From: Jerin Jacob Kollanukkaran <jerinj@marvell.com>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>
Cc: "thomas@monjalon.net" <thomas@monjalon.net>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] bpf: fix to allow ptr stack program type
Date: Tue, 13 Aug 2019 03:31:39 +0000 [thread overview]
Message-ID: <DM6PR18MB2425BD37658E265FAA97C339C8D20@DM6PR18MB2425.namprd18.prod.outlook.com> (raw)
In-Reply-To: <2601191342CEEE43887BDE71AB977258018115D7C8@irsmsx105.ger.corp.intel.com>
> -----Original Message-----
> From: Ananyev, Konstantin <konstantin.ananyev@intel.com>
> Sent: Monday, August 12, 2019 5:08 PM
> To: Jerin Jacob Kollanukkaran <jerinj@marvell.com>; dev@dpdk.org
> Cc: thomas@monjalon.net; stable@dpdk.org
> Subject: [EXT] RE: [dpdk-dev] [PATCH] bpf: fix to allow ptr stack program
> type
>
> External Email
>
> ----------------------------------------------------------------------
>
> > > Hi Jerin,
> >
> > Hi Konstantin,
> >
> > >
> > > >
> > > > bpf_validate does not allow to execute RTE_BPF_ARG_PTR_STACK for
> > > > no reason.
> > >
> > > I believe there is a reason,
> > > ARG_PTR_STACK is reserved for memory within BPF program internal
> > > stack only.
> > > User that calls BPF program should never pass parameter with that type.
> >
> > OK.
> > Shouldn't we remove that from public header file
> > (lib/librte_bpf/rte_bpf.h) then ?
>
> Probably... or might be just put extra comments to mark it as internal?
> The reason I left it here, so we can add new public values for enum here,
> before RTE_BPF_ARG_PTR_STACK.
> Of course in theory we can use for RTE_BPF_ARG_PTR_STACK some
> reserved value instead.
>
> >
> > > If the user allocates parameter for bpf function on the stack, he
> > > can still use RTE_BPF_ARG_PTR for it.
> >
> > I see the _stack_ is only allocated under RTE_BPF_ARG_PTR_STACK checks
> in bpf_validate.c.
> > Can you check? I agree that stack should be allocated for
> RTE_BPF_ARG_PTR as well.
>
> Not sure I understand your query here...
> Each BPF program can use up to MAX_BPF_STACK_SIZE bytes for stack.
> Though to avoid JIT to allocate unused space for the stack, in bpf_validate.c
> we figure out does given BPF program really allocate things on the stack and
> if yes, how many bytes is needed.
> This info is stored in rte_bpf.stack_sz and can be used later by the JIT.
> Let say for x86 jit is used in emit_prolog().
I thought, stack will be allocated only when user gives
RTE_BPF_ARG_PTR_STACK.
I tested following program with RTE_BPF_ARG_PTR. It allocates stacks
Properly. So everything is good.
stdw [r10-64], 0xab
mov r0, 0
exit
I will modify this patch to following to avoid any confusion to user:
1) Change RTE_BPF_ARG_PTR_STACK to RTE_BPF_ARG_RESERVED in public header file
2) In the implementation #define RTE_BPF_ARG_RESERVED BPF_ARG_PTR_STACK
Is it OK?
next prev parent reply other threads:[~2019-08-13 3:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 16:29 jerinj
2019-08-12 8:49 ` Ananyev, Konstantin
2019-08-12 10:34 ` Jerin Jacob Kollanukkaran
2019-08-12 11:37 ` Ananyev, Konstantin
2019-08-13 3:31 ` Jerin Jacob Kollanukkaran [this message]
2019-08-13 6:50 ` Ananyev, Konstantin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=DM6PR18MB2425BD37658E265FAA97C339C8D20@DM6PR18MB2425.namprd18.prod.outlook.com \
--to=jerinj@marvell.com \
--cc=dev@dpdk.org \
--cc=konstantin.ananyev@intel.com \
--cc=stable@dpdk.org \
--cc=thomas@monjalon.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).