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Date:   Mon, 11 Jul 2022 14:40:09 +0200
From:   Jiri Pirko <jiri@nvidia.com>
To:     Vikas Gupta <vikas.gupta@broadcom.com>
Cc:     kuba@kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, davem@davemloft.net,
        dsahern@kernel.org, stephen@networkplumber.org,
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        leon@kernel.org, linux-doc@vger.kernel.org, corbet@lwn.net,
        michael.chan@broadcom.com, andrew.gospodarek@broadcom.com
Subject: Re: [PATCH net-next v2 1/3] devlink: introduce framework for
 selftests
Message-ID: <YswaKcUs6nOndU2V@nanopsycho>
References: <20220628164241.44360-1-vikas.gupta@broadcom.com>
 <20220707182950.29348-1-vikas.gupta@broadcom.com>
 <20220707182950.29348-2-vikas.gupta@broadcom.com>
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Thu, Jul 07, 2022 at 08:29:48PM CEST, vikas.gupta@broadcom.com wrote:
>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: To query the supported selftests
>by the driver.
>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: Michael Chan <michael.chan@broadcom.com>
>Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
>---
> .../networking/devlink/devlink-selftests.rst  |  34 +++++
> include/net/devlink.h                         |  30 ++++
> include/uapi/linux/devlink.h                  |  26 ++++
> net/core/devlink.c                            | 144 ++++++++++++++++++
> 4 files changed, 234 insertions(+)
> create mode 100644 Documentation/networking/devlink/devlink-selftests.rst
>
>diff --git a/Documentation/networking/devlink/devlink-selftests.rst b/Documentation/networking/devlink/devlink-selftests.rst
>new file mode 100644
>index 000000000000..796d38f77038
>--- /dev/null
>+++ b/Documentation/networking/devlink/devlink-selftests.rst
>@@ -0,0 +1,34 @@
>+.. 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``
>+     - Runs a flash test on the device.
>+
>+example usage
>+-------------
>+
>+.. code:: shell
>+
>+    # Query selftests supported on the device
>+    $ devlink dev selftests show DEV
>+    # Executes selftests on the device
>+    $ devlink dev selftests run DEV test {flash | all}
>diff --git a/include/net/devlink.h b/include/net/devlink.h
>index 2a2a2a0c93f7..cb7c378cf720 100644
>--- a/include/net/devlink.h
>+++ b/include/net/devlink.h
>@@ -1215,6 +1215,18 @@ enum {
> 	DEVLINK_F_RELOAD = 1UL << 0,
> };
> 
>+#define DEVLINK_SELFTEST_FLASH_TEST_NAME "flash"
>+
>+static inline const char *devlink_selftest_name(int test)

I don't understand why this is needed. Better not to expose string to
the user. Just have it as well defined attr.


>+{
>+	switch (test) {
>+	case DEVLINK_SELFTEST_FLASH_BIT:
>+		return DEVLINK_SELFTEST_FLASH_TEST_NAME;
>+	default:
>+		return "unknown";
>+	}
>+}
>+
> struct devlink_ops {
> 	/**
> 	 * @supported_flash_update_params:
>@@ -1509,6 +1521,24 @@ struct devlink_ops {
> 				    struct devlink_rate *parent,
> 				    void *priv_child, void *priv_parent,
> 				    struct netlink_ext_ack *extack);
>+	/**
>+	 * selftests_show() - Shows selftests supported by device
>+	 * @devlink: Devlink instance
>+	 * @extack: extack for reporting error messages
>+	 *
>+	 * Return: test mask supported by driver
>+	 */
>+	u32 (*selftests_show)(struct devlink *devlink,
>+			      struct netlink_ext_ack *extack);
>+	/**
>+	 * selftests_run() - Runs selftests
>+	 * @devlink: Devlink instance
>+	 * @tests_mask: tests to be run by driver
>+	 * @results: test results by driver
>+	 * @extack: extack for reporting error messages
>+	 */
>+	void (*selftests_run)(struct devlink *devlink, u32 tests_mask,
>+			      u8 *results, struct netlink_ext_ack *extack);
> };
> 
> void *devlink_priv(struct devlink *devlink);
>diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
>index b3d40a5d72ff..1dba262328b9 100644
>--- a/include/uapi/linux/devlink.h
>+++ b/include/uapi/linux/devlink.h
>@@ -136,6 +136,9 @@ enum devlink_command {
> 	DEVLINK_CMD_LINECARD_NEW,
> 	DEVLINK_CMD_LINECARD_DEL,
> 
>+	DEVLINK_CMD_SELFTESTS_SHOW,
>+	DEVLINK_CMD_SELFTESTS_RUN,
>+
> 	/* add new commands above here */
> 	__DEVLINK_CMD_MAX,
> 	DEVLINK_CMD_MAX = __DEVLINK_CMD_MAX - 1
>@@ -276,6 +279,25 @@ enum {
> #define DEVLINK_SUPPORTED_FLASH_OVERWRITE_SECTIONS \
> 	(_BITUL(__DEVLINK_FLASH_OVERWRITE_MAX_BIT) - 1)
> 
>+/* Commonly used test cases */
>+enum {
>+	DEVLINK_SELFTEST_FLASH_BIT,
>+
>+	__DEVLINK_SELFTEST_MAX_BIT,
>+	DEVLINK_SELFTEST_MAX_BIT = __DEVLINK_SELFTEST_MAX_BIT - 1
>+};
>+
>+#define DEVLINK_SELFTEST_FLASH _BITUL(DEVLINK_SELFTEST_FLASH_BIT)
>+
>+#define DEVLINK_SELFTESTS_MASK \
>+	(_BITUL(__DEVLINK_SELFTEST_MAX_BIT) - 1)
>+
>+enum {
>+	DEVLINK_SELFTEST_SKIP,
>+	DEVLINK_SELFTEST_PASS,
>+	DEVLINK_SELFTEST_FAIL
>+};
>+
> /**
>  * enum devlink_trap_action - Packet trap action.
>  * @DEVLINK_TRAP_ACTION_DROP: Packet is dropped by the device and a copy is not
>@@ -576,6 +598,10 @@ enum devlink_attr {
> 	DEVLINK_ATTR_LINECARD_TYPE,		/* string */
> 	DEVLINK_ATTR_LINECARD_SUPPORTED_TYPES,	/* nested */
> 
>+	DEVLINK_ATTR_SELFTESTS_MASK,		/* u32 */

I don't see why this is u32 bitset. Just have one attr per test
(NLA_FLAG) in a nested attr instead.


>+	DEVLINK_ATTR_TEST_RESULT,		/* nested */
>+	DEVLINK_ATTR_TEST_NAME,			/* string */
>+	DEVLINK_ATTR_TEST_RESULT_VAL,		/* u8 */

Could you maintain the same "namespace" for all attrs related to
selftests?


> 	/* add new attributes above here, update the policy in devlink.c */
> 
> 	__DEVLINK_ATTR_MAX,
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index db61f3a341cb..0b7341ab6379 100644
>--- a/net/core/devlink.c
>+++ b/net/core/devlink.c
>@@ -4794,6 +4794,136 @@ static int devlink_nl_cmd_flash_update(struct sk_buff *skb,
> 	return ret;
> }
> 
>+static int devlink_selftest_name_put(struct sk_buff *skb, int test)
>+{
>+	const char *name = devlink_selftest_name(test);
>+	if (nla_put_string(skb, DEVLINK_ATTR_TEST_NAME, name))
>+		return -EMSGSIZE;
>+
>+	return 0;
>+}
>+
>+static int devlink_nl_cmd_selftests_show(struct sk_buff *skb,
>+					 struct genl_info *info)
>+{
>+	struct devlink *devlink = info->user_ptr[0];
>+	struct sk_buff *msg;
>+	unsigned long tests;
>+	int err = 0;
>+	void *hdr;
>+	int test;
>+
>+	if (!devlink->ops->selftests_show)
>+		return -EOPNOTSUPP;
>+
>+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
>+	if (!msg)
>+		return -ENOMEM;
>+
>+	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
>+			  &devlink_nl_family, 0, DEVLINK_CMD_SELFTESTS_SHOW);
>+	if (!hdr)
>+		goto free_msg;
>+
>+	if (devlink_nl_put_handle(msg, devlink))
>+		goto genlmsg_cancel;
>+
>+	tests = devlink->ops->selftests_show(devlink, info->extack);
>+
>+	for_each_set_bit(test, &tests, __DEVLINK_SELFTEST_MAX_BIT) {
>+		err = devlink_selftest_name_put(msg, test);
>+		if (err)
>+			goto genlmsg_cancel;
>+	}
>+
>+	genlmsg_end(msg, hdr);
>+
>+	return genlmsg_reply(msg, info);
>+
>+genlmsg_cancel:
>+	genlmsg_cancel(msg, hdr);
>+free_msg:
>+	nlmsg_free(msg);
>+	return err;
>+}
>+
>+static int devlink_selftest_result_put(struct sk_buff *skb, int test,
>+				       u8 result)
>+{
>+	const char *name = devlink_selftest_name(test);
>+	struct nlattr *result_attr;
>+
>+	result_attr = nla_nest_start_noflag(skb, DEVLINK_ATTR_TEST_RESULT);
>+	if (!result_attr)
>+		return -EMSGSIZE;
>+
>+	if (nla_put_string(skb, DEVLINK_ATTR_TEST_NAME, name) ||
>+	    nla_put_u8(skb, DEVLINK_ATTR_TEST_RESULT_VAL, result))
>+		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)
>+{
>+	u8 test_results[DEVLINK_SELFTEST_MAX_BIT + 1] = {};
>+	struct devlink *devlink = info->user_ptr[0];
>+	unsigned long tests;
>+	struct sk_buff *msg;
>+	u32 tests_mask;
>+	void *hdr;
>+	int err = 0;
>+	int test;
>+
>+	if (!devlink->ops->selftests_run)
>+		return -EOPNOTSUPP;
>+
>+	if (!info->attrs[DEVLINK_ATTR_SELFTESTS_MASK])
>+		return -EINVAL;
>+
>+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
>+	if (!msg)
>+		return -ENOMEM;
>+
>+	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;
>+
>+	tests_mask = nla_get_u32(info->attrs[DEVLINK_ATTR_SELFTESTS_MASK]);
>+
>+	devlink->ops->selftests_run(devlink, tests_mask, test_results,

Why don't you run it 1 by 1 and fill up the NL message 1 by 1 too?


>+				    info->extack);
>+	tests = tests_mask;
>+
>+	for_each_set_bit(test, &tests, __DEVLINK_SELFTEST_MAX_BIT) {
>+		err = devlink_selftest_result_put(msg, test,
>+						  test_results[test]);
>+		if (err)
>+			goto genlmsg_cancel;
>+	}
>+
>+	genlmsg_end(msg, hdr);
>+
>+	return genlmsg_reply(msg, info);
>+
>+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,
>@@ -9000,6 +9130,8 @@ 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_MASK] = NLA_POLICY_MASK(NLA_U32,
>+							DEVLINK_SELFTESTS_MASK),
> };
> 
> static const struct genl_small_ops devlink_nl_ops[] = {
>@@ -9361,6 +9493,18 @@ 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_SHOW,
>+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
>+		.doit = devlink_nl_cmd_selftests_show,

Why don't dump?


>+		.flags = GENL_ADMIN_PERM,
>+	},
>+	{
>+		.cmd = DEVLINK_CMD_SELFTESTS_RUN,
>+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
>+		.doit = devlink_nl_cmd_selftests_run,
>+		.flags = GENL_ADMIN_PERM,
>+	},
> };
> 
> static struct genl_family devlink_nl_family __ro_after_init = {
>-- 
>2.31.1
>