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@xxxxxxxx>
Signed-off-by: Emmanuel Deloget <emmanuel.deloget@xxxxxxxx>
Reviewed-by: Marcin Wojtas <mw@xxxxxxxxxxxx>
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
---
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@xxxxxxxx/
[2] https://lore.kernel.org/bpf/20211110144104.241589-1-louis.amas@xxxxxxxx/
[3] https://lore.kernel.org/bpf/20211206172220.602024-1-louis.amas@xxxxxxxx/
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, 0);
+ err = xdp_rxq_info_reg(&rxq->xdp_rxq_short, port->dev, rxq->logic_rxq, 0);
if (err < 0)
goto err_free_dma;
- err = xdp_rxq_info_reg(&rxq->xdp_rxq_long, port->dev, rxq->id, 0);
+ err = xdp_rxq_info_reg(&rxq->xdp_rxq_long, port->dev, rxq->logic_rxq, 0);
if (err < 0)
goto err_unregister_rxq_short;
--
2.25.1
