From 40fef85ceb9cce2021f7ba5ca6e3212baa193cb3 Mon Sep 17 00:00:00 2001 From: Ankit Garg Date: Thu, 6 Nov 2025 11:27:43 -0800 Subject: [PATCH 1/4] gve: Decouple header split from RX buffer length Previously, enabling header split via `gve_set_hsplit_config` also implicitly changed the RX buffer length to 4K (if supported by the device). This coupled two settings that should be orthogonal; this patch removes that side effect. After this change, `gve_set_hsplit_config` only toggles the header split configuration. The RX buffer length is no longer affected and must be configured independently. Signed-off-by: Ankit Garg Reviewed-by: Harshitha Ramamurthy Reviewed-by: Jordan Rhee Reviewed-by: Willem de Bruijn Signed-off-by: Joshua Washington Link: https://patch.msgid.link/20251106192746.243525-2-joshwash@google.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/google/gve/gve.h | 3 --- drivers/net/ethernet/google/gve/gve_ethtool.c | 2 -- drivers/net/ethernet/google/gve/gve_main.c | 10 ---------- 3 files changed, 15 deletions(-) diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h index cf95ec25b11a..c237d00c5ab3 100644 --- a/drivers/net/ethernet/google/gve/gve.h +++ b/drivers/net/ethernet/google/gve/gve.h @@ -59,8 +59,6 @@ #define GVE_DEFAULT_RX_BUFFER_SIZE 2048 -#define GVE_MAX_RX_BUFFER_SIZE 4096 - #define GVE_XDP_RX_BUFFER_SIZE_DQO 4096 #define GVE_DEFAULT_RX_BUFFER_OFFSET 2048 @@ -1249,7 +1247,6 @@ void gve_rx_free_rings_gqi(struct gve_priv *priv, struct gve_rx_alloc_rings_cfg *cfg); void gve_rx_start_ring_gqi(struct gve_priv *priv, int idx); void gve_rx_stop_ring_gqi(struct gve_priv *priv, int idx); -u16 gve_get_pkt_buf_size(const struct gve_priv *priv, bool enable_hplit); bool gve_header_split_supported(const struct gve_priv *priv); int gve_set_hsplit_config(struct gve_priv *priv, u8 tcp_data_split, struct gve_rx_alloc_rings_cfg *rx_alloc_cfg); diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c index b030a84b678c..db6fc855a511 100644 --- a/drivers/net/ethernet/google/gve/gve_ethtool.c +++ b/drivers/net/ethernet/google/gve/gve_ethtool.c @@ -606,8 +606,6 @@ static int gve_set_ringparam(struct net_device *netdev, } else { /* Set ring params for the next up */ priv->header_split_enabled = rx_alloc_cfg.enable_header_split; - priv->rx_cfg.packet_buffer_size = - rx_alloc_cfg.packet_buffer_size; priv->tx_desc_cnt = tx_alloc_cfg.ring_size; priv->rx_desc_cnt = rx_alloc_cfg.ring_size; } diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c index 29845e8f3c0d..8d825218965a 100644 --- a/drivers/net/ethernet/google/gve/gve_main.c +++ b/drivers/net/ethernet/google/gve/gve_main.c @@ -2041,14 +2041,6 @@ static void gve_tx_timeout(struct net_device *dev, unsigned int txqueue) priv->tx_timeo_cnt++; } -u16 gve_get_pkt_buf_size(const struct gve_priv *priv, bool enable_hsplit) -{ - if (enable_hsplit && priv->max_rx_buffer_size >= GVE_MAX_RX_BUFFER_SIZE) - return GVE_MAX_RX_BUFFER_SIZE; - else - return GVE_DEFAULT_RX_BUFFER_SIZE; -} - /* Header split is only supported on DQ RDA queue format. If XDP is enabled, * header split is not allowed. */ @@ -2080,8 +2072,6 @@ int gve_set_hsplit_config(struct gve_priv *priv, u8 tcp_data_split, return 0; rx_alloc_cfg->enable_header_split = enable_hdr_split; - rx_alloc_cfg->packet_buffer_size = - gve_get_pkt_buf_size(priv, enable_hdr_split); return 0; } From 091a3b6ff2b98354270cb9278faad6d17d5aa27d Mon Sep 17 00:00:00 2001 From: Ankit Garg Date: Thu, 6 Nov 2025 11:27:44 -0800 Subject: [PATCH 2/4] gve: Use extack to log xdp config verification errors Plumb extack as it allows us to send more detailed error messages back and append 'gve' suffix to method name per convention. NL_SET_ERR_MSG_FMT_MOD doesn't support format string longer than 80 chars so keeping netdev warning with actual queue count details. Signed-off-by: Ankit Garg Reviewed-by: Harshitha Ramamurthy Reviewed-by: Willem de Bruijn Signed-off-by: Joshua Washington Link: https://patch.msgid.link/20251106192746.243525-3-joshwash@google.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/google/gve/gve_main.c | 24 ++++++++++++++-------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c index 8d825218965a..616182f4fb81 100644 --- a/drivers/net/ethernet/google/gve/gve_main.c +++ b/drivers/net/ethernet/google/gve/gve_main.c @@ -1707,18 +1707,21 @@ static int gve_xsk_wakeup(struct net_device *dev, u32 queue_id, u32 flags) return 0; } -static int verify_xdp_configuration(struct net_device *dev) +static int gve_verify_xdp_configuration(struct net_device *dev, + struct netlink_ext_ack *extack) { struct gve_priv *priv = netdev_priv(dev); u16 max_xdp_mtu; if (dev->features & NETIF_F_LRO) { - netdev_warn(dev, "XDP is not supported when LRO is on.\n"); + NL_SET_ERR_MSG_MOD(extack, + "XDP is not supported when LRO is on."); return -EOPNOTSUPP; } if (priv->header_split_enabled) { - netdev_warn(dev, "XDP is not supported when header-data split is enabled.\n"); + NL_SET_ERR_MSG_MOD(extack, + "XDP is not supported when header-data split is enabled."); return -EOPNOTSUPP; } @@ -1727,17 +1730,20 @@ static int verify_xdp_configuration(struct net_device *dev) max_xdp_mtu -= GVE_RX_PAD; if (dev->mtu > max_xdp_mtu) { - netdev_warn(dev, "XDP is not supported for mtu %d.\n", - dev->mtu); + NL_SET_ERR_MSG_FMT_MOD(extack, + "XDP is not supported for mtu %d.", + dev->mtu); return -EOPNOTSUPP; } if (priv->rx_cfg.num_queues != priv->tx_cfg.num_queues || (2 * priv->tx_cfg.num_queues > priv->tx_cfg.max_queues)) { - netdev_warn(dev, "XDP load failed: The number of configured RX queues %d should be equal to the number of configured TX queues %d and the number of configured RX/TX queues should be less than or equal to half the maximum number of RX/TX queues %d", - priv->rx_cfg.num_queues, - priv->tx_cfg.num_queues, + netdev_warn(dev, + "XDP load failed: The number of configured RX queues %d should be equal to the number of configured TX queues %d and the number of configured RX/TX queues should be less than or equal to half the maximum number of RX/TX queues %d.", + priv->rx_cfg.num_queues, priv->tx_cfg.num_queues, priv->tx_cfg.max_queues); + NL_SET_ERR_MSG_MOD(extack, + "XDP load failed: The number of configured RX queues should be equal to the number of configured TX queues and the number of configured RX/TX queues should be less than or equal to half the maximum number of RX/TX queues"); return -EINVAL; } return 0; @@ -1748,7 +1754,7 @@ static int gve_xdp(struct net_device *dev, struct netdev_bpf *xdp) struct gve_priv *priv = netdev_priv(dev); int err; - err = verify_xdp_configuration(dev); + err = gve_verify_xdp_configuration(dev, xdp->extack); if (err) return err; switch (xdp->command) { From d235bb213f411ace8317bcca3740a1008628ea9c Mon Sep 17 00:00:00 2001 From: Ankit Garg Date: Thu, 6 Nov 2025 11:27:45 -0800 Subject: [PATCH 3/4] 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: Ankit Garg Reviewed-by: Harshitha Ramamurthy Reviewed-by: Jordan Rhee Reviewed-by: Willem de Bruijn Signed-off-by: Joshua Washington Link: https://patch.msgid.link/20251106192746.243525-4-joshwash@google.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/google/gve/gve.h | 9 +++++ drivers/net/ethernet/google/gve/gve_ethtool.c | 13 ++++++- drivers/net/ethernet/google/gve/gve_main.c | 39 +++++++++++++++++++ 3 files changed, 60 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h index c237d00c5ab3..a33b44c1eb86 100644 --- a/drivers/net/ethernet/google/gve/gve.h +++ b/drivers/net/ethernet/google/gve/gve.h @@ -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 */ diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c index db6fc855a511..52500ae8348e 100644 --- a/drivers/net/ethernet/google/gve/gve_ethtool.c +++ b/drivers/net/ethernet/google/gve/gve_ethtool.c @@ -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, diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c index 616182f4fb81..6fb8fbb38a7d 100644 --- a/drivers/net/ethernet/google/gve/gve_main.c +++ b/drivers/net/ethernet/google/gve/gve_main.c @@ -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) { From 09a81a0f4fb7346f80a7340f725aedccff8ef8e4 Mon Sep 17 00:00:00 2001 From: Ankit Garg Date: Thu, 6 Nov 2025 11:27:46 -0800 Subject: [PATCH 4/4] gve: Default to max_rx_buffer_size for DQO if device supported Change the driver's default behavior to prefer the largest available RX buffer length supported by the device for DQO format, rather than always using the hardcoded 2K default. Previously, the driver would initialize with `GVE_DEFAULT_RX_BUFFER_SIZE` (2K), even if the device advertised support for a larger length (e.g., 4K). Performance observations: - With LRO disabled, we observed >10% improvement in RX single stream throughput when MTU >=2048. - With LRO enabled, we observed >10% improvement in RX single stream throughput when MTU >=1460. - No regressions were observed. Signed-off-by: Ankit Garg Reviewed-by: Harshitha Ramamurthy Reviewed-by: Jordan Rhee Reviewed-by: Willem de Bruijn Signed-off-by: Joshua Washington Link: https://patch.msgid.link/20251106192746.243525-5-joshwash@google.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/google/gve/gve_adminq.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/ethernet/google/gve/gve_adminq.c b/drivers/net/ethernet/google/gve/gve_adminq.c index 4f33d094a2ef..b72cc0fa2ba2 100644 --- a/drivers/net/ethernet/google/gve/gve_adminq.c +++ b/drivers/net/ethernet/google/gve/gve_adminq.c @@ -987,6 +987,10 @@ static void gve_enable_supported_features(struct gve_priv *priv, dev_info(&priv->pdev->dev, "BUFFER SIZES device option enabled with max_rx_buffer_size of %u, header_buf_size of %u.\n", priv->max_rx_buffer_size, priv->header_buf_size); + if (gve_is_dqo(priv) && + priv->max_rx_buffer_size > GVE_DEFAULT_RX_BUFFER_SIZE) + priv->rx_cfg.packet_buffer_size = + priv->max_rx_buffer_size; } /* Read and store ring size ranges given by device */