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Message-Id: <20220628194812.1453059-10-alexandr.lobakin@intel.com>
Date: Tue, 28 Jun 2022 21:47:29 +0200
From: Alexander Lobakin <alexandr.lobakin@...el.com>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>
Cc: Alexander Lobakin <alexandr.lobakin@...el.com>,
Larysa Zaremba <larysa.zaremba@...el.com>,
Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>,
Jesper Dangaard Brouer <hawk@...nel.org>,
Björn Töpel <bjorn@...nel.org>,
Magnus Karlsson <magnus.karlsson@...el.com>,
Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
Jonathan Lemon <jonathan.lemon@...il.com>,
Toke Hoiland-Jorgensen <toke@...hat.com>,
Lorenzo Bianconi <lorenzo@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Jesse Brandeburg <jesse.brandeburg@...el.com>,
John Fastabend <john.fastabend@...il.com>,
Yajun Deng <yajun.deng@...ux.dev>,
Willem de Bruijn <willemb@...gle.com>, bpf@...r.kernel.org,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
xdp-hints@...-project.net
Subject: [PATCH RFC bpf-next 09/52] net, xdp: add ability to specify BTF ID for XDP metadata
Add the UAPI and the corresponding kernel part to be able to specify
the BTF ID of the format which the drivers should compose metadata
in (if supported).
A driver might be able to provide XDP metadata in different formats,
e.g. the generic one and one or several custom (with some
non-universal data from DMA descriptors etc.). In this case, a BPF
loader program will specify the wanted BTF ID and then BPF and
AF_XDP programs will be expecting this format in XDP metadata and
will be comparing different BTF IDs against the one that will be
put in front of a frame.
The BTF ID can be set and updated via both BPF link and rtnetlink
(the %IFLA_XDP_BTF_ID attribute) interfaces, got via &bpf_link_info
and is being passed to the drivers inside &netdev_bpf.
net_device_ops::ndo_bpf() is now being called not only when
@new_prog != @old_prog, but also when @new_prog == @old_prog &&
@new_btf_id != @btf_id, so the drivers should be able to handle
such cases.
Signed-off-by: Alexander Lobakin <alexandr.lobakin@...el.com>
---
include/linux/netdevice.h | 2 ++
include/net/xdp.h | 1 +
include/uapi/linux/bpf.h | 12 ++++++++++++
include/uapi/linux/if_link.h | 1 +
kernel/bpf/syscall.c | 2 +-
net/bpf/core.c | 1 +
net/bpf/dev.c | 26 +++++++++++++++++++++++---
net/core/rtnetlink.c | 6 ++++++
tools/include/uapi/linux/bpf.h | 12 ++++++++++++
tools/include/uapi/linux/if_link.h | 1 +
10 files changed, 60 insertions(+), 4 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 1e342c285f48..2218c1901daf 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -985,6 +985,7 @@ struct netdev_bpf {
/* XDP_SETUP_PROG */
struct {
u32 flags;
+ u64 btf_id;
struct bpf_prog *prog;
struct netlink_ext_ack *extack;
};
@@ -3852,6 +3853,7 @@ struct xdp_install_args {
struct net_device *dev;
struct netlink_ext_ack *extack;
u32 flags;
+ u64 btf_id;
};
DECLARE_STATIC_KEY_FALSE(generic_xdp_needed_key);
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 04c852c7a77f..13133c7493bc 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -400,6 +400,7 @@ static inline bool xdp_metalen_invalid(unsigned long metalen)
struct xdp_attachment_info {
struct bpf_prog *prog;
+ u64 btf_id;
u32 flags;
};
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e81362891596..c67ddb78915d 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1499,6 +1499,10 @@ union bpf_attr {
*/
__u64 cookie;
} tracing;
+ struct {
+ /* target metadata BTF + type ID */
+ __aligned_u64 btf_id;
+ } xdp;
};
} link_create;
@@ -1510,6 +1514,12 @@ union bpf_attr {
/* expected link's program fd; is specified only if
* BPF_F_REPLACE flag is set in flags */
__u32 old_prog_fd;
+ union {
+ struct {
+ /* new target metadata BTF + type ID */
+ __aligned_u64 new_btf_id;
+ } xdp;
+ };
} link_update;
struct {
@@ -6138,6 +6148,8 @@ struct bpf_link_info {
} netns;
struct {
__u32 ifindex;
+ __u32 :32;
+ __aligned_u64 btf_id;
} xdp;
};
} __attribute__((aligned(8)));
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 5f58dcfe2787..73cdcc86875e 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -1307,6 +1307,7 @@ enum {
IFLA_XDP_SKB_PROG_ID,
IFLA_XDP_HW_PROG_ID,
IFLA_XDP_EXPECTED_FD,
+ IFLA_XDP_BTF_ID,
__IFLA_XDP_MAX,
};
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index f7a674656067..2e86cfeae10f 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4575,7 +4575,7 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
return ret;
}
-#define BPF_LINK_UPDATE_LAST_FIELD link_update.old_prog_fd
+#define BPF_LINK_UPDATE_LAST_FIELD link_update.xdp.new_btf_id
static int link_update(union bpf_attr *attr)
{
diff --git a/net/bpf/core.c b/net/bpf/core.c
index fbb72792320a..e5abd5a64df7 100644
--- a/net/bpf/core.c
+++ b/net/bpf/core.c
@@ -552,6 +552,7 @@ void xdp_attachment_setup(struct xdp_attachment_info *info,
if (info->prog)
bpf_prog_put(info->prog);
info->prog = bpf->prog;
+ info->btf_id = bpf->btf_id;
info->flags = bpf->flags;
}
EXPORT_SYMBOL_GPL(xdp_attachment_setup);
diff --git a/net/bpf/dev.c b/net/bpf/dev.c
index 7df42bb886ad..e96986220126 100644
--- a/net/bpf/dev.c
+++ b/net/bpf/dev.c
@@ -273,6 +273,7 @@ struct bpf_xdp_link {
struct bpf_link link;
struct net_device *dev; /* protected by rtnl_lock, no refcnt held */
int flags;
+ u64 btf_id;
};
typedef int (*bpf_op_t)(struct net_device *dev, struct netdev_bpf *bpf);
@@ -357,8 +358,13 @@ static int dev_xdp_install(const struct xdp_install_args *args,
struct netdev_bpf xdp;
int err;
+ /* BTF ID must not be set when uninstalling the program */
+ if (!prog && args->btf_id)
+ return -EINVAL;
+
memset(&xdp, 0, sizeof(xdp));
xdp.command = mode == XDP_MODE_HW ? XDP_SETUP_PROG_HW : XDP_SETUP_PROG;
+ xdp.btf_id = args->btf_id;
xdp.extack = args->extack;
xdp.flags = args->flags;
xdp.prog = prog;
@@ -517,8 +523,11 @@ static int dev_xdp_attach(const struct xdp_install_args *args,
}
}
- /* don't call drivers if the effective program didn't change */
- if (new_prog != cur_prog) {
+ /* don't call drivers if the effective program or BTF ID didn't change.
+ * If @link == %NULL, we don't know the old value, so the only thing we
+ * can do is to call installing unconditionally
+ */
+ if (new_prog != cur_prog || !link || args->btf_id != link->btf_id) {
bpf_op = dev_xdp_bpf_op(dev, mode);
if (!bpf_op) {
NL_SET_ERR_MSG(extack, "Underlying driver does not support XDP in native mode");
@@ -545,6 +554,7 @@ static int dev_xdp_attach_link(struct bpf_xdp_link *link)
struct xdp_install_args args = {
.dev = link->dev,
.flags = link->flags,
+ .btf_id = link->btf_id,
};
return dev_xdp_attach(&args, link, NULL, NULL);
@@ -606,13 +616,16 @@ static void bpf_xdp_link_show_fdinfo(const struct bpf_link *link,
{
struct bpf_xdp_link *xdp_link = container_of(link, struct bpf_xdp_link, link);
u32 ifindex = 0;
+ u64 btf_id;
rtnl_lock();
if (xdp_link->dev)
ifindex = xdp_link->dev->ifindex;
+ btf_id = xdp_link->btf_id;
rtnl_unlock();
seq_printf(seq, "ifindex:\t%u\n", ifindex);
+ seq_printf(seq, "btf_id:\t0x%llx\n", btf_id);
}
static int bpf_xdp_link_fill_link_info(const struct bpf_link *link,
@@ -620,13 +633,16 @@ static int bpf_xdp_link_fill_link_info(const struct bpf_link *link,
{
struct bpf_xdp_link *xdp_link = container_of(link, struct bpf_xdp_link, link);
u32 ifindex = 0;
+ u64 btf_id;
rtnl_lock();
if (xdp_link->dev)
ifindex = xdp_link->dev->ifindex;
+ btf_id = xdp_link->btf_id;
rtnl_unlock();
info->xdp.ifindex = ifindex;
+ info->xdp.btf_id = btf_id;
return 0;
}
@@ -639,6 +655,7 @@ static int bpf_xdp_link_update(struct bpf_link *link,
struct xdp_install_args args = {
.dev = xdp_link->dev,
.flags = xdp_link->flags,
+ .btf_id = attr->link_update.xdp.new_btf_id,
};
enum bpf_xdp_mode mode;
bpf_op_t bpf_op;
@@ -663,7 +680,7 @@ static int bpf_xdp_link_update(struct bpf_link *link,
goto out_unlock;
}
- if (old_prog == new_prog) {
+ if (old_prog == new_prog && args.btf_id == xdp_link->btf_id) {
/* no-op, don't disturb drivers */
bpf_prog_put(new_prog);
goto out_unlock;
@@ -678,6 +695,8 @@ static int bpf_xdp_link_update(struct bpf_link *link,
old_prog = xchg(&link->prog, new_prog);
bpf_prog_put(old_prog);
+ xdp_link->btf_id = args.btf_id;
+
out_unlock:
rtnl_unlock();
return err;
@@ -716,6 +735,7 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
bpf_link_init(&link->link, BPF_LINK_TYPE_XDP, &bpf_xdp_link_lops, prog);
link->dev = dev;
link->flags = attr->link_create.flags;
+ link->btf_id = attr->link_create.xdp.btf_id;
err = bpf_link_prime(&link->link, &link_primer);
if (err) {
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 5b06ded689b2..a30723b0e50c 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1979,6 +1979,7 @@ static const struct nla_policy ifla_xdp_policy[IFLA_XDP_MAX + 1] = {
[IFLA_XDP_ATTACHED] = { .type = NLA_U8 },
[IFLA_XDP_FLAGS] = { .type = NLA_U32 },
[IFLA_XDP_PROG_ID] = { .type = NLA_U32 },
+ [IFLA_XDP_BTF_ID] = { .type = NLA_U64 },
};
static const struct rtnl_link_ops *linkinfo_to_kind_ops(const struct nlattr *nla)
@@ -2962,6 +2963,7 @@ static int do_setlink(const struct sk_buff *skb,
if (tb[IFLA_XDP]) {
struct nlattr *xdp[IFLA_XDP_MAX + 1];
u32 xdp_flags = 0;
+ u64 btf_id = 0;
err = nla_parse_nested_deprecated(xdp, IFLA_XDP_MAX,
tb[IFLA_XDP],
@@ -2986,10 +2988,14 @@ static int do_setlink(const struct sk_buff *skb,
}
}
+ if (xdp[IFLA_XDP_BTF_ID])
+ btf_id = nla_get_u64(xdp[IFLA_XDP_BTF_ID]);
+
if (xdp[IFLA_XDP_FD]) {
struct xdp_install_args args = {
.dev = dev,
.extack = extack,
+ .btf_id = btf_id,
.flags = xdp_flags,
};
int expected_fd = -1;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index e81362891596..c67ddb78915d 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1499,6 +1499,10 @@ union bpf_attr {
*/
__u64 cookie;
} tracing;
+ struct {
+ /* target metadata BTF + type ID */
+ __aligned_u64 btf_id;
+ } xdp;
};
} link_create;
@@ -1510,6 +1514,12 @@ union bpf_attr {
/* expected link's program fd; is specified only if
* BPF_F_REPLACE flag is set in flags */
__u32 old_prog_fd;
+ union {
+ struct {
+ /* new target metadata BTF + type ID */
+ __aligned_u64 new_btf_id;
+ } xdp;
+ };
} link_update;
struct {
@@ -6138,6 +6148,8 @@ struct bpf_link_info {
} netns;
struct {
__u32 ifindex;
+ __u32 :32;
+ __aligned_u64 btf_id;
} xdp;
};
} __attribute__((aligned(8)));
diff --git a/tools/include/uapi/linux/if_link.h b/tools/include/uapi/linux/if_link.h
index b339bf2196ca..68b126678dc8 100644
--- a/tools/include/uapi/linux/if_link.h
+++ b/tools/include/uapi/linux/if_link.h
@@ -1212,6 +1212,7 @@ enum {
IFLA_XDP_SKB_PROG_ID,
IFLA_XDP_HW_PROG_ID,
IFLA_XDP_EXPECTED_FD,
+ IFLA_XDP_BTF_ID,
__IFLA_XDP_MAX,
};
--
2.36.1
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