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170aafe35cb98e0f3fbacb446ea86389fbce22ea
linux/Documentation/netlink/specs/netdev.yaml
Mina Almasry 170aafe35c netdev: support binding dma-buf to netdevice 
Add a netdev_dmabuf_binding struct which represents the
dma-buf-to-netdevice binding. The netlink API will bind the dma-buf to
rx queues on the netdevice. On the binding, the dma_buf_attach
& dma_buf_map_attachment will occur. The entries in the sg_table from
mapping will be inserted into a genpool to make it ready
for allocation.

The chunks in the genpool are owned by a dmabuf_chunk_owner struct which
holds the dma-buf offset of the base of the chunk and the dma_addr of
the chunk. Both are needed to use allocations that come from this chunk.

We create a new type that represents an allocation from the genpool:
net_iov. We setup the net_iov allocation size in the
genpool to PAGE_SIZE for simplicity: to match the PAGE_SIZE normally
allocated by the page pool and given to the drivers.

The user can unbind the dmabuf from the netdevice by closing the netlink
socket that established the binding. We do this so that the binding is
automatically unbound even if the userspace process crashes.

The binding and unbinding leaves an indicator in struct netdev_rx_queue
that the given queue is bound, and the binding is actuated by resetting
the rx queue using the queue API.

The netdev_dmabuf_binding struct is refcounted, and releases its
resources only when all the refs are released.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com>
Signed-off-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> # excluding netlink
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20240910171458.219195-4-almasrymina@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-11 20:44:31 -07:00

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# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
name: netdev
doc:
netdev configuration over generic netlink.
definitions:
-
type: flags
name: xdp-act
render-max: true
entries:
-
name: basic
doc:
XDP features set supported by all drivers
(XDP_ABORTED, XDP_DROP, XDP_PASS, XDP_TX)
-
name: redirect
doc:
The netdev supports XDP_REDIRECT
-
name: ndo-xmit
doc:
This feature informs if netdev implements ndo_xdp_xmit callback.
-
name: xsk-zerocopy
doc:
This feature informs if netdev supports AF_XDP in zero copy mode.
-
name: hw-offload
doc:
This feature informs if netdev supports XDP hw offloading.
-
name: rx-sg
doc:
This feature informs if netdev implements non-linear XDP buffer
support in the driver napi callback.
-
name: ndo-xmit-sg
doc:
This feature informs if netdev implements non-linear XDP buffer
support in ndo_xdp_xmit callback.
-
type: flags
name: xdp-rx-metadata
entries:
-
name: timestamp
doc:
Device is capable of exposing receive HW timestamp via bpf_xdp_metadata_rx_timestamp().
-
name: hash
doc:
Device is capable of exposing receive packet hash via bpf_xdp_metadata_rx_hash().
-
name: vlan-tag
doc:
Device is capable of exposing receive packet VLAN tag via bpf_xdp_metadata_rx_vlan_tag().
-
type: flags
name: xsk-flags
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.
-
name: queue-type
type: enum
entries: [ rx, tx ]
-
name: qstats-scope
type: flags
entries: [ queue ]
attribute-sets:
-
name: dev
attributes:
-
name: ifindex
doc: netdev ifindex
type: u32
checks:
min: 1
-
name: pad
type: pad
-
name: xdp-features
doc: Bitmask of enabled xdp-features.
type: u64
enum: xdp-act
-
name: xdp-zc-max-segs
doc: max fragment count supported by ZC driver
type: u32
checks:
min: 1
-
name: xdp-rx-metadata-features
doc: Bitmask of supported XDP receive metadata features.
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
-
name: page-pool
attributes:
-
name: id
doc: Unique ID of a Page Pool instance.
type: uint
checks:
min: 1
max: u32-max
-
name: ifindex
doc: |
ifindex of the netdev to which the pool belongs.
May be reported as 0 if the page pool was allocated for a netdev
which got destroyed already (page pools may outlast their netdevs
because they wait for all memory to be returned).
type: u32
checks:
min: 1
max: s32-max
-
name: napi-id
doc: Id of NAPI using this Page Pool instance.
type: uint
checks:
min: 1
max: u32-max
-
name: inflight
type: uint
doc: |
Number of outstanding references to this page pool (allocated
but yet to be freed pages). Allocated pages may be held in
socket receive queues, driver receive ring, page pool recycling
ring, the page pool cache, etc.
-
name: inflight-mem
type: uint
doc: |
Amount of memory held by inflight pages.
-
name: detach-time
type: uint
doc: |
Seconds in CLOCK_BOOTTIME of when Page Pool was detached by
the driver. Once detached Page Pool can no longer be used to
allocate memory.
Page Pools wait for all the memory allocated from them to be freed
before truly disappearing. "Detached" Page Pools cannot be
"re-attached", they are just waiting to disappear.
Attribute is absent if Page Pool has not been detached, and
can still be used to allocate new memory.
-
name: page-pool-info
subset-of: page-pool
attributes:
-
name: id
-
name: ifindex
-
name: page-pool-stats
doc: |
Page pool statistics, see docs for struct page_pool_stats
for information about individual statistics.
attributes:
-
name: info
doc: Page pool identifying information.
type: nest
nested-attributes: page-pool-info
-
name: alloc-fast
type: uint
value: 8 # reserve some attr ids in case we need more metadata later
-
name: alloc-slow
type: uint
-
name: alloc-slow-high-order
type: uint
-
name: alloc-empty
type: uint
-
name: alloc-refill
type: uint
-
name: alloc-waive
type: uint
-
name: recycle-cached
type: uint
-
name: recycle-cache-full
type: uint
-
name: recycle-ring
type: uint
-
name: recycle-ring-full
type: uint
-
name: recycle-released-refcnt
type: uint
-
name: napi
attributes:
-
name: ifindex
doc: ifindex of the netdevice to which NAPI instance belongs.
type: u32
checks:
min: 1
-
name: id
doc: ID of the NAPI instance.
type: u32
-
name: irq
doc: The associated interrupt vector number for the napi
type: u32
-
name: pid
doc: PID of the napi thread, if NAPI is configured to operate in
threaded mode. If NAPI is not in threaded mode (i.e. uses normal
softirq context), the attribute will be absent.
type: u32
-
name: queue
attributes:
-
name: id
doc: Queue index; most queue types are indexed like a C array, with
indexes starting at 0 and ending at queue count - 1. Queue indexes
are scoped to an interface and queue type.
type: u32
-
name: ifindex
doc: ifindex of the netdevice to which the queue belongs.
type: u32
checks:
min: 1
-
name: type
doc: Queue type as rx, tx. Each queue type defines a separate ID space.
type: u32
enum: queue-type
-
name: napi-id
doc: ID of the NAPI instance which services this queue.
type: u32
-
name: qstats
doc: |
Get device statistics, scoped to a device or a queue.
These statistics extend (and partially duplicate) statistics available
in struct rtnl_link_stats64.
Value of the `scope` attribute determines how statistics are
aggregated. When aggregated for the entire device the statistics
represent the total number of events since last explicit reset of
the device (i.e. not a reconfiguration like changing queue count).
When reported per-queue, however, the statistics may not add
up to the total number of events, will only be reported for currently
active objects, and will likely report the number of events since last
reconfiguration.
attributes:
-
name: ifindex
doc: ifindex of the netdevice to which stats belong.
type: u32
checks:
min: 1
-
name: queue-type
doc: Queue type as rx, tx, for queue-id.
type: u32
enum: queue-type
-
name: queue-id
doc: Queue ID, if stats are scoped to a single queue instance.
type: u32
-
name: scope
doc: |
What object type should be used to iterate over the stats.
type: uint
enum: qstats-scope
-
name: rx-packets
doc: |
Number of wire packets successfully received and passed to the stack.
For drivers supporting XDP, XDP is considered the first layer
of the stack, so packets consumed by XDP are still counted here.
type: uint
value: 8 # reserve some attr ids in case we need more metadata later
-
name: rx-bytes
doc: Successfully received bytes, see `rx-packets`.
type: uint
-
name: tx-packets
doc: |
Number of wire packets successfully sent. Packet is considered to be
successfully sent once it is in device memory (usually this means
the device has issued a DMA completion for the packet).
type: uint
-
name: tx-bytes
doc: Successfully sent bytes, see `tx-packets`.
type: uint
-
name: rx-alloc-fail
doc: |
Number of times skb or buffer allocation failed on the Rx datapath.
Allocation failure may, or may not result in a packet drop, depending
on driver implementation and whether system recovers quickly.
type: uint
-
name: rx-hw-drops
doc: |
Number of all packets which entered the device, but never left it,
including but not limited to: packets dropped due to lack of buffer
space, processing errors, explicit or implicit policies and packet
filters.
type: uint
-
name: rx-hw-drop-overruns
doc: |
Number of packets dropped due to transient lack of resources, such as
buffer space, host descriptors etc.
type: uint
-
name: rx-csum-complete
doc: Number of packets that were marked as CHECKSUM_COMPLETE.
type: uint
-
name: rx-csum-unnecessary
doc: Number of packets that were marked as CHECKSUM_UNNECESSARY.
type: uint
-
name: rx-csum-none
doc: Number of packets that were not checksummed by device.
type: uint
-
name: rx-csum-bad
doc: |
Number of packets with bad checksum. The packets are not discarded,
but still delivered to the stack.
type: uint
-
name: rx-hw-gro-packets
doc: |
Number of packets that were coalesced from smaller packets by the device.
Counts only packets coalesced with the HW-GRO netdevice feature,
LRO-coalesced packets are not counted.
type: uint
-
name: rx-hw-gro-bytes
doc: See `rx-hw-gro-packets`.
type: uint
-
name: rx-hw-gro-wire-packets
doc: |
Number of packets that were coalesced to bigger packetss with the HW-GRO
netdevice feature. LRO-coalesced packets are not counted.
type: uint
-
name: rx-hw-gro-wire-bytes
doc: See `rx-hw-gro-wire-packets`.
type: uint
-
name: rx-hw-drop-ratelimits
doc: |
Number of the packets dropped by the device due to the received
packets bitrate exceeding the device rate limit.
type: uint
-
name: tx-hw-drops
doc: |
Number of packets that arrived at the device but never left it,
encompassing packets dropped for reasons such as processing errors, as
well as those affected by explicitly defined policies and packet
filtering criteria.
type: uint
-
name: tx-hw-drop-errors
doc: Number of packets dropped because they were invalid or malformed.
type: uint
-
name: tx-csum-none
doc: |
Number of packets that did not require the device to calculate the
checksum.
type: uint
-
name: tx-needs-csum
doc: |
Number of packets that required the device to calculate the checksum.
type: uint
-
name: tx-hw-gso-packets
doc: |
Number of packets that necessitated segmentation into smaller packets
by the device.
type: uint
-
name: tx-hw-gso-bytes
doc: See `tx-hw-gso-packets`.
type: uint
-
name: tx-hw-gso-wire-packets
doc: |
Number of wire-sized packets generated by processing
`tx-hw-gso-packets`
type: uint
-
name: tx-hw-gso-wire-bytes
doc: See `tx-hw-gso-wire-packets`.
type: uint
-
name: tx-hw-drop-ratelimits
doc: |
Number of the packets dropped by the device due to the transmit
packets bitrate exceeding the device rate limit.
type: uint
-
name: tx-stop
doc: |
Number of times driver paused accepting new tx packets
from the stack to this queue, because the queue was full.
Note that if BQL is supported and enabled on the device
the networking stack will avoid queuing a lot of data at once.
type: uint
-
name: tx-wake
doc: |
Number of times driver re-started accepting send
requests to this queue from the stack.
type: uint
-
name: queue-id
subset-of: queue
attributes:
-
name: id
-
name: type
-
name: dmabuf
attributes:
-
name: ifindex
doc: netdev ifindex to bind the dmabuf to.
type: u32
checks:
min: 1
-
name: queues
doc: receive queues to bind the dmabuf to.
type: nest
nested-attributes: queue-id
multi-attr: true
-
name: fd
doc: dmabuf file descriptor to bind.
type: u32
-
name: id
doc: id of the dmabuf binding
type: u32
checks:
min: 1
operations:
list:
-
name: dev-get
doc: Get / dump information about a netdev.
attribute-set: dev
do:
request:
attributes:
- ifindex
reply: &dev-all
attributes:
- ifindex
- xdp-features
- xdp-zc-max-segs
- xdp-rx-metadata-features
- xsk-features
dump:
reply: *dev-all
-
name: dev-add-ntf
doc: Notification about device appearing.
notify: dev-get
mcgrp: mgmt
-
name: dev-del-ntf
doc: Notification about device disappearing.
notify: dev-get
mcgrp: mgmt
-
name: dev-change-ntf
doc: Notification about device configuration being changed.
notify: dev-get
mcgrp: mgmt
-
name: page-pool-get
doc: |
Get / dump information about Page Pools.
(Only Page Pools associated with a net_device can be listed.)
attribute-set: page-pool
do:
request:
attributes:
- id
reply: &pp-reply
attributes:
- id
- ifindex
- napi-id
- inflight
- inflight-mem
- detach-time
dump:
reply: *pp-reply
config-cond: page-pool
-
name: page-pool-add-ntf
doc: Notification about page pool appearing.
notify: page-pool-get
mcgrp: page-pool
config-cond: page-pool
-
name: page-pool-del-ntf
doc: Notification about page pool disappearing.
notify: page-pool-get
mcgrp: page-pool
config-cond: page-pool
-
name: page-pool-change-ntf
doc: Notification about page pool configuration being changed.
notify: page-pool-get
mcgrp: page-pool
config-cond: page-pool
-
name: page-pool-stats-get
doc: Get page pool statistics.
attribute-set: page-pool-stats
do:
request:
attributes:
- info
reply: &pp-stats-reply
attributes:
- info
- alloc-fast
- alloc-slow
- alloc-slow-high-order
- alloc-empty
- alloc-refill
- alloc-waive
- recycle-cached
- recycle-cache-full
- recycle-ring
- recycle-ring-full
- recycle-released-refcnt
dump:
reply: *pp-stats-reply
config-cond: page-pool-stats
-
name: queue-get
doc: Get queue information from the kernel.
Only configured queues will be reported (as opposed to all available
hardware queues).
attribute-set: queue
do:
request:
attributes:
- ifindex
- type
- id
reply: &queue-get-op
attributes:
- id
- type
- napi-id
- ifindex
dump:
request:
attributes:
- ifindex
reply: *queue-get-op
-
name: napi-get
doc: Get information about NAPI instances configured on the system.
attribute-set: napi
do:
request:
attributes:
- id
reply: &napi-get-op
attributes:
- id
- ifindex
- irq
- pid
dump:
request:
attributes:
- ifindex
reply: *napi-get-op
-
name: qstats-get
doc: |
Get / dump fine grained statistics. Which statistics are reported
depends on the device and the driver, and whether the driver stores
software counters per-queue.
attribute-set: qstats
dump:
request:
attributes:
- ifindex
- scope
reply:
attributes:
- ifindex
- queue-type
- queue-id
- rx-packets
- rx-bytes
- tx-packets
- tx-bytes
-
name: bind-rx
doc: Bind dmabuf to netdev
attribute-set: dmabuf
flags: [ admin-perm ]
do:
request:
attributes:
- ifindex
- fd
- queues
reply:
attributes:
- id
kernel-family:
headers: [ "linux/list.h"]
sock-priv: struct list_head
mcast-groups:
list:
-
name: mgmt
-
name: page-pool
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