[Intel-wired-lan] [PATCH bpf v2 4/9] ice: change XDP RxQ frag_size from DMA write length to xdp.frame_sz

[Larysa Zaremba]

The only user of frag_size field in XDP RxQ info is
bpf_xdp_frags_increase_tail(). It clearly expects whole buff size instead
of DMA write size. Different assumptions in ice driver configuration lead
to negative tailroom.

This allows to trigger kernel panic, when using
XDP_ADJUST_TAIL_GROW_MULTI_BUFF xskxceiver test and changing packet size to
6912 and the requisted offset to a huge value, e.g.
XSK_UMEM__MAX_FRAME_SIZE * 100.

Due to other quirks of the ZC configuration in ice, panic is not observed
in ZC mode, but tailroom growing still fails when it should not.

Use fill queue buffer truesize instead of DMA write size in XDP RxQ info.
Fix ZC mode too by using the new helper.

Fixes: 2fba7dc5157b ("ice: Add support for XDP multi-buffer on Rx side")
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov at intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba at intel.com>
---
 drivers/net/ethernet/intel/ice/ice_base.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
index 511d803cf0a4..37ac5cbc7bcd 100644
--- a/drivers/net/ethernet/intel/ice/ice_base.c
+++ b/drivers/net/ethernet/intel/ice/ice_base.c
@@ -669,12 +669,14 @@ static int ice_vsi_cfg_rxq(struct ice_rx_ring *ring)
 			return err;
 
 		if (ring->xsk_pool) {
+			u32 frag_size =
+				xsk_pool_get_rx_frag_step(ring->xsk_pool);
 			rx_buf_len =
 				xsk_pool_get_rx_frame_size(ring->xsk_pool);
 			err = __xdp_rxq_info_reg(&ring->xdp_rxq, ring->netdev,
 						 ring->q_index,
 						 ring->q_vector->napi.napi_id,
-						 rx_buf_len);
+						 frag_size);
 			if (err)
 				return err;
 			err = xdp_rxq_info_reg_mem_model(&ring->xdp_rxq,
@@ -694,7 +696,7 @@ static int ice_vsi_cfg_rxq(struct ice_rx_ring *ring)
 			err = __xdp_rxq_info_reg(&ring->xdp_rxq, ring->netdev,
 						 ring->q_index,
 						 ring->q_vector->napi.napi_id,
-						 ring->rx_buf_len);
+						 ring->truesize);
 			if (err)
 				goto err_destroy_fq;
 
-- 
2.52.0