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

// SPDX-License-Identifier: (GPL-2.0 OR MIT)
/* Google virtual Ethernet (gve) driver
 *
 * Copyright (C) 2015-2019 Google, Inc.
 */

#include <linux/etherdevice.h>
#include <linux/pci.h>
#include "gve.h"
#include "gve_adminq.h"
#include "gve_register.h"

#define GVE_MAX_ADMINQ_RELEASE_CHECK	500
#define GVE_ADMINQ_SLEEP_LEN		20
#define GVE_MAX_ADMINQ_EVENT_COUNTER_CHECK	100

int gve_adminq_alloc(struct device *dev, struct gve_priv *priv)
{
	priv->adminq = dma_alloc_coherent(dev, PAGE_SIZE,
					  &priv->adminq_bus_addr, GFP_KERNEL);
	if (unlikely(!priv->adminq))
		return -ENOMEM;

	priv->adminq_mask = (PAGE_SIZE / sizeof(union gve_adminq_command)) - 1;
	priv->adminq_prod_cnt = 0;
	priv->adminq_cmd_fail = 0;
	priv->adminq_timeouts = 0;
	priv->adminq_describe_device_cnt = 0;
	priv->adminq_cfg_device_resources_cnt = 0;
	priv->adminq_register_page_list_cnt = 0;
	priv->adminq_unregister_page_list_cnt = 0;
	priv->adminq_create_tx_queue_cnt = 0;
	priv->adminq_create_rx_queue_cnt = 0;
	priv->adminq_destroy_tx_queue_cnt = 0;
	priv->adminq_destroy_rx_queue_cnt = 0;
	priv->adminq_dcfg_device_resources_cnt = 0;
	priv->adminq_set_driver_parameter_cnt = 0;
	priv->adminq_report_stats_cnt = 0;

	/* Setup Admin queue with the device */
	iowrite32be(priv->adminq_bus_addr / PAGE_SIZE,
		    &priv->reg_bar0->adminq_pfn);

	gve_set_admin_queue_ok(priv);
	return 0;
}

void gve_adminq_release(struct gve_priv *priv)
{
	int i = 0;

	/* Tell the device the adminq is leaving */
	iowrite32be(0x0, &priv->reg_bar0->adminq_pfn);
	while (ioread32be(&priv->reg_bar0->adminq_pfn)) {
		/* If this is reached the device is unrecoverable and still
		 * holding memory. Continue looping to avoid memory corruption,
		 * but WARN so it is visible what is going on.
		 */
		if (i == GVE_MAX_ADMINQ_RELEASE_CHECK)
			WARN(1, "Unrecoverable platform error!");
		i++;
		msleep(GVE_ADMINQ_SLEEP_LEN);
	}
	gve_clear_device_rings_ok(priv);
	gve_clear_device_resources_ok(priv);
	gve_clear_admin_queue_ok(priv);
}

void gve_adminq_free(struct device *dev, struct gve_priv *priv)
{
	if (!gve_get_admin_queue_ok(priv))
		return;
	gve_adminq_release(priv);
	dma_free_coherent(dev, PAGE_SIZE, priv->adminq, priv->adminq_bus_addr);
	gve_clear_admin_queue_ok(priv);
}

static void gve_adminq_kick_cmd(struct gve_priv *priv, u32 prod_cnt)
{
	iowrite32be(prod_cnt, &priv->reg_bar0->adminq_doorbell);
}

static bool gve_adminq_wait_for_cmd(struct gve_priv *priv, u32 prod_cnt)
{
	int i;

	for (i = 0; i < GVE_MAX_ADMINQ_EVENT_COUNTER_CHECK; i++) {
		if (ioread32be(&priv->reg_bar0->adminq_event_counter)
		    == prod_cnt)
			return true;
		msleep(GVE_ADMINQ_SLEEP_LEN);
	}

	return false;
}

static int gve_adminq_parse_err(struct gve_priv *priv, u32 status)
{
	if (status != GVE_ADMINQ_COMMAND_PASSED &&
	    status != GVE_ADMINQ_COMMAND_UNSET) {
		dev_err(&priv->pdev->dev, "AQ command failed with status %d\n", status);
		priv->adminq_cmd_fail++;
	}
	switch (status) {
	case GVE_ADMINQ_COMMAND_PASSED:
		return 0;
	case GVE_ADMINQ_COMMAND_UNSET:
		dev_err(&priv->pdev->dev, "parse_aq_err: err and status both unset, this should not be possible.\n");
		return -EINVAL;
	case GVE_ADMINQ_COMMAND_ERROR_ABORTED:
	case GVE_ADMINQ_COMMAND_ERROR_CANCELLED:
	case GVE_ADMINQ_COMMAND_ERROR_DATALOSS:
	case GVE_ADMINQ_COMMAND_ERROR_FAILED_PRECONDITION:
	case GVE_ADMINQ_COMMAND_ERROR_UNAVAILABLE:
		return -EAGAIN;
	case GVE_ADMINQ_COMMAND_ERROR_ALREADY_EXISTS:
	case GVE_ADMINQ_COMMAND_ERROR_INTERNAL_ERROR:
	case GVE_ADMINQ_COMMAND_ERROR_INVALID_ARGUMENT:
	case GVE_ADMINQ_COMMAND_ERROR_NOT_FOUND:
	case GVE_ADMINQ_COMMAND_ERROR_OUT_OF_RANGE:
	case GVE_ADMINQ_COMMAND_ERROR_UNKNOWN_ERROR:
		return -EINVAL;
	case GVE_ADMINQ_COMMAND_ERROR_DEADLINE_EXCEEDED:
		return -ETIME;
	case GVE_ADMINQ_COMMAND_ERROR_PERMISSION_DENIED:
	case GVE_ADMINQ_COMMAND_ERROR_UNAUTHENTICATED:
		return -EACCES;
	case GVE_ADMINQ_COMMAND_ERROR_RESOURCE_EXHAUSTED:
		return -ENOMEM;
	case GVE_ADMINQ_COMMAND_ERROR_UNIMPLEMENTED:
		return -ENOTSUPP;
	default:
		dev_err(&priv->pdev->dev, "parse_aq_err: unknown status code %d\n", status);
		return -EINVAL;
	}
}

/* Flushes all AQ commands currently queued and waits for them to complete.
 * If there are failures, it will return the first error.
 */
static int gve_adminq_kick_and_wait(struct gve_priv *priv)
{
	u32 tail, head;
	int i;

	tail = ioread32be(&priv->reg_bar0->adminq_event_counter);
	head = priv->adminq_prod_cnt;

	gve_adminq_kick_cmd(priv, head);
	if (!gve_adminq_wait_for_cmd(priv, head)) {
		dev_err(&priv->pdev->dev, "AQ commands timed out, need to reset AQ\n");
		priv->adminq_timeouts++;
		return -ENOTRECOVERABLE;
	}

	for (i = tail; i < head; i++) {
		union gve_adminq_command *cmd;
		u32 status, err;

		cmd = &priv->adminq[i & priv->adminq_mask];
		status = be32_to_cpu(READ_ONCE(cmd->status));
		err = gve_adminq_parse_err(priv, status);
		if (err)
			// Return the first error if we failed.
			return err;
	}

	return 0;
}

/* This function is not threadsafe - the caller is responsible for any
 * necessary locks.
 */
static int gve_adminq_issue_cmd(struct gve_priv *priv,
				union gve_adminq_command *cmd_orig)
{
	union gve_adminq_command *cmd;
	u32 tail;
	u32 opcode;

	tail = ioread32be(&priv->reg_bar0->adminq_event_counter);

	// Check if next command will overflow the buffer.
	if (((priv->adminq_prod_cnt + 1) & priv->adminq_mask) == tail) {
		int err;

		// Flush existing commands to make room.
		err = gve_adminq_kick_and_wait(priv);
		if (err)
			return err;

		// Retry.
		tail = ioread32be(&priv->reg_bar0->adminq_event_counter);
		if (((priv->adminq_prod_cnt + 1) & priv->adminq_mask) == tail) {
			// This should never happen. We just flushed the
			// command queue so there should be enough space.
			return -ENOMEM;
		}
	}

	cmd = &priv->adminq[priv->adminq_prod_cnt & priv->adminq_mask];
	priv->adminq_prod_cnt++;

	memcpy(cmd, cmd_orig, sizeof(*cmd_orig));
	opcode = be32_to_cpu(READ_ONCE(cmd->opcode));

	switch(opcode) {
	case GVE_ADMINQ_DESCRIBE_DEVICE:
		priv->adminq_describe_device_cnt++;
		break;
	case GVE_ADMINQ_CONFIGURE_DEVICE_RESOURCES:
		priv->adminq_cfg_device_resources_cnt++;
		break;
	case GVE_ADMINQ_REGISTER_PAGE_LIST:
		priv->adminq_register_page_list_cnt++;
		break;
	case GVE_ADMINQ_UNREGISTER_PAGE_LIST:
		priv->adminq_unregister_page_list_cnt++;
		break;
	case GVE_ADMINQ_CREATE_TX_QUEUE:
		priv->adminq_create_tx_queue_cnt++;
		break;
	case GVE_ADMINQ_CREATE_RX_QUEUE:
		priv->adminq_create_rx_queue_cnt++;
		break;
	case GVE_ADMINQ_DESTROY_TX_QUEUE:
		priv->adminq_destroy_tx_queue_cnt++;
		break;
	case GVE_ADMINQ_DESTROY_RX_QUEUE:
		priv->adminq_destroy_rx_queue_cnt++;
		break;
	case GVE_ADMINQ_DECONFIGURE_DEVICE_RESOURCES:
		priv->adminq_dcfg_device_resources_cnt++;
		break;
	case GVE_ADMINQ_SET_DRIVER_PARAMETER:
		priv->adminq_set_driver_parameter_cnt++;
		break;
	case GVE_ADMINQ_REPORT_STATS:
		priv->adminq_report_stats_cnt++;
		break;
	default:
		dev_err(&priv->pdev->dev, "unknown AQ command opcode %d\n", opcode);
	}

	return 0;
}

/* This function is not threadsafe - the caller is responsible for any
 * necessary locks.
 * The caller is also responsible for making sure there are no commands
 * waiting to be executed.
 */
static int gve_adminq_execute_cmd(struct gve_priv *priv,
			   union gve_adminq_command *cmd_orig)
{
	u32 tail, head;
	int err;

	tail = ioread32be(&priv->reg_bar0->adminq_event_counter);
	head = priv->adminq_prod_cnt;
	if (tail != head)
		// This is not a valid path
		return -EINVAL;

	err = gve_adminq_issue_cmd(priv, cmd_orig);
	if (err)
		return err;

	return gve_adminq_kick_and_wait(priv);
}

/* The device specifies that the management vector can either be the first irq
 * or the last irq. ntfy_blk_msix_base_idx indicates the first irq assigned to
 * the ntfy blks. It if is 0 then the management vector is last, if it is 1 then
 * the management vector is first.
 *
 * gve arranges the msix vectors so that the management vector is last.
 */
#define GVE_NTFY_BLK_BASE_MSIX_IDX	0
int gve_adminq_configure_device_resources(struct gve_priv *priv,
					  dma_addr_t counter_array_bus_addr,
					  u32 num_counters,
					  dma_addr_t db_array_bus_addr,
					  u32 num_ntfy_blks)
{
	union gve_adminq_command cmd;

	memset(&cmd, 0, sizeof(cmd));
	cmd.opcode = cpu_to_be32(GVE_ADMINQ_CONFIGURE_DEVICE_RESOURCES);
	cmd.configure_device_resources =
		(struct gve_adminq_configure_device_resources) {
		.counter_array = cpu_to_be64(counter_array_bus_addr),
		.num_counters = cpu_to_be32(num_counters),
		.irq_db_addr = cpu_to_be64(db_array_bus_addr),
		.num_irq_dbs = cpu_to_be32(num_ntfy_blks),
		.irq_db_stride = cpu_to_be32(sizeof(*priv->irq_db_indices)),
		.ntfy_blk_msix_base_idx =
					cpu_to_be32(GVE_NTFY_BLK_BASE_MSIX_IDX),
	};

	return gve_adminq_execute_cmd(priv, &cmd);
}

int gve_adminq_deconfigure_device_resources(struct gve_priv *priv)
{
	union gve_adminq_command cmd;

	memset(&cmd, 0, sizeof(cmd));
	cmd.opcode = cpu_to_be32(GVE_ADMINQ_DECONFIGURE_DEVICE_RESOURCES);

	return gve_adminq_execute_cmd(priv, &cmd);
}

int gve_adminq_create_tx_queues(struct gve_priv *priv, u32 num_queues)
{
	union gve_adminq_command cmd;
	struct gve_tx_ring *tx;
	u32 qpl_id;
	int err;
	int i;

	for (i = 0; i < num_queues; i++) {
		tx = &priv->tx[i];
		qpl_id = priv->raw_addressing ? GVE_RAW_ADDRESSING_QPL_ID :
			 tx->tx_fifo.qpl->id;
		memset(&cmd, 0, sizeof(cmd));
		cmd.opcode = cpu_to_be32(GVE_ADMINQ_CREATE_TX_QUEUE);
		cmd.create_tx_queue = (struct gve_adminq_create_tx_queue) {
			.queue_id = cpu_to_be32(i),
			.reserved = 0,
			.queue_resources_addr =
				cpu_to_be64(tx->q_resources_bus),
			.tx_ring_addr = cpu_to_be64(tx->bus),
			.queue_page_list_id = cpu_to_be32(qpl_id),
			.ntfy_id = cpu_to_be32(tx->ntfy_id),
		};
		err = gve_adminq_issue_cmd(priv, &cmd);
		if (err)
			return err;
	}

	return gve_adminq_kick_and_wait(priv);
}

int gve_adminq_create_rx_queues(struct gve_priv *priv, u32 num_queues)
{
	union gve_adminq_command cmd;
	struct gve_rx_ring *rx;
	u32 qpl_id;
	int err;
	int i;

	for (i = 0; i < num_queues; i++) {
		rx = &priv->rx[i];
		qpl_id = priv->raw_addressing ? GVE_RAW_ADDRESSING_QPL_ID :
			 rx->data.qpl->id;
		memset(&cmd, 0, sizeof(cmd));
		cmd.opcode = cpu_to_be32(GVE_ADMINQ_CREATE_RX_QUEUE);
		cmd.create_rx_queue = (struct gve_adminq_create_rx_queue) {
			.queue_id = cpu_to_be32(i),
			.index = cpu_to_be32(i),
			.reserved = 0,
			.ntfy_id = cpu_to_be32(rx->ntfy_id),
			.queue_resources_addr = cpu_to_be64(rx->q_resources_bus),
			.rx_desc_ring_addr = cpu_to_be64(rx->desc.bus),
			.rx_data_ring_addr = cpu_to_be64(rx->data.data_bus),
			.queue_page_list_id = cpu_to_be32(qpl_id),
		};
		err = gve_adminq_issue_cmd(priv, &cmd);
		if (err)
			return err;
	}

	return gve_adminq_kick_and_wait(priv);
}

int gve_adminq_destroy_tx_queues(struct gve_priv *priv, u32 num_queues)
{
	union gve_adminq_command cmd;
	int err;
	int i;

	for (i = 0; i < num_queues; i++) {
		memset(&cmd, 0, sizeof(cmd));
		cmd.opcode = cpu_to_be32(GVE_ADMINQ_DESTROY_TX_QUEUE);
		cmd.destroy_tx_queue = (struct gve_adminq_destroy_tx_queue) {
			.queue_id = cpu_to_be32(i),
		};
		err = gve_adminq_issue_cmd(priv, &cmd);
		if (err)
			return err;
	}

	return gve_adminq_kick_and_wait(priv);
}

int gve_adminq_destroy_rx_queues(struct gve_priv *priv, u32 num_queues)
{
	union gve_adminq_command cmd;
	int err;
	int i;

	for (i = 0; i < num_queues; i++) {
		memset(&cmd, 0, sizeof(cmd));
		cmd.opcode = cpu_to_be32(GVE_ADMINQ_DESTROY_RX_QUEUE);
		cmd.destroy_rx_queue = (struct gve_adminq_destroy_rx_queue) {
			.queue_id = cpu_to_be32(i),
		};
		err = gve_adminq_issue_cmd(priv, &cmd);
		if (err)
			return err;
	}

	return gve_adminq_kick_and_wait(priv);
}

int gve_adminq_describe_device(struct gve_priv *priv)
{
	struct gve_device_descriptor *descriptor;
	struct gve_device_option *dev_opt;
	union gve_adminq_command cmd;
	dma_addr_t descriptor_bus;
	u16 num_options;
	int err = 0;
	u8 *mac;
	u16 mtu;
	int i;

	memset(&cmd, 0, sizeof(cmd));
	descriptor = dma_alloc_coherent(&priv->pdev->dev, PAGE_SIZE,
					&descriptor_bus, GFP_KERNEL);
	if (!descriptor)
		return -ENOMEM;
	cmd.opcode = cpu_to_be32(GVE_ADMINQ_DESCRIBE_DEVICE);
	cmd.describe_device.device_descriptor_addr =
						cpu_to_be64(descriptor_bus);
	cmd.describe_device.device_descriptor_version =
			cpu_to_be32(GVE_ADMINQ_DEVICE_DESCRIPTOR_VERSION);
	cmd.describe_device.available_length = cpu_to_be32(PAGE_SIZE);

	err = gve_adminq_execute_cmd(priv, &cmd);
	if (err)
		goto free_device_descriptor;

	priv->tx_desc_cnt = be16_to_cpu(descriptor->tx_queue_entries);
	if (priv->tx_desc_cnt * sizeof(priv->tx->desc[0]) < PAGE_SIZE) {
		dev_err(&priv->pdev->dev, "Tx desc count %d too low\n",
						priv->tx_desc_cnt);
		err = -EINVAL;
		goto free_device_descriptor;
	}
	priv->rx_desc_cnt = be16_to_cpu(descriptor->rx_queue_entries);
	if (priv->rx_desc_cnt * sizeof(priv->rx->desc.desc_ring[0])
	    < PAGE_SIZE ||
	    priv->rx_desc_cnt * sizeof(priv->rx->data.data_ring[0])
	    < PAGE_SIZE) {
		dev_err(&priv->pdev->dev, "Rx desc count %d too low\n",
			  priv->rx_desc_cnt);
		err = -EINVAL;
		goto free_device_descriptor;
	}
	priv->max_registered_pages =
				be64_to_cpu(descriptor->max_registered_pages);
	mtu = be16_to_cpu(descriptor->mtu);
	if (mtu < ETH_MIN_MTU) {
		dev_err(&priv->pdev->dev, "MTU %d below minimum MTU\n",
			  mtu);
		err = -EINVAL;
		goto free_device_descriptor;
	}
	priv->dev->max_mtu = mtu;
	priv->num_event_counters = be16_to_cpu(descriptor->counters);
	ether_addr_copy(priv->dev->dev_addr, descriptor->mac);
	mac = descriptor->mac;
	dev_info(&priv->pdev->dev, "MAC addr: %pM\n", mac);
	priv->tx_pages_per_qpl = be16_to_cpu(descriptor->tx_pages_per_qpl);
	priv->rx_data_slot_cnt = be16_to_cpu(descriptor->rx_pages_per_qpl);
	if (priv->rx_data_slot_cnt < priv->rx_desc_cnt) {
		dev_err(&priv->pdev->dev, "rx_data_slot_cnt cannot be smaller than rx_desc_cnt, setting rx_desc_cnt down to %d.\n",
			  priv->rx_data_slot_cnt);
		priv->rx_desc_cnt = priv->rx_data_slot_cnt;
	}
	priv->default_num_queues = be16_to_cpu(descriptor->default_num_queues);
	dev_opt = (struct gve_device_option *)((void *)descriptor +
							sizeof(*descriptor));

	num_options = be16_to_cpu(descriptor->num_device_options);
	for (i = 0; i < num_options; i++) {
		u16 option_id;
		u16 option_length;

		if ((void *)dev_opt + sizeof(*dev_opt)  > (void *)descriptor +
				      be16_to_cpu(descriptor->total_length)) {
			dev_err(&priv->dev->dev,
				  "num_options in device_descriptor does not match total length.\n");
			err = -EINVAL;
			goto free_device_descriptor;
		}

		option_id = be16_to_cpu(dev_opt->option_id);
		option_length = be16_to_cpu(dev_opt->option_length);
		switch(option_id) {
		case GVE_DEV_OPT_ID_RAW_ADDRESSING:
			/* If the length or feature mask doesn't match,
			 * continue without enabling the feature.
			 */
			if (option_length != GVE_DEV_OPT_LEN_RAW_ADDRESSING ||
			    be32_to_cpu(dev_opt->feat_mask) !=
			    GVE_DEV_OPT_FEAT_MASK_RAW_ADDRESSING) {
				dev_info(&priv->pdev->dev,
					   "Raw addressing device option not enabled, length or features mask did not match expected.\n");
				priv->raw_addressing = false;
			} else {
				dev_info(&priv->pdev->dev,
					   "Raw addressing device option enabled.\n");
				priv->raw_addressing = true;
			}
			break;
		default:
			/* If we don't recognize the option just continue
			 * without doing anything.
			 */
			dev_info(&priv->pdev->dev,
				   "Unrecognized device option 0x%hx not enabled.\n",
				   option_id);
			break;
		}
		dev_opt = (void *)dev_opt + sizeof(*dev_opt) + option_length;
	}

free_device_descriptor:
	dma_free_coherent(&priv->pdev->dev, PAGE_SIZE, descriptor,
			  descriptor_bus);
	return err;
}

int gve_adminq_register_page_list(struct gve_priv *priv,
				  struct gve_queue_page_list *qpl)
{
	struct device *hdev = &priv->pdev->dev;
	u32 num_entries = qpl->num_entries;
	u32 size = num_entries * sizeof(qpl->page_buses[0]);
	union gve_adminq_command cmd;
	dma_addr_t page_list_bus;
	__be64 *page_list;
	int err;
	int i;

	memset(&cmd, 0, sizeof(cmd));
	page_list = dma_alloc_coherent(hdev, size, &page_list_bus, GFP_KERNEL);
	if (!page_list)
		return -ENOMEM;

	for (i = 0; i < num_entries; i++)
		page_list[i] = cpu_to_be64(qpl->page_buses[i]);

	cmd.opcode = cpu_to_be32(GVE_ADMINQ_REGISTER_PAGE_LIST);
	cmd.reg_page_list = (struct gve_adminq_register_page_list) {
		.page_list_id = cpu_to_be32(qpl->id),
		.num_pages = cpu_to_be32(num_entries),
		.page_address_list_addr = cpu_to_be64(page_list_bus),
	};

	err = gve_adminq_execute_cmd(priv, &cmd);
	dma_free_coherent(hdev, size, page_list, page_list_bus);
	return err;
}

int gve_adminq_unregister_page_list(struct gve_priv *priv, u32 page_list_id)
{
	union gve_adminq_command cmd;

	memset(&cmd, 0, sizeof(cmd));
	cmd.opcode = cpu_to_be32(GVE_ADMINQ_UNREGISTER_PAGE_LIST);
	cmd.unreg_page_list = (struct gve_adminq_unregister_page_list) {
		.page_list_id = cpu_to_be32(page_list_id),
	};

	return gve_adminq_execute_cmd(priv, &cmd);
}

int gve_adminq_set_mtu(struct gve_priv *priv, u64 mtu)
{
	union gve_adminq_command cmd;

	memset(&cmd, 0, sizeof(cmd));
	cmd.opcode = cpu_to_be32(GVE_ADMINQ_SET_DRIVER_PARAMETER);
	cmd.set_driver_param = (struct gve_adminq_set_driver_parameter) {
		.parameter_type = cpu_to_be32(GVE_SET_PARAM_MTU),
		.parameter_value = cpu_to_be64(mtu),
	};

	return gve_adminq_execute_cmd(priv, &cmd);
}

int gve_adminq_report_stats(struct gve_priv *priv, u64 stats_report_len,
			    dma_addr_t stats_report_addr, u64 interval)
{
	union gve_adminq_command cmd;

	memset(&cmd, 0, sizeof(cmd));
	cmd.opcode = cpu_to_be32(GVE_ADMINQ_REPORT_STATS);
	cmd.report_stats = (struct gve_adminq_report_stats) {
		.stats_report_len = cpu_to_be64(stats_report_len),
		.stats_report_addr = cpu_to_be64(stats_report_addr),
		.interval = cpu_to_be64(interval),
	};

	return gve_adminq_execute_cmd(priv, &cmd);
}

int gve_adminq_report_link_speed(struct gve_priv *priv)
{
	union gve_adminq_command gvnic_cmd;
	dma_addr_t link_speed_region_bus;
	u64* link_speed_region;
	int err;

	link_speed_region = dma_alloc_coherent(&priv->pdev->dev,
		sizeof(*link_speed_region), &link_speed_region_bus, GFP_KERNEL);

	if (!link_speed_region)
		return -ENOMEM;

	memset(&gvnic_cmd, 0, sizeof(gvnic_cmd));
	gvnic_cmd.opcode = cpu_to_be32(GVE_ADMINQ_REPORT_LINK_SPEED);
	gvnic_cmd.report_link_speed.link_speed_address =
		cpu_to_be64(link_speed_region_bus);

	err = gve_adminq_execute_cmd(priv, &gvnic_cmd);

	priv->link_speed = be64_to_cpu(*link_speed_region);
	dma_free_coherent(&priv->pdev->dev, sizeof(*link_speed_region),
					  link_speed_region, link_speed_region_bus);
	return err;
}