RE: [PATCH v6 0/9] bpf: JIT related bug fixes

[Marat Khalili <marat.khalili@huawei.com>]

> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: Thursday 25 June 2026 18:30
> To: dev@dpdk.org
> Cc: Stephen Hemminger <stephen@networkplumber.org>
> Subject: [PATCH v6 0/9] bpf: JIT related bug fixes
> 
> While implementing JIT for packet capture ran into several issues:
>   1. x86 JIT had a pre-existing bug which would crash.
>   2. The arm64 JIT was missing the packet-access instructions, found
>      previously [1].
>   3. Shift counts were not masked to the operand width as RFC 9669
>      requires: undefined behavior in the interpreter and an encoding
>      failure in the arm64 JIT.
>   4. Tests related to JIT were not being run or were missing coverage.
> 
> Fixed all of these. Patches are ordered with the most urgent fix (the
> x86 crash) first, each fix followed by the test that exercises it. The
> arm64 packet-load support is kept ahead of the "check JIT was generated"
> patch so the series bisects cleanly on arm64.
> 
> The arm64 epilogue branch fix (patch 6) was originally posted by
> Christophe Fontaine [1]; that series stalled, so it is carried here with
> his authorship.
> 
> [1] https://inbox.dpdk.org/dev/20260319114500.9757-2-cfontain@redhat.com/
> 
> v6:
>  - address Marat's review ARM64 JIT of LD IND instructions
>    need to handle offsets outside of 32 bit range.
> 
> 
> Christophe Fontaine (1):
>   bpf/arm64: fix offset type to allow a negative jump
> 
> Stephen Hemminger (8):
>   bpf/x86: fix JIT encoding of fixed-width immediates
>   test/bpf: add JSET test with small immediate
>   bpf: mask shift count in interpreter per RFC 9669
>   bpf/arm64: mask shift count per RFC 9669
>   test/bpf: add test for large shift
>   bpf/arm64: add BPF_ABS/BPF_IND packet load support
>   test/bpf: check that JIT was generated
>   test/bpf: check that bpf_convert can be JIT'd
> 
>  app/test/test_bpf.c     | 320 +++++++++++++++++++++++++++++++---------
>  lib/bpf/bpf_exec.c      |  31 ++--
>  lib/bpf/bpf_jit_arm64.c | 185 ++++++++++++++++++++++-
>  lib/bpf/bpf_jit_x86.c   |   6 +-
>  lib/bpf/meson.build     |   2 +
>  5 files changed, 456 insertions(+), 88 deletions(-)
> 
> --
> 2.53.0

Series-tested-by: Marat Khalili <marat.khalili@huawei.com>

(Maybe it actually deserves a release note at this point?)