Adds support for fq's Earliest Departure Time to HBM (Host Bandwidth
Manager). Includes a new BPF program supporting EDT, and also updates
corresponding programs.

It will drop packets with an EDT of more than 500us in the future
unless the packet belongs to a flow with less than 2 packets in flight.
This is done so each flow has at least 2 packets in flight, so they
will not starve, and also to help prevent delayed ACK timeouts.

It will also work with ECN enabled traffic, where the packets will be
CE marked if their EDT is more than 50us in the future.

The table below shows some performance numbers. The flows are back to
back RPCS. One server sending to another, either 2 or 4 flows.
One flow is a 10KB RPC, the rest are 1MB RPCs. When there are more
than one flow of a given RPC size, the numbers represent averages.

The rate limit applies to all flows (they are in the same cgroup).
Tests ending with "-edt" ran with the new BPF program supporting EDT.
Tests ending with "-hbt" ran on top HBT qdisc with the specified rate
(i.e. no HBM). The other tests ran with the HBM BPF program included
in the HBM patch-set.

EDT has limited value when using DCTCP, but it helps in many cases when
using Cubic. It usually achieves larger link utilization and lower
99% latencies for the 1MB RPCs.
HBM ends up queueing a lot of packets with its default parameter values,
reducing the goodput of the 10KB RPCs and increasing their latency. Also,
the RTTs seen by the flows are quite large.

                         Aggr              10K  10K  10K   1MB  1MB  1MB
         Limit           rate drops  RTT  rate  P90  P99  rate  P90  P99
Test      rate  Flows    Mbps   %     us  Mbps   us   us  Mbps   ms   ms
--------  ----  -----    ---- -----  ---  ---- ---- ----  ---- ---- ----
cubic       1G    2       904  0.02  108   257  511  539   647 13.4 24.5
cubic-edt   1G    2       982  0.01  156   239  656  967   743 14.0 17.2
dctcp       1G    2       977  0.00  105   324  408  744   653 14.5 15.9
dctcp-edt   1G    2       981  0.01  142   321  417  811   660 15.7 17.0
cubic-htb   1G    2       919  0.00 1825    40 2822 4140   879  9.7  9.9

cubic     200M    2       155  0.30  220    81  532  655    74  283  450
cubic-edt 200M    2       188  0.02  222    87 1035 1095   101   84   85
dctcp     200M    2       188  0.03  111    77  912  939   111   76  325
dctcp-edt 200M    2       188  0.03  217    74 1416 1738   114   76   79
cubic-htb 200M    2       188  0.00 5015     8 14ms 15ms   180   48   50

cubic       1G    4       952  0.03  110   165  516  546   262   38  154
cubic-edt   1G    4       973  0.01  190   111 1034 1314   287   65   79
dctcp       1G    4       951  0.00  103   180  617  905   257   37   38
dctcp-edt   1G    4       967  0.00  163   151  732 1126   272   43   55
cubic-htb   1G    4       914  0.00 3249    13  7ms  8ms   300   29   34

cubic       5G    4      4236  0.00  134   305  490  624  1310   10   17
cubic-edt   5G    4      4865  0.00  156   306  425  759  1520   10   16
dctcp       5G    4      4936  0.00  128   485  221  409  1484    7    9
dctcp-edt   5G    4      4924  0.00  148   390  392  623  1508   11   26

v1 -> v2: Incorporated Andrii's suggestions
v2 -> v3: Incorporated Yonghong's suggestions
v3 -> v4: Removed credit update that is not needed
Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Based on the following report from Smatch, fix the potential NULL
pointer dereference check:

  tools/lib/bpf/libbpf.c:3493
  bpf_prog_load_xattr() warn: variable dereferenced before check 'attr'
  (see line 3483)

  3479 int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
  3480                         struct bpf_object **pobj, int *prog_fd)
  3481 {
  3482         struct bpf_object_open_attr open_attr = {
  3483                 .file           = attr->file,
  3484                 .prog_type      = attr->prog_type,
                                         ^^^^^^
  3485         };

At the head of function, it directly access 'attr' without checking
if it's NULL pointer. This patch moves the values assignment after
validating 'attr' and 'attr->file'.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

GCC8 started emitting warning about using strncpy with number of bytes
exactly equal destination size, which is generally unsafe, as can lead
to non-zero terminated string being copied. Use IFNAMSIZ - 1 as number
of bytes to ensure name is always zero-terminated.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Cc: Magnus Karlsson <magnus.karlsson@intel.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

When equivalent state is found the current state needs to propagate precision marks.
Otherwise the verifier will prune the search incorrectly.

There is a price for correctness:
                      before      before    broken    fixed
                      cnst spill  precise   precise
bpf_lb-DLB_L3.o       1923        8128      1863      1898
bpf_lb-DLB_L4.o       3077        6707      2468      2666
bpf_lb-DUNKNOWN.o     1062        1062      544       544
bpf_lxc-DDROP_ALL.o   166729      380712    22629     36823
bpf_lxc-DUNKNOWN.o    174607      440652    28805     45325
bpf_netdev.o          8407        31904     6801      7002
bpf_overlay.o         5420        23569     4754      4858
bpf_lxc_jit.o         39389       359445    50925     69631
Overall precision tracking is still very effective.

Fixes: b5dc0163 ("bpf: precise scalar_value tracking")
Reported-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Tested-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Toke Høiland-Jørgensen says:

====================
When using the bpf_redirect_map() helper to redirect packets from XDP, the eBPF
program cannot currently know whether the redirect will succeed, which makes it
impossible to gracefully handle errors. To properly fix this will probably
require deeper changes to the way TX resources are allocated, but one thing that
is fairly straight forward to fix is to allow lookups into devmaps, so programs
can at least know when a redirect is *guaranteed* to fail because there is no
entry in the map. Currently, programs work around this by keeping a shadow map
of another type which indicates whether a map index is valid.

This series contains two changes that are complementary ways to fix this issue:

- Moving the map lookup into the bpf_redirect_map() helper (and caching the
  result), so the helper can return an error if no value is found in the map.
  This includes a refactoring of the devmap and cpumap code to not care about
  the index on enqueue.

- Allowing regular lookups into devmaps from eBPF programs, using the read-only
  flag to make sure they don't change the values.

The performance impact of the series is negligible, in the sense that I cannot
measure it because the variance between test runs is higher than the difference
pre/post series.

Changelog:

v6:
  - Factor out list handling in maps to a helper in list.h (new patch 1)
  - Rename variables in struct bpf_redirect_info (new patch 3 + patch 4)
  - Explain why we are clearing out the map in the info struct on lookup failure
  - Remove unneeded check for forwarding target in tracepoint macro

v5:
  - Rebase on latest bpf-next.
  - Update documentation for bpf_redirect_map() with the new meaning of flags.

v4:
  - Fix a few nits from Andrii
  - Lose the #defines in bpf.h and just compare the flags argument directly to
    XDP_TX in bpf_xdp_redirect_map().

v3:
  - Adopt Jonathan's idea of using the lower two bits of the flag value as the
    return code.
  - Always do the lookup, and cache the result for use in xdp_do_redirect(); to
    achieve this, refactor the devmap and cpumap code to get rid the bitmap for
    selecting which devices to flush.

v2:
  - For patch 1, make it clear that the change works for any map type.
  - For patch 2, just use the new BPF_F_RDONLY_PROG flag to make the return
    value read-only.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

We don't currently allow lookups into a devmap from eBPF, because the map
lookup returns a pointer directly to the dev->ifindex, which shouldn't be
modifiable from eBPF.

However, being able to do lookups in devmaps is useful to know (e.g.)
whether forwarding to a specific interface is enabled. Currently, programs
work around this by keeping a shadow map of another type which indicates
whether a map index is valid.

Since we now have a flag to make maps read-only from the eBPF side, we can
simply lift the lookup restriction if we make sure this flag is always set.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

The bpf_redirect_map() helper used by XDP programs doesn't return any
indication of whether it can successfully redirect to the map index it was
given. Instead, BPF programs have to track this themselves, leading to
programs using duplicate maps to track which entries are populated in the
devmap.

This patch fixes this by moving the map lookup into the bpf_redirect_map()
helper, which makes it possible to return failure to the eBPF program. The
lower bits of the flags argument is used as the return code, which means
that existing users who pass a '0' flag argument will get XDP_ABORTED.

With this, a BPF program can check the return code from the helper call and
react by, for instance, substituting a different redirect. This works for
any type of map used for redirect.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

The bpf_redirect_info struct has an 'ifindex' member which was named back
when the redirects could only target egress interfaces. Now that we can
also redirect to sockets and CPUs, this is a bit misleading, so rename the
member to tgt_index.

Reorder the struct members so we can have 'tgt_index' and 'tgt_value' next
to each other in a subsequent patch.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

The socket map uses a linked list instead of a bitmap to keep track of
which entries to flush. Do the same for devmap and cpumap, as this means we
don't have to care about the map index when enqueueing things into the
map (and so we can cache the map lookup).
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Add a helper in list.h for the non-standard way of clearing a list that is
used in xskmap. This makes it easier to reuse it in the other map types,
and also makes sure this usage is not forgotten in any list refactorings in
the future.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Let's use union with u8[4] and u32 members for sockopt buffer,
that should fix any possible aliasing issues.

test_sockopt_sk.c: In function ‘getsetsockopt’:
test_sockopt_sk.c:115:2: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
  if (*(__u32 *)buf != 0x55AA*2) {
  ^~
test_sockopt_sk.c:116:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
   log_err("Unexpected getsockopt(SO_SNDBUF) 0x%x != 0x55AA*2",
   ^~~~~~~

Fixes: 8a027dc0 ("selftests/bpf: add sockopt test that exercises sk helpers")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Stanislav Fomichev says:

====================
This series implements two new per-cgroup hooks: getsockopt and
setsockopt along with a new sockopt program type. The idea is pretty
similar to recently introduced cgroup sysctl hooks, but
implementation is simpler (no need to convert to/from strings).

What this can be applied to:
* move business logic of what tos/priority/etc can be set by
  containers (either pass or reject)
* handle existing options (or introduce new ones) differently by
  propagating some information in cgroup/socket local storage

Compared to a simple syscall/{g,s}etsockopt tracepoint, those
hooks are context aware. Meaning, they can access underlying socket
and use cgroup and socket local storage.

v9:
* allow overwriting setsocktop arguments (Alexei Starovoitov)
  (see individual changes for more changelog details)
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Support sockopt prog type and cgroup hooks in the bpftool.

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Provide user documentation about sockopt prog type and cgroup hooks.

v9:
* add details about setsockopt context and inheritance

v7:
* add description for retval=0 and optlen=-1

v6:
* describe cgroup chaining, add example

v2:
* use return code 2 for kernel bypass

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

sockopt test that verifies chaining behavior.

v9:
* setsockopt chaining example

v7:
* rework the test to verify cgroup getsockopt chaining

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

socktop test that introduces new SOL_CUSTOM sockopt level and
stores whatever users sets in sk storage. Whenever getsockopt
is called, the original value is retrieved.

v9:
* SO_SNDBUF example to override user-supplied buffer

v7:
* use retval=0 and optlen-1

v6:
* test 'ret=1' use-case as well (Alexei Starovoitov)

v4:
* don't call bpf_sk_fullsock helper

v3:
* drop (__u8 *)(long) casts for optval{,_end}

v2:
* new test

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add sockopt selftests:
* require proper expected_attach_type
* enforce context field read/write access
* test bpf_sockopt_handled handler
* test EPERM
* test limiting optlen from getsockopt
* test out-of-bounds access

v9:
* add tests for setsockopt argument mangling

v7:
* remove return 2; test retval=0 and optlen=-1

v3:
* use DW for optval{,_end} loads

v2:
* use return code 2 for kernel bypass

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add tests that make sure libbpf section detection works.

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Make libbpf aware of new sockopt hooks so it can derive prog type
and hook point from the section names.

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Export new prog type and hook points to the libbpf.

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Implement new BPF_PROG_TYPE_CGROUP_SOCKOPT program type and
BPF_CGROUP_{G,S}ETSOCKOPT cgroup hooks.

BPF_CGROUP_SETSOCKOPT can modify user setsockopt arguments before
passing them down to the kernel or bypass kernel completely.
BPF_CGROUP_GETSOCKOPT can can inspect/modify getsockopt arguments that
kernel returns.
Both hooks reuse existing PTR_TO_PACKET{,_END} infrastructure.

The buffer memory is pre-allocated (because I don't think there is
a precedent for working with __user memory from bpf). This might be
slow to do for each {s,g}etsockopt call, that's why I've added
__cgroup_bpf_prog_array_is_empty that exits early if there is nothing
attached to a cgroup. Note, however, that there is a race between
__cgroup_bpf_prog_array_is_empty and BPF_PROG_RUN_ARRAY where cgroup
program layout might have changed; this should not be a problem
because in general there is a race between multiple calls to
{s,g}etsocktop and user adding/removing bpf progs from a cgroup.

The return code of the BPF program is handled as follows:
* 0: EPERM
* 1: success, continue with next BPF program in the cgroup chain

v9:
* allow overwriting setsockopt arguments (Alexei Starovoitov):
  * use set_fs (same as kernel_setsockopt)
  * buffer is always kzalloc'd (no small on-stack buffer)

v8:
* use s32 for optlen (Andrii Nakryiko)

v7:
* return only 0 or 1 (Alexei Starovoitov)
* always run all progs (Alexei Starovoitov)
* use optval=0 as kernel bypass in setsockopt (Alexei Starovoitov)
  (decided to use optval=-1 instead, optval=0 might be a valid input)
* call getsockopt hook after kernel handlers (Alexei Starovoitov)

v6:
* rework cgroup chaining; stop as soon as bpf program returns
  0 or 2; see patch with the documentation for the details
* drop Andrii's and Martin's Acked-by (not sure they are comfortable
  with the new state of things)

v5:
* skip copy_to_user() and put_user() when ret == 0 (Martin Lau)

v4:
* don't export bpf_sk_fullsock helper (Martin Lau)
* size != sizeof(__u64) for uapi pointers (Martin Lau)
* offsetof instead of bpf_ctx_range when checking ctx access (Martin Lau)

v3:
* typos in BPF_PROG_CGROUP_SOCKOPT_RUN_ARRAY comments (Andrii Nakryiko)
* reverse christmas tree in BPF_PROG_CGROUP_SOCKOPT_RUN_ARRAY (Andrii
  Nakryiko)
* use __bpf_md_ptr instead of __u32 for optval{,_end} (Martin Lau)
* use BPF_FIELD_SIZEOF() for consistency (Martin Lau)
* new CG_SOCKOPT_ACCESS macro to wrap repeated parts

v2:
* moved bpf_sockopt_kern fields around to remove a hole (Martin Lau)
* aligned bpf_sockopt_kern->buf to 8 bytes (Martin Lau)
* bpf_prog_array_is_empty instead of bpf_prog_array_length (Martin Lau)
* added [0,2] return code check to verifier (Martin Lau)
* dropped unused buf[64] from the stack (Martin Lau)
* use PTR_TO_SOCKET for bpf_sockopt->sk (Martin Lau)
* dropped bpf_target_off from ctx rewrites (Martin Lau)
* use return code for kernel bypass (Martin Lau & Andrii Nakryiko)

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Tariq Toukan says:

====================
This series contains improvements to the AF_XDP kernel infrastructure
and AF_XDP support in mlx5e. The infrastructure improvements are
required for mlx5e, but also some of them benefit to all drivers, and
some can be useful for other drivers that want to implement AF_XDP.

The performance testing was performed on a machine with the following
configuration:

- 24 cores of Intel Xeon E5-2620 v3 @ 2.40 GHz
- Mellanox ConnectX-5 Ex with 100 Gbit/s link

The results with retpoline disabled, single stream:

txonly: 33.3 Mpps (21.5 Mpps with queue and app pinned to the same CPU)
rxdrop: 12.2 Mpps
l2fwd: 9.4 Mpps

The results with retpoline enabled, single stream:

txonly: 21.3 Mpps (14.1 Mpps with queue and app pinned to the same CPU)
rxdrop: 9.9 Mpps
l2fwd: 6.8 Mpps

v2 changes:

Added patches for mlx5e and addressed the comments for v1. Rebased for
bpf-next.

v3 changes:

Rebased for the newer bpf-next, resolved conflicts in libbpf. Addressed
Björn's comments for coding style. Fixed a bug in error handling flow in
mlx5e_open_xsk.

v4 changes:

UAPI is not changed, XSK RX queues are exposed to the kernel. The lower
half of the available amount of RX queues are regular queues, and the
upper half are XSK RX queues. The patch "xsk: Extend channels to support
combined XSK/non-XSK traffic" was dropped. The final patch was reworked
accordingly.

Added "net/mlx5e: Attach/detach XDP program safely", as the changes
introduced in the XSK patch base on the stuff from this one.

Added "libbpf: Support drivers with non-combined channels", which aligns
the condition in libbpf with the condition in the kernel.

Rebased over the newer bpf-next.

v5 changes:

In v4, ethtool reports the number of channels as 'combined' and the
number of XSK RX queues as 'rx' for mlx5e. It was changed, so that 'rx'
is 0, and 'combined' reports the double amount of channels if there is
an active UMEM - to make libbpf happy.

The patch for libbpf was dropped. Although it's still useful and fixes
things, it raises some disagreement, so I'm dropping it - it's no longer
useful for mlx5e anymore after the change above.

v6 changes:

As Maxim is out of office, I rebased the series on behalf of him,
solved some conflicts, and re-spinned.
====================
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Tested-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

This commit adds support for AF_XDP zero-copy RX and TX.

We create a dedicated XSK RQ inside the channel, it means that two
RQs are running simultaneously: one for non-XSK traffic and the other
for XSK traffic. The regular and XSK RQs use a single ID namespace split
into two halves: the lower half is regular RQs, and the upper half is
XSK RQs. When any zero-copy AF_XDP socket is active, changing the number
of channels is not allowed, because it would break to mapping between
XSK RQ IDs and channels.

XSK requires different page allocation and release routines. Such
functions as mlx5e_{alloc,free}_rx_mpwqe and mlx5e_{get,put}_rx_frag are
generic enough to be used for both regular and XSK RQs, and they use the
mlx5e_page_{alloc,release} wrappers around the real allocation
functions. Function pointers are not used to avoid losing the
performance with retpolines. Wherever it's certain that the regular
(non-XSK) page release function should be used, it's called directly.

Only the stats that could be meaningful for XSK are exposed to the
userspace. Those that don't take part in the XSK flow are not
considered.

Note that we don't wait for WQEs on the XSK RQ (unlike the regular RQ),
because the newer xdpsock sample doesn't provide any Fill Ring entries
at the setup stage.

We create a dedicated XSK SQ in the channel. This separation has its
advantages:

1. When the UMEM is closed, the XSK SQ can also be closed and stop
receiving completions. If an existing SQ was used for XSK, it would
continue receiving completions for the packets of the closed socket. If
a new UMEM was opened at that point, it would start getting completions
that don't belong to it.

2. Calculating statistics separately.

When the userspace kicks the TX, the driver triggers a hardware
interrupt by posting a NOP to a dedicated XSK ICO (internal control
operations) SQ, in order to trigger NAPI on the right CPU core. This XSK
ICO SQ is protected by a spinlock, as the userspace application may kick
the TX from any core.

Store the pointers to the UMEMs in the net device private context,
independently from the kernel. This way the driver can distinguish
between the zero-copy and non-zero-copy UMEMs. The kernel function
xdp_get_umem_from_qid does not care about this difference, but the
driver is only interested in zero-copy UMEMs, particularly, on the
cleanup it determines whether to close the XSK RQ and SQ or not by
looking at the presence of the UMEM. Use state_lock to protect the
access to this area of UMEM pointers.

LRO isn't compatible with XDP, but there may be active UMEMs while
XDP is off. If this is the case, don't allow LRO to ensure XDP can
be reenabled at any time.

The validation of XSK parameters typically happens when XSK queues
open. However, when the interface is down or the XDP program isn't
set, it's still possible to have active AF_XDP sockets and even to
open new, but the XSK queues will be closed. To cover these cases,
perform the validation also in these flows:

1. A new UMEM is registered, but the XSK queues aren't going to be
created due to missing XDP program or interface being down.

2. MTU changes while there are UMEMs registered.

Having this early check prevents mlx5e_open_channels from failing
at a later stage, where recovery is impossible and the application
has no chance to handle the error, because it got the successful
return value for an MTU change or XSK open operation.

The performance testing was performed on a machine with the following
configuration:

- 24 cores of Intel Xeon E5-2620 v3 @ 2.40 GHz
- Mellanox ConnectX-5 Ex with 100 Gbit/s link

The results with retpoline disabled, single stream:

txonly: 33.3 Mpps (21.5 Mpps with queue and app pinned to the same CPU)
rxdrop: 12.2 Mpps
l2fwd: 9.4 Mpps

The results with retpoline enabled, single stream:

txonly: 21.3 Mpps (14.1 Mpps with queue and app pinned to the same CPU)
rxdrop: 9.9 Mpps
l2fwd: 6.8 Mpps
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

structs mlx5e_{rq,sq,cq,channel}_param are going to be used in the
upcoming XSK RX and TX patches. Move them to a header file to make
them accessible from other C files.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Create new functions mlx5e_{open,close}_queues to encapsulate opening
and closing RQs and SQs, and call the new functions from
mlx5e_{open,close}_channel. It simplifies the existing functions a bit
and prepares them for the upcoming AF_XDP changes.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Use the existing mlx5e_get_linear_rq_headroom function to calculate the
headroom for mlx5e_xdp_max_mtu. This function takes the XSK headroom
into consideration, which will be used in the following patches.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

When an XDP program returns XDP_TX, and the RQ is XSK-enabled, it
requires careful handling, because convert_to_xdp_frame creates a new
page and copies the data there, while our driver expects the xdp_frame
to point to the same memory as the xdp_buff. Handle this case
separately: map the page, and in the end unmap it and call
xdp_return_frame.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Put the XDP SQ that is used for XDP_TX into the channel. It used to be a
part of the RQ, but with introduction of AF_XDP there will be one more
RQ that could share the same XDP SQ. This patch is a preparation for
that change.

Separate XDP_TX statistics per RQ were implemented in one of the previous
patches.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Currently, struct mlx5e_xdp_info has some issues that have to be cleaned
up before the upcoming AF_XDP support makes things too complicated and
messy. This structure is used both when sending the packet and on
completion. Moreover, the cleanup procedure on completion depends on the
origin of the packet (XDP_REDIRECT, XDP_TX). Adding AF_XDP support will
add new flows that use this structure even differently. To avoid
overcomplicating the code, this commit refactors the usage of this
structure in the following ways:

1. struct mlx5e_xdp_info is split into two different structures. One is
struct mlx5e_xdp_xmit_data, a transient structure that doesn't need to
be stored and is only used while sending the packet. The other is still
struct mlx5e_xdp_info that is stored in a FIFO and contains the fields
needed on completion.

2. The fields of struct mlx5e_xdp_info that are used in different flows
are put into a union. A special enum indicates the cleanup mode and
helps choose the right union member. This approach is clear and
explicit. Although it could be possible to "guess" the mode by looking
at the values of the fields and at the XDP SQ type, it wouldn't be that
clear and extendable and would require looking through the whole chain
to understand what's going on.

For the reference, there are the fields of struct mlx5e_xdp_info that
are used in different flows (including AF_XDP ones):

Packet origin          | Fields used on completion | Cleanup steps
-----------------------+---------------------------+------------------
XDP_REDIRECT,          | xdpf, dma_addr            | DMA unmap and
XDP_TX from XSK RQ     |                           | xdp_return_frame.
-----------------------+---------------------------+------------------
XDP_TX from regular RQ | di                        | Recycle page.
-----------------------+---------------------------+------------------
AF_XDP TX              | (none)                    | Increment the
                       |                           | producer index in
                       |                           | Completion Ring.

On send, the same set of mlx5e_xdp_xmit_data fields is used in all
flows: DMA and virtual addresses and length.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Prepare to creation of the XSK RQ, which will require posting UMRs, too.
The same ICO SQ will be used for both RQs and also to trigger interrupts
by posting NOPs. UMR WQEs can't be reused any more. Optimization
introduced in commit ab966d7e ("net/mlx5e: RX, Recycle buffer of
UMR WQEs") is reverted.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Additional conditions introduced:

- XSK implies XDP.
- Headroom includes the XSK headroom if it exists.
- No space is reserved for struct shared_skb_info in XSK mode.
- Fragment size smaller than the XSK chunk size is not allowed.

A new auxiliary function mlx5e_get_linear_rq_headroom with the support
for XSK is introduced. Use this function in the implementation of
mlx5e_get_rq_headroom. Change headroom to u32 to match the headroom
field in struct xdp_umem.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

The PCI API for DMA is deprecated, and PCI_DMA_TODEVICE is just defined
to DMA_TO_DEVICE for backward compatibility. Just use DMA_TO_DEVICE.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Some drivers want to access the data transmitted in order to implement
acceleration features of the NICs. It is also useful in AF_XDP TX flow.

Change the xsk_umem_consume_tx API to return the whole xdp_desc, that
contains the data pointer, length and DMA address, instead of only the
latter two. Adapt the implementation of i40e and ixgbe to this change.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Cc: Björn Töpel <bjorn.topel@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@intel.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

The typical XDP memory scheme is one packet per page. Change the AF_XDP
frame size in libbpf to 4096, which is the page size on x86, to allow
libbpf to be used with the drivers with the packet-per-page scheme.

Add a command line option -f to xdpsock to allow to specify a custom
frame size.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Query XDP_OPTIONS in libbpf to determine if the zero-copy mode is active
or not.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Make it possible for the application to determine whether the AF_XDP
socket is running in zero-copy mode. To achieve this, add a new
getsockopt option XDP_OPTIONS that returns flags. The only flag
supported for now is the zero-copy mode indicator.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Add a function that checks whether the Fill Ring has the specified
amount of descriptors available. It will be useful for mlx5e that wants
to check in advance, whether it can allocate a bulk of RX descriptors,
to get the best performance.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

When an XDP program is set, a full reopen of all channels happens in two
cases:

1. When there was no program set, and a new one is being set.

2. When there was a program set, but it's being unset.

The full reopen is necessary, because the channel parameters may change
if XDP is enabled or disabled. However, it's performed in an unsafe way:
if the new channels fail to open, the old ones are already closed, and
the interface goes down. Use the safe way to switch channels instead.
The same way is already used for other configuration changes.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Since commit 4bfc0bb2 ("bpf: decouple the lifetime of cgroup_bpf
from cgroup itself"), cgroup_bpf release occurs asynchronously
(from a worker context), and before the release of the cgroup itself.

This introduced a previously non-existing race between the release
and update paths. E.g. if a leaf's cgroup_bpf is released and a new
bpf program is attached to the one of ancestor cgroups at the same
time. The race may result in double-free and other memory corruptions.

To fix the problem, let's protect the body of cgroup_bpf_release()
with cgroup_mutex, as it was effectively previously, when all this
code was called from the cgroup release path with cgroup mutex held.

Also let's skip cgroups, which have no chances to invoke a bpf
program, on the update path. If the cgroup bpf refcnt reached 0,
it means that the cgroup is offline (no attached processes), and
there are no associated sockets left. It means there is no point
in updating effective progs array! And it can lead to a leak,
if it happens after the release. So, let's skip such cgroups.

Big thanks for Tejun Heo for discovering and debugging of this problem!

Fixes: 4bfc0bb2 ("bpf: decouple the lifetime of cgroup_bpf from cgroup itself")
Reported-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Fix sparse warning:

net/core/xdp.c:88:6: warning:
 symbol '__mem_id_disconnect' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>