diff mbox series

[bpf,V7,3/7] xdp: rss hash types representation

Message ID 168098189148.96582.2939096178283411428.stgit@firesoul (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series XDP-hints: API change for RX-hash kfunc bpf_xdp_metadata_rx_hash | expand

Checks

Context Check Description
bpf/vmtest-bpf-PR success PR summary
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netdev/series_format success Posting correctly formatted
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netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
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netdev/cc_maintainers success CCed 16 of 16 maintainers
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netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
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netdev/checkpatch warning WARNING: line length of 83 exceeds 80 columns WARNING: line length of 85 exceeds 80 columns WARNING: line length of 86 exceeds 80 columns
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Commit Message

Jesper Dangaard Brouer April 8, 2023, 7:24 p.m. UTC
The RSS hash type specifies what portion of packet data NIC hardware used
when calculating RSS hash value. The RSS types are focused on Internet
traffic protocols at OSI layers L3 and L4. L2 (e.g. ARP) often get hash
value zero and no RSS type. For L3 focused on IPv4 vs. IPv6, and L4
primarily TCP vs UDP, but some hardware supports SCTP.

Hardware RSS types are differently encoded for each hardware NIC. Most
hardware represent RSS hash type as a number. Determining L3 vs L4 often
requires a mapping table as there often isn't a pattern or sorting
according to ISO layer.

The patch introduce a XDP RSS hash type (enum xdp_rss_hash_type) that
contain combinations to be used by drivers, which gets build up with bits
from enum xdp_rss_type_bits. Both enum xdp_rss_type_bits and
xdp_rss_hash_type get exposed to BPF via BTF, and it is up to the
BPF-programmer to match using these defines.

This proposal change the kfunc API bpf_xdp_metadata_rx_hash() adding
a pointer value argument for provide the RSS hash type.

Change function signature for all xmo_rx_hash calls in drivers to make it
compile. The RSS type implementations for each driver comes as separate
patches.

Fixes: 3d76a4d3d4e5 ("bpf: XDP metadata RX kfuncs")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_rx.c       |    3 +
 drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c |    3 +
 drivers/net/veth.c                               |    3 +
 include/linux/netdevice.h                        |    3 +
 include/net/xdp.h                                |   45 ++++++++++++++++++++++
 net/core/xdp.c                                   |   10 ++++-
 6 files changed, 62 insertions(+), 5 deletions(-)

Comments

Simon Horman April 10, 2023, 3:04 p.m. UTC | #1
On Sat, Apr 08, 2023 at 09:24:51PM +0200, Jesper Dangaard Brouer wrote:
> The RSS hash type specifies what portion of packet data NIC hardware used
> when calculating RSS hash value. The RSS types are focused on Internet
> traffic protocols at OSI layers L3 and L4. L2 (e.g. ARP) often get hash
> value zero and no RSS type. For L3 focused on IPv4 vs. IPv6, and L4
> primarily TCP vs UDP, but some hardware supports SCTP.
> 
> Hardware RSS types are differently encoded for each hardware NIC. Most
> hardware represent RSS hash type as a number. Determining L3 vs L4 often
> requires a mapping table as there often isn't a pattern or sorting
> according to ISO layer.
> 
> The patch introduce a XDP RSS hash type (enum xdp_rss_hash_type) that
> contain combinations to be used by drivers, which gets build up with bits
> from enum xdp_rss_type_bits. Both enum xdp_rss_type_bits and
> xdp_rss_hash_type get exposed to BPF via BTF, and it is up to the
> BPF-programmer to match using these defines.
> 
> This proposal change the kfunc API bpf_xdp_metadata_rx_hash() adding
> a pointer value argument for provide the RSS hash type.
> 
> Change function signature for all xmo_rx_hash calls in drivers to make it
> compile. The RSS type implementations for each driver comes as separate
> patches.
> 
> Fixes: 3d76a4d3d4e5 ("bpf: XDP metadata RX kfuncs")
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
> Acked-by: Stanislav Fomichev <sdf@google.com>
> ---
>  drivers/net/ethernet/mellanox/mlx4/en_rx.c       |    3 +
>  drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c |    3 +
>  drivers/net/veth.c                               |    3 +
>  include/linux/netdevice.h                        |    3 +
>  include/net/xdp.h                                |   45 ++++++++++++++++++++++
>  net/core/xdp.c                                   |   10 ++++-
>  6 files changed, 62 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> index 4b5e459b6d49..73d10aa4c503 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> @@ -681,7 +681,8 @@ int mlx4_en_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
>  	return 0;
>  }
>  
> -int mlx4_en_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
> +int mlx4_en_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
> +			enum xdp_rss_hash_type *rss_type)
>  {
>  	struct mlx4_en_xdp_buff *_ctx = (void *)ctx;
>  

Hi Jesper,

I think you also need to update the declaration of mlx4_en_xdp_rx_hash()
in mlx4_en.h.

...
Jesper Dangaard Brouer April 12, 2023, 11:16 a.m. UTC | #2
On 10/04/2023 17.04, Simon Horman wrote:
> On Sat, Apr 08, 2023 at 09:24:51PM +0200, Jesper Dangaard Brouer wrote:
>> The RSS hash type specifies what portion of packet data NIC hardware used
>> when calculating RSS hash value. The RSS types are focused on Internet
>> traffic protocols at OSI layers L3 and L4. L2 (e.g. ARP) often get hash
>> value zero and no RSS type. For L3 focused on IPv4 vs. IPv6, and L4
>> primarily TCP vs UDP, but some hardware supports SCTP.
>>
>> Hardware RSS types are differently encoded for each hardware NIC. Most
>> hardware represent RSS hash type as a number. Determining L3 vs L4 often
>> requires a mapping table as there often isn't a pattern or sorting
>> according to ISO layer.
>>
>> The patch introduce a XDP RSS hash type (enum xdp_rss_hash_type) that
>> contain combinations to be used by drivers, which gets build up with bits
>> from enum xdp_rss_type_bits. Both enum xdp_rss_type_bits and
>> xdp_rss_hash_type get exposed to BPF via BTF, and it is up to the
>> BPF-programmer to match using these defines.
>>
>> This proposal change the kfunc API bpf_xdp_metadata_rx_hash() adding
>> a pointer value argument for provide the RSS hash type.
>>
>> Change function signature for all xmo_rx_hash calls in drivers to make it
>> compile. The RSS type implementations for each driver comes as separate
>> patches.
>>
>> Fixes: 3d76a4d3d4e5 ("bpf: XDP metadata RX kfuncs")
>> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
>> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
>> Acked-by: Stanislav Fomichev <sdf@google.com>
>> ---
>>   drivers/net/ethernet/mellanox/mlx4/en_rx.c       |    3 +
>>   drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c |    3 +
>>   drivers/net/veth.c                               |    3 +
>>   include/linux/netdevice.h                        |    3 +
>>   include/net/xdp.h                                |   45 ++++++++++++++++++++++
>>   net/core/xdp.c                                   |   10 ++++-
>>   6 files changed, 62 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
>> index 4b5e459b6d49..73d10aa4c503 100644
>> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
>> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
>> @@ -681,7 +681,8 @@ int mlx4_en_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
>>   	return 0;
>>   }
>>   
>> -int mlx4_en_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
>> +int mlx4_en_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
>> +			enum xdp_rss_hash_type *rss_type)
>>   {
>>   	struct mlx4_en_xdp_buff *_ctx = (void *)ctx;
>>   
> 
> Hi Jesper,
> 
> I think you also need to update the declaration of mlx4_en_xdp_rx_hash()
> in mlx4_en.h.
> 

Thanks a lot for spotting this. fixed in V8.
--Jesper
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index 4b5e459b6d49..73d10aa4c503 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -681,7 +681,8 @@  int mlx4_en_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
 	return 0;
 }
 
-int mlx4_en_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
+int mlx4_en_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
+			enum xdp_rss_hash_type *rss_type)
 {
 	struct mlx4_en_xdp_buff *_ctx = (void *)ctx;
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
index c5dae48b7932..efe609f8e3aa 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
@@ -169,7 +169,8 @@  static int mlx5e_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
 	return 0;
 }
 
-static int mlx5e_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
+static int mlx5e_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
+			     enum xdp_rss_hash_type *rss_type)
 {
 	const struct mlx5e_xdp_buff *_ctx = (void *)ctx;
 
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index c1178915496d..424e8876a16b 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1648,7 +1648,8 @@  static int veth_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
 	return 0;
 }
 
-static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
+static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
+			    enum xdp_rss_hash_type *rss_type)
 {
 	struct veth_xdp_buff *_ctx = (void *)ctx;
 
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 470085b121d3..c35f04f636f1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1624,7 +1624,8 @@  struct net_device_ops {
 
 struct xdp_metadata_ops {
 	int	(*xmo_rx_timestamp)(const struct xdp_md *ctx, u64 *timestamp);
-	int	(*xmo_rx_hash)(const struct xdp_md *ctx, u32 *hash);
+	int	(*xmo_rx_hash)(const struct xdp_md *ctx, u32 *hash,
+			       enum xdp_rss_hash_type *rss_type);
 };
 
 /**
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 41c57b8b1671..a76c4ea203ea 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -8,6 +8,7 @@ 
 
 #include <linux/skbuff.h> /* skb_shared_info */
 #include <uapi/linux/netdev.h>
+#include <linux/bitfield.h>
 
 /**
  * DOC: XDP RX-queue information
@@ -425,6 +426,50 @@  XDP_METADATA_KFUNC_xxx
 MAX_XDP_METADATA_KFUNC,
 };
 
+enum xdp_rss_hash_type {
+	/* First part: Individual bits for L3/L4 types */
+	XDP_RSS_L3_IPV4		= BIT(0),
+	XDP_RSS_L3_IPV6		= BIT(1),
+
+	/* The fixed (L3) IPv4 and IPv6 headers can both be followed by
+	 * variable/dynamic headers, IPv4 called Options and IPv6 called
+	 * Extension Headers. HW RSS type can contain this info.
+	 */
+	XDP_RSS_L3_DYNHDR	= BIT(2),
+
+	/* When RSS hash covers L4 then drivers MUST set XDP_RSS_L4 bit in
+	 * addition to the protocol specific bit.  This ease interaction with
+	 * SKBs and avoids reserving a fixed mask for future L4 protocol bits.
+	 */
+	XDP_RSS_L4		= BIT(3), /* L4 based hash, proto can be unknown */
+	XDP_RSS_L4_TCP		= BIT(4),
+	XDP_RSS_L4_UDP		= BIT(5),
+	XDP_RSS_L4_SCTP		= BIT(6),
+	XDP_RSS_L4_IPSEC	= BIT(7), /* L4 based hash include IPSEC SPI */
+
+	/* Second part: RSS hash type combinations used for driver HW mapping */
+	XDP_RSS_TYPE_NONE            = 0,
+	XDP_RSS_TYPE_L2              = XDP_RSS_TYPE_NONE,
+
+	XDP_RSS_TYPE_L3_IPV4         = XDP_RSS_L3_IPV4,
+	XDP_RSS_TYPE_L3_IPV6         = XDP_RSS_L3_IPV6,
+	XDP_RSS_TYPE_L3_IPV4_OPT     = XDP_RSS_L3_IPV4 | XDP_RSS_L3_DYNHDR,
+	XDP_RSS_TYPE_L3_IPV6_EX      = XDP_RSS_L3_IPV6 | XDP_RSS_L3_DYNHDR,
+
+	XDP_RSS_TYPE_L4_ANY          = XDP_RSS_L4,
+	XDP_RSS_TYPE_L4_IPV4_TCP     = XDP_RSS_L3_IPV4 | XDP_RSS_L4 | XDP_RSS_L4_TCP,
+	XDP_RSS_TYPE_L4_IPV4_UDP     = XDP_RSS_L3_IPV4 | XDP_RSS_L4 | XDP_RSS_L4_UDP,
+	XDP_RSS_TYPE_L4_IPV4_SCTP    = XDP_RSS_L3_IPV4 | XDP_RSS_L4 | XDP_RSS_L4_SCTP,
+
+	XDP_RSS_TYPE_L4_IPV6_TCP     = XDP_RSS_L3_IPV6 | XDP_RSS_L4 | XDP_RSS_L4_TCP,
+	XDP_RSS_TYPE_L4_IPV6_UDP     = XDP_RSS_L3_IPV6 | XDP_RSS_L4 | XDP_RSS_L4_UDP,
+	XDP_RSS_TYPE_L4_IPV6_SCTP    = XDP_RSS_L3_IPV6 | XDP_RSS_L4 | XDP_RSS_L4_SCTP,
+
+	XDP_RSS_TYPE_L4_IPV6_TCP_EX  = XDP_RSS_TYPE_L4_IPV6_TCP  | XDP_RSS_L3_DYNHDR,
+	XDP_RSS_TYPE_L4_IPV6_UDP_EX  = XDP_RSS_TYPE_L4_IPV6_UDP  | XDP_RSS_L3_DYNHDR,
+	XDP_RSS_TYPE_L4_IPV6_SCTP_EX = XDP_RSS_TYPE_L4_IPV6_SCTP | XDP_RSS_L3_DYNHDR,
+};
+
 #ifdef CONFIG_NET
 u32 bpf_xdp_metadata_kfunc_id(int id);
 bool bpf_dev_bound_kfunc_id(u32 btf_id);
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 528d4b37983d..fb85aca81961 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -734,13 +734,21 @@  __bpf_kfunc int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, u64 *tim
  * bpf_xdp_metadata_rx_hash - Read XDP frame RX hash.
  * @ctx: XDP context pointer.
  * @hash: Return value pointer.
+ * @rss_type: Return value pointer for RSS type.
+ *
+ * The RSS hash type (@rss_type) specifies what portion of packet headers NIC
+ * hardware used when calculating RSS hash value.  The RSS type can be decoded
+ * via &enum xdp_rss_hash_type either matching on individual L3/L4 bits
+ * ``XDP_RSS_L*`` or by combined traditional *RSS Hashing Types*
+ * ``XDP_RSS_TYPE_L*``.
  *
  * Return:
  * * Returns 0 on success or ``-errno`` on error.
  * * ``-EOPNOTSUPP`` : means device driver doesn't implement kfunc
  * * ``-ENODATA``    : means no RX-hash available for this frame
  */
-__bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash)
+__bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash,
+					 enum xdp_rss_hash_type *rss_type)
 {
 	return -EOPNOTSUPP;
 }