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From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
To: intel-wired-lan@lists.osuosl.org
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net,
	anthony.l.nguyen@intel.com, kuba@kernel.org, bjorn@kernel.org,
	Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Subject: [PATCH intel-next 1/2] ice: unify xdp_rings accesses
Date: Tue,  1 Jun 2021 13:32:35 +0200	[thread overview]
Message-ID: <20210601113236.42651-2-maciej.fijalkowski@intel.com> (raw)
In-Reply-To: <20210601113236.42651-1-maciej.fijalkowski@intel.com>

There has been a long lasting issue of improper xdp_rings indexing for
XDP_TX and XDP_REDIRECT actions. Given that currently rx_ring->q_index
is mixed with smp_processor_id(), there could be a situation where Tx
descriptors are produced onto XDP Tx ring, but tail is never bumped -
for example pin a particular queue id to non-matching IRQ line.
Moreover, user can reduce the count of Rx queues which is the base for
sizing xdp_rings array so smp_processor_id() could cause an out of
bounds access.

Address that problem by ignoring the user ring count setting and always
initialize the xdp_rings array to be of num_possible_cpus() size. Then,
always use the smp_processor_id() as an index to xdp_rings array. This
provides serialization as at given time only a single softirq can run on
a particular CPU.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
 drivers/net/ethernet/intel/ice/ice_lib.c      | 2 +-
 drivers/net/ethernet/intel/ice/ice_main.c     | 2 +-
 drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index 2c33b0c56c94..3c8668d8b964 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -3099,7 +3099,7 @@ int ice_vsi_rebuild(struct ice_vsi *vsi, bool init_vsi)
 		if (ice_is_xdp_ena_vsi(vsi)) {
-			vsi->num_xdp_txq = vsi->alloc_rxq;
+			vsi->num_xdp_txq = num_possible_cpus();
 			ret = ice_prepare_xdp_rings(vsi, vsi->xdp_prog);
 			if (ret)
 				goto err_vectors;
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 0eb2307325d3..1915b6a734e2 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -2534,7 +2534,7 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog,
 	if (!ice_is_xdp_ena_vsi(vsi) && prog) {
-		vsi->num_xdp_txq = vsi->alloc_rxq;
+		vsi->num_xdp_txq = num_possible_cpus();
 		xdp_ring_err = ice_prepare_xdp_rings(vsi, prog);
 		if (xdp_ring_err)
 			NL_SET_ERR_MSG_MOD(extack, "Setting up XDP Tx resources failed");
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
index 207f6ee3a7f6..e1c05d69f017 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
@@ -279,7 +279,7 @@ void ice_finalize_xdp_rx(struct ice_ring *rx_ring, unsigned int xdp_res)
 	if (xdp_res & ICE_XDP_TX) {
 		struct ice_ring *xdp_ring =
-			rx_ring->vsi->xdp_rings[rx_ring->q_index];
+			rx_ring->vsi->xdp_rings[smp_processor_id()];

  reply	other threads:[~2021-06-01 11:46 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-01 11:32 [PATCH intel-next 0/2] ice: bring up XDP_TX back to life Maciej Fijalkowski
2021-06-01 11:32 ` Maciej Fijalkowski [this message]
2021-06-01 11:32 ` [PATCH intel-next 2/2] ice: introduce XDP Tx fallback path Maciej Fijalkowski
2021-06-01 12:38   ` Toke Høiland-Jørgensen
2021-06-08 12:12     ` Maciej Fijalkowski
2021-06-08 21:43       ` Toke Høiland-Jørgensen
2021-06-03  0:52   ` Nguyen, Anthony L
2021-06-08 12:13     ` Maciej Fijalkowski
2021-06-03  8:42   ` Jesper Dangaard Brouer

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