Re: [PATCH 08/14] net/cnxk: resolve mbuf from CPT CQ format in SSO work cb

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 17 Sep 2026 12:40:10 +0530
Rahul Bhansali <rbhansali@marvell.com> wrote:

> From: Rakesh Kudurumalla <rkudurumalla@marvell.com>
> 
> When handling NIX inline CPT CQ events (type < NIX_INL_SSO), derive the
> mbuf from the completion queue word layout using fmt bits: WQE_PTR_CPTR
> uses w1.esn; CPTR_WQE_PTR uses w3.comp_ptr shifted left by 3 for the byte
> address. Pass the mbuf into cn20k_eth_sec_post_event instead of NULL.
> Drop RTE_SET_USED(args) since args is consumed by post_event.
> 
> Signed-off-by: Rakesh Kudurumalla <rkudurumalla@marvell.com>
> Signed-off-by: Rahul Bhansali <rbhansali@marvell.com>
> ---


Patch 8/14 net/cnxk: resolve mbuf from CPT CQ format in SSO work cb
------------------------------------------------------------------
Error: wrong mbuf address for inbound events.
  mbuf = (struct rte_mbuf *)(uintptr_t)gw[1];
- gw[1] is the raw WQE pointer; patch 7 only masks the low 3 bits.
- Outbound is correct: the Tx path stores (uintptr_t)m | 1 in CPT
  word 3.
- For inbound, the same function's RTE_EVENT_TYPE_ETHDEV case uses
    gw[1] - sizeof(struct rte_mbuf)
- So cn20k_eth_sec_post_event() reads *rte_security_dynfield(mbuf)
  from the wrong address.
Subtract sizeof(struct rte_mbuf) for NIX_INL_INB_CPT_CQ.

Warning: WQE_PTR_ANTI_REPLAY events are dropped.
- eth_dev stays NULL.
- post_event() builds desc and skips rte_eth_dev_callback_process()
  because of "if (eth_dev)".
- It returns false, so nothing is freed either.
Resolve the port for this format, or do not dispatch it.

Warning: the commit log does not match the code. It says WQE_PTR_CPTR
takes the mbuf from w1.esn and CPTR_WQE_PTR from w3.comp_ptr "shifted
left by 3". The code (patch 7) is the other way round, and masks
instead of shifting:
  WQE_PTR_CPTR:  wqe = w3.comp_ptr & ~7
  CPTR_WQE_PTR:  wqe = w1.esn & ~7
That derivation lives in patch 7, not here.

Info: post_event() log messages still say "Outbound error" for
inbound events.