* [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together
@ 2023-09-14 8:37 Larysa Zaremba
2023-09-14 16:29 ` Stanislav Fomichev
2023-09-14 16:38 ` Maciej Fijalkowski
0 siblings, 2 replies; 7+ messages in thread
From: Larysa Zaremba @ 2023-09-14 8:37 UTC (permalink / raw)
To: bpf
Cc: Larysa Zaremba, Alexei Starovoitov, Daniel Borkmann,
Andrii Nakryiko, Martin KaFai Lau, Song Liu, Yonghong Song,
John Fastabend, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
linux-kernel
There is no fundamental reason, why multi-buffer XDP and XDP kfunc RX hints
cannot coexist in a single program.
Allow those features to be used together by modifying the flags conditions.
Suggested-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/CAKH8qBuzgtJj=OKMdsxEkyML36VsAuZpcrsXcyqjdKXSJCBq=Q@mail.gmail.com/
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
---
kernel/bpf/offload.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index ee35f33a96d1..43aded96c79b 100644
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -232,7 +232,11 @@ int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
attr->prog_type != BPF_PROG_TYPE_XDP)
return -EINVAL;
- if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY)
+ if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
+ return -EINVAL;
+
+ if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS &&
+ !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY))
return -EINVAL;
if (attr->prog_type == BPF_PROG_TYPE_SCHED_CLS &&
--
2.41.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together
2023-09-14 8:37 [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together Larysa Zaremba
@ 2023-09-14 16:29 ` Stanislav Fomichev
2023-09-14 16:49 ` Larysa Zaremba
2023-09-14 16:38 ` Maciej Fijalkowski
1 sibling, 1 reply; 7+ messages in thread
From: Stanislav Fomichev @ 2023-09-14 16:29 UTC (permalink / raw)
To: Larysa Zaremba
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, Hao Luo, Jiri Olsa, linux-kernel
On 09/14, Larysa Zaremba wrote:
> There is no fundamental reason, why multi-buffer XDP and XDP kfunc RX hints
> cannot coexist in a single program.
>
> Allow those features to be used together by modifying the flags conditions.
>
> Suggested-by: Stanislav Fomichev <sdf@google.com>
> Link: https://lore.kernel.org/bpf/CAKH8qBuzgtJj=OKMdsxEkyML36VsAuZpcrsXcyqjdKXSJCBq=Q@mail.gmail.com/
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
> ---
> kernel/bpf/offload.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
> index ee35f33a96d1..43aded96c79b 100644
> --- a/kernel/bpf/offload.c
> +++ b/kernel/bpf/offload.c
> @@ -232,7 +232,11 @@ int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
> attr->prog_type != BPF_PROG_TYPE_XDP)
> return -EINVAL;
>
> - if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY)
> + if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
> + return -EINVAL;
> +
[..]
> + if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS &&
> + !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY))
> return -EINVAL;
Any reason we have 'attr->prog_flags & BPF_F_XDP_HAS_FRAGS' part here?
Seems like doing '!(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY)' should
be enough, right? We only want to bail out here when BPF_F_XDP_DEV_BOUND_ONLY
is not set and we don't really care whether BPF_F_XDP_HAS_FRAGS is set
or not at this point.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together
2023-09-14 8:37 [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together Larysa Zaremba
2023-09-14 16:29 ` Stanislav Fomichev
@ 2023-09-14 16:38 ` Maciej Fijalkowski
2023-09-14 16:53 ` Larysa Zaremba
1 sibling, 1 reply; 7+ messages in thread
From: Maciej Fijalkowski @ 2023-09-14 16:38 UTC (permalink / raw)
To: Larysa Zaremba
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa, linux-kernel
On Thu, Sep 14, 2023 at 10:37:11AM +0200, Larysa Zaremba wrote:
> There is no fundamental reason, why multi-buffer XDP and XDP kfunc RX hints
> cannot coexist in a single program.
>
> Allow those features to be used together by modifying the flags conditions.
>
> Suggested-by: Stanislav Fomichev <sdf@google.com>
> Link: https://lore.kernel.org/bpf/CAKH8qBuzgtJj=OKMdsxEkyML36VsAuZpcrsXcyqjdKXSJCBq=Q@mail.gmail.com/
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Though it would be worth spelling out something in the commit msg about
additional check you're adding (frags flag can't go without dev bound)
> ---
> kernel/bpf/offload.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
> index ee35f33a96d1..43aded96c79b 100644
> --- a/kernel/bpf/offload.c
> +++ b/kernel/bpf/offload.c
> @@ -232,7 +232,11 @@ int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
> attr->prog_type != BPF_PROG_TYPE_XDP)
> return -EINVAL;
>
> - if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY)
> + if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
> + return -EINVAL;
> +
> + if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS &&
> + !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY))
> return -EINVAL;
>
> if (attr->prog_type == BPF_PROG_TYPE_SCHED_CLS &&
> --
> 2.41.0
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together
2023-09-14 16:29 ` Stanislav Fomichev
@ 2023-09-14 16:49 ` Larysa Zaremba
2023-09-14 17:05 ` Stanislav Fomichev
0 siblings, 1 reply; 7+ messages in thread
From: Larysa Zaremba @ 2023-09-14 16:49 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, Hao Luo, Jiri Olsa, linux-kernel
On Thu, Sep 14, 2023 at 09:29:57AM -0700, Stanislav Fomichev wrote:
> On 09/14, Larysa Zaremba wrote:
> > There is no fundamental reason, why multi-buffer XDP and XDP kfunc RX hints
> > cannot coexist in a single program.
> >
> > Allow those features to be used together by modifying the flags conditions.
> >
> > Suggested-by: Stanislav Fomichev <sdf@google.com>
> > Link: https://lore.kernel.org/bpf/CAKH8qBuzgtJj=OKMdsxEkyML36VsAuZpcrsXcyqjdKXSJCBq=Q@mail.gmail.com/
> > Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
> > ---
> > kernel/bpf/offload.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
> > index ee35f33a96d1..43aded96c79b 100644
> > --- a/kernel/bpf/offload.c
> > +++ b/kernel/bpf/offload.c
> > @@ -232,7 +232,11 @@ int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
> > attr->prog_type != BPF_PROG_TYPE_XDP)
> > return -EINVAL;
> >
> > - if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY)
> > + if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
> > + return -EINVAL;
> > +
>
> [..]
>
> > + if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS &&
> > + !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY))
> > return -EINVAL;
>
> Any reason we have 'attr->prog_flags & BPF_F_XDP_HAS_FRAGS' part here?
> Seems like doing '!(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY)' should
> be enough, right? We only want to bail out here when BPF_F_XDP_DEV_BOUND_ONLY
> is not set and we don't really care whether BPF_F_XDP_HAS_FRAGS is set
> or not at this point.
If !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY) at this point, program could
be requesting offload.
Now I have thought about those conditions once more and they could be reduced to
this:
if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY) &&
attr->prog_flags != (BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
return -EINVAL;
What do you think?
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together
2023-09-14 16:38 ` Maciej Fijalkowski
@ 2023-09-14 16:53 ` Larysa Zaremba
0 siblings, 0 replies; 7+ messages in thread
From: Larysa Zaremba @ 2023-09-14 16:53 UTC (permalink / raw)
To: Maciej Fijalkowski
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa, linux-kernel
On Thu, Sep 14, 2023 at 06:38:15PM +0200, Maciej Fijalkowski wrote:
> On Thu, Sep 14, 2023 at 10:37:11AM +0200, Larysa Zaremba wrote:
> > There is no fundamental reason, why multi-buffer XDP and XDP kfunc RX hints
> > cannot coexist in a single program.
> >
> > Allow those features to be used together by modifying the flags conditions.
> >
> > Suggested-by: Stanislav Fomichev <sdf@google.com>
> > Link: https://lore.kernel.org/bpf/CAKH8qBuzgtJj=OKMdsxEkyML36VsAuZpcrsXcyqjdKXSJCBq=Q@mail.gmail.com/
> > Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
>
> Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
>
> Though it would be worth spelling out something in the commit msg about
> additional check you're adding (frags flag can't go without dev bound)
>
Ok, I'll add to the commit message the below:
Frags are allowed only if program is dev-bound-only, but not if it is requesting
bpf offload.
> > ---
> > kernel/bpf/offload.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
> > index ee35f33a96d1..43aded96c79b 100644
> > --- a/kernel/bpf/offload.c
> > +++ b/kernel/bpf/offload.c
> > @@ -232,7 +232,11 @@ int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
> > attr->prog_type != BPF_PROG_TYPE_XDP)
> > return -EINVAL;
> >
> > - if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY)
> > + if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
> > + return -EINVAL;
> > +
> > + if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS &&
> > + !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY))
> > return -EINVAL;
> >
> > if (attr->prog_type == BPF_PROG_TYPE_SCHED_CLS &&
> > --
> > 2.41.0
> >
> >
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together
2023-09-14 17:05 ` Stanislav Fomichev
@ 2023-09-14 17:04 ` Larysa Zaremba
0 siblings, 0 replies; 7+ messages in thread
From: Larysa Zaremba @ 2023-09-14 17:04 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, Hao Luo, Jiri Olsa, linux-kernel
On Thu, Sep 14, 2023 at 10:05:47AM -0700, Stanislav Fomichev wrote:
> On Thu, Sep 14, 2023 at 9:55 AM Larysa Zaremba <larysa.zaremba@intel.com> wrote:
> >
> > On Thu, Sep 14, 2023 at 09:29:57AM -0700, Stanislav Fomichev wrote:
> > > On 09/14, Larysa Zaremba wrote:
> > > > There is no fundamental reason, why multi-buffer XDP and XDP kfunc RX hints
> > > > cannot coexist in a single program.
> > > >
> > > > Allow those features to be used together by modifying the flags conditions.
> > > >
> > > > Suggested-by: Stanislav Fomichev <sdf@google.com>
> > > > Link: https://lore.kernel.org/bpf/CAKH8qBuzgtJj=OKMdsxEkyML36VsAuZpcrsXcyqjdKXSJCBq=Q@mail.gmail.com/
> > > > Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
> > > > ---
> > > > kernel/bpf/offload.c | 6 +++++-
> > > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
> > > > index ee35f33a96d1..43aded96c79b 100644
> > > > --- a/kernel/bpf/offload.c
> > > > +++ b/kernel/bpf/offload.c
> > > > @@ -232,7 +232,11 @@ int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
> > > > attr->prog_type != BPF_PROG_TYPE_XDP)
> > > > return -EINVAL;
> > > >
> > > > - if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY)
> > > > + if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
> > > > + return -EINVAL;
> > > > +
> > >
> > > [..]
> > >
> > > > + if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS &&
> > > > + !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY))
> > > > return -EINVAL;
> > >
> > > Any reason we have 'attr->prog_flags & BPF_F_XDP_HAS_FRAGS' part here?
> > > Seems like doing '!(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY)' should
> > > be enough, right? We only want to bail out here when BPF_F_XDP_DEV_BOUND_ONLY
> > > is not set and we don't really care whether BPF_F_XDP_HAS_FRAGS is set
> > > or not at this point.
> >
> > If !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY) at this point, program could
> > be requesting offload.
> >
> > Now I have thought about those conditions once more and they could be reduced to
> > this:
> >
> > if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY) &&
> > attr->prog_flags != (BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
> > return -EINVAL;
> >
> > What do you think?
>
> Ah, so this check is here to protect against the mbuf+offloaded
> combination? (looking at that other thread with Maciej)
> Let's keep your current way with two separate checks, but let's add
> your "/* Frags are allowed only if program is dev-bound-only, but not
> if it is requesting
> bpf offload. */" as a comment to the second check?
Ok, sound good to me.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together
2023-09-14 16:49 ` Larysa Zaremba
@ 2023-09-14 17:05 ` Stanislav Fomichev
2023-09-14 17:04 ` Larysa Zaremba
0 siblings, 1 reply; 7+ messages in thread
From: Stanislav Fomichev @ 2023-09-14 17:05 UTC (permalink / raw)
To: Larysa Zaremba
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, Hao Luo, Jiri Olsa, linux-kernel
On Thu, Sep 14, 2023 at 9:55 AM Larysa Zaremba <larysa.zaremba@intel.com> wrote:
>
> On Thu, Sep 14, 2023 at 09:29:57AM -0700, Stanislav Fomichev wrote:
> > On 09/14, Larysa Zaremba wrote:
> > > There is no fundamental reason, why multi-buffer XDP and XDP kfunc RX hints
> > > cannot coexist in a single program.
> > >
> > > Allow those features to be used together by modifying the flags conditions.
> > >
> > > Suggested-by: Stanislav Fomichev <sdf@google.com>
> > > Link: https://lore.kernel.org/bpf/CAKH8qBuzgtJj=OKMdsxEkyML36VsAuZpcrsXcyqjdKXSJCBq=Q@mail.gmail.com/
> > > Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
> > > ---
> > > kernel/bpf/offload.c | 6 +++++-
> > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
> > > index ee35f33a96d1..43aded96c79b 100644
> > > --- a/kernel/bpf/offload.c
> > > +++ b/kernel/bpf/offload.c
> > > @@ -232,7 +232,11 @@ int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
> > > attr->prog_type != BPF_PROG_TYPE_XDP)
> > > return -EINVAL;
> > >
> > > - if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY)
> > > + if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
> > > + return -EINVAL;
> > > +
> >
> > [..]
> >
> > > + if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS &&
> > > + !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY))
> > > return -EINVAL;
> >
> > Any reason we have 'attr->prog_flags & BPF_F_XDP_HAS_FRAGS' part here?
> > Seems like doing '!(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY)' should
> > be enough, right? We only want to bail out here when BPF_F_XDP_DEV_BOUND_ONLY
> > is not set and we don't really care whether BPF_F_XDP_HAS_FRAGS is set
> > or not at this point.
>
> If !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY) at this point, program could
> be requesting offload.
>
> Now I have thought about those conditions once more and they could be reduced to
> this:
>
> if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY) &&
> attr->prog_flags != (BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS))
> return -EINVAL;
>
> What do you think?
Ah, so this check is here to protect against the mbuf+offloaded
combination? (looking at that other thread with Maciej)
Let's keep your current way with two separate checks, but let's add
your "/* Frags are allowed only if program is dev-bound-only, but not
if it is requesting
bpf offload. */" as a comment to the second check?
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-09-14 17:10 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-09-14 8:37 [PATCH bpf-next] bpf: Allow to use kfunc XDP hints and frags together Larysa Zaremba
2023-09-14 16:29 ` Stanislav Fomichev
2023-09-14 16:49 ` Larysa Zaremba
2023-09-14 17:05 ` Stanislav Fomichev
2023-09-14 17:04 ` Larysa Zaremba
2023-09-14 16:38 ` Maciej Fijalkowski
2023-09-14 16:53 ` Larysa Zaremba
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