devlink: introduce framework for selftests

Add a framework for running selftests.
Framework exposes devlink commands and test suite(s) to the user
to execute and query the supported tests by the driver.

Below are new entries in devlink_nl_ops
devlink_nl_cmd_selftests_show_doit/dumpit: To query the supported
selftests by the drivers.
devlink_nl_cmd_selftests_run: To execute selftests. Users can
provide a test mask for executing group tests or standalone tests.

Documentation/networking/devlink/ path is already part of MAINTAINERS &
the new files come under this path. Hence no update needed to the
MAINTAINERS
Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/networking/devlink/devlink-selftests.rst

+.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+=================
+Devlink Selftests
+=================
+
+The ``devlink-selftests`` API allows executing selftests on the device.
+
+Tests Mask
+==========
+The ``devlink-selftests`` command should be run with a mask indicating
+the tests to be executed.
+
+Tests Description
+=================
+The following is a list of tests that drivers may execute.
+
+.. list-table:: List of tests
+   :widths: 5 90
+
+   * - Name
+     - Description
+   * - ``DEVLINK_SELFTEST_FLASH``
+     - Devices may have the firmware on non-volatile memory on the board, e.g.
+       flash. This particular test helps to run a flash selftest on the device.
+       Implementation of the test is left to the driver/firmware.
+
+example usage
+-------------
+
+.. code:: shell
+
+    # Query selftests supported on the devlink device
+    $ devlink dev selftests show DEV
+    # Query selftests supported on all devlink devices
+    $ devlink dev selftests show
+    # Executes selftests on the device
+    $ devlink dev selftests run DEV id flash

include/net/devlink.h

@@ -1509,6 +1509,27 @@ struct devlink_ops {
 				    struct devlink_rate *parent,
 				    void *priv_child, void *priv_parent,
 				    struct netlink_ext_ack *extack);
+	/**
+	 * selftests_check() - queries if selftest is supported
+	 * @devlink: devlink instance
+	 * @id: test index
+	 * @extack: extack for reporting error messages
+	 *
+	 * Return: true if test is supported by the driver
+	 */
+	bool (*selftest_check)(struct devlink *devlink, unsigned int id,
+			       struct netlink_ext_ack *extack);
+	/**
+	 * selftest_run() - Runs a selftest
+	 * @devlink: devlink instance
+	 * @id: test index
+	 * @extack: extack for reporting error messages
+	 *
+	 * Return: status of the test
+	 */
+	enum devlink_selftest_status
+	(*selftest_run)(struct devlink *devlink, unsigned int id,
+			struct netlink_ext_ack *extack);
 };
 
 void *devlink_priv(struct devlink *devlink);

include/uapi/linux/devlink.h

@@ -136,6 +136,9 @@ enum devlink_command {
 	DEVLINK_CMD_LINECARD_NEW,
 	DEVLINK_CMD_LINECARD_DEL,
 
+	DEVLINK_CMD_SELFTESTS_GET,	/* can dump */
+	DEVLINK_CMD_SELFTESTS_RUN,
+
 	/* add new commands above here */
 	__DEVLINK_CMD_MAX,
 	DEVLINK_CMD_MAX = __DEVLINK_CMD_MAX - 1
@@ -276,6 +279,30 @@ enum {
 #define DEVLINK_SUPPORTED_FLASH_OVERWRITE_SECTIONS \
 	(_BITUL(__DEVLINK_FLASH_OVERWRITE_MAX_BIT) - 1)
 
+enum devlink_attr_selftest_id {
+	DEVLINK_ATTR_SELFTEST_ID_UNSPEC,
+	DEVLINK_ATTR_SELFTEST_ID_FLASH,	/* flag */
+
+	__DEVLINK_ATTR_SELFTEST_ID_MAX,
+	DEVLINK_ATTR_SELFTEST_ID_MAX = __DEVLINK_ATTR_SELFTEST_ID_MAX - 1
+};
+
+enum devlink_selftest_status {
+	DEVLINK_SELFTEST_STATUS_SKIP,
+	DEVLINK_SELFTEST_STATUS_PASS,
+	DEVLINK_SELFTEST_STATUS_FAIL
+};
+
+enum devlink_attr_selftest_result {
+	DEVLINK_ATTR_SELFTEST_RESULT_UNSPEC,
+	DEVLINK_ATTR_SELFTEST_RESULT,		/* nested */
+	DEVLINK_ATTR_SELFTEST_RESULT_ID,	/* u32, enum devlink_attr_selftest_id */
+	DEVLINK_ATTR_SELFTEST_RESULT_STATUS,	/* u8, enum devlink_selftest_status */
+
+	__DEVLINK_ATTR_SELFTEST_RESULT_MAX,
+	DEVLINK_ATTR_SELFTEST_RESULT_MAX = __DEVLINK_ATTR_SELFTEST_RESULT_MAX - 1
+};
+
 /**
  * enum devlink_trap_action - Packet trap action.
  * @DEVLINK_TRAP_ACTION_DROP: Packet is dropped by the device and a copy is not
@@ -578,6 +605,8 @@ enum devlink_attr {
 
 	DEVLINK_ATTR_NESTED_DEVLINK,		/* nested */
 
+	DEVLINK_ATTR_SELFTESTS,			/* nested */
+
 	/* add new attributes above here, update the policy in devlink.c */
 
 	__DEVLINK_ATTR_MAX,

net/core/devlink.c

@@ -201,6 +201,10 @@ static const struct nla_policy devlink_function_nl_policy[DEVLINK_PORT_FUNCTION_
 				 DEVLINK_PORT_FN_STATE_ACTIVE),
 };
 
+static const struct nla_policy devlink_selftest_nl_policy[DEVLINK_ATTR_SELFTEST_ID_MAX + 1] = {
+	[DEVLINK_ATTR_SELFTEST_ID_FLASH] = { .type = NLA_FLAG },
+};
+
 static DEFINE_XARRAY_FLAGS(devlinks, XA_FLAGS_ALLOC);
 #define DEVLINK_REGISTERED XA_MARK_1
 
@@ -4826,6 +4830,206 @@ static int devlink_nl_cmd_flash_update(struct sk_buff *skb,
 	return ret;
 }
 
+static int
+devlink_nl_selftests_fill(struct sk_buff *msg, struct devlink *devlink,
+			  u32 portid, u32 seq, int flags,
+			  struct netlink_ext_ack *extack)
+{
+	struct nlattr *selftests;
+	void *hdr;
+	int err;
+	int i;
+
+	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags,
+			  DEVLINK_CMD_SELFTESTS_GET);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	err = -EMSGSIZE;
+	if (devlink_nl_put_handle(msg, devlink))
+		goto err_cancel_msg;
+
+	selftests = nla_nest_start(msg, DEVLINK_ATTR_SELFTESTS);
+	if (!selftests)
+		goto err_cancel_msg;
+
+	for (i = DEVLINK_ATTR_SELFTEST_ID_UNSPEC + 1;
+	     i <= DEVLINK_ATTR_SELFTEST_ID_MAX; i++) {
+		if (devlink->ops->selftest_check(devlink, i, extack)) {
+			err = nla_put_flag(msg, i);
+			if (err)
+				goto err_cancel_msg;
+		}
+	}
+
+	nla_nest_end(msg, selftests);
+	genlmsg_end(msg, hdr);
+	return 0;
+
+err_cancel_msg:
+	genlmsg_cancel(msg, hdr);
+	return err;
+}
+
+static int devlink_nl_cmd_selftests_get_doit(struct sk_buff *skb,
+					     struct genl_info *info)
+{
+	struct devlink *devlink = info->user_ptr[0];
+	struct sk_buff *msg;
+	int err;
+
+	if (!devlink->ops->selftest_check)
+		return -EOPNOTSUPP;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	err = devlink_nl_selftests_fill(msg, devlink, info->snd_portid,
+					info->snd_seq, 0, info->extack);
+	if (err) {
+		nlmsg_free(msg);
+		return err;
+	}
+
+	return genlmsg_reply(msg, info);
+}
+
+static int devlink_nl_cmd_selftests_get_dumpit(struct sk_buff *msg,
+					       struct netlink_callback *cb)
+{
+	struct devlink *devlink;
+	int start = cb->args[0];
+	unsigned long index;
+	int idx = 0;
+	int err = 0;
+
+	mutex_lock(&devlink_mutex);
+	devlinks_xa_for_each_registered_get(sock_net(msg->sk), index, devlink) {
+		if (idx < start || !devlink->ops->selftest_check)
+			goto inc;
+
+		devl_lock(devlink);
+		err = devlink_nl_selftests_fill(msg, devlink,
+						NETLINK_CB(cb->skb).portid,
+						cb->nlh->nlmsg_seq, NLM_F_MULTI,
+						cb->extack);
+		devl_unlock(devlink);
+		if (err) {
+			devlink_put(devlink);
+			break;
+		}
+inc:
+		idx++;
+		devlink_put(devlink);
+	}
+	mutex_unlock(&devlink_mutex);
+
+	if (err != -EMSGSIZE)
+		return err;
+
+	cb->args[0] = idx;
+	return msg->len;
+}
+
+static int devlink_selftest_result_put(struct sk_buff *skb, unsigned int id,
+				       enum devlink_selftest_status test_status)
+{
+	struct nlattr *result_attr;
+
+	result_attr = nla_nest_start(skb, DEVLINK_ATTR_SELFTEST_RESULT);
+	if (!result_attr)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(skb, DEVLINK_ATTR_SELFTEST_RESULT_ID, id) ||
+	    nla_put_u8(skb, DEVLINK_ATTR_SELFTEST_RESULT_STATUS,
+		       test_status))
+		goto nla_put_failure;
+
+	nla_nest_end(skb, result_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(skb, result_attr);
+	return -EMSGSIZE;
+}
+
+static int devlink_nl_cmd_selftests_run(struct sk_buff *skb,
+					struct genl_info *info)
+{
+	struct nlattr *tb[DEVLINK_ATTR_SELFTEST_ID_MAX + 1];
+	struct devlink *devlink = info->user_ptr[0];
+	struct nlattr *attrs, *selftests;
+	struct sk_buff *msg;
+	void *hdr;
+	int err;
+	int i;
+
+	if (!devlink->ops->selftest_run || !devlink->ops->selftest_check)
+		return -EOPNOTSUPP;
+
+	if (!info->attrs[DEVLINK_ATTR_SELFTESTS]) {
+		NL_SET_ERR_MSG_MOD(info->extack, "selftest required");
+		return -EINVAL;
+	}
+
+	attrs = info->attrs[DEVLINK_ATTR_SELFTESTS];
+
+	err = nla_parse_nested(tb, DEVLINK_ATTR_SELFTEST_ID_MAX, attrs,
+			       devlink_selftest_nl_policy, info->extack);
+	if (err < 0)
+		return err;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	err = -EMSGSIZE;
+	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
+			  &devlink_nl_family, 0, DEVLINK_CMD_SELFTESTS_RUN);
+	if (!hdr)
+		goto free_msg;
+
+	if (devlink_nl_put_handle(msg, devlink))
+		goto genlmsg_cancel;
+
+	selftests = nla_nest_start(msg, DEVLINK_ATTR_SELFTESTS);
+	if (!selftests)
+		goto genlmsg_cancel;
+
+	for (i = DEVLINK_ATTR_SELFTEST_ID_UNSPEC + 1;
+	     i <= DEVLINK_ATTR_SELFTEST_ID_MAX; i++) {
+		enum devlink_selftest_status test_status;
+
+		if (nla_get_flag(tb[i])) {
+			if (!devlink->ops->selftest_check(devlink, i,
+							  info->extack)) {
+				if (devlink_selftest_result_put(msg, i,
+								DEVLINK_SELFTEST_STATUS_SKIP))
+					goto selftests_nest_cancel;
+				continue;
+			}
+
+			test_status = devlink->ops->selftest_run(devlink, i,
+								 info->extack);
+			if (devlink_selftest_result_put(msg, i, test_status))
+				goto selftests_nest_cancel;
+		}
+	}
+
+	nla_nest_end(msg, selftests);
+	genlmsg_end(msg, hdr);
+	return genlmsg_reply(msg, info);
+
+selftests_nest_cancel:
+	nla_nest_cancel(msg, selftests);
+genlmsg_cancel:
+	genlmsg_cancel(msg, hdr);
+free_msg:
+	nlmsg_free(msg);
+	return err;
+}
+
 static const struct devlink_param devlink_param_generic[] = {
 	{
 		.id = DEVLINK_PARAM_GENERIC_ID_INT_ERR_RESET,
@@ -8969,6 +9173,7 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_RATE_PARENT_NODE_NAME] = { .type = NLA_NUL_STRING },
 	[DEVLINK_ATTR_LINECARD_INDEX] = { .type = NLA_U32 },
 	[DEVLINK_ATTR_LINECARD_TYPE] = { .type = NLA_NUL_STRING },
+	[DEVLINK_ATTR_SELFTESTS] = { .type = NLA_NESTED },
 };
 
 static const struct genl_small_ops devlink_nl_ops[] = {
@@ -9328,6 +9533,17 @@ static const struct genl_small_ops devlink_nl_ops[] = {
 		.doit = devlink_nl_cmd_trap_policer_set_doit,
 		.flags = GENL_ADMIN_PERM,
 	},
+	{
+		.cmd = DEVLINK_CMD_SELFTESTS_GET,
+		.doit = devlink_nl_cmd_selftests_get_doit,
+		.dumpit = devlink_nl_cmd_selftests_get_dumpit
+		/* can be retrieved by unprivileged users */
+	},
+	{
+		.cmd = DEVLINK_CMD_SELFTESTS_RUN,
+		.doit = devlink_nl_cmd_selftests_run,
+		.flags = GENL_ADMIN_PERM,
+	},
 };
 
 static struct genl_family devlink_nl_family __ro_after_init = {