selftests/xsk: add option to run single test

Add a command line option to be able to run a single test. This option
(-t) takes a number from the list of tests available with the "-l"
option. Here ar

selftests/xsk: add option to run single test

Add a command line option to be able to run a single test. This option
(-t) takes a number from the list of tests available with the "-l"
option. Here are two examples:

Run test number 2, the "receive single packet" test in all available modes:

./test_xsk.sh -t 2

Run test number 21, the metadata copy test in skb mode only

./test_xsh.sh -t 21 -m skb

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230914084900.492-8-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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selftests/xsk: add option that lists all tests

Add a command line option (-l) that lists all the tests. The number
before the test will be used in the next commit for specifying a
single test to run

selftests/xsk: add option that lists all tests

Add a command line option (-l) that lists all the tests. The number
before the test will be used in the next commit for specifying a
single test to run. Here is an example of the output:

Tests:
0: SEND_RECEIVE
1: SEND_RECEIVE_2K_FRAME
2: SEND_RECEIVE_SINGLE_PKT
3: POLL_RX
4: POLL_TX
5: POLL_RXQ_FULL
6: POLL_TXQ_FULL
7: SEND_RECEIVE_UNALIGNED
:
:

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230914084900.492-7-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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selftests/xsk: declare test names in struct

Declare the test names statically in a struct so that we can refer to
them when adding the support to execute a single test in the next
commit. Before thi

selftests/xsk: declare test names in struct

Declare the test names statically in a struct so that we can refer to
them when adding the support to execute a single test in the next
commit. Before this patch, the names of them were not declared in a
single place which made it not possible to refer to them.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230914084900.492-6-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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selftests/xsk: move all tests to separate functions

Prepare for the capability to be able to run a single test by moving
all the tests to their own functions. This function can then be called
to exe

selftests/xsk: move all tests to separate functions

Prepare for the capability to be able to run a single test by moving
all the tests to their own functions. This function can then be called
to execute that test in the next commit.

Also, the tests named RUN_TO_COMPLETION_* were not named well, so
change them to SEND_RECEIVE_* as it is just a basic send and receive
test of 4K packets.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230914084900.492-5-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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selftests/xsk: add option to only run tests in a single mode

Add an option -m on the command line that allows the user to run the
tests in a single mode instead of all of them. Valid modes are skb,

selftests/xsk: add option to only run tests in a single mode

Add an option -m on the command line that allows the user to run the
tests in a single mode instead of all of them. Valid modes are skb,
drv, and zc (zero-copy). An example:

To run test suite in drv mode only:

./test_xsk.sh -m drv

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230914084900.492-4-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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selftests/xsk: add timeout for Tx thread

Add a timeout for the transmission thread. If packets are not
completed properly, for some reason, the test harness would previously
get stuck forever in a w

selftests/xsk: add timeout for Tx thread

Add a timeout for the transmission thread. If packets are not
completed properly, for some reason, the test harness would previously
get stuck forever in a while loop. But with this patch, this timeout
will trigger, flag the test as a failure, and continue with the next
test.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230914084900.492-3-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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selftests/xsk: print per packet info in verbose mode

Print info about every packet in verbose mode, both for Tx and
Rx. This is useful to have when a test fails or to validate that a
test is really

selftests/xsk: print per packet info in verbose mode

Print info about every packet in verbose mode, both for Tx and
Rx. This is useful to have when a test fails or to validate that a
test is really doing what it was designed to do. Info on what is
supposed to be received and sent is also printed for the custom packet
streams since they differ from the base line. Here is an example:

Tx addr: 37e0 len: 64 options: 0 pkt_nb: 8
Tx addr: 4000 len: 64 options: 0 pkt_nb: 9
Rx: addr: 100 len: 64 options: 0 pkt_nb: 0 valid: 1
Rx: addr: 1100 len: 64 options: 0 pkt_nb: 1 valid: 1
Rx: addr: 2100 len: 64 options: 0 pkt_nb: 4 valid: 1
Rx: addr: 3100 len: 64 options: 0 pkt_nb: 8 valid: 1
Rx: addr: 4100 len: 64 options: 0 pkt_nb: 9 valid: 1

One pointless verbose print statement is also deleted and another one
is made clearer.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230914084900.492-2-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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Merge drm/drm-fixes into drm-misc-fixes

Forwarding to v6.6-rc1.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge tag 'v6.5' into next

Sync up with mainline to bring in updates to the shared infrastructure.

Merge branch 'next' into for-linus

Prepare input updates for 6.6 merge window.

Merge tag 'net-next-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Paolo Abeni:
"Core:

- Increase size limits for to-be-sent skb frag allocat

Merge tag 'net-next-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Paolo Abeni:
"Core:

- Increase size limits for to-be-sent skb frag allocations. This
allows tun, tap devices and packet sockets to better cope with
large writes operations

- Store netdevs in an xarray, to simplify iterating over netdevs

- Refactor nexthop selection for multipath routes

- Improve sched class lifetime handling

- Add backup nexthop ID support for bridge

- Implement drop reasons support in openvswitch

- Several data races annotations and fixes

- Constify the sk parameter of routing functions

- Prepend kernel version to netconsole message

Protocols:

- Implement support for TCP probing the peer being under memory
pressure

- Remove hard coded limitation on IPv6 specific info placement inside
the socket struct

- Get rid of sysctl_tcp_adv_win_scale and use an auto-estimated per
socket scaling factor

- Scaling-up the IPv6 expired route GC via a separated list of
expiring routes

- In-kernel support for the TLS alert protocol

- Better support for UDP reuseport with connected sockets

- Add NEXT-C-SID support for SRv6 End.X behavior, reducing the SR
header size

- Get rid of additional ancillary per MPTCP connection struct socket

- Implement support for BPF-based MPTCP packet schedulers

- Format MPTCP subtests selftests results in TAP

- Several new SMC 2.1 features including unique experimental options,
max connections per lgr negotiation, max links per lgr negotiation

BPF:

- Multi-buffer support in AF_XDP

- Add multi uprobe BPF links for attaching multiple uprobes and usdt
probes, which is significantly faster and saves extra fds

- Implement an fd-based tc BPF attach API (TCX) and BPF link support
on top of it

- Add SO_REUSEPORT support for TC bpf_sk_assign

- Support new instructions from cpu v4 to simplify the generated code
and feature completeness, for x86, arm64, riscv64

- Support defragmenting IPv(4|6) packets in BPF

- Teach verifier actual bounds of bpf_get_smp_processor_id() and fix
perf+libbpf issue related to custom section handling

- Introduce bpf map element count and enable it for all program types

- Add a BPF hook in sys_socket() to change the protocol ID from
IPPROTO_TCP to IPPROTO_MPTCP to cover migration for legacy

- Introduce bpf_me_mcache_free_rcu() and fix OOM under stress

- Add uprobe support for the bpf_get_func_ip helper

- Check skb ownership against full socket

- Support for up to 12 arguments in BPF trampoline

- Extend link_info for kprobe_multi and perf_event links

Netfilter:

- Speed-up process exit by aborting ruleset validation if a fatal
signal is pending

- Allow NLA_POLICY_MASK to be used with BE16/BE32 types

Driver API:

- Page pool optimizations, to improve data locality and cache usage

- Introduce ndo_hwtstamp_get() and ndo_hwtstamp_set() to avoid the
need for raw ioctl() handling in drivers

- Simplify genetlink dump operations (doit/dumpit) providing them the
common information already populated in struct genl_info

- Extend and use the yaml devlink specs to [re]generate the split ops

- Introduce devlink selective dumps, to allow SF filtering SF based
on handle and other attributes

- Add yaml netlink spec for netlink-raw families, allow route, link
and address related queries via the ynl tool

- Remove phylink legacy mode support

- Support offload LED blinking to phy

- Add devlink port function attributes for IPsec

New hardware / drivers:

- Ethernet:
- Broadcom ASP 2.0 (72165) ethernet controller
- MediaTek MT7988 SoC
- Texas Instruments AM654 SoC
- Texas Instruments IEP driver
- Atheros qca8081 phy
- Marvell 88Q2110 phy
- NXP TJA1120 phy

- WiFi:
- MediaTek mt7981 support

- Can:
- Kvaser SmartFusion2 PCI Express devices
- Allwinner T113 controllers
- Texas Instruments tcan4552/4553 chips

- Bluetooth:
- Intel Gale Peak
- Qualcomm WCN3988 and WCN7850
- NXP AW693 and IW624
- Mediatek MT2925

Drivers:

- Ethernet NICs:
- nVidia/Mellanox:
- mlx5:
- support UDP encapsulation in packet offload mode
- IPsec packet offload support in eswitch mode
- improve aRFS observability by adding new set of counters
- extends MACsec offload support to cover RoCE traffic
- dynamic completion EQs
- mlx4:
- convert to use auxiliary bus instead of custom interface
logic
- Intel
- ice:
- implement switchdev bridge offload, even for LAG
interfaces
- implement SRIOV support for LAG interfaces
- igc:
- add support for multiple in-flight TX timestamps
- Broadcom:
- bnxt:
- use the unified RX page pool buffers for XDP and non-XDP
- use the NAPI skb allocation cache
- OcteonTX2:
- support Round Robin scheduling HTB offload
- TC flower offload support for SPI field
- Freescale:
- add XDP_TX feature support
- AMD:
- ionic: add support for PCI FLR event
- sfc:
- basic conntrack offload
- introduce eth, ipv4 and ipv6 pedit offloads
- ST Microelectronics:
- stmmac: maximze PTP timestamping resolution

- Virtual NICs:
- Microsoft vNIC:
- batch ringing RX queue doorbell on receiving packets
- add page pool for RX buffers
- Virtio vNIC:
- add per queue interrupt coalescing support
- Google vNIC:
- add queue-page-list mode support

- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add port range matching tc-flower offload
- permit enslavement to netdevices with uppers

- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- convert to phylink_pcs
- Renesas:
- r8A779fx: add speed change support
- rzn1: enables vlan support

- Ethernet PHYs:
- convert mv88e6xxx to phylink_pcs

- WiFi:
- Qualcomm Wi-Fi 7 (ath12k):
- extremely High Throughput (EHT) PHY support
- RealTek (rtl8xxxu):
- enable AP mode for: RTL8192FU, RTL8710BU (RTL8188GU),
RTL8192EU and RTL8723BU
- RealTek (rtw89):
- Introduce Time Averaged SAR (TAS) support

- Connector:
- support for event filtering"

* tag 'net-next-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1806 commits)
net: ethernet: mtk_wed: minor change in wed_{tx,rx}info_show
net: ethernet: mtk_wed: add some more info in wed_txinfo_show handler
net: stmmac: clarify difference between "interface" and "phy_interface"
r8152: add vendor/device ID pair for D-Link DUB-E250
devlink: move devlink_notify_register/unregister() to dev.c
devlink: move small_ops definition into netlink.c
devlink: move tracepoint definitions into core.c
devlink: push linecard related code into separate file
devlink: push rate related code into separate file
devlink: push trap related code into separate file
devlink: use tracepoint_enabled() helper
devlink: push region related code into separate file
devlink: push param related code into separate file
devlink: push resource related code into separate file
devlink: push dpipe related code into separate file
devlink: move and rename devlink_dpipe_send_and_alloc_skb() helper
devlink: push shared buffer related code into separate file
devlink: push port related code into separate file
devlink: push object register/unregister notifications into separate helpers
inet: fix IP_TRANSPARENT error handling
...

show more ...

Merge drm/drm-next into drm-intel-next

Catching-up with drm-next and drm-intel-gt-next.
It will unblock a code refactor around the platform
definitions (names vs acronyms).

Signed-off-by: Rodrigo V

Merge drm/drm-next into drm-intel-next

Catching-up with drm-next and drm-intel-gt-next.
It will unblock a code refactor around the platform
definitions (names vs acronyms).

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

show more ...

Merge drm/drm-next into drm-intel-gt-next

Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as
a dependency for https://patchwork.freedesktop.org/series/1

Merge drm/drm-next into drm-intel-gt-next

Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as
a dependency for https://patchwork.freedesktop.org/series/121735/

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

show more ...

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Martin KaFai Lau says:

====================
pull-request: bpf-next 2023-08-03

We've added 54 non-merge commit

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Martin KaFai Lau says:

====================
pull-request: bpf-next 2023-08-03

We've added 54 non-merge commits during the last 10 day(s) which contain
a total of 84 files changed, 4026 insertions(+), 562 deletions(-).

The main changes are:

1) Add SO_REUSEPORT support for TC bpf_sk_assign from Lorenz Bauer,
Daniel Borkmann

2) Support new insns from cpu v4 from Yonghong Song

3) Non-atomically allocate freelist during prefill from YiFei Zhu

4) Support defragmenting IPv(4|6) packets in BPF from Daniel Xu

5) Add tracepoint to xdp attaching failure from Leon Hwang

6) struct netdev_rx_queue and xdp.h reshuffling to reduce
rebuild time from Jakub Kicinski

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (54 commits)
net: invert the netdevice.h vs xdp.h dependency
net: move struct netdev_rx_queue out of netdevice.h
eth: add missing xdp.h includes in drivers
selftests/bpf: Add testcase for xdp attaching failure tracepoint
bpf, xdp: Add tracepoint to xdp attaching failure
selftests/bpf: fix static assert compilation issue for test_cls_*.c
bpf: fix bpf_probe_read_kernel prototype mismatch
riscv, bpf: Adapt bpf trampoline to optimized riscv ftrace framework
libbpf: fix typos in Makefile
tracing: bpf: use struct trace_entry in struct syscall_tp_t
bpf, devmap: Remove unused dtab field from bpf_dtab_netdev
bpf, cpumap: Remove unused cmap field from bpf_cpu_map_entry
netfilter: bpf: Only define get_proto_defrag_hook() if necessary
bpf: Fix an array-index-out-of-bounds issue in disasm.c
net: remove duplicate INDIRECT_CALLABLE_DECLARE of udp[6]_ehashfn
docs/bpf: Fix malformed documentation
bpf: selftests: Add defrag selftests
bpf: selftests: Support custom type and proto for client sockets
bpf: selftests: Support not connecting client socket
netfilter: bpf: Support BPF_F_NETFILTER_IP_DEFRAG in netfilter link
...
====================

Link: https://lore.kernel.org/r/20230803174845.825419-1-martin.lau@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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selftests/xsk: Fix spelling mistake "querrying" -> "querying"

There is a spelling mistake in an error message. Fix it.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Björn Töpel <

selftests/xsk: Fix spelling mistake "querrying" -> "querying"

There is a spelling mistake in an error message. Fix it.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20230720104815.123146-1-colin.i.king@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

show more ...

Merge drm/drm-next into drm-misc-next

Backmerging to get v6.5-rc2.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2023-07-19

We've added 45 non-merge comm

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2023-07-19

We've added 45 non-merge commits during the last 3 day(s) which contain
a total of 71 files changed, 7808 insertions(+), 592 deletions(-).

The main changes are:

1) multi-buffer support in AF_XDP, from Maciej Fijalkowski,
Magnus Karlsson, Tirthendu Sarkar.

2) BPF link support for tc BPF programs, from Daniel Borkmann.

3) Enable bpf_map_sum_elem_count kfunc for all program types,
from Anton Protopopov.

4) Add 'owner' field to bpf_rb_node to fix races in shared ownership,
Dave Marchevsky.

5) Prevent potential skb_header_pointer() misuse, from Alexei Starovoitov.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (45 commits)
bpf, net: Introduce skb_pointer_if_linear().
bpf: sync tools/ uapi header with
selftests/bpf: Add mprog API tests for BPF tcx links
selftests/bpf: Add mprog API tests for BPF tcx opts
bpftool: Extend net dump with tcx progs
libbpf: Add helper macro to clear opts structs
libbpf: Add link-based API for tcx
libbpf: Add opts-based attach/detach/query API for tcx
bpf: Add fd-based tcx multi-prog infra with link support
bpf: Add generic attach/detach/query API for multi-progs
selftests/xsk: reset NIC settings to default after running test suite
selftests/xsk: add test for too many frags
selftests/xsk: add metadata copy test for multi-buff
selftests/xsk: add invalid descriptor test for multi-buffer
selftests/xsk: add unaligned mode test for multi-buffer
selftests/xsk: add basic multi-buffer test
selftests/xsk: transmit and receive multi-buffer packets
xsk: add multi-buffer documentation
i40e: xsk: add TX multi-buffer support
ice: xsk: Tx multi-buffer support
...
====================

Link: https://lore.kernel.org/r/20230719175424.75717-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

Merge branch 'xsk-multi-buffer-support'

Maciej Fijalkowski says:

====================
xsk: multi-buffer support

v6->v7:
- rebase...[Alexei]

v5->v6:
- update bpf_xdp_query_opts__last_field in patc

Merge branch 'xsk-multi-buffer-support'

Maciej Fijalkowski says:

====================
xsk: multi-buffer support

v6->v7:
- rebase...[Alexei]

v5->v6:
- update bpf_xdp_query_opts__last_field in patch 10 [Alexei]

v4->v5:
- align options argument size to match options from xdp_desc [Benjamin]
- cleanup skb from xdp_sock on socket termination [Toke]
- introduce new netlink attribute for letting user space know about Tx
frag limit; this substitutes xdp_features flag previously dedicated
for setting ZC multi-buffer support [Toke, Jakub]
- include i40e ZC multi-buffer support
- enable TOO_MANY_FRAGS for ZC on xskxceiver; this is now possible due
to netlink attribute mentioned two bullets above

v3->v4:
-rely on ynl for adding new xdp_features flag [Jakub]
- move xskb_list to xsk_buff_pool

v2->v3:
- Fix issue with the next valid packet getting dropped after an invalid
packet with MAX_SKB_FRAGS + 1 frags [Magnus]
- query NETDEV_XDP_ACT_ZC_SG flag within xskxceiver and act on it
- remove redundant include in xsk.c [kernel test robot]
- s/NETDEV_XDP_ACT_NDO_ZC_SG/NETDEV_XDP_ACT_ZC_SG + kernel doc [Magnus,
Simon]

v1->v2:
- fix spelling issues in commit messages [Simon]
- remove XSK_DESC_MAX_FRAGS, use MAX_SKB_FRAGS instead [Stan, Alexei]
- add documentation patch
- fix build error from kernel test robot on patch 10

This series of patches add multi-buffer support for AF_XDP. XDP and
various NIC drivers already have support for multi-buffer packets. With
this patch set, programs using AF_XDP sockets can now also receive and
transmit multi-buffer packets both in copy as well as zero-copy mode.
ZC multi-buffer implementation is based on ice driver.

Some definitions to put us all on the same page:

* A packet consists of one or more frames

* A descriptor in one of the AF_XDP rings always refers to a single
frame. In the case the packet consists of a single frame, the
descriptor refers to the whole packet.

To represent a packet consisting of multiple frames, we introduce a
new flag called XDP_PKT_CONTD in the options field of the Rx and Tx
descriptors. If it is true (1) the packet continues with the next
descriptor and if it is false (0) it means this is the last descriptor
of the packet. Why the reverse logic of end-of-packet (eop) flag found
in many NICs? Just to preserve compatibility with non-multi-buffer
applications that have this bit set to false for all packets on Rx, and
the apps set the options field to zero for Tx, as anything else will
be treated as an invalid descriptor.

These are the semantics for producing packets onto XSK Tx ring
consisting of multiple frames:

* When an invalid descriptor is found, all the other
descriptors/frames of this packet are marked as invalid and not
completed. The next descriptor is treated as the start of a new
packet, even if this was not the intent (because we cannot guess
the intent). As before, if your program is producing invalid
descriptors you have a bug that must be fixed.

* Zero length descriptors are treated as invalid descriptors.

* For copy mode, the maximum supported number of frames in a packet is
equal to CONFIG_MAX_SKB_FRAGS + 1. If it is exceeded, all
descriptors accumulated so far are dropped and treated as
invalid. To produce an application that will work on any system
regardless of this config setting, limit the number of frags to 18,
as the minimum value of the config is 17.

* For zero-copy mode, the limit is up to what the NIC HW
supports. User space can discover this via newly introduced
NETDEV_A_DEV_XDP_ZC_MAX_SEGS netlink attribute.

Here is an example Tx path pseudo-code (using libxdp interfaces for
simplicity) ignoring that the umem is finite in size, and that we
eventually will run out of packets to send. Also assumes pkts.addr
points to a valid location in the umem.

void tx_packets(struct xsk_socket_info *xsk, struct pkt *pkts,
int batch_size)
{
u32 idx, i, pkt_nb = 0;

xsk_ring_prod__reserve(&xsk->tx, batch_size, &idx);

for (i = 0; i < batch_size;) {
u64 addr = pkts[pkt_nb].addr;
u32 len = pkts[pkt_nb].size;

do {
struct xdp_desc *tx_desc;

tx_desc = xsk_ring_prod__tx_desc(&xsk->tx, idx + i++);
tx_desc->addr = addr;

if (len > xsk_frame_size) {
tx_desc->len = xsk_frame_size;
tx_desc->options |= XDP_PKT_CONTD;
} else {
tx_desc->len = len;
tx_desc->options = 0;
pkt_nb++;
}
len -= tx_desc->len;
addr += xsk_frame_size;

if (i == batch_size) {
/* Remember len, addr, pkt_nb for next
* iteration. Skipped for simplicity.
*/
break;
}
} while (len);
}

xsk_ring_prod__submit(&xsk->tx, i);
}

On the Rx path in copy mode, the xsk core copies the XDP data into
multiple descriptors, if needed, and sets the XDP_PKT_CONTD flag as
detailed before. Zero-copy mode in order to avoid the copies has to
maintain a chain of xdp_buff_xsk structs that represent whole packet.
This is because what actually is redirected is the xdp_buff and we
currently have no equivalent mechanism that is used for copy mode
(embedded skb_shared_info in xdp_buff) to carry the frags. This means
xdp_buff_xsk grows in size but these members are at the end and should
not be touched when data path is not dealing with fragmented packets.
This solution kept us within assumed performance impact, hence we
decided to proceed with it.

When the application gets a descriptor with the
XDP_PKT_CONTD flag set to one, it means that the packet consists of
multiple buffers and it continues with the next buffer in the following
descriptor. When a descriptor with XDP_PKT_CONTD == 0 is received, it
means that this is the last buffer of the packet. AF_XDP guarantees that
only a complete packet (all frames in the packet) is sent to the
application.

If application reads a batch of descriptors, using for example the libxdp
interfaces, it is not guaranteed that the batch will end with a full
packet. It might end in the middle of a packet and the rest of the
buffers of that packet will arrive at the beginning of the next batch,
since the libxdp interface does not read the whole ring (unless you
have an enormous batch size or a very small ring size).

Here is a simple Rx path pseudo-code example (using libxdp interfaces for
simplicity). Error paths have been excluded for simplicity:

void rx_packets(struct xsk_socket_info *xsk)
{
static bool new_packet = true;
u32 idx_rx = 0, idx_fq = 0;
static char *pkt;

int rcvd = xsk_ring_cons__peek(&xsk->rx, opt_batch_size, &idx_rx);

xsk_ring_prod__reserve(&xsk->umem->fq, rcvd, &idx_fq);

for (int i = 0; i < rcvd; i++) {
struct xdp_desc *desc = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx++);
char *frag = xsk_umem__get_data(xsk->umem->buffer, desc->addr);
bool eop = !(desc->options & XDP_PKT_CONTD);

if (new_packet)
pkt = frag;
else
add_frag_to_pkt(pkt, frag);

if (eop)
process_pkt(pkt);

new_packet = eop;

*xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) = desc->addr;
}

xsk_ring_prod__submit(&xsk->umem->fq, rcvd);
xsk_ring_cons__release(&xsk->rx, rcvd);
}

We had to introduce a new bind flag (XDP_USE_SG) on the AF_XDP level to
enable multi-buffer support. The reason we need to differentiate between
non multi-buffer and multi-buffer is the behaviour when the kernel gets
a packet that is larger than the frame size. Without multi-buffer, this
packet is dropped and marked in the stats. With multi-buffer on, we want
to split it up into multiple frames instead.

At the start, we thought that riding on the .frags section name of
the XDP program was a good idea. You do not have to introduce yet
another flag and all AF_XDP users must load an XDP program anyway
to get any traffic up to the socket, so why not just say that the XDP
program decides if the AF_XDP socket should get multi-buffer packets
or not? The problem is that we can create an AF_XDP socket that is Tx
only and that works without having to load an XDP program at
all. Another problem is that the XDP program might change during the
execution, so we would have to check this for every single packet.

Here is the observed throughput when compared to a codebase without any
multi-buffer changes and measured with xdpsock for 64B packets.
Apparently ZC Tx takes a hit from explicit zero length descriptors
validation. Overall, in terms of ZC performance, there is a room for
improvement, but for now we think this work is in a good shape in terms
of correctness and functionality. We were targetting for up to 5%
overhead though. Note that ZC performance drops come from core + driver
support being combined, whereas copy mode had already driver support in
place.

Mode rxdrop l2fwd txonly
ice-zc -4% -7% -6%
i40e-zc -7% -6% -7%
drv -1.2% 0% +2%
skb -0.6% -1% +2%

Thank you,
Tirthendu, Magnus and Maciej
====================

Link: https://lore.kernel.org/r/20230719132421.584801-1-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

show more ...

selftests/xsk: add test for too many frags

Add a test that will exercise maximum number of supported fragments.
This number depends on mode of the test - for SKB and DRV it will be 18
whereas for ZC

selftests/xsk: add test for too many frags

Add a test that will exercise maximum number of supported fragments.
This number depends on mode of the test - for SKB and DRV it will be 18
whereas for ZC this is defined by a value from NETDEV_A_DEV_XDP_ZC_MAX_SEGS
netlink attribute.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> # made use of new netlink attribute
Link: https://lore.kernel.org/r/20230719132421.584801-24-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

show more ...

selftests/xsk: add metadata copy test for multi-buff

Enable the already existing metadata copy test to also run in
multi-buffer mode with 9K packets.

Signed-off-by: Magnus Karlsson <magnus.karlsson

selftests/xsk: add metadata copy test for multi-buff

Enable the already existing metadata copy test to also run in
multi-buffer mode with 9K packets.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-23-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

show more ...

selftests/xsk: add invalid descriptor test for multi-buffer

Add a test that produces lots of nasty descriptors testing the corner
cases of the descriptor validation. Some of these descriptors are
va

selftests/xsk: add invalid descriptor test for multi-buffer

Add a test that produces lots of nasty descriptors testing the corner
cases of the descriptor validation. Some of these descriptors are
valid and some are not as indicated by the valid flag. For a
description of all the test combinations, please see the code.

To stress the API, we need to be able to generate combinations of
descriptors that make little sense. A new verbatim mode is introduced
for the packet_stream to accomplish this. In this mode, all packets in
the packet_stream are sent as is. We do not try to chop them up into
frames that are of the right size that we know are going to work as we
would normally do. The packets are just written into the Tx ring even
if we know they make no sense.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> # adjusted valid flags for frags
Link: https://lore.kernel.org/r/20230719132421.584801-22-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

show more ...

selftests/xsk: add unaligned mode test for multi-buffer

Add a test for multi-buffer AF_XDP when using unaligned mode. The test
sends 4096 9K-buffers.

Signed-off-by: Magnus Karlsson <magnus.karlsson

selftests/xsk: add unaligned mode test for multi-buffer

Add a test for multi-buffer AF_XDP when using unaligned mode. The test
sends 4096 9K-buffers.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-21-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

show more ...

selftests/xsk: add basic multi-buffer test

Add the first basic multi-buffer test that sends a stream of 9K
packets and validates that they are received at the other end. In
order to enable sending a

selftests/xsk: add basic multi-buffer test

Add the first basic multi-buffer test that sends a stream of 9K
packets and validates that they are received at the other end. In
order to enable sending and receiving multi-buffer packets, code that
sets the MTU is introduced as well as modifications to the XDP
programs so that they signal that they are multi-buffer enabled.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-20-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

show more ...

selftests/xsk: transmit and receive multi-buffer packets

Add the ability to send and receive packets that are larger than the
size of a umem frame, using the AF_XDP /XDP multi-buffer
support. There

selftests/xsk: transmit and receive multi-buffer packets

Add the ability to send and receive packets that are larger than the
size of a umem frame, using the AF_XDP /XDP multi-buffer
support. There are three pieces of code that need to be changed to
achieve this: the Rx path, the Tx path, and the validation logic.

Both the Rx path and Tx could only deal with a single fragment per
packet. The Tx path is extended with a new function called
pkt_nb_frags() that can be used to retrieve the number of fragments a
packet will consume. We then create these many fragments in a loop and
fill the N-1 first ones to the max size limit to use the buffer space
efficiently, and the Nth one with whatever data that is left. This
goes on until we have filled in at the most BATCH_SIZE worth of
descriptors and fragments. If we detect that the next packet would
lead to BATCH_SIZE number of fragments sent being exceeded, we do not
send this packet and finish the batch. This packet is instead sent in
the next iteration of BATCH_SIZE fragments.

For Rx, we loop over all fragments we receive as usual, but for every
descriptor that we receive we call a new validation function called
is_frag_valid() to validate the consistency of this fragment. The code
then checks if the packet continues in the next frame. If so, it loops
over the next packet and performs the same validation. once we have
received the last fragment of the packet we also call the function
is_pkt_valid() to validate the packet as a whole. If we get to the end
of the batch and we are not at the end of the current packet, we back
out the partial packet and end the loop. Once we get into the receive
loop next time, we start over from the beginning of that packet. This
so the code becomes simpler at the cost of some performance.

The validation function is_frag_valid() checks that the sequence and
packet numbers are correct at the start and end of each fragment.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-19-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

show more ...

Merge tag 'v6.4' into next

Sync up with mainline to bring in updates to shared infrastructure.