commit a50e659b2a1be14784e80f8492aab177e67c53a2 upstream

The registration of XDP queue information is incorrect because the RX queue id we use is invalid. When port->id == 0 it appears to works as expected yet it's no longer the case when port->id != 0.

The problem arised while using a recent kernel version on the MACCHIATOBin. This board has several ports: * eth0 and eth1 are 10Gbps interfaces ; both ports has port->id == 0; * eth2 is a 1Gbps interface with port->id != 0.

Code from xdp-tutorial (more specifically advanced03-AF_XDP) was used to test packet capture and injection on all these interfaces. The XDP kernel was simplified to:

SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx) { int index = ctx->rx_queue_index;

/* A set entry here means that the correspnding queue_id * has an active AF_XDP socket bound to it. */ if (bpf_map_lookup_elem(&xsks_map, &index)) return bpf_redirect_map(&xsks_map, index, 0);

return XDP_PASS; }

Starting the program using:

./af_xdp_user -d DEV

Gives the following result:

* eth0 : ok * eth1 : ok * eth2 : no capture, no injection

Investigating the issue shows that XDP rx queues for eth2 are wrong: XDP expects their id to be in the range [0..3] but we found them to be in the range [32..35].

Trying to force rx queue ids using:

./af_xdp_user -d eth2 -Q 32

fails as expected (we shall not have more than 4 queues).

When we register the XDP rx queue information (using xdp_rxq_info_reg() in function mvpp2_rxq_init()) we tell it to use rxq->id as the queue id. This value is computed as:

rxq->id = port->id * max_rxq_count + queue_id

where max_rxq_count depends on the device version. In the MACCHIATOBin case, this value is 32, meaning that rx queues on eth2 are numbered from 32 to 35 - there are four of them.

Clearly, this is not the per-port queue id that XDP is expecting: it wants a value in the range [0..3]. It shall directly use queue_id which is stored in rxq->logic_rxq -- so let's use that value instead.

rxq->id is left untouched ; its value is indeed valid but it should not be used in this context.

This is consistent with the remaining part of the code in mvpp2_rxq_init().

With this change, packet capture is working as expected on all the MACCHIATOBin ports.

Fixes: b27db2274ba8 ("mvpp2: use page_pool allocator") Signed-off-by: Louis Amas louis.amas@eho.link Signed-off-by: Emmanuel Deloget emmanuel.deloget@eho.link Reviewed-by: Marcin Wojtas mw@semihalf.com Acked-by: John Fastabend john.fastabend@gmail.com Acked-by: Jesper Dangaard Brouer brouer@redhat.com ---

Patch history

v1 : original submission [1] v2 : commit message rework (no change in the patch) [2] v3 : commit message rework (no change in the patch) + added Acked-by [3] v4 : fix mail corruption by malevolent SMTP + rebase on net/master v5 : (this version) add tags back

[1] https://lore.kernel.org/bpf/20211109103101.92382-1-louis.amas@eho.link/ [2] https://lore.kernel.org/bpf/20211110144104.241589-1-louis.amas@eho.link/ [3] https://lore.kernel.org/bpf/20211206172220.602024-1-louis.amas@eho.link/

drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c index 6480696c979b..6da8a595026b 100644 --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c @@ -2960,11 +2960,11 @@ static int mvpp2_rxq_init(struct mvpp2_port *port, mvpp2_rxq_status_update(port, rxq->id, 0, rxq->size);

if (priv->percpu_pools) { - err = xdp_rxq_info_reg(&rxq->xdp_rxq_short, port->dev, rxq->id); + err = xdp_rxq_info_reg(&rxq->xdp_rxq_short, port->dev, rxq->logic_rxq); if (err < 0) goto err_free_dma;

- err = xdp_rxq_info_reg(&rxq->xdp_rxq_long, port->dev, rxq->id); + err = xdp_rxq_info_reg(&rxq->xdp_rxq_long, port->dev, rxq->logic_rxq); if (err < 0) goto err_unregister_rxq_short;