Re: [PATCH net-next v2 12/14] octeontx2-pf: ipsec: Process CPT metapackets

CPT hardware forwards decrypted IPsec packets to NIX via the X2P bus
as metapackets which are of 256 bytes in length. Each metapacket
contains CPT_PARSE_HDR_S and initial bytes of the decrypted packet
that helps NIX RX in classifying and submitting to CPU. Additionally,
CPT also sets BIT(11) of the channel number to indicate that it's a
2nd pass packet from CPT.

Since the metapackets are not complete packets, they don't have to go
through L3/L4 layer length and checksum verification so these are
disabled via the NIX_LF_INLINE_RQ_CFG mailbox during IPsec initialization.

The CPT_PARSE_HDR_S contains a WQE pointer to the complete decrypted
packet. Add code in the rx NAPI handler to parse the header and extract
WQE pointer. Later, use this WQE pointer to construct the skb, set the
XFRM packet mode flags to indicate successful decryption before submitting
it to the network stack.

Signed-off-by: Tanmay Jagdale <redacted>
---
Changes in V2:
- Removed unnecessary casts
- Don't convert complete cpt_parse_hdr from BE to LE and just
  convert required fields
- Fixed logic to avoid repeated calculation for start and end in sg

V1 Link: https://lore.kernel.org/netdev/20250502132005.611698-15-tanmay@marvell.com/ (local)

 .../marvell/octeontx2/nic/cn10k_ipsec.c       | 52 +++++++++++++++++++
 .../marvell/octeontx2/nic/cn10k_ipsec.h       | 48 +++++++++++++++++
 .../marvell/octeontx2/nic/otx2_common.h       |  2 +
 .../marvell/octeontx2/nic/otx2_struct.h       | 16 ++++++
 .../marvell/octeontx2/nic/otx2_txrx.c         | 29 +++++++++--
 5 files changed, 144 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_ipsec.c b/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_ipsec.c
index 5cb6bc835e56..a95878378334 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_ipsec.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_ipsec.c

@@ -346,6 +346,58 @@ static int cn10k_outb_cpt_init(struct net_device *netdev)
 	return ret;
 }
 
+struct nix_wqe_rx_s *cn10k_ipsec_process_cpt_metapkt(struct otx2_nic *pfvf,
+						     struct nix_cqe_rx_s *cqe,
+						     struct sk_buff *skb,
+						     int qidx)
+{
+	struct nix_rx_sg_s *sg = &cqe->sg;
+	struct nix_wqe_rx_s *wqe = NULL;
+	u64 *seg_addr = &sg->seg_addr;
+	struct cpt_parse_hdr_s *cptp;
+	struct xfrm_offload *xo;
+	struct xfrm_state *xs;
+	struct sec_path *sp;
+	void *va;
+
+	/* CPT_PARSE_HDR_S is present in the beginning of the buffer */
+	va = phys_to_virt(otx2_iova_to_phys(pfvf->iommu_domain, *seg_addr));
+
+	cptp = (struct cpt_parse_hdr_s *)va;
+
+	/* Convert the wqe_ptr from CPT_PARSE_HDR_S to a CPU usable pointer */
+	wqe = phys_to_virt(otx2_iova_to_phys(pfvf->iommu_domain,
+					     be64_to_cpu(cptp->wqe_ptr)));

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_ipsec.h b/drivers/net/ethernet/marvell/octeontx2/nic/cn10k_ipsec.h

@@ -302,6 +303,41 @@ struct cpt_sg_s {
 	u64 rsvd_63_50	: 14;
 };
 
+/* CPT Parse Header Structure for Inbound packets */
+struct cpt_parse_hdr_s {
+	/* Word 0 */
+	u64 cookie      : 32;
+	u64 match_id    : 16;
+	u64 err_sum     : 1;
+	u64 reas_sts    : 4;
+	u64 reserved_53 : 1;
+	u64 et_owr      : 1;
+	u64 pkt_fmt     : 1;
+	u64 pad_len     : 3;
+	u64 num_frags   : 3;
+	u64 pkt_out     : 2;
+
+	/* Word 1 */
+	u64 wqe_ptr;
+
+	/* Word 2 */
+	u64 frag_age    : 16;
+	u64 res_32_16   : 16;
+	u64 pf_func     : 16;
+	u64 il3_off     : 8;
+	u64 fi_pad      : 3;
+	u64 fi_offset   : 5;
+
+	/* Word 3 */
+	u64 hw_ccode    : 8;
+	u64 uc_ccode    : 8;
+	u64 res3_32_16  : 16;
+	u64 spi         : 32;
+
+	/* Word 4 */
+	u64 misc;
+};
+
 /* CPT LF_INPROG Register */
 #define CPT_LF_INPROG_INFLIGHT	GENMASK_ULL(8, 0)
 #define CPT_LF_INPROG_GRB_CNT	GENMASK_ULL(39, 32)