From: Stanislav Fomichev <sdf@fomichev.me>
Add bind-tx netlink call to attach dmabuf for TX; queue is not
required, only ifindex and dmabuf fd for attachment.
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Mina Almasry <almasrymina@google.com>
---
v3:
- Fix ynl-regen.sh error (Simon).
---
Documentation/netlink/specs/netdev.yaml | 12 ++++++++++++
include/uapi/linux/netdev.h | 1 +
net/core/netdev-genl-gen.c | 13 +++++++++++++
net/core/netdev-genl-gen.h | 1 +
net/core/netdev-genl.c | 6 ++++++
tools/include/uapi/linux/netdev.h | 1 +
6 files changed, 34 insertions(+)
diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index f5e0750ab71db..c0ef6d0d77865 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -743,6 +743,18 @@ operations:
- defer-hard-irqs
- gro-flush-timeout
- irq-suspend-timeout
+ -
+ name: bind-tx
+ doc: Bind dmabuf to netdev for TX
+ attribute-set: dmabuf
+ do:
+ request:
+ attributes:
+ - ifindex
+ - fd
+ reply:
+ attributes:
+ - id
kernel-family:
headers: [ "net/netdev_netlink.h"]
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index 7600bf62dbdf0..7eb9571786b83 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -219,6 +219,7 @@ enum {
NETDEV_CMD_QSTATS_GET,
NETDEV_CMD_BIND_RX,
NETDEV_CMD_NAPI_SET,
+ NETDEV_CMD_BIND_TX,
__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c
index 739f7b6506a6a..4fc44587f4936 100644
--- a/net/core/netdev-genl-gen.c
+++ b/net/core/netdev-genl-gen.c
@@ -99,6 +99,12 @@ static const struct nla_policy netdev_napi_set_nl_policy[NETDEV_A_NAPI_IRQ_SUSPE
[NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT] = { .type = NLA_UINT, },
};
+/* NETDEV_CMD_BIND_TX - do */
+static const struct nla_policy netdev_bind_tx_nl_policy[NETDEV_A_DMABUF_FD + 1] = {
+ [NETDEV_A_DMABUF_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1),
+ [NETDEV_A_DMABUF_FD] = { .type = NLA_U32, },
+};
+
/* Ops table for netdev */
static const struct genl_split_ops netdev_nl_ops[] = {
{
@@ -190,6 +196,13 @@ static const struct genl_split_ops netdev_nl_ops[] = {
.maxattr = NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT,
.flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
},
+ {
+ .cmd = NETDEV_CMD_BIND_TX,
+ .doit = netdev_nl_bind_tx_doit,
+ .policy = netdev_bind_tx_nl_policy,
+ .maxattr = NETDEV_A_DMABUF_FD,
+ .flags = GENL_CMD_CAP_DO,
+ },
};
static const struct genl_multicast_group netdev_nl_mcgrps[] = {
diff --git a/net/core/netdev-genl-gen.h b/net/core/netdev-genl-gen.h
index 17d39fd64c948..cf3fad74511f5 100644
--- a/net/core/netdev-genl-gen.h
+++ b/net/core/netdev-genl-gen.h
@@ -34,6 +34,7 @@ int netdev_nl_qstats_get_dumpit(struct sk_buff *skb,
struct netlink_callback *cb);
int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info);
int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info);
+int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info);
enum {
NETDEV_NLGRP_MGMT,
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 2c104947d224f..410df19d98d78 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -934,6 +934,12 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
return err;
}
+/* stub */
+int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
+{
+ return 0;
+}
+
void netdev_nl_sock_priv_init(struct netdev_nl_sock *priv)
{
INIT_LIST_HEAD(&priv->bindings);
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index 7600bf62dbdf0..7eb9571786b83 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -219,6 +219,7 @@ enum {
NETDEV_CMD_QSTATS_GET,
NETDEV_CMD_BIND_RX,
NETDEV_CMD_NAPI_SET,
+ NETDEV_CMD_BIND_TX,
__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
--
2.49.0.805.g082f7c87e0-googMina Almasry <almasrymina@google.com> writes: > From: Stanislav Fomichev <sdf@fomichev.me> > > Add bind-tx netlink call to attach dmabuf for TX; queue is not > required, only ifindex and dmabuf fd for attachment. > > Signed-off-by: Stanislav Fomichev <sdf@fomichev.me> > Signed-off-by: Mina Almasry <almasrymina@google.com> > > --- > > v3: > - Fix ynl-regen.sh error (Simon). > > --- > Documentation/netlink/specs/netdev.yaml | 12 ++++++++++++ > include/uapi/linux/netdev.h | 1 + > net/core/netdev-genl-gen.c | 13 +++++++++++++ > net/core/netdev-genl-gen.h | 1 + > net/core/netdev-genl.c | 6 ++++++ > tools/include/uapi/linux/netdev.h | 1 + > 6 files changed, 34 insertions(+) > > diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml > index f5e0750ab71db..c0ef6d0d77865 100644 > --- a/Documentation/netlink/specs/netdev.yaml > +++ b/Documentation/netlink/specs/netdev.yaml > @@ -743,6 +743,18 @@ operations: > - defer-hard-irqs > - gro-flush-timeout > - irq-suspend-timeout > + - > + name: bind-tx > + doc: Bind dmabuf to netdev for TX nit: maybe add "for RX" to the bind-rx doc. > + attribute-set: dmabuf The bind-rx op has "flags: [ admin-perm ]", should bind-tx also? > + do: > + request: > + attributes: > + - ifindex > + - fd > + reply: > + attributes: > + - id
On Wed, Apr 23, 2025 at 5:11 AM Donald Hunter <donald.hunter@gmail.com> wrote: > > Mina Almasry <almasrymina@google.com> writes: > > > From: Stanislav Fomichev <sdf@fomichev.me> > > > > Add bind-tx netlink call to attach dmabuf for TX; queue is not > > required, only ifindex and dmabuf fd for attachment. > > > > Signed-off-by: Stanislav Fomichev <sdf@fomichev.me> > > Signed-off-by: Mina Almasry <almasrymina@google.com> > > > > --- > > > > v3: > > - Fix ynl-regen.sh error (Simon). > > > > --- > > Documentation/netlink/specs/netdev.yaml | 12 ++++++++++++ > > include/uapi/linux/netdev.h | 1 + > > net/core/netdev-genl-gen.c | 13 +++++++++++++ > > net/core/netdev-genl-gen.h | 1 + > > net/core/netdev-genl.c | 6 ++++++ > > tools/include/uapi/linux/netdev.h | 1 + > > 6 files changed, 34 insertions(+) > > > > diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml > > index f5e0750ab71db..c0ef6d0d77865 100644 > > --- a/Documentation/netlink/specs/netdev.yaml > > +++ b/Documentation/netlink/specs/netdev.yaml > > @@ -743,6 +743,18 @@ operations: > > - defer-hard-irqs > > - gro-flush-timeout > > - irq-suspend-timeout > > + - > > + name: bind-tx > > + doc: Bind dmabuf to netdev for TX > > nit: maybe add "for RX" to the bind-rx doc. > Thanks, will pull this with the next iteration. > > + attribute-set: dmabuf > > The bind-rx op has "flags: [ admin-perm ]", should bind-tx also? > The omission of admin-perm for tx is intentional. Binding a dmabuf to an rx queue should and is a privileged operation, because basically the application doing the binding is taking ownership of this rx queue. For TX, no such queue ownership is being taken. The TX binding just gives the netdevice access to the dmabuf dma-addresses so the netdevice can send from there. It's very similar to a normal dma-map with normal memory. There is no need for privilege checks. -- Thanks, Mina
Mina Almasry <almasrymina@google.com> writes: >> >> The bind-rx op has "flags: [ admin-perm ]", should bind-tx also? > > The omission of admin-perm for tx is intentional. > > Binding a dmabuf to an rx queue should and is a privileged operation, > because basically the application doing the binding is taking > ownership of this rx queue. For TX, no such queue ownership is being > taken. The TX binding just gives the netdevice access to the dmabuf > dma-addresses so the netdevice can send from there. It's very similar > to a normal dma-map with normal memory. There is no need for privilege > checks. Thanks for the explanation. I couldn't find any mention of ownership in the docs.
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