Re: [net-next v2 11/11] ice: add a devlink region for dumping NVM contents

From: Jiri Pirko <jiri@resnulli.us>
To: Jacob Keller <jacob.e.keller@intel.com>
Cc: netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>
Subject: Re: [net-next v2 11/11] ice: add a devlink region for dumping NVM contents
Date: Thu, 26 Mar 2020 10:02:50 +0100	[thread overview]
Message-ID: <20200326090250.GQ11304@nanopsycho.orion> (raw)
In-Reply-To: <20200326035157.2211090-12-jacob.e.keller@intel.com>

Thu, Mar 26, 2020 at 04:51:57AM CET, jacob.e.keller@intel.com wrote:
>Add a devlink region for exposing the device's Non Volatime Memory flash
>contents.
>
>Support the recently added .snapshot operation, enabling userspace to
>request a snapshot of the NVM contents via DEVLINK_CMD_REGION_NEW.
>
>Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
>---
> Documentation/networking/devlink/ice.rst     | 26 +++++
> drivers/net/ethernet/intel/ice/ice.h         |  2 +
> drivers/net/ethernet/intel/ice/ice_devlink.c | 99 ++++++++++++++++++++
> drivers/net/ethernet/intel/ice/ice_devlink.h |  3 +
> drivers/net/ethernet/intel/ice/ice_main.c    |  4 +
> 5 files changed, 134 insertions(+)
>
>diff --git a/Documentation/networking/devlink/ice.rst b/Documentation/networking/devlink/ice.rst
>index 37fbbd40a5e5..f3d6a3b50342 100644
>--- a/Documentation/networking/devlink/ice.rst
>+++ b/Documentation/networking/devlink/ice.rst
>@@ -69,3 +69,29 @@ The ``ice`` driver reports the following versions
>       - The version of the DDP package that is active in the device. Note
>         that both the name (as reported by ``fw.app.name``) and version are
>         required to uniquely identify the package.
>+
>+Regions
>+=======
>+
>+The ``ice`` driver enables access to the contents of the Non Volatile Memory
>+flash chip via the ``nvm-flash`` region.
>+
>+Users can request an immediate capture of a snapshot via the
>+``DEVLINK_CMD_REGION_NEW``
>+
>+.. code:: shell
>+
>+    $ devlink region new pci/0000:01:00.0/nvm-flash snapshot 1
>+    $ devlink region dump pci/0000:01:00.0/nvm-flash snapshot 1
>+
>+    $ devlink region dump pci/0000:01:00.0/nvm-flash snapshot 1
>+    0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30
>+    0000000000000010 0000 0000 ffff ff04 0029 8c00 0028 8cc8
>+    0000000000000020 0016 0bb8 0016 1720 0000 0000 c00f 3ffc
>+    0000000000000030 bada cce5 bada cce5 bada cce5 bada cce5
>+
>+    $ devlink region read pci/0000:01:00.0/nvm-flash snapshot 1 address 0
>+        length 16

Don't wrap the cmdline.

>+    0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30
>+
>+    $ devlink region delete pci/0000:01:00.0/nvm-flash snapshot 1
>diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
>index 8ce3afcfeca0..5c11448bfbb3 100644
>--- a/drivers/net/ethernet/intel/ice/ice.h
>+++ b/drivers/net/ethernet/intel/ice/ice.h
>@@ -351,6 +351,8 @@ struct ice_pf {
> 	/* devlink port data */
> 	struct devlink_port devlink_port;
> 
>+	struct devlink_region *nvm_region;
>+
> 	/* OS reserved IRQ details */
> 	struct msix_entry *msix_entries;
> 	struct ice_res_tracker *irq_tracker;
>diff --git a/drivers/net/ethernet/intel/ice/ice_devlink.c b/drivers/net/ethernet/intel/ice/ice_devlink.c
>index 27c5034c039a..91edeffd73b1 100644
>--- a/drivers/net/ethernet/intel/ice/ice_devlink.c
>+++ b/drivers/net/ethernet/intel/ice/ice_devlink.c
>@@ -318,3 +318,102 @@ void ice_devlink_destroy_port(struct ice_pf *pf)
> 	devlink_port_type_clear(&pf->devlink_port);
> 	devlink_port_unregister(&pf->devlink_port);
> }
>+
>+/**
>+ * ice_devlink_nvm_snapshot - Capture a snapshot of the Shadow RAM contents
>+ * @devlink: the devlink instance
>+ * @extack: extended ACK response structure
>+ * @data: on exit points to snapshot data buffer
>+ *
>+ * This function is called in response to the DEVLINK_CMD_REGION_TRIGGER for
>+ * the shadow-ram devlink region. It captures a snapshot of the shadow ram
>+ * contents. This snapshot can later be viewed via the devlink-region
>+ * interface.
>+ *
>+ * @returns zero on success, and updates the data pointer. Returns a non-zero
>+ * error code on failure.
>+ */
>+static int
>+ice_devlink_nvm_snapshot(struct devlink *devlink, struct netlink_ext_ack *extack,
>+			u8 **data)
>+{
>+	struct ice_pf *pf = devlink_priv(devlink);
>+	struct device *dev = ice_pf_to_dev(pf);
>+	struct ice_hw *hw = &pf->hw;
>+	enum ice_status status;
>+	void *nvm_data;
>+	u32 nvm_size;
>+
>+	nvm_size = hw->nvm.flash_size;
>+	nvm_data = vzalloc(nvm_size);
>+	if (!nvm_data) {
>+		NL_SET_ERR_MSG_MOD(extack, "Out of memory");

Pointless extack message. It is obvious from -ENOMEM. Please remove.

>+		return -ENOMEM;
>+	}
>+
>+	status = ice_acquire_nvm(hw, ICE_RES_READ);
>+	if (status) {
>+		dev_dbg(dev, "ice_acquire_nvm failed, err %d aq_err %d\n",
>+			status, hw->adminq.sq_last_status);
>+		NL_SET_ERR_MSG_MOD(extack, "Failed to acquire NVM semaphore");
>+		vfree(nvm_data);
>+		return -EIO;
>+	}
>+
>+	status = ice_read_flat_nvm(hw, 0, &nvm_size, nvm_data, false);
>+	if (status) {
>+		dev_dbg(dev, "ice_read_flat_nvm failed after reading %u bytes, err %d aq_err %d\n",
>+			nvm_size, status, hw->adminq.sq_last_status);
>+		NL_SET_ERR_MSG_MOD(extack, "Failed to read NVM contents");
>+		ice_release_nvm(hw);
>+		vfree(nvm_data);
>+		return -EIO;
>+	}
>+
>+	ice_release_nvm(hw);
>+
>+	*data = nvm_data;
>+
>+	return 0;
>+}
>+
>+static const struct devlink_region_ops ice_nvm_region_ops = {
>+	.name = "nvm-flash",
>+	.destructor = vfree,
>+	.snapshot = ice_devlink_nvm_snapshot,
>+};
>+
>+/**
>+ * ice_devlink_init_regions - Initialize devlink regions
>+ * @pf: the PF device structure
>+ *
>+ * Create devlink regions used to enable access to dump the contents of the
>+ * flash memory on the device.
>+ */
>+void ice_devlink_init_regions(struct ice_pf *pf)
>+{
>+	struct devlink *devlink = priv_to_devlink(pf);
>+	struct device *dev = ice_pf_to_dev(pf);
>+	u64 nvm_size;
>+
>+	nvm_size = pf->hw.nvm.flash_size;
>+	pf->nvm_region = devlink_region_create(devlink, &ice_nvm_region_ops, 1,
>+					       nvm_size);
>+	if (IS_ERR(pf->nvm_region)) {
>+		dev_err(dev, "failed to create NVM devlink region, err %ld\n",
>+			PTR_ERR(pf->nvm_region));
>+		pf->nvm_region = NULL;
>+	}
>+}
>+
>+/**
>+ * ice_devlink_destroy_regions - Destroy devlink regions
>+ * @pf: the PF device structure
>+ *
>+ * Remove previously created regions for this PF.
>+ */
>+void ice_devlink_destroy_regions(struct ice_pf *pf)
>+{
>+	if (pf->nvm_region)
>+		devlink_region_destroy(pf->nvm_region);
>+}
>diff --git a/drivers/net/ethernet/intel/ice/ice_devlink.h b/drivers/net/ethernet/intel/ice/ice_devlink.h
>index f94dc93c24c5..6e806a08dc23 100644
>--- a/drivers/net/ethernet/intel/ice/ice_devlink.h
>+++ b/drivers/net/ethernet/intel/ice/ice_devlink.h
>@@ -11,4 +11,7 @@ void ice_devlink_unregister(struct ice_pf *pf);
> int ice_devlink_create_port(struct ice_pf *pf);
> void ice_devlink_destroy_port(struct ice_pf *pf);
> 
>+void ice_devlink_init_regions(struct ice_pf *pf);
>+void ice_devlink_destroy_regions(struct ice_pf *pf);
>+
> #endif /* _ICE_DEVLINK_H_ */
>diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
>index 359ff8544773..306a4e5b2320 100644
>--- a/drivers/net/ethernet/intel/ice/ice_main.c
>+++ b/drivers/net/ethernet/intel/ice/ice_main.c
>@@ -3276,6 +3276,8 @@ ice_probe(struct pci_dev *pdev, const struct pci_device_id __always_unused *ent)
> 		goto err_init_pf_unroll;
> 	}
> 
>+	ice_devlink_init_regions(pf);
>+
> 	pf->num_alloc_vsi = hw->func_caps.guar_num_vsi;
> 	if (!pf->num_alloc_vsi) {
> 		err = -EIO;
>@@ -3385,6 +3387,7 @@ ice_probe(struct pci_dev *pdev, const struct pci_device_id __always_unused *ent)
> 	devm_kfree(dev, pf->vsi);
> err_init_pf_unroll:
> 	ice_deinit_pf(pf);
>+	ice_devlink_destroy_regions(pf);
> 	ice_deinit_hw(hw);
> err_exit_unroll:
> 	ice_devlink_unregister(pf);
>@@ -3427,6 +3430,7 @@ static void ice_remove(struct pci_dev *pdev)
> 		ice_vsi_free_q_vectors(pf->vsi[i]);
> 	}
> 	ice_deinit_pf(pf);
>+	ice_devlink_destroy_regions(pf);
> 	ice_deinit_hw(&pf->hw);
> 	ice_devlink_unregister(pf);
> 
>-- 
>2.24.1
>