From: "Björn Töpel" <bjorn.topel@intel.com>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: maciej.fijalkowski@intel.com, hawk@kernel.org, toke@redhat.com,
magnus.karlsson@intel.com, john.fastabend@gmail.com,
kuba@kernel.org, davem@davemloft.net,
"Björn Töpel" <bjorn.topel@gmail.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org, ast@kernel.org
Subject: Re: [PATCH bpf-next v4 1/2] bpf, xdp: make bpf_redirect_map() a map operation
Date: Sat, 27 Feb 2021 10:04:40 +0100 [thread overview]
Message-ID: <69b51d70-a885-d39a-cff3-92e8ef703a20@intel.com> (raw)
In-Reply-To: <c36e681a-673d-d0d2-816a-e8f2c8ef5df7@iogearbox.net>
On 2021-02-26 22:48, Daniel Borkmann wrote:
> On 2/26/21 12:23 PM, Björn Töpel wrote:
>> From: Björn Töpel <bjorn.topel@intel.com>
>>
>> Currently the bpf_redirect_map() implementation dispatches to the
>> correct map-lookup function via a switch-statement. To avoid the
>> dispatching, this change adds bpf_redirect_map() as a map
>> operation. Each map provides its bpf_redirect_map() version, and
>> correct function is automatically selected by the BPF verifier.
>>
>> A nice side-effect of the code movement is that the map lookup
>> functions are now local to the map implementation files, which removes
>> one additional function call.
>>
>> Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
>> ---
>> include/linux/bpf.h | 26 ++++++--------------------
>> include/linux/filter.h | 27 +++++++++++++++++++++++++++
>> include/net/xdp_sock.h | 19 -------------------
>> kernel/bpf/cpumap.c | 8 +++++++-
>> kernel/bpf/devmap.c | 16 ++++++++++++++--
>> kernel/bpf/verifier.c | 11 +++++++++--
>> net/core/filter.c | 39 +--------------------------------------
>> net/xdp/xskmap.c | 18 ++++++++++++++++++
>> 8 files changed, 82 insertions(+), 82 deletions(-)
>>
>> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
>> index cccaef1088ea..a44ba904ca37 100644
>> --- a/include/linux/bpf.h
>> +++ b/include/linux/bpf.h
>> @@ -117,6 +117,9 @@ struct bpf_map_ops {
>> void *owner, u32 size);
>> struct bpf_local_storage __rcu ** (*map_owner_storage_ptr)(void
>> *owner);
>> + /* XDP helpers.*/
>> + int (*xdp_redirect_map)(struct bpf_map *map, u32 ifindex, u64
>> flags);
>> +
>> /* map_meta_equal must be implemented for maps that can be
>> * used as an inner map. It is a runtime check to ensure
>> * an inner map can be inserted to an outer map.
> [...]
>> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
>> index 1dda9d81f12c..96705a49225e 100644
>> --- a/kernel/bpf/verifier.c
>> +++ b/kernel/bpf/verifier.c
>> @@ -5409,7 +5409,8 @@ record_func_map(struct bpf_verifier_env *env,
>> struct bpf_call_arg_meta *meta,
>> func_id != BPF_FUNC_map_delete_elem &&
>> func_id != BPF_FUNC_map_push_elem &&
>> func_id != BPF_FUNC_map_pop_elem &&
>> - func_id != BPF_FUNC_map_peek_elem)
>> + func_id != BPF_FUNC_map_peek_elem &&
>> + func_id != BPF_FUNC_redirect_map)
>> return 0;
>> if (map == NULL) {
>> @@ -11762,7 +11763,8 @@ static int fixup_bpf_calls(struct
>> bpf_verifier_env *env)
>> insn->imm == BPF_FUNC_map_delete_elem ||
>> insn->imm == BPF_FUNC_map_push_elem ||
>> insn->imm == BPF_FUNC_map_pop_elem ||
>> - insn->imm == BPF_FUNC_map_peek_elem)) {
>> + insn->imm == BPF_FUNC_map_peek_elem ||
>> + insn->imm == BPF_FUNC_redirect_map)) {
>> aux = &env->insn_aux_data[i + delta];
>> if (bpf_map_ptr_poisoned(aux))
>> goto patch_call_imm;
>> @@ -11804,6 +11806,8 @@ static int fixup_bpf_calls(struct
>> bpf_verifier_env *env)
>> (int (*)(struct bpf_map *map, void *value))NULL));
>> BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
>> (int (*)(struct bpf_map *map, void *value))NULL));
>> + BUILD_BUG_ON(!__same_type(ops->xdp_redirect_map,
>> + (int (*)(struct bpf_map *map, u32 ifindex, u64
>> flags))NULL));
>> patch_map_ops_generic:
>> switch (insn->imm) {
>> case BPF_FUNC_map_lookup_elem:
>> @@ -11830,6 +11834,9 @@ static int fixup_bpf_calls(struct
>> bpf_verifier_env *env)
>> insn->imm = BPF_CAST_CALL(ops->map_peek_elem) -
>> __bpf_call_base;
>> continue;
>> + case BPF_FUNC_redirect_map:
>> + insn->imm = BPF_CAST_CALL(ops->xdp_redirect_map) -
>> __bpf_call_base;
>
> Small nit: I would name the generic callback ops->map_redirect so that
> this is in line with
> the general naming convention for the map ops. Otherwise this looks much
> better, thx!
>
I'll respin! Thanks for the input!
I'll ignore the BPF_CAST_CALL W=1 warnings ([-Wcast-function-type]), or
do you have any thoughts on that? I don't think it's a good idea to
silence that warning for the whole verifier.c
Björn
>> + continue;
>> }
>> goto patch_call_imm;
next prev parent reply other threads:[~2021-02-27 9:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 11:23 [PATCH bpf-next v4 0/2] Optimize bpf_redirect_map()/xdp_do_redirect() Björn Töpel
2021-02-26 11:23 ` [PATCH bpf-next v4 1/2] bpf, xdp: make bpf_redirect_map() a map operation Björn Töpel
2021-02-26 11:37 ` Toke Høiland-Jørgensen
2021-02-26 11:40 ` Björn Töpel
2021-02-26 12:04 ` Björn Töpel
2021-02-26 12:26 ` Toke Høiland-Jørgensen
2021-02-26 14:28 ` Jesper Dangaard Brouer
2021-02-26 14:27 ` Jesper Dangaard Brouer
2021-02-26 14:29 ` Jesper Dangaard Brouer
2021-02-26 15:23 ` kernel test robot
2021-02-26 21:48 ` Daniel Borkmann
2021-02-27 9:04 ` Björn Töpel [this message]
2021-02-27 10:22 ` Daniel Borkmann
2021-02-26 11:23 ` [PATCH bpf-next v4 2/2] bpf, xdp: restructure redirect actions Björn Töpel
2021-02-26 11:35 ` [PATCH bpf-next v4 0/2] Optimize bpf_redirect_map()/xdp_do_redirect() Toke Høiland-Jørgensen
2021-02-26 11:38 ` Björn Töpel
2021-02-26 11:43 ` Toke Høiland-Jørgensen
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