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kernel/files/2101-gve-Add-adminq-support-for-modifiable-ring-size.patch
eabdullin d5335bead2 Add gve patches
2026-08-21 12:35:59 +03:00

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From: Joshua Washington <joshwash@google.com>
Date: Fri, 5 Jun 2026 00:00:00 +0000
Subject: gve: Add adminq support for modifiable ring size
Add support for the gVNIC "modify ring" device option, which allows the
device to report the maximum and minimum TX/RX ring sizes it supports.
Store those bounds in the priv struct and report the device-provided
maximums through ethtool -g "Pre-set maximums" instead of hardcoding the
current (default) ring size as the maximum.
If the device does not provide minimums, fall back to the default
minimums of 256 descriptors for TX and 512 for RX.
This is the first half of the upstream gve modifiable-ring-size feature.
It only changes the advertised ring size range; actually resizing the
rings is added in the following patch.
[Jonathan Wright: backported the upstream modifiable-ring-size support to
this kernel's gve, using the implementation carried by the RHEL 10 /
AlmaLinux 10 gve driver (kernel 6.12.0-211.7.1.el10_2) as the reference,
since this 5.14-based gve predates the feature entirely. Adaptations:
threaded dev_op_modify_ring through this tree's smaller
gve_parse_device_option()/gve_process_device_options() signatures; seeded
the default ring-size ranges in both gve_set_desc_cnt() and
gve_set_desc_cnt_dqo(). Dropped the upstream
"if (priv->queue_format != GVE_DQO_QPL_FORMAT)" guard around the max ring
size assignment: that guard exists because DQO-QPL used a fixed QPL page
budget, which no longer applies now that QPL pages scale with ring size
(see 1106-gve-Update-QPL-page-registration-logic.patch), and keeping it
would deny DQO-QPL VMs the larger ring sizes this feature is for.]
Signed-off-by: Jonathan Wright <jonathan@almalinux.org>
---
diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h
index f916e81..a3c1caa 100644
--- a/drivers/net/ethernet/google/gve/gve.h
+++ b/drivers/net/ethernet/google/gve/gve.h
@@ -52,6 +52,9 @@
#define GVE_DEFAULT_RX_BUFFER_OFFSET 2048
+#define GVE_DEFAULT_MIN_TX_RING_SIZE 256
+#define GVE_DEFAULT_MIN_RX_RING_SIZE 512
+
#define GVE_XDP_ACTIONS 5
#define GVE_GQ_TX_MIN_PKT_DESC_BYTES 182
@@ -647,6 +650,12 @@ struct gve_priv {
u16 num_event_counters;
u16 tx_desc_cnt; /* num desc per ring */
u16 rx_desc_cnt; /* num desc per ring */
+ u16 max_tx_desc_cnt;
+ u16 max_rx_desc_cnt;
+ u16 min_tx_desc_cnt;
+ u16 min_rx_desc_cnt;
+ bool modify_ring_size_enabled;
+ bool default_min_ring_size;
u16 tx_pages_per_qpl; /* Number of pages per qpl for TX queues */
u16 rx_pages_per_qpl; /* Number of pages per qpl for RX queues */
u16 rx_data_slot_cnt; /* rx buffer length */
diff --git a/drivers/net/ethernet/google/gve/gve_adminq.c b/drivers/net/ethernet/google/gve/gve_adminq.c
index 62817f8..b7f86bc 100644
--- a/drivers/net/ethernet/google/gve/gve_adminq.c
+++ b/drivers/net/ethernet/google/gve/gve_adminq.c
@@ -20,6 +20,8 @@
#define GVE_DEVICE_OPTION_TOO_BIG_FMT "Length of %s option larger than expected. Possible older version of guest driver.\n"
+#define GVE_DEVICE_OPTION_NO_MIN_RING_SIZE 8
+
static
struct gve_device_option *gve_get_next_option(struct gve_device_descriptor *descriptor,
struct gve_device_option *option)
@@ -40,7 +42,8 @@ void gve_parse_device_option(struct gve_priv *priv,
struct gve_device_option_gqi_qpl **dev_op_gqi_qpl,
struct gve_device_option_dqo_rda **dev_op_dqo_rda,
struct gve_device_option_jumbo_frames **dev_op_jumbo_frames,
- struct gve_device_option_dqo_qpl **dev_op_dqo_qpl)
+ struct gve_device_option_dqo_qpl **dev_op_dqo_qpl,
+ struct gve_device_option_modify_ring **dev_op_modify_ring)
{
u32 req_feat_mask = be32_to_cpu(option->required_features_mask);
u16 option_length = be16_to_cpu(option->option_length);
@@ -129,6 +132,27 @@ void gve_parse_device_option(struct gve_priv *priv,
}
*dev_op_dqo_qpl = (void *)(option + 1);
break;
+ case GVE_DEV_OPT_ID_MODIFY_RING:
+ if (option_length < GVE_DEVICE_OPTION_NO_MIN_RING_SIZE ||
+ req_feat_mask != GVE_DEV_OPT_REQ_FEAT_MASK_MODIFY_RING) {
+ dev_warn(&priv->pdev->dev, GVE_DEVICE_OPTION_ERROR_FMT,
+ "Modify Ring", (int)sizeof(**dev_op_modify_ring),
+ GVE_DEV_OPT_REQ_FEAT_MASK_MODIFY_RING,
+ option_length, req_feat_mask);
+ break;
+ }
+
+ if (option_length > sizeof(**dev_op_modify_ring)) {
+ dev_warn(&priv->pdev->dev,
+ GVE_DEVICE_OPTION_TOO_BIG_FMT, "Modify Ring");
+ }
+
+ *dev_op_modify_ring = (void *)(option + 1);
+
+ /* device has not provided min ring size */
+ if (option_length == GVE_DEVICE_OPTION_NO_MIN_RING_SIZE)
+ priv->default_min_ring_size = true;
+ break;
case GVE_DEV_OPT_ID_JUMBO_FRAMES:
if (option_length < sizeof(**dev_op_jumbo_frames) ||
req_feat_mask != GVE_DEV_OPT_REQ_FEAT_MASK_JUMBO_FRAMES) {
@@ -164,7 +188,8 @@ gve_process_device_options(struct gve_priv *priv,
struct gve_device_option_gqi_qpl **dev_op_gqi_qpl,
struct gve_device_option_dqo_rda **dev_op_dqo_rda,
struct gve_device_option_jumbo_frames **dev_op_jumbo_frames,
- struct gve_device_option_dqo_qpl **dev_op_dqo_qpl)
+ struct gve_device_option_dqo_qpl **dev_op_dqo_qpl,
+ struct gve_device_option_modify_ring **dev_op_modify_ring)
{
const int num_options = be16_to_cpu(descriptor->num_device_options);
struct gve_device_option *dev_opt;
@@ -185,7 +210,7 @@ gve_process_device_options(struct gve_priv *priv,
gve_parse_device_option(priv, descriptor, dev_opt,
dev_op_gqi_rda, dev_op_gqi_qpl,
dev_op_dqo_rda, dev_op_jumbo_frames,
- dev_op_dqo_qpl);
+ dev_op_dqo_qpl, dev_op_modify_ring);
dev_opt = next_opt;
}
@@ -728,6 +753,12 @@ static int gve_set_desc_cnt(struct gve_priv *priv,
{
priv->tx_desc_cnt = be16_to_cpu(descriptor->tx_queue_entries);
priv->rx_desc_cnt = be16_to_cpu(descriptor->rx_queue_entries);
+
+ /* set default ranges */
+ priv->max_tx_desc_cnt = priv->tx_desc_cnt;
+ priv->max_rx_desc_cnt = priv->rx_desc_cnt;
+ priv->min_tx_desc_cnt = priv->tx_desc_cnt;
+ priv->min_rx_desc_cnt = priv->rx_desc_cnt;
return 0;
}
@@ -739,6 +770,12 @@ gve_set_desc_cnt_dqo(struct gve_priv *priv,
priv->tx_desc_cnt = be16_to_cpu(descriptor->tx_queue_entries);
priv->rx_desc_cnt = be16_to_cpu(descriptor->rx_queue_entries);
+ /* set default ranges */
+ priv->max_tx_desc_cnt = priv->tx_desc_cnt;
+ priv->max_rx_desc_cnt = priv->rx_desc_cnt;
+ priv->min_tx_desc_cnt = priv->tx_desc_cnt;
+ priv->min_rx_desc_cnt = priv->rx_desc_cnt;
+
if (priv->queue_format == GVE_DQO_QPL_FORMAT)
return 0;
@@ -755,7 +792,9 @@ static void gve_enable_supported_features(struct gve_priv *priv,
const struct gve_device_option_jumbo_frames
*dev_op_jumbo_frames,
const struct gve_device_option_dqo_qpl
- *dev_op_dqo_qpl)
+ *dev_op_dqo_qpl,
+ const struct gve_device_option_modify_ring
+ *dev_op_modify_ring)
{
/* Before control reaches this point, the page-size-capped max MTU from
* the gve_device_descriptor field has already been stored in
@@ -767,10 +806,29 @@ static void gve_enable_supported_features(struct gve_priv *priv,
"JUMBO FRAMES device option enabled.\n");
priv->dev->max_mtu = be16_to_cpu(dev_op_jumbo_frames->max_mtu);
}
+
+ /* Read and store ring size ranges given by device */
+ if (dev_op_modify_ring &&
+ (supported_features_mask & GVE_SUP_MODIFY_RING_MASK)) {
+ priv->modify_ring_size_enabled = true;
+
+ priv->max_rx_desc_cnt = be16_to_cpu(dev_op_modify_ring->max_rx_ring_size);
+ priv->max_tx_desc_cnt = be16_to_cpu(dev_op_modify_ring->max_tx_ring_size);
+
+ if (priv->default_min_ring_size) {
+ /* If device hasn't provided minimums, use default minimums */
+ priv->min_tx_desc_cnt = GVE_DEFAULT_MIN_TX_RING_SIZE;
+ priv->min_rx_desc_cnt = GVE_DEFAULT_MIN_RX_RING_SIZE;
+ } else {
+ priv->min_rx_desc_cnt = be16_to_cpu(dev_op_modify_ring->min_rx_ring_size);
+ priv->min_tx_desc_cnt = be16_to_cpu(dev_op_modify_ring->min_tx_ring_size);
+ }
+ }
}
int gve_adminq_describe_device(struct gve_priv *priv)
{
+ struct gve_device_option_modify_ring *dev_op_modify_ring = NULL;
struct gve_device_option_jumbo_frames *dev_op_jumbo_frames = NULL;
struct gve_device_option_gqi_rda *dev_op_gqi_rda = NULL;
struct gve_device_option_gqi_qpl *dev_op_gqi_qpl = NULL;
@@ -804,7 +862,7 @@ int gve_adminq_describe_device(struct gve_priv *priv)
err = gve_process_device_options(priv, descriptor, &dev_op_gqi_rda,
&dev_op_gqi_qpl, &dev_op_dqo_rda,
&dev_op_jumbo_frames,
- &dev_op_dqo_qpl);
+ &dev_op_dqo_qpl, &dev_op_modify_ring);
if (err)
goto free_device_descriptor;
@@ -873,7 +931,8 @@ int gve_adminq_describe_device(struct gve_priv *priv)
priv->default_num_queues = be16_to_cpu(descriptor->default_num_queues);
gve_enable_supported_features(priv, supported_features_mask,
- dev_op_jumbo_frames, dev_op_dqo_qpl);
+ dev_op_jumbo_frames, dev_op_dqo_qpl,
+ dev_op_modify_ring);
free_device_descriptor:
dma_pool_free(priv->adminq_pool, descriptor, descriptor_bus);
diff --git a/drivers/net/ethernet/google/gve/gve_adminq.h b/drivers/net/ethernet/google/gve/gve_adminq.h
index 5865ccd..0d1dd38 100644
--- a/drivers/net/ethernet/google/gve/gve_adminq.h
+++ b/drivers/net/ethernet/google/gve/gve_adminq.h
@@ -125,6 +125,16 @@ struct gve_device_option_jumbo_frames {
static_assert(sizeof(struct gve_device_option_jumbo_frames) == 8);
+struct gve_device_option_modify_ring {
+ __be32 supported_featured_mask;
+ __be16 max_rx_ring_size;
+ __be16 max_tx_ring_size;
+ __be16 min_rx_ring_size;
+ __be16 min_tx_ring_size;
+};
+
+static_assert(sizeof(struct gve_device_option_modify_ring) == 12);
+
/* Terminology:
*
* RDA - Raw DMA Addressing - Buffers associated with SKBs are directly DMA
@@ -138,6 +148,7 @@ enum gve_dev_opt_id {
GVE_DEV_OPT_ID_GQI_RDA = 0x2,
GVE_DEV_OPT_ID_GQI_QPL = 0x3,
GVE_DEV_OPT_ID_DQO_RDA = 0x4,
+ GVE_DEV_OPT_ID_MODIFY_RING = 0x6,
GVE_DEV_OPT_ID_DQO_QPL = 0x7,
GVE_DEV_OPT_ID_JUMBO_FRAMES = 0x8,
};
@@ -149,9 +160,11 @@ enum gve_dev_opt_req_feat_mask {
GVE_DEV_OPT_REQ_FEAT_MASK_DQO_RDA = 0x0,
GVE_DEV_OPT_REQ_FEAT_MASK_JUMBO_FRAMES = 0x0,
GVE_DEV_OPT_REQ_FEAT_MASK_DQO_QPL = 0x0,
+ GVE_DEV_OPT_REQ_FEAT_MASK_MODIFY_RING = 0x0,
};
enum gve_sup_feature_mask {
+ GVE_SUP_MODIFY_RING_MASK = 1 << 0,
GVE_SUP_JUMBO_FRAMES_MASK = 1 << 2,
};
diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c
index e5397aa..fb7b477 100644
--- a/drivers/net/ethernet/google/gve/gve_ethtool.c
+++ b/drivers/net/ethernet/google/gve/gve_ethtool.c
@@ -476,8 +476,8 @@ static void gve_get_ringparam(struct net_device *netdev,
{
struct gve_priv *priv = netdev_priv(netdev);
- cmd->rx_max_pending = priv->rx_desc_cnt;
- cmd->tx_max_pending = priv->tx_desc_cnt;
+ cmd->rx_max_pending = priv->max_rx_desc_cnt;
+ cmd->tx_max_pending = priv->max_tx_desc_cnt;
cmd->rx_pending = priv->rx_desc_cnt;
cmd->tx_pending = priv->tx_desc_cnt;
}
--
2.43.0
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