This is a note to let you know that I've just added the patch titled
net/mlx5e: Lower maximum allowed MTU in XSK to match XDP prerequisites
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-mlx5e-lower-maximum-allowed-mtu-in-xsk-to-match-.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 455536e949d2e58938370e85180cf5245424ddcb
Author: Adham Faris <afaris@xxxxxxxxxx>
Date: Mon Jan 23 10:09:01 2023 +0200
net/mlx5e: Lower maximum allowed MTU in XSK to match XDP prerequisites
[ Upstream commit 78dee7befd56987283c13877b834c0aa97ad51b9 ]
XSK redirecting XDP programs require linearity, hence applies
restrictions on the MTU. For PAGE_SIZE=4K, MTU shouldn't exceed 3498.
Features that contradict with XDP such HW-LRO and HW-GRO are enforced
by the driver in advance, during XSK params validation, except for MTU,
which was not enforced before this patch.
This has been spotted during test scenario described below:
Attaching xdpsock program (PAGE_SIZE=4K), with MTU < 3498, detaching
XDP program, changing the MTU to arbitrary value in the range
[3499, 3754], attaching XDP program again, which ended up with failure
since MTU is > 3498.
This commit lowers the XSK MTU limitation to be aligned with XDP MTU
limitation, since XSK socket is meaningless without XDP program.
Signed-off-by: Adham Faris <afaris@xxxxxxxxxx>
Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 3b5c5064cfafc..5e01de4c32037 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -4104,13 +4104,17 @@ static bool mlx5e_xsk_validate_mtu(struct net_device *netdev,
struct xsk_buff_pool *xsk_pool =
mlx5e_xsk_get_pool(&chs->params, chs->params.xsk, ix);
struct mlx5e_xsk_param xsk;
+ int max_xdp_mtu;
if (!xsk_pool)
continue;
mlx5e_build_xsk_param(xsk_pool, &xsk);
+ max_xdp_mtu = mlx5e_xdp_max_mtu(new_params, &xsk);
- if (!mlx5e_validate_xsk_param(new_params, &xsk, mdev)) {
+ /* Validate XSK params and XDP MTU in advance */
+ if (!mlx5e_validate_xsk_param(new_params, &xsk, mdev) ||
+ new_params->sw_mtu > max_xdp_mtu) {
u32 hr = mlx5e_get_linear_rq_headroom(new_params, &xsk);
int max_mtu_frame, max_mtu_page, max_mtu;
@@ -4120,9 +4124,9 @@ static bool mlx5e_xsk_validate_mtu(struct net_device *netdev,
*/
max_mtu_frame = MLX5E_HW2SW_MTU(new_params, xsk.chunk_size - hr);
max_mtu_page = MLX5E_HW2SW_MTU(new_params, SKB_MAX_HEAD(0));
- max_mtu = min(max_mtu_frame, max_mtu_page);
+ max_mtu = min3(max_mtu_frame, max_mtu_page, max_xdp_mtu);
- netdev_err(netdev, "MTU %d is too big for an XSK running on channel %u. Try MTU <= %d\n",
+ netdev_err(netdev, "MTU %d is too big for an XSK running on channel %u or its redirection XDP program. Try MTU <= %d\n",
new_params->sw_mtu, ix, max_mtu);
return false;
}
