[PATCH iwl-net 1/1] igc: skip RX timestamp header for frame preemption verification

[KhaiWenTan <khai.wen.tan@linux.intel.com>]

When RX hardware timestamping is enabled, a 16-byte inline timestamp header
is added to the start of the packet buffer, causing FPE handshake
verification to fail.

Because an incorrect packet buffer is passed to igc_fpe_handle_mpacket(),
the mem_is_zero() check inspects the timestamp metadata instead of the
actual mPacket payload. As a result, valid Verify/Response mPackets can be
missed when inline RX timestamps are present.

Pass pktbuf + pkt_offset to igc_fpe_handle_mpacket() so it inspects the
actual mPacket payload instead of the timestamp header.

Fixes: 5422570c0010 ("igc: add support for frame preemption verification")
Co-developed-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
Signed-off-by: KhaiWenTan <khai.wen.tan@linux.intel.com>
---
 drivers/net/ethernet/intel/igc/igc_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 8ac16808023c..c470d2354ce8 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -2649,7 +2649,7 @@ static int igc_clean_rx_irq(struct igc_q_vector *q_vector, const int budget)
 		}
 
 		if (igc_fpe_is_pmac_enabled(adapter) &&
-		    igc_fpe_handle_mpacket(adapter, rx_desc, size, pktbuf)) {
+		    igc_fpe_handle_mpacket(adapter, rx_desc, size, pktbuf + pkt_offset)) {
 			/* Advance the ring next-to-clean */
 			igc_is_non_eop(rx_ring, rx_desc);
 			cleaned_count++;
-- 
2.43.0