;
>+	else
>+		compl->tx_timestamp = NULL;
>+}
>+
>+/**
>+ *  xsk_tx_metadata_request - Evaluate AF_XDP TX metadata at submission
>+ *  and call appropriate xsk_tx_metadata_ops operation.
>+ *  @meta: pointer to AF_XDP metadata area
>+ *  @ops: pointer to struct xsk_tx_metadata_ops
>+ *  @priv: pointer to driver-private aread
>+ *
>+ *  This function should be called by the networking device when
>+ *  it prepares AF_XDP egress packet.
>+ */
>+static inline void xsk_tx_metadata_request(const struct xsk_tx_metadata *meta,
>+					   const struct xsk_tx_metadata_ops *ops,
>+					   void *priv)
>+{
>+	if (!meta)
>+		return;
>+
>+	if (ops->tmo_request_timestamp)
>+		if (meta->flags & XDP_TX_METADATA_TIMESTAMP)
>+			ops->tmo_request_timestamp(priv);
>+
>+	if (ops->tmo_request_checksum)
>+		if (meta->flags & XDP_TX_METADATA_CHECKSUM)
>+			ops->tmo_request_checksum(meta->csum_start, meta-
>>csum_offset, priv);
>+}
>+
>+/**
>+ *  xsk_tx_metadata_complete - Evaluate AF_XDP TX metadata at completion
>+ *  and call appropriate xsk_tx_metadata_ops operation.
>+ *  @compl: pointer to completion metadata produced from
>xsk_tx_metadata_to_compl
>+ *  @ops: pointer to struct xsk_tx_metadata_ops
>+ *  @priv: pointer to driver-private aread
>+ *
>+ *  This function should be called by the networking device upon
>+ *  AF_XDP egress completion.
>+ */
>+static inline void xsk_tx_metadata_complete(struct xsk_tx_metadata_compl *compl,
>+					    const struct xsk_tx_metadata_ops *ops,
>+					    void *priv)
>+{
>+	if (!compl)
>+		return;
>+
>+	*compl->tx_timestamp = ops->tmo_fill_timestamp(priv);
>+}
>+
> #else
>
> static inline int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
>@@ -108,6 +176,23 @@ static inline void __xsk_map_flush(void)
> {
> }
>
>+static inline void xsk_tx_metadata_to_compl(struct xsk_tx_metadata *meta,
>+					    struct xsk_tx_metadata_compl *compl)
>+{
>+}
>+
>+static inline void xsk_tx_metadata_request(struct xsk_tx_metadata *meta,
>+					   const struct xsk_tx_metadata_ops *ops,
>+					   void *priv)
>+{
>+}
>+
>+static inline void xsk_tx_metadata_complete(struct xsk_tx_metadata_compl *compl,
>+					    const struct xsk_tx_metadata_ops *ops,
>+					    void *priv)
>+{
>+}
>+
> #endif /* CONFIG_XDP_SOCKETS */
>
> #if defined(CONFIG_XDP_SOCKETS) && defined(CONFIG_DEBUG_NET)
>diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h
>index 1f6fc8c7a84c..e2558ac3e195 100644
>--- a/include/net/xdp_sock_drv.h
>+++ b/include/net/xdp_sock_drv.h
>@@ -165,6 +165,14 @@ static inline void *xsk_buff_raw_get_data(struct
>xsk_buff_pool *pool, u64 addr)
> 	return xp_raw_get_data(pool, addr);
> }
>
>+static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool
>*pool, u64 addr)
>+{
>+	if (!pool->tx_metadata_len)
>+		return NULL;
>+
>+	return xp_raw_get_data(pool, addr) - pool->tx_metadata_len;
>+}
>+
> static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct
>xsk_buff_pool *pool)
> {
> 	struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);
>@@ -324,6 +332,11 @@ static inline void *xsk_buff_raw_get_data(struct
>xsk_buff_pool *pool, u64 addr)
> 	return NULL;
> }
>
>+static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool
>*pool, u64 addr)
>+{
>+	return NULL;
>+}
>+
> static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct
>xsk_buff_pool *pool)
> {
> }
>diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
>index 1985ffaf9b0c..97f5cc10d79e 100644
>--- a/include/net/xsk_buff_pool.h
>+++ b/include/net/xsk_buff_pool.h
>@@ -33,6 +33,7 @@ struct xdp_buff_xsk {
> };
>
> #define XSK_CHECK_PRIV_TYPE(t) BUILD_BUG_ON(sizeof(t) > offsetofend(struct
>xdp_buff_xsk, cb))
>+#define XSK_TX_COMPL_FITS(t) BUILD_BUG_ON(sizeof(struct
>xsk_tx_metadata_compl) > sizeof(t))
>
> struct xsk_dma_map {
> 	dma_addr_t *dma_pages;
>@@ -234,4 +235,9 @@ static inline u64 xp_get_handle(struct xdp_buff_xsk *xskb)
> 	return xskb->orig_addr + (offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT);
> }
>
>+static inline bool xp_tx_metadata_enabled(const struct xsk_buff_pool *pool)
>+{
>+	return pool->tx_metadata_len > 0;
>+}
>+
> #endif /* XSK_BUFF_POOL_H_ */
>diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
>index 2ecf79282c26..ecfd67988283 100644
>--- a/include/uapi/linux/if_xdp.h
>+++ b/include/uapi/linux/if_xdp.h
>@@ -106,6 +106,43 @@ struct xdp_options {
> #define XSK_UNALIGNED_BUF_ADDR_MASK \
> 	((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)
>
>+/* Request transmit timestamp. Upon completion, put it into tx_timestamp
>+ * field of struct xsk_tx_metadata.
>+ */
>+#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
>+
>+/* Request transmit checksum offload. Checksum start position and offset
>+ * are communicated via csum_start and csum_offset fields of struct
>+ * xsk_tx_metadata.
>+ */
>+#define XDP_TX_METADATA_CHECKSUM		(1 << 1)
>+
>+/* Force checksum calculation in software. Can be used for testing or
>+ * working around potential HW issues. This option causes performance
>+ * degradation and only works in XDP_COPY mode.
>+ */
>+#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)
>+
>+struct xsk_tx_metadata {
>+	union {
>+		struct {
>+			__u32 flags;
>+
>+			/* XDP_TX_METADATA_CHECKSUM */
>+
>+			/* Offset from desc->addr where checksumming should start.
>*/
>+			__u16 csum_start;
>+			/* Offset from csum_start where checksum should be stored.
>*/
>+			__u16 csum_offset;
>+		};
>+
>+		struct {
>+			/* XDP_TX_METADATA_TIMESTAMP */
>+			__u64 tx_timestamp;
>+		} completion;
>+	};
>+};
>+
> /* Rx/Tx descriptor */
> struct xdp_desc {
> 	__u64 addr;
>@@ -122,4 +159,7 @@ struct xdp_desc {
>  */
> #define XDP_PKT_CONTD (1 << 0)
>
>+/* TX packet carries valid metadata. */
>+#define XDP_TX_METADATA (1 << 1)
>+
> #endif /* _LINUX_IF_XDP_H */
>diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
>index 2943a151d4f1..48d5477a668c 100644
>--- a/include/uapi/linux/netdev.h
>+++ b/include/uapi/linux/netdev.h
>@@ -53,12 +53,28 @@ enum netdev_xdp_rx_metadata {
> 	NETDEV_XDP_RX_METADATA_MASK = 3,
> };
>
>+/**
>+ * enum netdev_xsk_flags
>+ * @NETDEV_XSK_FLAGS_TX_TIMESTAMP: HW timestamping egress packets is
>supported
>+ *   by the driver.
>+ * @NETDEV_XSK_FLAGS_TX_CHECKSUM: L3 checksum HW offload is supported by
>the
>+ *   driver.
>+ */
>+enum netdev_xsk_flags {
>+	NETDEV_XSK_FLAGS_TX_TIMESTAMP = 1,
>+	NETDEV_XSK_FLAGS_TX_CHECKSUM = 2,
>+
>+	/* private: */
>+	NETDEV_XSK_FLAGS_MASK = 3,
>+};
>+
> enum {
> 	NETDEV_A_DEV_IFINDEX = 1,
> 	NETDEV_A_DEV_PAD,
> 	NETDEV_A_DEV_XDP_FEATURES,
> 	NETDEV_A_DEV_XDP_ZC_MAX_SEGS,
> 	NETDEV_A_DEV_XDP_RX_METADATA_FEATURES,
>+	NETDEV_A_DEV_XSK_FEATURES,
>
> 	__NETDEV_A_DEV_MAX,
> 	NETDEV_A_DEV_MAX = (__NETDEV_A_DEV_MAX - 1)
>diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
>index fe61f85bcf33..5d889c2425fd 100644
>--- a/net/core/netdev-genl.c
>+++ b/net/core/netdev-genl.c
>@@ -14,6 +14,7 @@ netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff
>*rsp,
> 		   const struct genl_info *info)
> {
> 	u64 xdp_rx_meta = 0;
>+	u64 xsk_features = 0;
> 	void *hdr;
>
> 	hdr = genlmsg_iput(rsp, info);
>@@ -26,11 +27,20 @@ netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff
>*rsp,
> XDP_METADATA_KFUNC_xxx
> #undef XDP_METADATA_KFUNC
>
>+	if (netdev->xsk_tx_metadata_ops) {
>+		if (netdev->xsk_tx_metadata_ops->tmo_fill_timestamp)
>+			xsk_features |= NETDEV_XSK_FLAGS_TX_TIMESTAMP;
>+		if (netdev->xsk_tx_metadata_ops->tmo_request_checksum)
>+			xsk_features |= NETDEV_XSK_FLAGS_TX_CHECKSUM;
>+	}
>+
> 	if (nla_put_u32(rsp, NETDEV_A_DEV_IFINDEX, netdev->ifindex) ||
> 	    nla_put_u64_64bit(rsp, NETDEV_A_DEV_XDP_FEATURES,
> 			      netdev->xdp_features, NETDEV_A_DEV_PAD) ||
> 	    nla_put_u64_64bit(rsp, NETDEV_A_DEV_XDP_RX_METADATA_FEATURES,
>-			      xdp_rx_meta, NETDEV_A_DEV_PAD)) {
>+			      xdp_rx_meta, NETDEV_A_DEV_PAD) ||
>+	    nla_put_u64_64bit(rsp, NETDEV_A_DEV_XSK_FEATURES,
>+			      xsk_features, NETDEV_A_DEV_PAD)) {
> 		genlmsg_cancel(rsp, hdr);
> 		return -EINVAL;
> 	}
>diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
>index ba4c77a24a83..c441a9eadbd5 100644
>--- a/net/xdp/xsk.c
>+++ b/net/xdp/xsk.c
>@@ -553,6 +553,13 @@ static u32 xsk_get_num_desc(struct sk_buff *skb)
>
> static void xsk_destruct_skb(struct sk_buff *skb)
> {
>+	struct xsk_tx_metadata_compl *compl = &skb_shinfo(skb)->xsk_meta;
>+
>+	if (compl->tx_timestamp) {
>+		/* sw completion timestamp, not a real one */
>+		*compl->tx_timestamp = ktime_get_tai_fast_ns();
>+	}
>+
> 	xsk_cq_submit_locked(xdp_sk(skb->sk), xsk_get_num_desc(skb));
> 	sock_wfree(skb);
> }
>@@ -637,8 +644,10 @@ static struct sk_buff *xsk_build_skb_zerocopy(struct
>xdp_sock *xs,
> static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
> 				     struct xdp_desc *desc)
> {
>+	struct xsk_tx_metadata *meta = NULL;
> 	struct net_device *dev = xs->dev;
> 	struct sk_buff *skb = xs->skb;
>+	bool first_frag = false;
> 	int err;
>
> 	if (dev->priv_flags & IFF_TX_SKB_NO_LINEAR) {
>@@ -669,6 +678,8 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
> 				kfree_skb(skb);
> 				goto free_err;
> 			}
>+
>+			first_frag = true;
> 		} else {
> 			int nr_frags = skb_shinfo(skb)->nr_frags;
> 			struct page *page;
>@@ -691,12 +702,40 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
>
> 			skb_add_rx_frag(skb, nr_frags, page, 0, len, 0);
> 		}
>+
>+		if (first_frag && desc->options & XDP_TX_METADATA) {
>+			if (unlikely(xs->pool->tx_metadata_len == 0)) {
>+				err = -EINVAL;
>+				goto free_err;
>+			}
>+
>+			meta = buffer - xs->pool->tx_metadata_len;
>+
>+			if (meta->flags & XDP_TX_METADATA_CHECKSUM) {
>+				if (unlikely(meta->csum_start + meta->csum_offset +
>+					     sizeof(__sum16) > len)) {
>+					err = -EINVAL;
>+					goto free_err;
>+				}
>+
>+				skb->csum_start = hr + meta->csum_start;
>+				skb->csum_offset = meta->csum_offset;
>+				skb->ip_summed = CHECKSUM_PARTIAL;
>+
>+				if (unlikely(meta->flags &
>XDP_TX_METADATA_CHECKSUM_SW)) {
>+					err = skb_checksum_help(skb);
>+					if (err)
>+						goto free_err;
>+				}
>+			}
>+		}
> 	}
>
> 	skb->dev = dev;
> 	skb->priority = READ_ONCE(xs->sk.sk_priority);
> 	skb->mark = READ_ONCE(xs->sk.sk_mark);
> 	skb->destructor = xsk_destruct_skb;
>+	xsk_tx_metadata_to_compl(meta, &skb_shinfo(skb)->xsk_meta);
> 	xsk_set_destructor_arg(skb);
>
> 	return skb;
>diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
>index c74a1372bcb9..6f2d1621c992 100644
>--- a/net/xdp/xsk_queue.h
>+++ b/net/xdp/xsk_queue.h
>@@ -137,7 +137,7 @@ static inline bool xskq_cons_read_addr_unchecked(struct
>xsk_queue *q, u64 *addr)
>
> static inline bool xp_unused_options_set(u32 options)
> {
>-	return options & ~XDP_PKT_CONTD;
>+	return options & ~(XDP_PKT_CONTD | XDP_TX_METADATA);
> }
>
> static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
>diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
>index 34411a2e5b6c..53ceaae10dd1 100644
>--- a/tools/include/uapi/linux/if_xdp.h
>+++ b/tools/include/uapi/linux/if_xdp.h
>@@ -26,11 +26,11 @@
>  */
> #define XDP_USE_NEED_WAKEUP (1 << 3)
> /* By setting this option, userspace application indicates that it can
>- * handle multiple descriptors per packet thus enabling xsk core to split
>+ * handle multiple descriptors per packet thus enabling AF_XDP to split
>  * multi-buffer XDP frames into multiple Rx descriptors. Without this set
>- * such frames will be dropped by xsk.
>+ * such frames will be dropped.
>  */
>-#define XDP_USE_SG     (1 << 4)
>+#define XDP_USE_SG	(1 << 4)
>
> /* Flags for xsk_umem_config flags */
> #define XDP_UMEM_UNALIGNED_CHUNK_FLAG (1 << 0)
>@@ -106,6 +106,43 @@ struct xdp_options {
> #define XSK_UNALIGNED_BUF_ADDR_MASK \
> 	((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)
>
>+/* Request transmit timestamp. Upon completion, put it into tx_timestamp
>+ * field of union xsk_tx_metadata.
>+ */
>+#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
>+
>+/* Request transmit checksum offload. Checksum start position and offset
>+ * are communicated via csum_start and csum_offset fields of union
>+ * xsk_tx_metadata.
>+ */
>+#define XDP_TX_METADATA_CHECKSUM		(1 << 1)
>+
>+/* Force checksum calculation in software. Can be used for testing or
>+ * working around potential HW issues. This option causes performance
>+ * degradation and only works in XDP_COPY mode.
>+ */
>+#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)
>+
>+struct xsk_tx_metadata {
>+	union {
>+		struct {
>+			__u32 flags;
>+
>+			/* XDP_TX_METADATA_CHECKSUM */
>+
>+			/* Offset from desc->addr where checksumming should start.
>*/
>+			__u16 csum_start;
>+			/* Offset from csum_start where checksum should be stored.
>*/
>+			__u16 csum_offset;
>+		};
>+
>+		struct {
>+			/* XDP_TX_METADATA_TIMESTAMP */
>+			__u64 tx_timestamp;
>+		} completion;
>+	};
>+};
>+
> /* Rx/Tx descriptor */
> struct xdp_desc {
> 	__u64 addr;
>@@ -113,9 +150,16 @@ struct xdp_desc {
> 	__u32 options;
> };
>
>-/* Flag indicating packet constitutes of multiple buffers*/
>+/* UMEM descriptor is __u64 */
>+
>+/* Flag indicating that the packet continues with the buffer pointed out by the
>+ * next frame in the ring. The end of the packet is signalled by setting this
>+ * bit to zero. For single buffer packets, every descriptor has 'options' set
>+ * to 0 and this maintains backward compatibility.
>+ */
> #define XDP_PKT_CONTD (1 << 0)
>
>-/* UMEM descriptor is __u64 */
>+/* TX packet carries valid metadata. */
>+#define XDP_TX_METADATA (1 << 1)
>
> #endif /* _LINUX_IF_XDP_H */
>diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
>index 2943a151d4f1..48d5477a668c 100644
>--- a/tools/include/uapi/linux/netdev.h
>+++ b/tools/include/uapi/linux/netdev.h
>@@ -53,12 +53,28 @@ enum netdev_xdp_rx_metadata {
> 	NETDEV_XDP_RX_METADATA_MASK = 3,
> };
>
>+/**
>+ * enum netdev_xsk_flags
>+ * @NETDEV_XSK_FLAGS_TX_TIMESTAMP: HW timestamping egress packets is
>supported
>+ *   by the driver.
>+ * @NETDEV_XSK_FLAGS_TX_CHECKSUM: L3 checksum HW offload is supported by
>the
>+ *   driver.
>+ */
>+enum netdev_xsk_flags {
>+	NETDEV_XSK_FLAGS_TX_TIMESTAMP = 1,
>+	NETDEV_XSK_FLAGS_TX_CHECKSUM = 2,
>+
>+	/* private: */
>+	NETDEV_XSK_FLAGS_MASK = 3,
>+};
>+
> enum {
> 	NETDEV_A_DEV_IFINDEX = 1,
> 	NETDEV_A_DEV_PAD,
> 	NETDEV_A_DEV_XDP_FEATURES,
> 	NETDEV_A_DEV_XDP_ZC_MAX_SEGS,
> 	NETDEV_A_DEV_XDP_RX_METADATA_FEATURES,
>+	NETDEV_A_DEV_XSK_FEATURES,
>
> 	__NETDEV_A_DEV_MAX,
> 	NETDEV_A_DEV_MAX = (__NETDEV_A_DEV_MAX - 1)
>diff --git a/tools/net/ynl/generated/netdev-user.c b/tools/net/ynl/generated/netdev-
>user.c
>index b5ffe8cd1144..6283d87dad37 100644
>--- a/tools/net/ynl/generated/netdev-user.c
>+++ b/tools/net/ynl/generated/netdev-user.c
>@@ -58,6 +58,19 @@ const char *netdev_xdp_rx_metadata_str(enum
>netdev_xdp_rx_metadata value)
> 	return netdev_xdp_rx_metadata_strmap[value];
> }
>
>+static const char * const netdev_xsk_flags_strmap[] = {
>+	[0] = "tx-timestamp",
>+	[1] = "tx-checksum",
>+};
>+
>+const char *netdev_xsk_flags_str(enum netdev_xsk_flags value)
>+{
>+	value = ffs(value) - 1;
>+	if (value < 0 || value >= (int)MNL_ARRAY_SIZE(netdev_xsk_flags_strmap))
>+		return NULL;
>+	return netdev_xsk_flags_strmap[value];
>+}
>+
> /* Policies */
> struct ynl_policy_attr netdev_dev_policy[NETDEV_A_DEV_MAX + 1] = {
> 	[NETDEV_A_DEV_IFINDEX] = { .name = "ifindex", .type = YNL_PT_U32, },
>@@ -65,6 +78,7 @@ struct ynl_policy_attr netdev_dev_policy[NETDEV_A_DEV_MAX
>+ 1] = {
> 	[NETDEV_A_DEV_XDP_FEATURES] = { .name = "xdp-features", .type =
>YNL_PT_U64, },
> 	[NETDEV_A_DEV_XDP_ZC_MAX_SEGS] = { .name = "xdp-zc-max-segs", .type =
>YNL_PT_U32, },
> 	[NETDEV_A_DEV_XDP_RX_METADATA_FEATURES] = { .name = "xdp-rx-
>metadata-features", .type = YNL_PT_U64, },
>+	[NETDEV_A_DEV_XSK_FEATURES] = { .name = "xsk-features", .type =
>YNL_PT_U64, },
> };
>
> struct ynl_policy_nest netdev_dev_nest = {
>@@ -116,6 +130,11 @@ int netdev_dev_get_rsp_parse(const struct nlmsghdr *nlh,
>void *data)
> 				return MNL_CB_ERROR;
> 			dst->_present.xdp_rx_metadata_features = 1;
> 			dst->xdp_rx_metadata_features = mnl_attr_get_u64(attr);
>+		} else if (type == NETDEV_A_DEV_XSK_FEATURES) {
>+			if (ynl_attr_validate(yarg, attr))
>+				return MNL_CB_ERROR;
>+			dst->_present.xsk_features = 1;
>+			dst->xsk_features = mnl_attr_get_u64(attr);
> 		}
> 	}
>
>diff --git a/tools/net/ynl/generated/netdev-user.h b/tools/net/ynl/generated/netdev-
>user.h
>index b4351ff34595..bdbd1766ce46 100644
>--- a/tools/net/ynl/generated/netdev-user.h
>+++ b/tools/net/ynl/generated/netdev-user.h
>@@ -19,6 +19,7 @@ extern const struct ynl_family ynl_netdev_family;
> const char *netdev_op_str(int op);
> const char *netdev_xdp_act_str(enum netdev_xdp_act value);
> const char *netdev_xdp_rx_metadata_str(enum netdev_xdp_rx_metadata value);
>+const char *netdev_xsk_flags_str(enum netdev_xsk_flags value);
>
> /* Common nested types */
> /* ============== NETDEV_CMD_DEV_GET ============== */
>@@ -50,12 +51,14 @@ struct netdev_dev_get_rsp {
> 		__u32 xdp_features:1;
> 		__u32 xdp_zc_max_segs:1;
> 		__u32 xdp_rx_metadata_features:1;
>+		__u32 xsk_features:1;
> 	} _present;
>
> 	__u32 ifindex;
> 	__u64 xdp_features;
> 	__u32 xdp_zc_max_segs;
> 	__u64 xdp_rx_metadata_features;
>+	__u64 xsk_features;
> };
>
> void netdev_dev_get_rsp_free(struct netdev_dev_get_rsp *rsp);
>--
>2.42.0.655.g421f12c284-goog

Re: [PATCH bpf-next v4 02/11] xsk: Add TX timestamp and TX checksum offload support

[Alexei Starovoitov]

On Thu, Oct 19, 2023 at 10:49:35AM -0700, Stanislav Fomichev wrote:
> diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
> index 2ecf79282c26..ecfd67988283 100644
> --- a/include/uapi/linux/if_xdp.h
> +++ b/include/uapi/linux/if_xdp.h
> @@ -106,6 +106,43 @@ struct xdp_options {
>  #define XSK_UNALIGNED_BUF_ADDR_MASK \
>  	((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)
>  
> +/* Request transmit timestamp. Upon completion, put it into tx_timestamp
> + * field of struct xsk_tx_metadata.
> + */
> +#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
> +
> +/* Request transmit checksum offload. Checksum start position and offset
> + * are communicated via csum_start and csum_offset fields of struct
> + * xsk_tx_metadata.
> + */
> +#define XDP_TX_METADATA_CHECKSUM		(1 << 1)
> +
> +/* Force checksum calculation in software. Can be used for testing or
> + * working around potential HW issues. This option causes performance
> + * degradation and only works in XDP_COPY mode.
> + */
> +#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)
> +
> +struct xsk_tx_metadata {
> +	union {
> +		struct {
> +			__u32 flags;
> +
> +			/* XDP_TX_METADATA_CHECKSUM */
> +
> +			/* Offset from desc->addr where checksumming should start. */
> +			__u16 csum_start;
> +			/* Offset from csum_start where checksum should be stored. */
> +			__u16 csum_offset;
> +		};
> +
> +		struct {
> +			/* XDP_TX_METADATA_TIMESTAMP */
> +			__u64 tx_timestamp;
> +		} completion;
> +	};
> +};

Could you add a comment to above union that csum fields are consumed by the driver
before it xmits the packet while timestamp is filled during xmit, so union
doesn't prevent using both features simultaneously.
It's clear from the example, but not obvious from uapi and the doc in patch 11
doesn't clarify it either.

Also please add a name to csum part of the union like you did for completion.
We've learned it the hard way with bpf_attr. All anon structs better have field name
within a union. Helps extensibility (avoid conflicts) in the long term.

Other than this the patch set looks great to me.
With Saeed and Magnus acks we can take it in.

Re: [PATCH bpf-next v4 02/11] xsk: Add TX timestamp and TX checksum offload support

[Stanislav Fomichev]

On 10/20, Alexei Starovoitov wrote:
> On Thu, Oct 19, 2023 at 10:49:35AM -0700, Stanislav Fomichev wrote:
> > diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
> > index 2ecf79282c26..ecfd67988283 100644
> > --- a/include/uapi/linux/if_xdp.h
> > +++ b/include/uapi/linux/if_xdp.h
> > @@ -106,6 +106,43 @@ struct xdp_options {
> >  #define XSK_UNALIGNED_BUF_ADDR_MASK \
> >  	((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)
> >  
> > +/* Request transmit timestamp. Upon completion, put it into tx_timestamp
> > + * field of struct xsk_tx_metadata.
> > + */
> > +#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
> > +
> > +/* Request transmit checksum offload. Checksum start position and offset
> > + * are communicated via csum_start and csum_offset fields of struct
> > + * xsk_tx_metadata.
> > + */
> > +#define XDP_TX_METADATA_CHECKSUM		(1 << 1)
> > +
> > +/* Force checksum calculation in software. Can be used for testing or
> > + * working around potential HW issues. This option causes performance
> > + * degradation and only works in XDP_COPY mode.
> > + */
> > +#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)
> > +
> > +struct xsk_tx_metadata {
> > +	union {
> > +		struct {
> > +			__u32 flags;
> > +
> > +			/* XDP_TX_METADATA_CHECKSUM */
> > +
> > +			/* Offset from desc->addr where checksumming should start. */
> > +			__u16 csum_start;
> > +			/* Offset from csum_start where checksum should be stored. */
> > +			__u16 csum_offset;
> > +		};
> > +
> > +		struct {
> > +			/* XDP_TX_METADATA_TIMESTAMP */
> > +			__u64 tx_timestamp;
> > +		} completion;
> > +	};
> > +};
> 
> Could you add a comment to above union that csum fields are consumed by the driver
> before it xmits the packet while timestamp is filled during xmit, so union
> doesn't prevent using both features simultaneously.
> It's clear from the example, but not obvious from uapi and the doc in patch 11
> doesn't clarify it either.
> 
> Also please add a name to csum part of the union like you did for completion.
> We've learned it the hard way with bpf_attr. All anon structs better have field name
> within a union. Helps extensibility (avoid conflicts) in the long term.

Sure, will do, thanks!

> Other than this the patch set looks great to me.
> With Saeed and Magnus acks we can take it in.

Magnus is on CC, so I hope see sees the request.

Added Saeed here as well. Saeed, can you please take a look at the mlx part?
You've been on CC for a particular patch, but just in case:
https://lore.kernel.org/bpf/20231019174944.3376335-5-sdf@google.com/T/#u

Re: [PATCH bpf-next v4 02/11] xsk: Add TX timestamp and TX checksum offload support

[Jakub Kicinski]

On Thu, 19 Oct 2023 10:49:35 -0700 Stanislav Fomichev wrote:
> diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
> index 14511b13f305..22d2649a34ee 100644
> --- a/Documentation/netlink/specs/netdev.yaml
> +++ b/Documentation/netlink/specs/netdev.yaml
> @@ -55,6 +55,19 @@ name: netdev
>          name: hash
>          doc:
>            Device is capable of exposing receive packet hash via bpf_xdp_metadata_rx_hash().
> +  -
> +    type: flags
> +    name: xsk-flags
> +    render-max: true

I don't think you're using the MAX, maybe don't render it.
IDK what purpose it'd serve for feature flag enums.

> +/*
> + * This structure defines the AF_XDP TX metadata hooks for network devices.

s/This structure defines the //

> + * The following hooks can be defined; unless noted otherwise, they are
> + * optional and can be filled with a null pointer.
> + *
> + * void (*tmo_request_timestamp)(void *priv)
> + *     This function is called when AF_XDP frame requested egress timestamp.

s/This function is // in many places

> + * u64 (*tmo_fill_timestamp)(void *priv)
> + *     This function is called when AF_XDP frame, that had requested
> + *     egress timestamp, received a completion. The hook needs to return
> + *     the actual HW timestamp.
> + *
> + * void (*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv)
> + *     This function is called when AF_XDP frame requested HW checksum
> + *     offload. csum_start indicates position where checksumming should start.
> + *     csum_offset indicates position where checksum should be stored.
> + *
> + */
> +struct xsk_tx_metadata_ops {
> +	void	(*tmo_request_timestamp)(void *priv);
> +	u64	(*tmo_fill_timestamp)(void *priv);
> +	void	(*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv);
> +};

Could you move the definition of the struct to include/net/xdp_sock.h ?
netdevice.h doesn't need it.

> +/* Request transmit timestamp. Upon completion, put it into tx_timestamp
> + * field of struct xsk_tx_metadata.
> + */
> +#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
> +
> +/* Request transmit checksum offload. Checksum start position and offset
> + * are communicated via csum_start and csum_offset fields of struct
> + * xsk_tx_metadata.
> + */
> +#define XDP_TX_METADATA_CHECKSUM		(1 << 1)

Reuse of enum netdev_xsk_flags is not an option?

> +/* Force checksum calculation in software. Can be used for testing or
> + * working around potential HW issues. This option causes performance
> + * degradation and only works in XDP_COPY mode.
> + */
> +#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)

Is there a need for this to be on packet-by-packet basis?
HW issues should generally be fixed by the driver, is there 
any type of problem in particular you have in mind here?

> diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
> index fe61f85bcf33..5d889c2425fd 100644
> --- a/net/core/netdev-genl.c
> +++ b/net/core/netdev-genl.c
> @@ -14,6 +14,7 @@ netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp,
>  		   const struct genl_info *info)
>  {
>  	u64 xdp_rx_meta = 0;
> +	u64 xsk_features = 0;

rev xmas tree? :)

> +			meta = buffer - xs->pool->tx_metadata_len;
> +
> +			if (meta->flags & XDP_TX_METADATA_CHECKSUM) {

Do we need to worry about reserved / unsupported meta->flags ?

> +				if (unlikely(meta->csum_start + meta->csum_offset +
> +					     sizeof(__sum16) > len)) {
> +					err = -EINVAL;
> +					goto free_err;
> +				}

Re: [PATCH bpf-next v4 03/11] tools: ynl: Print xsk-features from the sample

[Jakub Kicinski]

On Thu, 19 Oct 2023 10:49:36 -0700 Stanislav Fomichev wrote:
> Regenerate the userspace specs and print xsk-features bitmask.

I'm afraid you regenerated in previous patch already :]
Perhaps we should add an easy-to-use flag to ynl-regen to skip tools/ ?

> diff --git a/tools/net/ynl/samples/netdev.c b/tools/net/ynl/samples/netdev.c
> index b828225daad0..da7c2848f773 100644
> --- a/tools/net/ynl/samples/netdev.c
> +++ b/tools/net/ynl/samples/netdev.c
> @@ -44,6 +44,12 @@ static void netdev_print_device(struct netdev_dev_get_rsp *d, unsigned int op)
>  			printf(" %s", netdev_xdp_rx_metadata_str(1 << i));
>  	}
>  
> +	printf(" xsk-features (%llx):", d->xsk_features);
> +	for (int i = 0; d->xsk_features > 1U << i; i++) {

Shouldn't this be >= ?

> +		if (d->xsk_features & (1U << i))
> +			printf(" %s", netdev_xsk_flags_str(1 << i));
> +	}

Re: [PATCH bpf-next v4 01/11] xsk: Support tx_metadata_len

[Jakub Kicinski]

On Thu, 19 Oct 2023 10:49:34 -0700 Stanislav Fomichev wrote:
> - 4-byte aligned

But there is an 8B field in it. Won't this trap on some funky
architecture of yore?

Re: [PATCH bpf-next v4 01/11] xsk: Support tx_metadata_len

[Magnus Karlsson]

On Thu, 19 Oct 2023 at 19:50, Stanislav Fomichev <sdf@google.com> wrote:
>
> For zerocopy mode, tx_desc->addr can point to the arbitrary offset

nit: the -> an

> and carry some TX metadata in the headroom. For copy mode, there
> is no way currently to populate skb metadata.
>
> Introduce new tx_metadata_len umem config option that indicates how many
> bytes to treat as metadata. Metadata bytes come prior to tx_desc address
> (same as in RX case).
>
> The size of the metadata has the same constraints as XDP:
> - less than 256 bytes
> - 4-byte aligned
> - non-zero
>
> This data is not interpreted in any way right now.
>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>
> ---
>  include/net/xdp_sock.h            |  1 +
>  include/net/xsk_buff_pool.h       |  1 +
>  include/uapi/linux/if_xdp.h       |  1 +
>  net/xdp/xdp_umem.c                |  4 ++++
>  net/xdp/xsk.c                     | 12 +++++++++++-
>  net/xdp/xsk_buff_pool.c           |  1 +
>  net/xdp/xsk_queue.h               | 17 ++++++++++-------
>  tools/include/uapi/linux/if_xdp.h |  1 +
>  8 files changed, 30 insertions(+), 8 deletions(-)
>
> diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
> index 7dd0df2f6f8e..5ae88a00f34a 100644
> --- a/include/net/xdp_sock.h
> +++ b/include/net/xdp_sock.h
> @@ -30,6 +30,7 @@ struct xdp_umem {
>         struct user_struct *user;
>         refcount_t users;
>         u8 flags;
> +       u8 tx_metadata_len;
>         bool zc;
>         struct page **pgs;
>         int id;
> diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
> index b0bdff26fc88..1985ffaf9b0c 100644
> --- a/include/net/xsk_buff_pool.h
> +++ b/include/net/xsk_buff_pool.h
> @@ -77,6 +77,7 @@ struct xsk_buff_pool {
>         u32 chunk_size;
>         u32 chunk_shift;
>         u32 frame_len;
> +       u8 tx_metadata_len; /* inherited from umem */
>         u8 cached_need_wakeup;
>         bool uses_need_wakeup;
>         bool dma_need_sync;
> diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
> index 8d48863472b9..2ecf79282c26 100644
> --- a/include/uapi/linux/if_xdp.h
> +++ b/include/uapi/linux/if_xdp.h
> @@ -76,6 +76,7 @@ struct xdp_umem_reg {
>         __u32 chunk_size;
>         __u32 headroom;
>         __u32 flags;
> +       __u32 tx_metadata_len;
>  };
>
>  struct xdp_statistics {
> diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
> index 06cead2b8e34..333f3d53aad4 100644
> --- a/net/xdp/xdp_umem.c
> +++ b/net/xdp/xdp_umem.c
> @@ -199,6 +199,9 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
>         if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
>                 return -EINVAL;
>
> +       if (mr->tx_metadata_len > 256 || mr->tx_metadata_len % 4)
> +               return -EINVAL;

Should be >= 256 since the final internal destination is a u8 and the
documentation says "should be less than 256 bytes".

> +
>         umem->size = size;
>         umem->headroom = headroom;
>         umem->chunk_size = chunk_size;
> @@ -207,6 +210,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
>         umem->pgs = NULL;
>         umem->user = NULL;
>         umem->flags = mr->flags;
> +       umem->tx_metadata_len = mr->tx_metadata_len;
>
>         INIT_LIST_HEAD(&umem->xsk_dma_list);
>         refcount_set(&umem->users, 1);
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index ba070fd37d24..ba4c77a24a83 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -1265,6 +1265,14 @@ struct xdp_umem_reg_v1 {
>         __u32 headroom;
>  };
>
> +struct xdp_umem_reg_v2 {
> +       __u64 addr; /* Start of packet data area */
> +       __u64 len; /* Length of packet data area */
> +       __u32 chunk_size;
> +       __u32 headroom;
> +       __u32 flags;
> +};
> +
>  static int xsk_setsockopt(struct socket *sock, int level, int optname,
>                           sockptr_t optval, unsigned int optlen)
>  {
> @@ -1308,8 +1316,10 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname,
>
>                 if (optlen < sizeof(struct xdp_umem_reg_v1))
>                         return -EINVAL;
> -               else if (optlen < sizeof(mr))
> +               else if (optlen < sizeof(struct xdp_umem_reg_v2))
>                         mr_size = sizeof(struct xdp_umem_reg_v1);
> +               else if (optlen < sizeof(mr))
> +                       mr_size = sizeof(struct xdp_umem_reg_v2);
>
>                 if (copy_from_sockptr(&mr, optval, mr_size))
>                         return -EFAULT;
> diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
> index 49cb9f9a09be..386eddcdf837 100644
> --- a/net/xdp/xsk_buff_pool.c
> +++ b/net/xdp/xsk_buff_pool.c
> @@ -85,6 +85,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
>                 XDP_PACKET_HEADROOM;
>         pool->umem = umem;
>         pool->addrs = umem->addrs;
> +       pool->tx_metadata_len = umem->tx_metadata_len;
>         INIT_LIST_HEAD(&pool->free_list);
>         INIT_LIST_HEAD(&pool->xskb_list);
>         INIT_LIST_HEAD(&pool->xsk_tx_list);
> diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
> index 13354a1e4280..c74a1372bcb9 100644
> --- a/net/xdp/xsk_queue.h
> +++ b/net/xdp/xsk_queue.h
> @@ -143,15 +143,17 @@ static inline bool xp_unused_options_set(u32 options)
>  static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
>                                             struct xdp_desc *desc)
>  {
> -       u64 offset = desc->addr & (pool->chunk_size - 1);
> +       u64 addr = desc->addr - pool->tx_metadata_len;
> +       u64 len = desc->len + pool->tx_metadata_len;
> +       u64 offset = addr & (pool->chunk_size - 1);
>
>         if (!desc->len)
>                 return false;
>
> -       if (offset + desc->len > pool->chunk_size)
> +       if (offset + len > pool->chunk_size)
>                 return false;
>
> -       if (desc->addr >= pool->addrs_cnt)
> +       if (addr >= pool->addrs_cnt)
>                 return false;
>
>         if (xp_unused_options_set(desc->options))
> @@ -162,16 +164,17 @@ static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
>  static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool,
>                                               struct xdp_desc *desc)
>  {
> -       u64 addr = xp_unaligned_add_offset_to_addr(desc->addr);
> +       u64 addr = xp_unaligned_add_offset_to_addr(desc->addr) - pool->tx_metadata_len;
> +       u64 len = desc->len + pool->tx_metadata_len;
>
>         if (!desc->len)
>                 return false;
>
> -       if (desc->len > pool->chunk_size)
> +       if (len > pool->chunk_size)
>                 return false;
>
> -       if (addr >= pool->addrs_cnt || addr + desc->len > pool->addrs_cnt ||
> -           xp_desc_crosses_non_contig_pg(pool, addr, desc->len))
> +       if (addr >= pool->addrs_cnt || addr + len > pool->addrs_cnt ||
> +           xp_desc_crosses_non_contig_pg(pool, addr, len))
>                 return false;
>
>         if (xp_unused_options_set(desc->options))
> diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
> index 73a47da885dc..34411a2e5b6c 100644
> --- a/tools/include/uapi/linux/if_xdp.h
> +++ b/tools/include/uapi/linux/if_xdp.h
> @@ -76,6 +76,7 @@ struct xdp_umem_reg {
>         __u32 chunk_size;
>         __u32 headroom;
>         __u32 flags;
> +       __u32 tx_metadata_len;
>  };
>
>  struct xdp_statistics {
> --
> 2.42.0.655.g421f12c284-goog
>
>

Re: [PATCH bpf-next v4 11/11] xsk: Document tx_metadata_len layout

[Magnus Karlsson]

On Thu, 19 Oct 2023 at 19:50, Stanislav Fomichev <sdf@google.com> wrote:
>
> - how to use
> - how to query features
> - pointers to the examples
>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>
> ---
>  Documentation/networking/index.rst           |  1 +
>  Documentation/networking/xsk-tx-metadata.rst | 77 ++++++++++++++++++++
>  2 files changed, 78 insertions(+)
>  create mode 100644 Documentation/networking/xsk-tx-metadata.rst
>
> diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst
> index 2ffc5ad10295..f3c2566d6cad 100644
> --- a/Documentation/networking/index.rst
> +++ b/Documentation/networking/index.rst
> @@ -122,6 +122,7 @@ Refer to :ref:`netdev-FAQ` for a guide on netdev development process specifics.
>     xfrm_sync
>     xfrm_sysctl
>     xdp-rx-metadata
> +   xsk-tx-metadata
>
>  .. only::  subproject and html
>
> diff --git a/Documentation/networking/xsk-tx-metadata.rst b/Documentation/networking/xsk-tx-metadata.rst
> new file mode 100644
> index 000000000000..b7289f06745c
> --- /dev/null
> +++ b/Documentation/networking/xsk-tx-metadata.rst
> @@ -0,0 +1,77 @@
> +==================
> +AF_XDP TX Metadata
> +==================
> +
> +This document describes how to enable offloads when transmitting packets
> +via :doc:`af_xdp`. Refer to :doc:`xdp-rx-metadata` on how to access similar
> +metadata on the receive side.
> +
> +General Design
> +==============
> +
> +The headroom for the metadata is reserved via ``tx_metadata_len`` in
> +``struct xdp_umem_reg``. The metadata length is therefore the same for
> +every socket that shares the same umem. The metadata layout is a fixed UAPI,
> +refer to ``union xsk_tx_metadata`` in ``include/uapi/linux/if_xdp.h``.
> +Thus, generally, the ``tx_metadata_len`` field above should contain
> +``sizeof(union xsk_tx_metadata)``.
> +
> +The headroom and the metadata itself should be located right before
> +``xdp_desc->addr`` in the umem frame. Within a frame, the metadata
> +layout is as follows::
> +
> +           tx_metadata_len
> +     /                         \
> +    +-----------------+---------+----------------------------+
> +    | xsk_tx_metadata | padding |          payload           |
> +    +-----------------+---------+----------------------------+
> +                                ^
> +                                |
> +                          xdp_desc->addr
> +
> +An AF_XDP application can request headrooms larger than ``sizeof(struct
> +xsk_tx_metadata)``. The kernel will ignore the padding (and will still
> +use ``xdp_desc->addr - tx_metadata_len`` to locate
> +the ``xsk_tx_metadata``). For the frames that shouldn't carry
> +any metadata (i.e., the ones that don't have ``XDP_TX_METADATA`` option),
> +the metadata area is ignored by the kernel as well.
> +
> +The flags field enables the particular offload:
> +
> +- ``XDP_TX_METADATA_TIMESTAMP``: requests the device to put transmission
> +  timestamp into ``tx_timestamp`` field of ``union xsk_tx_metadata``.
> +- ``XDP_TX_METADATA_CHECKSUM``: requests the device to calculate L4
> +  checksum. ``csum_start`` specifies byte offset of there the checksumming

nit: of there -> where

> +  should start and ``csum_offset`` specifies byte offset where the
> +  device should store the computed checksum.
> +- ``XDP_TX_METADATA_CHECKSUM_SW``: requests checksum calculation to
> +  be done in software; this mode works only in ``XSK_COPY`` mode and
> +  is mostly intended for testing. Do not enable this option, it
> +  will negatively affect performance.
> +
> +Besides the flags above, in order to trigger the offloads, the first
> +packet's ``struct xdp_desc`` descriptor should set ``XDP_TX_METADATA``
> +bit in the ``options`` field. Also not that in a multi-buffer packet

nit: not -> note

> +only the first chunk should carry the metadata.
> +
> +Querying Device Capabilities
> +============================
> +
> +Every devices exports its offloads capabilities via netlink netdev family.
> +Refer to ``xsk-flags`` features bitmask in
> +``Documentation/netlink/specs/netdev.yaml``.
> +
> +- ``tx-timestamp``: device supports ``XDP_TX_METADATA_TIMESTAMP``
> +- ``tx-checksum``: device supports ``XDP_TX_METADATA_CHECKSUM``
> +
> +Note that every devices supports ``XDP_TX_METADATA_CHECKSUM_SW`` when
> +running in ``XSK_COPY`` mode.
> +
> +See ``tools/net/ynl/samples/netdev.c`` on how to query this information.
> +
> +Example
> +=======
> +
> +See ``tools/testing/selftests/bpf/xdp_hw_metadata.c`` for an example
> +program that handles TX metadata. Also see https://github.com/fomichev/xskgen
> +for a more bare-bones example.
> --
> 2.42.0.655.g421f12c284-goog
>
>

Re: [PATCH bpf-next v4 00/11] xsk: TX metadata

[Magnus Karlsson]

On Thu, 19 Oct 2023 at 19:49, Stanislav Fomichev <sdf@google.com> wrote:
>
> This series implements initial TX metadata (offloads) for AF_XDP.
> See patch #2 for the main implementation and mlx5/stmmac ones for the
> example on how to consume the metadata on the device side.
>
> Starting with two types of offloads:
> - request TX timestamp (and write it back into the metadata area)
> - request TX checksum offload
>
> Changes since v3:
> - fix xsk_tx_metadata_ops kdoc (Song Yoong Siang)
> - add missing xsk_tx_metadata_to_compl for XDP_SOCKETS=n (Vinicius Costa Gomes and Intel bots)
> - add reference timestamps to the selftests + refactor existing ones (Jesper)
>
> v3: https://lore.kernel.org/bpf/20231003200522.1914523-1-sdf@google.com/

Thanks for working on this Stanislav. I went through the patch set and
it looks good to me. You have addressed all the feedback that Maciej
and I had on a previous version. Just had some small things in two of
the patches. Apart from that, you are good to go and you can add my
ack to the next version.

Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>

Again, really appreciate all your work with this!

> Performance (mlx5):
>
> I've implemented a small xskgen tool to try to saturate single tx queue:
> https://github.com/fomichev/xskgen/tree/master
>
> Here are the performance numbers with some analysis.
>
> 1. Baseline. Running with commit eb62e6aef940 ("Merge branch 'bpf:
> Support bpf_get_func_ip helper in uprobes'"), nothing from this series:
>
> - with 1400 bytes of payload: 98 gbps, 8 mpps
> ./xskgen -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189130 sec, 98.357623 gbps 8.409509 mpps
>
> - with 200 bytes of payload: 49 gbps, 23 mpps
> ./xskgen -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000064 packets 20960134144 bits, took 0.422235 sec, 49.640921 gbps 23.683645 mpps
>
> 2. Adding single commit that supports reserving tx_metadata_len
>    changes nothing numbers-wise.
>
> - baseline for 1400
> ./xskgen -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189247 sec, 98.347946 gbps 8.408682 mpps
>
> - baseline for 200
> ./xskgen -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 20960000000 bits, took 0.421248 sec, 49.756913 gbps 23.738985 mpps
>
> 3. Adding -M flag causes xskgen to reserve the metadata and fill it, but
>    doesn't set XDP_TX_METADATA descriptor option.
>
> - new baseline for 1400 (with only filling the metadata)
> ./xskgen -M -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.188767 sec, 98.387657 gbps 8.412077 mpps
>
> - new baseline for 200 (with only filling the metadata)
> ./xskgen -M -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 20960000000 bits, took 0.410213 sec, 51.095407 gbps 24.377579 mpps
> (the numbers go sligtly up here, not really sure why, maybe some cache-related
> side-effects?
>
> 4. Next, I'm running the same test but with the commit that adds actual
>    general infra to parse XDP_TX_METADATA (but no driver support).
>    Essentially applying "xsk: add TX timestamp and TX checksum offload support"
>    from this series. Numbers are the same.
>
> - fill metadata for 1400
> ./xskgen -M -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.188430 sec, 98.415557 gbps 8.414463 mpps
>
> - fill metadata for 200
> ./xskgen -M -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 20960000000 bits, took 0.411559 sec, 50.928299 gbps 24.297853 mpps
>
> - request metadata for 1400
> ./xskgen -m -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.188723 sec, 98.391299 gbps 8.412389 mpps
>
> - request metadata for 200
> ./xskgen -m -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000064 packets 20960134144 bits, took 0.411240 sec, 50.968131 gbps 24.316856 mpps
>
> 5. Now, for the most interesting part, I'm adding mlx5 driver support.
>    The mpps for 200 bytes case goes down from 23 mpps to 19 mpps, but
>    _only_ when I enable the metadata. This looks like a side effect
>    of me pushing extra metadata pointer via mlx5e_xdpi_fifo_push.
>    Hence, this part is wrapped into 'if (xp_tx_metadata_enabled)'
>    to not affect the existing non-metadata use-cases. Since this is not
>    regressing existing workloads, I'm not spending any time trying to
>    optimize it more (and leaving it up to mlx owners to purse if
>    they see any good way to do it).
>
> - same baseline
> ./xskgen -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189434 sec, 98.332484 gbps 8.407360 mpps
>
> ./xskgen -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000128 packets 20960268288 bits, took 0.425254 sec, 49.288821 gbps 23.515659 mpps
>
> - fill metadata for 1400
> ./xskgen -M -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189528 sec, 98.324714 gbps 8.406696 mpps
>
> - fill metadata for 200
> ./xskgen -M -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000128 packets 20960268288 bits, took 0.519085 sec, 40.379260 gbps 19.264914 mpps
>
> - request metadata for 1400
> ./xskgen -m -s 1400 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000000 packets 116960000000 bits, took 1.189329 sec, 98.341165 gbps 8.408102 mpps
>
> - request metadata for 200
> ./xskgen -m -s 200 -b eth3 10:70:fd:48:10:77 10:70:fd:48:10:87 fe80::1270:fdff:fe48:1077 fe80::1270:fdff:fe48:1087 1 1
> sent 10000128 packets 20960268288 bits, took 0.519929 sec, 40.313713 gbps 19.233642 mpps
>
> Song Yoong Siang (1):
>   net: stmmac: Add Tx HWTS support to XDP ZC
>
> Stanislav Fomichev (10):
>   xsk: Support tx_metadata_len
>   xsk: Add TX timestamp and TX checksum offload support
>   tools: ynl: Print xsk-features from the sample
>   net/mlx5e: Implement AF_XDP TX timestamp and checksum offload
>   selftests/xsk: Support tx_metadata_len
>   selftests/bpf: Add csum helpers
>   selftests/bpf: Add TX side to xdp_metadata
>   selftests/bpf: Convert xdp_hw_metadata to XDP_USE_NEED_WAKEUP
>   selftests/bpf: Add TX side to xdp_hw_metadata
>   xsk: Document tx_metadata_len layout
>
>  Documentation/netlink/specs/netdev.yaml       |  19 ++
>  Documentation/networking/index.rst            |   1 +
>  Documentation/networking/xsk-tx-metadata.rst  |  77 ++++++
>  drivers/net/ethernet/mellanox/mlx5/core/en.h  |   4 +-
>  .../net/ethernet/mellanox/mlx5/core/en/xdp.c  |  72 +++++-
>  .../net/ethernet/mellanox/mlx5/core/en/xdp.h  |  11 +-
>  .../ethernet/mellanox/mlx5/core/en/xsk/tx.c   |  17 +-
>  .../net/ethernet/mellanox/mlx5/core/en_main.c |   1 +
>  drivers/net/ethernet/stmicro/stmmac/stmmac.h  |  12 +
>  .../net/ethernet/stmicro/stmmac/stmmac_main.c |  63 ++++-
>  include/linux/netdevice.h                     |  27 ++
>  include/linux/skbuff.h                        |  14 +-
>  include/net/xdp_sock.h                        |  86 +++++++
>  include/net/xdp_sock_drv.h                    |  13 +
>  include/net/xsk_buff_pool.h                   |   7 +
>  include/uapi/linux/if_xdp.h                   |  41 ++++
>  include/uapi/linux/netdev.h                   |  16 ++
>  net/core/netdev-genl.c                        |  12 +-
>  net/xdp/xdp_umem.c                            |   4 +
>  net/xdp/xsk.c                                 |  51 +++-
>  net/xdp/xsk_buff_pool.c                       |   1 +
>  net/xdp/xsk_queue.h                           |  19 +-
>  tools/include/uapi/linux/if_xdp.h             |  55 ++++-
>  tools/include/uapi/linux/netdev.h             |  16 ++
>  tools/net/ynl/generated/netdev-user.c         |  19 ++
>  tools/net/ynl/generated/netdev-user.h         |   3 +
>  tools/net/ynl/samples/netdev.c                |   6 +
>  tools/testing/selftests/bpf/network_helpers.h |  43 ++++
>  .../selftests/bpf/prog_tests/xdp_metadata.c   |  31 ++-
>  tools/testing/selftests/bpf/xdp_hw_metadata.c | 230 ++++++++++++++++--
>  tools/testing/selftests/bpf/xsk.c             |   3 +
>  tools/testing/selftests/bpf/xsk.h             |   1 +
>  32 files changed, 914 insertions(+), 61 deletions(-)
>  create mode 100644 Documentation/networking/xsk-tx-metadata.rst
>
> --
> 2.42.0.655.g421f12c284-goog
>
>

Re: [PATCH bpf-next v4 02/11] xsk: Add TX timestamp and TX checksum offload support

[Stanislav Fomichev]

On 10/20, Jakub Kicinski wrote:
> On Thu, 19 Oct 2023 10:49:35 -0700 Stanislav Fomichev wrote:
> > diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
> > index 14511b13f305..22d2649a34ee 100644
> > --- a/Documentation/netlink/specs/netdev.yaml
> > +++ b/Documentation/netlink/specs/netdev.yaml
> > @@ -55,6 +55,19 @@ name: netdev
> >          name: hash
> >          doc:
> >            Device is capable of exposing receive packet hash via bpf_xdp_metadata_rx_hash().
> > +  -
> > +    type: flags
> > +    name: xsk-flags
> > +    render-max: true
> 
> I don't think you're using the MAX, maybe don't render it.
> IDK what purpose it'd serve for feature flag enums.

I was gonna say 'to iterate over every possible bit', but we are using
that 'xxx > 1U << i' implementation (which you also found a bug in).

I can drop it, but the question is: should I drop it from the rest as
well? xdp-act and xdp-rx-metadata have it.

> > +/*
> > + * This structure defines the AF_XDP TX metadata hooks for network devices.
> 
> s/This structure defines the //
> 
> > + * The following hooks can be defined; unless noted otherwise, they are
> > + * optional and can be filled with a null pointer.
> > + *
> > + * void (*tmo_request_timestamp)(void *priv)
> > + *     This function is called when AF_XDP frame requested egress timestamp.
> 
> s/This function is // in many places

SG for this and the one above.

> > + * u64 (*tmo_fill_timestamp)(void *priv)
> > + *     This function is called when AF_XDP frame, that had requested
> > + *     egress timestamp, received a completion. The hook needs to return
> > + *     the actual HW timestamp.
> > + *
> > + * void (*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv)
> > + *     This function is called when AF_XDP frame requested HW checksum
> > + *     offload. csum_start indicates position where checksumming should start.
> > + *     csum_offset indicates position where checksum should be stored.
> > + *
> > + */
> > +struct xsk_tx_metadata_ops {
> > +	void	(*tmo_request_timestamp)(void *priv);
> > +	u64	(*tmo_fill_timestamp)(void *priv);
> > +	void	(*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv);
> > +};
> 
> Could you move the definition of the struct to include/net/xdp_sock.h ?
> netdevice.h doesn't need it.

Let me try..

> > +/* Request transmit timestamp. Upon completion, put it into tx_timestamp
> > + * field of struct xsk_tx_metadata.
> > + */
> > +#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
> > +
> > +/* Request transmit checksum offload. Checksum start position and offset
> > + * are communicated via csum_start and csum_offset fields of struct
> > + * xsk_tx_metadata.
> > + */
> > +#define XDP_TX_METADATA_CHECKSUM		(1 << 1)
> 
> Reuse of enum netdev_xsk_flags is not an option?

It is an option, but probably better to keep them separate? Netlink is
for observability, and here have a tighter control over the defines and
UAPI (and the don't have to map 1:1 as in the case of
XDP_TX_METADATA_CHECKSUM_SW, for example).

> > +/* Force checksum calculation in software. Can be used for testing or
> > + * working around potential HW issues. This option causes performance
> > + * degradation and only works in XDP_COPY mode.
> > + */
> > +#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)
> 
> Is there a need for this to be on packet-by-packet basis?
> HW issues should generally be fixed by the driver, is there 
> any type of problem in particular you have in mind here?

No, not really, do you think it makes sense to move it to a setsockopt
or something? We'd still have to check it on a per-packet case
though (from xsk_sock), so not sure it is strictly better?

Regarding HW issues: I don't have a good problem in mind, but I
think having a SW path is useful. It least it was useful for me
during developing (to compare the checksum) and I hope it will be
useful for other people as well (mostly as well during development).
Because the API is still a bit complicated and requires getting
pseudo header csum right. Plus the fact that csum_offset is an
offset from csum_start was not super intuitive to me.

> > diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
> > index fe61f85bcf33..5d889c2425fd 100644
> > --- a/net/core/netdev-genl.c
> > +++ b/net/core/netdev-genl.c
> > @@ -14,6 +14,7 @@ netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp,
> >  		   const struct genl_info *info)
> >  {
> >  	u64 xdp_rx_meta = 0;
> > +	u64 xsk_features = 0;
> 
> rev xmas tree? :)

Oops.

> > +			meta = buffer - xs->pool->tx_metadata_len;
> > +
> > +			if (meta->flags & XDP_TX_METADATA_CHECKSUM) {
> 
> Do we need to worry about reserved / unsupported meta->flags ?

I don't think so, probably not worth the cycles to check for the
unsupported bits? Or do you think it makes sense to clearly return
an error here and this extra check won't actually affect anything?

Re: [PATCH bpf-next v4 03/11] tools: ynl: Print xsk-features from the sample

[Stanislav Fomichev]

On 10/20, Jakub Kicinski wrote:
> On Thu, 19 Oct 2023 10:49:36 -0700 Stanislav Fomichev wrote:
> > Regenerate the userspace specs and print xsk-features bitmask.
> 
> I'm afraid you regenerated in previous patch already :]
> Perhaps we should add an easy-to-use flag to ynl-regen to skip tools/ ?

Oops, leftover :-(

I do find it useful that we now regenerate everything, so not sure the
flag is needed (I'm probably missing the intent). I hope we eventually can
drop those generated files altogether from the tree and generate everything
during the build.

> > diff --git a/tools/net/ynl/samples/netdev.c b/tools/net/ynl/samples/netdev.c
> > index b828225daad0..da7c2848f773 100644
> > --- a/tools/net/ynl/samples/netdev.c
> > +++ b/tools/net/ynl/samples/netdev.c
> > @@ -44,6 +44,12 @@ static void netdev_print_device(struct netdev_dev_get_rsp *d, unsigned int op)
> >  			printf(" %s", netdev_xdp_rx_metadata_str(1 << i));
> >  	}
> >  
> > +	printf(" xsk-features (%llx):", d->xsk_features);
> > +	for (int i = 0; d->xsk_features > 1U << i; i++) {
> 
> Shouldn't this be >= ?

Oh, good catch, will fix the other ones as well. But this is subtle and
still mostly works during my tests.

For bits 1 and 2 we get 3 and 'd->xsk_features > 1U << i' is always
true for both 1 and 2.

Re: [PATCH bpf-next v4 01/11] xsk: Support tx_metadata_len

[Stanislav Fomichev]

On 10/20, Jakub Kicinski wrote:
> On Thu, 19 Oct 2023 10:49:34 -0700 Stanislav Fomichev wrote:
> > - 4-byte aligned
> 
> But there is an 8B field in it. Won't this trap on some funky
> architecture of yore?

Hmm, good point, will update this to 8 byte alignment and will use
8-bit timestamp as a reason.

Re: [PATCH bpf-next v4 02/11] xsk: Add TX timestamp and TX checksum offload support

[Jakub Kicinski]

On Mon, 23 Oct 2023 10:21:53 -0700 Stanislav Fomichev wrote:
> On 10/20, Jakub Kicinski wrote:
> > On Thu, 19 Oct 2023 10:49:35 -0700 Stanislav Fomichev wrote:  
> > > diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
> > > index 14511b13f305..22d2649a34ee 100644
> > > --- a/Documentation/netlink/specs/netdev.yaml
> > > +++ b/Documentation/netlink/specs/netdev.yaml
> > > @@ -55,6 +55,19 @@ name: netdev
> > >          name: hash
> > >          doc:
> > >            Device is capable of exposing receive packet hash via bpf_xdp_metadata_rx_hash().
> > > +  -
> > > +    type: flags
> > > +    name: xsk-flags
> > > +    render-max: true  
> > 
> > I don't think you're using the MAX, maybe don't render it.
> > IDK what purpose it'd serve for feature flag enums.  
> 
> I was gonna say 'to iterate over every possible bit', but we are using
> that 'xxx > 1U << i' implementation (which you also found a bug in).
> 
> I can drop it, but the question is: should I drop it from the rest as
> well? xdp-act and xdp-rx-metadata have it.

The xdp-act one looks used. xdp-rx-metadata looks unused, so you could
drop. But up to you if you want to clean it up.

> > > +/* Request transmit timestamp. Upon completion, put it into tx_timestamp
> > > + * field of struct xsk_tx_metadata.
> > > + */
> > > +#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
> > > +
> > > +/* Request transmit checksum offload. Checksum start position and offset
> > > + * are communicated via csum_start and csum_offset fields of struct
> > > + * xsk_tx_metadata.
> > > + */
> > > +#define XDP_TX_METADATA_CHECKSUM		(1 << 1)  
> > 
> > Reuse of enum netdev_xsk_flags is not an option?  
> 
> It is an option, but probably better to keep them separate? Netlink is
> for observability, and here have a tighter control over the defines and
> UAPI (and the don't have to map 1:1 as in the case of
> XDP_TX_METADATA_CHECKSUM_SW, for example).

The duplication is rather apparent, and they are flags so compiler
can't help us catch misuses of one set vs the other.

If you prefer to keep the separate defines - I'd rename them to tie 
them to the field more strongly. Specifically they should have the
word "flags" in them?

XDP_TXMD_FLAGS_TIMESTAMP
XDP_TXMD_FLAGS_CHECKSUM

maybe?

> > > +/* Force checksum calculation in software. Can be used for testing or
> > > + * working around potential HW issues. This option causes performance
> > > + * degradation and only works in XDP_COPY mode.
> > > + */
> > > +#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)  
> > 
> > Is there a need for this to be on packet-by-packet basis?
> > HW issues should generally be fixed by the driver, is there 
> > any type of problem in particular you have in mind here?  
> 
> No, not really, do you think it makes sense to move it to a setsockopt
> or something? We'd still have to check it on a per-packet case
> though (from xsk_sock), so not sure it is strictly better?

Setsockopt or just ethtool -K $ifc tx off ? And check device features?
Maybe I'm overly sensitive but descriptor bits are usually super
precious :)

> Regarding HW issues: I don't have a good problem in mind, but I
> think having a SW path is useful. It least it was useful for me
> during developing (to compare the checksum) and I hope it will be
> useful for other people as well (mostly as well during development).
> Because the API is still a bit complicated and requires getting
> pseudo header csum right. Plus the fact that csum_offset is an
> offset from csum_start was not super intuitive to me.

Okay, I'm not strongly opposed, I just wanted to flag it.
If nobody else feels the same way, and you like the separate bit - 
perfectly fine by me.

> > > +			meta = buffer - xs->pool->tx_metadata_len;
> > > +
> > > +			if (meta->flags & XDP_TX_METADATA_CHECKSUM) {  
> > 
> > Do we need to worry about reserved / unsupported meta->flags ?  
> 
> I don't think so, probably not worth the cycles to check for the
> unsupported bits? Or do you think it makes sense to clearly return
> an error here and this extra check won't actually affect anything?

Hm, it is uAPI, isn't it? We try to validate anything kernel gets these
days, why would the flags be different? Shouldn't be more than 2 cycles.

Re: [PATCH bpf-next v4 11/11] xsk: Document tx_metadata_len layout

[Stanislav Fomichev]

On 10/23, Magnus Karlsson wrote:
> On Thu, 19 Oct 2023 at 19:50, Stanislav Fomichev <sdf@google.com> wrote:
> >
> > - how to use
> > - how to query features
> > - pointers to the examples
> >
> > Signed-off-by: Stanislav Fomichev <sdf@google.com>
> > ---
> >  Documentation/networking/index.rst           |  1 +
> >  Documentation/networking/xsk-tx-metadata.rst | 77 ++++++++++++++++++++
> >  2 files changed, 78 insertions(+)
> >  create mode 100644 Documentation/networking/xsk-tx-metadata.rst
> >
> > diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst
> > index 2ffc5ad10295..f3c2566d6cad 100644
> > --- a/Documentation/networking/index.rst
> > +++ b/Documentation/networking/index.rst
> > @@ -122,6 +122,7 @@ Refer to :ref:`netdev-FAQ` for a guide on netdev development process specifics.
> >     xfrm_sync
> >     xfrm_sysctl
> >     xdp-rx-metadata
> > +   xsk-tx-metadata
> >
> >  .. only::  subproject and html
> >
> > diff --git a/Documentation/networking/xsk-tx-metadata.rst b/Documentation/networking/xsk-tx-metadata.rst
> > new file mode 100644
> > index 000000000000..b7289f06745c
> > --- /dev/null
> > +++ b/Documentation/networking/xsk-tx-metadata.rst
> > @@ -0,0 +1,77 @@
> > +==================
> > +AF_XDP TX Metadata
> > +==================
> > +
> > +This document describes how to enable offloads when transmitting packets
> > +via :doc:`af_xdp`. Refer to :doc:`xdp-rx-metadata` on how to access similar
> > +metadata on the receive side.
> > +
> > +General Design
> > +==============
> > +
> > +The headroom for the metadata is reserved via ``tx_metadata_len`` in
> > +``struct xdp_umem_reg``. The metadata length is therefore the same for
> > +every socket that shares the same umem. The metadata layout is a fixed UAPI,
> > +refer to ``union xsk_tx_metadata`` in ``include/uapi/linux/if_xdp.h``.
> > +Thus, generally, the ``tx_metadata_len`` field above should contain
> > +``sizeof(union xsk_tx_metadata)``.
> > +
> > +The headroom and the metadata itself should be located right before
> > +``xdp_desc->addr`` in the umem frame. Within a frame, the metadata
> > +layout is as follows::
> > +
> > +           tx_metadata_len
> > +     /                         \
> > +    +-----------------+---------+----------------------------+
> > +    | xsk_tx_metadata | padding |          payload           |
> > +    +-----------------+---------+----------------------------+
> > +                                ^
> > +                                |
> > +                          xdp_desc->addr
> > +
> > +An AF_XDP application can request headrooms larger than ``sizeof(struct
> > +xsk_tx_metadata)``. The kernel will ignore the padding (and will still
> > +use ``xdp_desc->addr - tx_metadata_len`` to locate
> > +the ``xsk_tx_metadata``). For the frames that shouldn't carry
> > +any metadata (i.e., the ones that don't have ``XDP_TX_METADATA`` option),
> > +the metadata area is ignored by the kernel as well.
> > +
> > +The flags field enables the particular offload:
> > +
> > +- ``XDP_TX_METADATA_TIMESTAMP``: requests the device to put transmission
> > +  timestamp into ``tx_timestamp`` field of ``union xsk_tx_metadata``.
> > +- ``XDP_TX_METADATA_CHECKSUM``: requests the device to calculate L4
> > +  checksum. ``csum_start`` specifies byte offset of there the checksumming
> 
> nit: of there -> where
> 
> > +  should start and ``csum_offset`` specifies byte offset where the
> > +  device should store the computed checksum.
> > +- ``XDP_TX_METADATA_CHECKSUM_SW``: requests checksum calculation to
> > +  be done in software; this mode works only in ``XSK_COPY`` mode and
> > +  is mostly intended for testing. Do not enable this option, it
> > +  will negatively affect performance.
> > +
> > +Besides the flags above, in order to trigger the offloads, the first
> > +packet's ``struct xdp_desc`` descriptor should set ``XDP_TX_METADATA``
> > +bit in the ``options`` field. Also not that in a multi-buffer packet
> 
> nit: not -> note

Thank you for both, will fix!

Re: [PATCH bpf-next v4 01/11] xsk: Support tx_metadata_len

[Stanislav Fomichev]

On 10/23, Magnus Karlsson wrote:
> On Thu, 19 Oct 2023 at 19:50, Stanislav Fomichev <sdf@google.com> wrote:
> >
> > For zerocopy mode, tx_desc->addr can point to the arbitrary offset
> 
> nit: the -> an

Thanks!
 
> > and carry some TX metadata in the headroom. For copy mode, there
> > is no way currently to populate skb metadata.
> >
> > Introduce new tx_metadata_len umem config option that indicates how many
> > bytes to treat as metadata. Metadata bytes come prior to tx_desc address
> > (same as in RX case).
> >
> > The size of the metadata has the same constraints as XDP:
> > - less than 256 bytes
> > - 4-byte aligned
> > - non-zero
> >
> > This data is not interpreted in any way right now.
> >
> > Signed-off-by: Stanislav Fomichev <sdf@google.com>
> > ---
> >  include/net/xdp_sock.h            |  1 +
> >  include/net/xsk_buff_pool.h       |  1 +
> >  include/uapi/linux/if_xdp.h       |  1 +
> >  net/xdp/xdp_umem.c                |  4 ++++
> >  net/xdp/xsk.c                     | 12 +++++++++++-
> >  net/xdp/xsk_buff_pool.c           |  1 +
> >  net/xdp/xsk_queue.h               | 17 ++++++++++-------
> >  tools/include/uapi/linux/if_xdp.h |  1 +
> >  8 files changed, 30 insertions(+), 8 deletions(-)
> >
> > diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
> > index 7dd0df2f6f8e..5ae88a00f34a 100644
> > --- a/include/net/xdp_sock.h
> > +++ b/include/net/xdp_sock.h
> > @@ -30,6 +30,7 @@ struct xdp_umem {
> >         struct user_struct *user;
> >         refcount_t users;
> >         u8 flags;
> > +       u8 tx_metadata_len;
> >         bool zc;
> >         struct page **pgs;
> >         int id;
> > diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
> > index b0bdff26fc88..1985ffaf9b0c 100644
> > --- a/include/net/xsk_buff_pool.h
> > +++ b/include/net/xsk_buff_pool.h
> > @@ -77,6 +77,7 @@ struct xsk_buff_pool {
> >         u32 chunk_size;
> >         u32 chunk_shift;
> >         u32 frame_len;
> > +       u8 tx_metadata_len; /* inherited from umem */
> >         u8 cached_need_wakeup;
> >         bool uses_need_wakeup;
> >         bool dma_need_sync;
> > diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
> > index 8d48863472b9..2ecf79282c26 100644
> > --- a/include/uapi/linux/if_xdp.h
> > +++ b/include/uapi/linux/if_xdp.h
> > @@ -76,6 +76,7 @@ struct xdp_umem_reg {
> >         __u32 chunk_size;
> >         __u32 headroom;
> >         __u32 flags;
> > +       __u32 tx_metadata_len;
> >  };
> >
> >  struct xdp_statistics {
> > diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
> > index 06cead2b8e34..333f3d53aad4 100644
> > --- a/net/xdp/xdp_umem.c
> > +++ b/net/xdp/xdp_umem.c
> > @@ -199,6 +199,9 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
> >         if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
> >                 return -EINVAL;
> >
> > +       if (mr->tx_metadata_len > 256 || mr->tx_metadata_len % 4)
> > +               return -EINVAL;
> 
> Should be >= 256 since the final internal destination is a u8 and the
> documentation says "should be less than 256 bytes".

Thanks, will fix.

Re: [PATCH bpf-next v4 00/11] xsk: TX metadata

[Stanislav Fomichev]

On 10/23, Magnus Karlsson wrote:
> On Thu, 19 Oct 2023 at 19:49, Stanislav Fomichev <sdf@google.com> wrote:
> >
> > This series implements initial TX metadata (offloads) for AF_XDP.
> > See patch #2 for the main implementation and mlx5/stmmac ones for the
> > example on how to consume the metadata on the device side.
> >
> > Starting with two types of offloads:
> > - request TX timestamp (and write it back into the metadata area)
> > - request TX checksum offload
> >
> > Changes since v3:
> > - fix xsk_tx_metadata_ops kdoc (Song Yoong Siang)
> > - add missing xsk_tx_metadata_to_compl for XDP_SOCKETS=n (Vinicius Costa Gomes and Intel bots)
> > - add reference timestamps to the selftests + refactor existing ones (Jesper)
> >
> > v3: https://lore.kernel.org/bpf/20231003200522.1914523-1-sdf@google.com/
> 
> Thanks for working on this Stanislav. I went through the patch set and
> it looks good to me. You have addressed all the feedback that Maciej
> and I had on a previous version. Just had some small things in two of
> the patches. Apart from that, you are good to go and you can add my
> ack to the next version.
> 
> Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
> 
> Again, really appreciate all your work with this!

Thank you! Appreciate the review and comments as well!

Re: [PATCH bpf-next v4 02/11] xsk: Add TX timestamp and TX checksum offload support

[Stanislav Fomichev]

On 10/23, Jakub Kicinski wrote:
> On Mon, 23 Oct 2023 10:21:53 -0700 Stanislav Fomichev wrote:
> > On 10/20, Jakub Kicinski wrote:
> > > On Thu, 19 Oct 2023 10:49:35 -0700 Stanislav Fomichev wrote:  
> > > > diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
> > > > index 14511b13f305..22d2649a34ee 100644
> > > > --- a/Documentation/netlink/specs/netdev.yaml
> > > > +++ b/Documentation/netlink/specs/netdev.yaml
> > > > @@ -55,6 +55,19 @@ name: netdev
> > > >          name: hash
> > > >          doc:
> > > >            Device is capable of exposing receive packet hash via bpf_xdp_metadata_rx_hash().
> > > > +  -
> > > > +    type: flags
> > > > +    name: xsk-flags
> > > > +    render-max: true  
> > > 
> > > I don't think you're using the MAX, maybe don't render it.
> > > IDK what purpose it'd serve for feature flag enums.  
> > 
> > I was gonna say 'to iterate over every possible bit', but we are using
> > that 'xxx > 1U << i' implementation (which you also found a bug in).
> > 
> > I can drop it, but the question is: should I drop it from the rest as
> > well? xdp-act and xdp-rx-metadata have it.
> 
> The xdp-act one looks used. xdp-rx-metadata looks unused, so you could
> drop. But up to you if you want to clean it up.

Ok. I'll cleanup xdp-rx-metadata in the same path. Might we worth it
to limit copy-paste spread..
 
> > > > +/* Request transmit timestamp. Upon completion, put it into tx_timestamp
> > > > + * field of struct xsk_tx_metadata.
> > > > + */
> > > > +#define XDP_TX_METADATA_TIMESTAMP		(1 << 0)
> > > > +
> > > > +/* Request transmit checksum offload. Checksum start position and offset
> > > > + * are communicated via csum_start and csum_offset fields of struct
> > > > + * xsk_tx_metadata.
> > > > + */
> > > > +#define XDP_TX_METADATA_CHECKSUM		(1 << 1)  
> > > 
> > > Reuse of enum netdev_xsk_flags is not an option?  
> > 
> > It is an option, but probably better to keep them separate? Netlink is
> > for observability, and here have a tighter control over the defines and
> > UAPI (and the don't have to map 1:1 as in the case of
> > XDP_TX_METADATA_CHECKSUM_SW, for example).
> 
> The duplication is rather apparent, and they are flags so compiler
> can't help us catch misuses of one set vs the other.
> 
> If you prefer to keep the separate defines - I'd rename them to tie 
> them to the field more strongly. Specifically they should have the
> word "flags" in them?
> 
> XDP_TXMD_FLAGS_TIMESTAMP
> XDP_TXMD_FLAGS_CHECKSUM
> 
> maybe?

Sg, will rename.

> > > > +/* Force checksum calculation in software. Can be used for testing or
> > > > + * working around potential HW issues. This option causes performance
> > > > + * degradation and only works in XDP_COPY mode.
> > > > + */
> > > > +#define XDP_TX_METADATA_CHECKSUM_SW		(1 << 2)  
> > > 
> > > Is there a need for this to be on packet-by-packet basis?
> > > HW issues should generally be fixed by the driver, is there 
> > > any type of problem in particular you have in mind here?  
> > 
> > No, not really, do you think it makes sense to move it to a setsockopt
> > or something? We'd still have to check it on a per-packet case
> > though (from xsk_sock), so not sure it is strictly better?
> 
> Setsockopt or just ethtool -K $ifc tx off ? And check device features?
> Maybe I'm overly sensitive but descriptor bits are usually super
> precious :)

Good point on the descriptor bits. Let me try to move to a setsockopt.

> > Regarding HW issues: I don't have a good problem in mind, but I
> > think having a SW path is useful. It least it was useful for me
> > during developing (to compare the checksum) and I hope it will be
> > useful for other people as well (mostly as well during development).
> > Because the API is still a bit complicated and requires getting
> > pseudo header csum right. Plus the fact that csum_offset is an
> > offset from csum_start was not super intuitive to me.
> 
> Okay, I'm not strongly opposed, I just wanted to flag it.
> If nobody else feels the same way, and you like the separate bit - 
> perfectly fine by me.
> 
> > > > +			meta = buffer - xs->pool->tx_metadata_len;
> > > > +
> > > > +			if (meta->flags & XDP_TX_METADATA_CHECKSUM) {  
> > > 
> > > Do we need to worry about reserved / unsupported meta->flags ?  
> > 
> > I don't think so, probably not worth the cycles to check for the
> > unsupported bits? Or do you think it makes sense to clearly return
> > an error here and this extra check won't actually affect anything?
> 
> Hm, it is uAPI, isn't it? We try to validate anything kernel gets these
> days, why would the flags be different? Shouldn't be more than 2 cycles.

Yeah, agreed, worst case we can have some static_branch to disable it.
But fair point that unlikely we'll see it cause any issues.

RE: [PATCH bpf-next v4 10/11] selftests/bpf: Add TX side to xdp_hw_metadata

[Song, Yoong Siang]

On Friday, October 20, 2023 1:50 AM Stanislav Fomichev <sdf@google.com> wrote:
>When we get a packet on port 9091, we swap src/dst and send it out.
>At this point we also request the timestamp and checksum offloads.
>
>Checksum offload is verified by looking at the tcpdump on the other side.
>The tool prints pseudo-header csum and the final one it expects.
>The final checksum actually matches the incoming packets checksum
>because we only flip the src/dst and don't change the payload.
>
>Some other related changes:
>- switched to zerocopy mode by default; new flag can be used to force
>  old behavior
>- request fixed tx_metadata_len headroom
>- some other small fixes (umem size, fill idx+i, etc)
>
>mvbz3:~# ./xdp_hw_metadata eth3
>...
>xsk_ring_cons__peek: 1
>0x19546f8: rx_desc[0]->addr=80100 addr=80100 comp_addr=80100
>rx_hash: 0x80B7EA8B with RSS type:0x2A
>rx_timestamp:  1697580171852147395 (sec:1697580171.8521)
>HW RX-time:   1697580171852147395 (sec:1697580171.8521), delta to User RX-time sec:0.2797 (279673.082 usec)
>XDP RX-time:   1697580172131699047 (sec:1697580172.1317), delta to User RX-time sec:0.0001 (121.430 usec)
>0x19546f8: ping-pong with csum=3b8e (want d862) csum_start=54 csum_offset=6
>0x19546f8: complete tx idx=0 addr=8
>tx_timestamp:  1697580172056756493 (sec:1697580172.0568)

Hi Stanislav,

rx_timestamp is duplicating HW RX-time while tx_timestamp is duplicating HW TX-complete-time,
so, I think can remove printing of rx_timestamp and tx_timestamp to avoid confusion.

>HW TX-complete-time:   1697580172056756493 (sec:1697580172.0568), delta to User TX-complete-time sec:0.0852 (85175.537 usec)
>XDP RX-time:   1697580172131699047 (sec:1697580172.1317), delta to User TX-complete-time sec:0.0102 (10232.983 usec)
>HW RX-time:   1697580171852147395 (sec:1697580171.8521), delta to HW TX-complete-time sec:0.2046 (204609.098 usec)
>0x19546f8: complete rx idx=128 addr=80100
>
>mvbz4:~# nc  -Nu -q1 ${MVBZ3_LINK_LOCAL_IP}%eth3 9091
>
>mvbz4:~# tcpdump -vvx -i eth3 udp
>        tcpdump: listening on eth3, link-type EN10MB (Ethernet), snapshot length 262144
>bytes
>12:26:09.301074 IP6 (flowlabel 0x35fa5, hlim 127, next-header UDP (17) payload
>length: 11) fe80::1270:fdff:fe48:1087.55807 > fe80::1270:fdff:fe48:1077.9091: [bad
>udp cksum 0x3b8e -> 0xde7e!] UDP, length 3
>        0x0000:  6003 5fa5 000b 117f fe80 0000 0000 0000
>        0x0010:  1270 fdff fe48 1087 fe80 0000 0000 0000
>        0x0020:  1270 fdff fe48 1077 d9ff 2383 000b 3b8e
>        0x0030:  7864 70
>12:26:09.301976 IP6 (flowlabel 0x35fa5, hlim 127, next-header UDP (17) payload
>length: 11) fe80::1270:fdff:fe48:1077.9091 > fe80::1270:fdff:fe48:1087.55807: [udp
>sum ok] UDP, length 3
>        0x0000:  6003 5fa5 000b 117f fe80 0000 0000 0000
>        0x0010:  1270 fdff fe48 1077 fe80 0000 0000 0000
>        0x0020:  1270 fdff fe48 1087 2383 d9ff 000b de7e
>        0x0030:  7864 70
>
>This reverts commit c3c9abc1d0c989e0be21d78cccd99076cc94ec44.

It didn't looked like this patch is reverting something.
If this is not a mistake, can you add the commit title behind the ID?

Thanks & Regards
Siang

>
>Signed-off-by: Stanislav Fomichev <sdf@google.com>
>---
> tools/testing/selftests/bpf/xdp_hw_metadata.c | 159 +++++++++++++++++-
> 1 file changed, 157 insertions(+), 2 deletions(-)
>
>diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c
>b/tools/testing/selftests/bpf/xdp_hw_metadata.c
>index 057f7c145f62..d9421c5889f8 100644
>--- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
>+++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
>@@ -10,7 +10,9 @@
>  *   - rx_hash
>  *
>  * TX:
>- * - TBD
>+ * - UDP 9091 packets trigger TX reply
>+ * - TX HW timestamp is requested and reported back upon completion
>+ * - TX checksum is requested
>  */
>
> #include <test_progs.h>
>@@ -24,11 +26,14 @@
> #include <linux/net_tstamp.h>
> #include <linux/udp.h>
> #include <linux/sockios.h>
>+#include <linux/if_xdp.h>
> #include <sys/mman.h>
> #include <net/if.h>
> #include <ctype.h>
> #include <poll.h>
> #include <time.h>
>+#include <unistd.h>
>+#include <libgen.h>
>
> #include "xdp_metadata.h"
>
>@@ -53,6 +58,9 @@ struct xsk *rx_xsk;
> const char *ifname;
> int ifindex;
> int rxq;
>+bool skip_tx;
>+__u64 last_hw_rx_timestamp;
>+__u64 last_xdp_rx_timestamp;
>
> void test__fail(void) { /* for network_helpers.c */ }
>
>@@ -69,6 +77,7 @@ static int open_xsk(int ifindex, struct xsk *xsk, __u32 queue_id)
> 		.comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS,
> 		.frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE,
> 		.flags = XSK_UMEM__DEFAULT_FLAGS,
>+		.tx_metadata_len = sizeof(struct xsk_tx_metadata),
> 	};
> 	__u32 idx;
> 	u64 addr;
>@@ -190,6 +199,10 @@ static void verify_xdp_metadata(void *data, clockid_t
>clock_id)
> 	if (meta->rx_timestamp) {
> 		__u64 ref_tstamp = gettime(clock_id);
>
>+		/* store received timestamps to calculate a delta at tx */
>+		last_hw_rx_timestamp = meta->rx_timestamp;
>+		last_xdp_rx_timestamp = meta->xdp_timestamp;
>+
> 		print_tstamp_delta("HW RX-time", "User RX-time",
> 				   meta->rx_timestamp, ref_tstamp);
> 		print_tstamp_delta("XDP RX-time", "User RX-time",
>@@ -242,6 +255,128 @@ static void verify_skb_metadata(int fd)
> 	printf("skb hwtstamp is not found!\n");
> }
>
>+static bool complete_tx(struct xsk *xsk, clockid_t clock_id)
>+{
>+	struct xsk_tx_metadata *meta;
>+	__u64 addr;
>+	void *data;
>+	__u32 idx;
>+
>+	if (!xsk_ring_cons__peek(&xsk->comp, 1, &idx))
>+		return false;
>+
>+	addr = *xsk_ring_cons__comp_addr(&xsk->comp, idx);
>+	data = xsk_umem__get_data(xsk->umem_area, addr);
>+	meta = data - sizeof(struct xsk_tx_metadata);
>+
>+	printf("%p: complete tx idx=%u addr=%llx\n", xsk, idx, addr);
>+
>+	printf("tx_timestamp:  %llu (sec:%0.4f)\n", meta->completion.tx_timestamp,
>+	       (double)meta->completion.tx_timestamp / NANOSEC_PER_SEC);
>+	if (meta->completion.tx_timestamp) {
>+		__u64 ref_tstamp = gettime(clock_id);
>+
>+		print_tstamp_delta("HW TX-complete-time", "User TX-complete-
>time",
>+				   meta->completion.tx_timestamp, ref_tstamp);
>+		print_tstamp_delta("XDP RX-time", "User TX-complete-time",
>+				   last_xdp_rx_timestamp, ref_tstamp);
>+		print_tstamp_delta("HW RX-time", "HW TX-complete-time",
>+				   last_hw_rx_timestamp, meta-
>>completion.tx_timestamp);
>+	}
>+
>+	xsk_ring_cons__release(&xsk->comp, 1);
>+
>+	return true;
>+}
>+
>+#define swap(a, b, len) do { \
>+	for (int i = 0; i < len; i++) { \
>+		__u8 tmp = ((__u8 *)a)[i]; \
>+		((__u8 *)a)[i] = ((__u8 *)b)[i]; \
>+		((__u8 *)b)[i] = tmp; \
>+	} \
>+} while (0)
>+
>+static void ping_pong(struct xsk *xsk, void *rx_packet, clockid_t clock_id)
>+{
>+	struct xsk_tx_metadata *meta;
>+	struct ipv6hdr *ip6h = NULL;
>+	struct iphdr *iph = NULL;
>+	struct xdp_desc *tx_desc;
>+	struct udphdr *udph;
>+	struct ethhdr *eth;
>+	__sum16 want_csum;
>+	void *data;
>+	__u32 idx;
>+	int ret;
>+	int len;
>+
>+	ret = xsk_ring_prod__reserve(&xsk->tx, 1, &idx);
>+	if (ret != 1) {
>+		printf("%p: failed to reserve tx slot\n", xsk);
>+		return;
>+	}
>+
>+	tx_desc = xsk_ring_prod__tx_desc(&xsk->tx, idx);
>+	tx_desc->addr = idx % (UMEM_NUM / 2) * UMEM_FRAME_SIZE +
>sizeof(struct xsk_tx_metadata);
>+	data = xsk_umem__get_data(xsk->umem_area, tx_desc->addr);
>+
>+	meta = data - sizeof(struct xsk_tx_metadata);
>+	memset(meta, 0, sizeof(*meta));
>+	meta->flags = XDP_TX_METADATA_TIMESTAMP;
>+
>+	eth = rx_packet;
>+
>+	if (eth->h_proto == htons(ETH_P_IP)) {
>+		iph = (void *)(eth + 1);
>+		udph = (void *)(iph + 1);
>+	} else if (eth->h_proto == htons(ETH_P_IPV6)) {
>+		ip6h = (void *)(eth + 1);
>+		udph = (void *)(ip6h + 1);
>+	} else {
>+		printf("%p: failed to detect IP version for ping pong %04x\n", xsk, eth-
>>h_proto);
>+		xsk_ring_prod__cancel(&xsk->tx, 1);
>+		return;
>+	}
>+
>+	len = ETH_HLEN;
>+	if (ip6h)
>+		len += sizeof(*ip6h) + ntohs(ip6h->payload_len);
>+	if (iph)
>+		len += ntohs(iph->tot_len);
>+
>+	swap(eth->h_dest, eth->h_source, ETH_ALEN);
>+	if (iph)
>+		swap(&iph->saddr, &iph->daddr, 4);
>+	else
>+		swap(&ip6h->saddr, &ip6h->daddr, 16);
>+	swap(&udph->source, &udph->dest, 2);
>+
>+	want_csum = udph->check;
>+	if (ip6h)
>+		udph->check = ~csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
>+					       ntohs(udph->len), IPPROTO_UDP, 0);
>+	else
>+		udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
>+						 ntohs(udph->len), IPPROTO_UDP, 0);
>+
>+	meta->flags |= XDP_TX_METADATA_CHECKSUM;
>+	if (iph)
>+		meta->csum_start = sizeof(*eth) + sizeof(*iph);
>+	else
>+		meta->csum_start = sizeof(*eth) + sizeof(*ip6h);
>+	meta->csum_offset = offsetof(struct udphdr, check);
>+
>+	printf("%p: ping-pong with csum=%04x (want %04x) csum_start=%d
>csum_offset=%d\n",
>+	       xsk, ntohs(udph->check), ntohs(want_csum), meta->csum_start, meta-
>>csum_offset);
>+
>+	memcpy(data, rx_packet, len); /* don't share umem chunk for simplicity */
>+	tx_desc->options |= XDP_TX_METADATA;
>+	tx_desc->len = len;
>+
>+	xsk_ring_prod__submit(&xsk->tx, 1);
>+}
>+
> static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t clock_id)
> {
> 	const struct xdp_desc *rx_desc;
>@@ -307,6 +442,22 @@ static int verify_metadata(struct xsk *rx_xsk, int rxq, int
>server_fd, clockid_t
> 				verify_xdp_metadata(xsk_umem__get_data(xsk-
>>umem_area, addr),
> 						    clock_id);
> 				first_seg = false;
>+
>+				if (!skip_tx) {
>+					/* mirror first chunk back */
>+					ping_pong(xsk, xsk_umem__get_data(xsk-
>>umem_area, addr),
>+						  clock_id);
>+
>+					ret = kick_tx(xsk);
>+					if (ret)
>+						printf("kick_tx ret=%d\n", ret);
>+
>+					for (int j = 0; j < 500; j++) {
>+						if (complete_tx(xsk, clock_id))
>+							break;
>+						usleep(10*1000);
>+					}
>+				}
> 			}
>
> 			xsk_ring_cons__release(&xsk->rx, 1);
>@@ -442,6 +593,7 @@ static void print_usage(void)
> 		"  -c    Run in copy mode (zerocopy is default)\n"
> 		"  -h    Display this help and exit\n\n"
> 		"  -m    Enable multi-buffer XDP for larger MTU\n"
>+		"  -r    Don't generate AF_XDP reply (rx metadata only)\n"
> 		"Generate test packets on the other machine with:\n"
> 		"  echo -n xdp | nc -u -q1 <dst_ip> 9091\n";
>
>@@ -452,7 +604,7 @@ static void read_args(int argc, char *argv[])
> {
> 	char opt;
>
>-	while ((opt = getopt(argc, argv, "chm")) != -1) {
>+	while ((opt = getopt(argc, argv, "chmr")) != -1) {
> 		switch (opt) {
> 		case 'c':
> 			bind_flags &= ~XDP_USE_NEED_WAKEUP;
>@@ -465,6 +617,9 @@ static void read_args(int argc, char *argv[])
> 		case 'm':
> 			bind_flags |= XDP_USE_SG;
> 			break;
>+		case 'r':
>+			skip_tx = true;
>+			break;
> 		case '?':
> 			if (isprint(optopt))
> 				fprintf(stderr, "Unknown option: -%c\n", optopt);
>--
>2.42.0.655.g421f12c284-goog

Re: [PATCH bpf-next v4 10/11] selftests/bpf: Add TX side to xdp_hw_metadata

[Stanislav Fomichev]

On Mon, Oct 23, 2023 at 7:19 PM Song, Yoong Siang
<yoong.siang.song@intel.com> wrote:
>
> On Friday, October 20, 2023 1:50 AM Stanislav Fomichev <sdf@google.com> wrote:
> >When we get a packet on port 9091, we swap src/dst and send it out.
> >At this point we also request the timestamp and checksum offloads.
> >
> >Checksum offload is verified by looking at the tcpdump on the other side.
> >The tool prints pseudo-header csum and the final one it expects.
> >The final checksum actually matches the incoming packets checksum
> >because we only flip the src/dst and don't change the payload.
> >
> >Some other related changes:
> >- switched to zerocopy mode by default; new flag can be used to force
> >  old behavior
> >- request fixed tx_metadata_len headroom
> >- some other small fixes (umem size, fill idx+i, etc)
> >
> >mvbz3:~# ./xdp_hw_metadata eth3
> >...
> >xsk_ring_cons__peek: 1
> >0x19546f8: rx_desc[0]->addr=80100 addr=80100 comp_addr=80100
> >rx_hash: 0x80B7EA8B with RSS type:0x2A
> >rx_timestamp:  1697580171852147395 (sec:1697580171.8521)
> >HW RX-time:   1697580171852147395 (sec:1697580171.8521), delta to User RX-time sec:0.2797 (279673.082 usec)
> >XDP RX-time:   1697580172131699047 (sec:1697580172.1317), delta to User RX-time sec:0.0001 (121.430 usec)
> >0x19546f8: ping-pong with csum=3b8e (want d862) csum_start=54 csum_offset=6
> >0x19546f8: complete tx idx=0 addr=8
> >tx_timestamp:  1697580172056756493 (sec:1697580172.0568)
>
> Hi Stanislav,
>
> rx_timestamp is duplicating HW RX-time while tx_timestamp is duplicating HW TX-complete-time,
> so, I think can remove printing of rx_timestamp and tx_timestamp to avoid confusion.

That's fair, I think I'll do the following:

if (meta->rx_timestamp) {
  /* print all those reference points */
} else {
  printf("No rx_timestamp\n");
}

And the same for tx. So at least the users get a signal that the
timestamps weren't set.

> >HW TX-complete-time:   1697580172056756493 (sec:1697580172.0568), delta to User TX-complete-time sec:0.0852 (85175.537 usec)
> >XDP RX-time:   1697580172131699047 (sec:1697580172.1317), delta to User TX-complete-time sec:0.0102 (10232.983 usec)
> >HW RX-time:   1697580171852147395 (sec:1697580171.8521), delta to HW TX-complete-time sec:0.2046 (204609.098 usec)
> >0x19546f8: complete rx idx=128 addr=80100
> >
> >mvbz4:~# nc  -Nu -q1 ${MVBZ3_LINK_LOCAL_IP}%eth3 9091
> >
> >mvbz4:~# tcpdump -vvx -i eth3 udp
> >        tcpdump: listening on eth3, link-type EN10MB (Ethernet), snapshot length 262144
> >bytes
> >12:26:09.301074 IP6 (flowlabel 0x35fa5, hlim 127, next-header UDP (17) payload
> >length: 11) fe80::1270:fdff:fe48:1087.55807 > fe80::1270:fdff:fe48:1077.9091: [bad
> >udp cksum 0x3b8e -> 0xde7e!] UDP, length 3
> >        0x0000:  6003 5fa5 000b 117f fe80 0000 0000 0000
> >        0x0010:  1270 fdff fe48 1087 fe80 0000 0000 0000
> >        0x0020:  1270 fdff fe48 1077 d9ff 2383 000b 3b8e
> >        0x0030:  7864 70
> >12:26:09.301976 IP6 (flowlabel 0x35fa5, hlim 127, next-header UDP (17) payload
> >length: 11) fe80::1270:fdff:fe48:1077.9091 > fe80::1270:fdff:fe48:1087.55807: [udp
> >sum ok] UDP, length 3
> >        0x0000:  6003 5fa5 000b 117f fe80 0000 0000 0000
> >        0x0010:  1270 fdff fe48 1077 fe80 0000 0000 0000
> >        0x0020:  1270 fdff fe48 1087 2383 d9ff 000b de7e
> >        0x0030:  7864 70
> >
> >This reverts commit c3c9abc1d0c989e0be21d78cccd99076cc94ec44.
>
> It didn't looked like this patch is reverting something.
> If this is not a mistake, can you add the commit title behind the ID?

Ah, that's a leftover from my rebasing and reshuffling, will drop, thanks!