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gve: Add a jumbo-frame device option.
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A widely deployed driver has a bug that will cause the driver not
to load when a max_mtu > 2048 is present in the device descriptor.

To avoid this bug while still enabling jumbo frames, we present a lower
max_mtu in the device descriptor and pass the actual max_mtu in
a separate device option.

The driver supports 2 different queue formats. To enable features
on one queue format, but not the other, a supported_features mask
was added to the device options in the device descriptor.

Signed-off-by: Shailend Chand <shailend@google.com>
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Shailend Chand authored and David S. Miller committed Oct 25, 2021
1 parent 37149e9 commit 255489f
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Showing 2 changed files with 68 additions and 4 deletions.
58 changes: 54 additions & 4 deletions drivers/net/ethernet/google/gve/gve_adminq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,8 @@ void gve_parse_device_option(struct gve_priv *priv,
struct gve_device_option *option,
struct gve_device_option_gqi_rda **dev_op_gqi_rda,
struct gve_device_option_gqi_qpl **dev_op_gqi_qpl,
struct gve_device_option_dqo_rda **dev_op_dqo_rda)
struct gve_device_option_dqo_rda **dev_op_dqo_rda,
struct gve_device_option_jumbo_frames **dev_op_jumbo_frames)
{
u32 req_feat_mask = be32_to_cpu(option->required_features_mask);
u16 option_length = be16_to_cpu(option->option_length);
Expand Down Expand Up @@ -111,6 +112,24 @@ void gve_parse_device_option(struct gve_priv *priv,
}
*dev_op_dqo_rda = (void *)(option + 1);
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) {
dev_warn(&priv->pdev->dev, GVE_DEVICE_OPTION_ERROR_FMT,
"Jumbo Frames",
(int)sizeof(**dev_op_jumbo_frames),
GVE_DEV_OPT_REQ_FEAT_MASK_JUMBO_FRAMES,
option_length, req_feat_mask);
break;
}

if (option_length > sizeof(**dev_op_jumbo_frames)) {
dev_warn(&priv->pdev->dev,
GVE_DEVICE_OPTION_TOO_BIG_FMT,
"Jumbo Frames");
}
*dev_op_jumbo_frames = (void *)(option + 1);
break;
default:
/* If we don't recognize the option just continue
* without doing anything.
Expand All @@ -126,7 +145,8 @@ gve_process_device_options(struct gve_priv *priv,
struct gve_device_descriptor *descriptor,
struct gve_device_option_gqi_rda **dev_op_gqi_rda,
struct gve_device_option_gqi_qpl **dev_op_gqi_qpl,
struct gve_device_option_dqo_rda **dev_op_dqo_rda)
struct gve_device_option_dqo_rda **dev_op_dqo_rda,
struct gve_device_option_jumbo_frames **dev_op_jumbo_frames)
{
const int num_options = be16_to_cpu(descriptor->num_device_options);
struct gve_device_option *dev_opt;
Expand All @@ -146,7 +166,7 @@ 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_dqo_rda, dev_op_jumbo_frames);
dev_opt = next_opt;
}

Expand Down Expand Up @@ -661,12 +681,31 @@ gve_set_desc_cnt_dqo(struct gve_priv *priv,
return 0;
}

static void gve_enable_supported_features(struct gve_priv *priv,
u32 supported_features_mask,
const struct gve_device_option_jumbo_frames
*dev_op_jumbo_frames)
{
/* Before control reaches this point, the page-size-capped max MTU from
* the gve_device_descriptor field has already been stored in
* priv->dev->max_mtu. We overwrite it with the true max MTU below.
*/
if (dev_op_jumbo_frames &&
(supported_features_mask & GVE_SUP_JUMBO_FRAMES_MASK)) {
dev_info(&priv->pdev->dev,
"JUMBO FRAMES device option enabled.\n");
priv->dev->max_mtu = be16_to_cpu(dev_op_jumbo_frames->max_mtu);
}
}

int gve_adminq_describe_device(struct gve_priv *priv)
{
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;
struct gve_device_option_dqo_rda *dev_op_dqo_rda = NULL;
struct gve_device_descriptor *descriptor;
u32 supported_features_mask = 0;
union gve_adminq_command cmd;
dma_addr_t descriptor_bus;
int err = 0;
Expand All @@ -690,7 +729,8 @@ int gve_adminq_describe_device(struct gve_priv *priv)
goto free_device_descriptor;

err = gve_process_device_options(priv, descriptor, &dev_op_gqi_rda,
&dev_op_gqi_qpl, &dev_op_dqo_rda);
&dev_op_gqi_qpl, &dev_op_dqo_rda,
&dev_op_jumbo_frames);
if (err)
goto free_device_descriptor;

Expand All @@ -705,12 +745,19 @@ int gve_adminq_describe_device(struct gve_priv *priv)
priv->queue_format = GVE_DQO_RDA_FORMAT;
dev_info(&priv->pdev->dev,
"Driver is running with DQO RDA queue format.\n");
supported_features_mask =
be32_to_cpu(dev_op_dqo_rda->supported_features_mask);
} else if (dev_op_gqi_rda) {
priv->queue_format = GVE_GQI_RDA_FORMAT;
dev_info(&priv->pdev->dev,
"Driver is running with GQI RDA queue format.\n");
supported_features_mask =
be32_to_cpu(dev_op_gqi_rda->supported_features_mask);
} else {
priv->queue_format = GVE_GQI_QPL_FORMAT;
if (dev_op_gqi_qpl)
supported_features_mask =
be32_to_cpu(dev_op_gqi_qpl->supported_features_mask);
dev_info(&priv->pdev->dev,
"Driver is running with GQI QPL queue format.\n");
}
Expand Down Expand Up @@ -747,6 +794,9 @@ 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);

free_device_descriptor:
dma_free_coherent(&priv->pdev->dev, PAGE_SIZE, descriptor,
descriptor_bus);
Expand Down
14 changes: 14 additions & 0 deletions drivers/net/ethernet/google/gve/gve_adminq.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,14 @@ struct gve_device_option_dqo_rda {

static_assert(sizeof(struct gve_device_option_dqo_rda) == 8);

struct gve_device_option_jumbo_frames {
__be32 supported_features_mask;
__be16 max_mtu;
u8 padding[2];
};

static_assert(sizeof(struct gve_device_option_jumbo_frames) == 8);

/* Terminology:
*
* RDA - Raw DMA Addressing - Buffers associated with SKBs are directly DMA
Expand All @@ -121,13 +129,19 @@ 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_JUMBO_FRAMES = 0x8,
};

enum gve_dev_opt_req_feat_mask {
GVE_DEV_OPT_REQ_FEAT_MASK_GQI_RAW_ADDRESSING = 0x0,
GVE_DEV_OPT_REQ_FEAT_MASK_GQI_RDA = 0x0,
GVE_DEV_OPT_REQ_FEAT_MASK_GQI_QPL = 0x0,
GVE_DEV_OPT_REQ_FEAT_MASK_DQO_RDA = 0x0,
GVE_DEV_OPT_REQ_FEAT_MASK_JUMBO_FRAMES = 0x0,
};

enum gve_sup_feature_mask {
GVE_SUP_JUMBO_FRAMES_MASK = 1 << 2,
};

#define GVE_DEV_OPT_LEN_GQI_RAW_ADDRESSING 0x0
Expand Down

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