Commit d235bb21 authored by Ankit Garg's avatar Ankit Garg Committed by Jakub Kicinski
Browse files

gve: Allow ethtool to configure rx_buf_len 



Add support for getting and setting the RX buffer length via the
ethtool ring parameters (`ethtool -g`/`-G`). The driver restricts the
allowed buffer length to 2048 (SZ_2K) by default and allows 4096 (SZ_4K)
based on device options.

As XDP is only supported when the `rx_buf_len` is 2048, the driver now
enforces this in two places:
1.  In `gve_xdp_set`, rejecting XDP programs if the current buffer
    length is not 2048.
2.  In `gve_set_rx_buf_len_config`, rejecting buffer length changes if XDP
    is loaded and the new length is not 2048.

Signed-off-by: default avatarAnkit Garg <nktgrg@google.com>
Reviewed-by: default avatarHarshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: default avatarJordan Rhee <jordanrhee@google.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarJoshua Washington <joshwash@google.com>
Link: https://patch.msgid.link/20251106192746.243525-4-joshwash@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 091a3b6f

drivers/net/ethernet/google/gve/gve.h

+9 −0
Original line number Diff line number Diff line
@@ -1167,6 +1167,12 @@ static inline bool gve_is_gqi(struct gve_priv *priv) 
		priv->queue_format == GVE_GQI_QPL_FORMAT;

}



static inline bool gve_is_dqo(struct gve_priv *priv)

{

	return priv->queue_format == GVE_DQO_RDA_FORMAT ||

	       priv->queue_format == GVE_DQO_QPL_FORMAT;

}



static inline u32 gve_num_tx_queues(struct gve_priv *priv)

{

	return priv->tx_cfg.num_queues + priv->tx_cfg.num_xdp_queues;
@@ -1248,6 +1254,9 @@ void gve_rx_free_rings_gqi(struct gve_priv *priv, 
void gve_rx_start_ring_gqi(struct gve_priv *priv, int idx);

void gve_rx_stop_ring_gqi(struct gve_priv *priv, int idx);

bool gve_header_split_supported(const struct gve_priv *priv);

int gve_set_rx_buf_len_config(struct gve_priv *priv, u32 rx_buf_len,

			      struct netlink_ext_ack *extack,

			      struct gve_rx_alloc_rings_cfg *rx_alloc_cfg);

int gve_set_hsplit_config(struct gve_priv *priv, u8 tcp_data_split,

			  struct gve_rx_alloc_rings_cfg *rx_alloc_cfg);

/* rx buffer handling */

drivers/net/ethernet/google/gve/gve_ethtool.c

+12 −1
Original line number Diff line number Diff line
@@ -529,6 +529,8 @@ static void gve_get_ringparam(struct net_device *netdev, 
	cmd->rx_pending = priv->rx_desc_cnt;

	cmd->tx_pending = priv->tx_desc_cnt;



	kernel_cmd->rx_buf_len = priv->rx_cfg.packet_buffer_size;



	if (!gve_header_split_supported(priv))

		kernel_cmd->tcp_data_split = ETHTOOL_TCP_DATA_SPLIT_UNKNOWN;

	else if (priv->header_split_enabled)
@@ -589,6 +591,12 @@ static int gve_set_ringparam(struct net_device *netdev, 
	int err;



	gve_get_curr_alloc_cfgs(priv, &tx_alloc_cfg, &rx_alloc_cfg);



	err = gve_set_rx_buf_len_config(priv, kernel_cmd->rx_buf_len, extack,

					&rx_alloc_cfg);

	if (err)

		return err;



	err = gve_set_hsplit_config(priv, kernel_cmd->tcp_data_split,

				    &rx_alloc_cfg);

	if (err)
@@ -605,6 +613,8 @@ static int gve_set_ringparam(struct net_device *netdev, 
			return err;

	} else {

		/* Set ring params for the next up */

		priv->rx_cfg.packet_buffer_size =

			rx_alloc_cfg.packet_buffer_size;

		priv->header_split_enabled = rx_alloc_cfg.enable_header_split;

		priv->tx_desc_cnt = tx_alloc_cfg.ring_size;

		priv->rx_desc_cnt = rx_alloc_cfg.ring_size;
@@ -944,7 +954,8 @@ static int gve_get_ts_info(struct net_device *netdev, 


const struct ethtool_ops gve_ethtool_ops = {

	.supported_coalesce_params = ETHTOOL_COALESCE_USECS,

	.supported_ring_params = ETHTOOL_RING_USE_TCP_DATA_SPLIT,

	.supported_ring_params = ETHTOOL_RING_USE_TCP_DATA_SPLIT |

				 ETHTOOL_RING_USE_RX_BUF_LEN,

	.get_drvinfo = gve_get_drvinfo,

	.get_strings = gve_get_strings,

	.get_sset_count = gve_get_sset_count,

drivers/net/ethernet/google/gve/gve_main.c

+39 −0
Original line number Diff line number Diff line
@@ -1725,6 +1725,13 @@ static int gve_verify_xdp_configuration(struct net_device *dev, 
		return -EOPNOTSUPP;

	}



	if (priv->rx_cfg.packet_buffer_size != SZ_2K) {

		NL_SET_ERR_MSG_FMT_MOD(extack,

				       "XDP is not supported for Rx buf len %d, only %d supported.",

				       priv->rx_cfg.packet_buffer_size, SZ_2K);

		return -EOPNOTSUPP;

	}



	max_xdp_mtu = priv->rx_cfg.packet_buffer_size - sizeof(struct ethhdr);

	if (priv->queue_format == GVE_GQI_QPL_FORMAT)

		max_xdp_mtu -= GVE_RX_PAD;
@@ -2056,6 +2063,38 @@ bool gve_header_split_supported(const struct gve_priv *priv) 
		priv->queue_format == GVE_DQO_RDA_FORMAT && !priv->xdp_prog;

}



int gve_set_rx_buf_len_config(struct gve_priv *priv, u32 rx_buf_len,

			      struct netlink_ext_ack *extack,

			      struct gve_rx_alloc_rings_cfg *rx_alloc_cfg)

{

	u32 old_rx_buf_len = rx_alloc_cfg->packet_buffer_size;



	if (rx_buf_len == old_rx_buf_len)

		return 0;



	/* device options may not always contain support for 4K buffers */

	if (!gve_is_dqo(priv) || priv->max_rx_buffer_size < SZ_4K) {

		NL_SET_ERR_MSG_MOD(extack,

				   "Modifying Rx buf len is not supported");

		return -EOPNOTSUPP;

	}



	if (priv->xdp_prog && rx_buf_len != SZ_2K) {

		NL_SET_ERR_MSG_MOD(extack,

				   "Rx buf len can only be 2048 when XDP is on");

		return -EINVAL;

	}



	if (rx_buf_len != SZ_2K && rx_buf_len != SZ_4K) {

		NL_SET_ERR_MSG_MOD(extack,

				   "Rx buf len can only be 2048 or 4096");

		return -EINVAL;

	}

	rx_alloc_cfg->packet_buffer_size = rx_buf_len;



	return 0;

}



int gve_set_hsplit_config(struct gve_priv *priv, u8 tcp_data_split,

			  struct gve_rx_alloc_rings_cfg *rx_alloc_cfg)

{