Hi Bart,
sorry for not replying earlier, as I am very new to NVMe/UFS spec and was
figuring out few details about them.
On 7/21/23 18:40, Shyam Saini wrote:
+config RPMB
+ tristate "RPMB partition interface"
+ help
+ Unified RPMB partition interface for RPMB capable devices such as
+ eMMC and UFS. Provides interface for in kernel security
controllers to
+ access RPMB partition.
+
+ If unsure, select N.
Please also mention NVMe.
Sure,
Please change the word "partition" into "unit" to avoid confusion with the
concept "LBA range partition".
sure, in next iteration
+static DEFINE_IDA(rpmb_ida);
How are accesses to this IDA serialized?
I will look into that.
+/**
+ * rpmb_get_capacity() - returns the capacity of the rpmb device
+ * @rdev: rpmb device
+ *
+ * Return:
+ * * capacity of the device in units of 128K, on success
+ * * -EINVAL on wrong parameters
+ * * -EOPNOTSUPP if device doesn't support the requested operation
+ * * < 0 if the operation fails
+ */
Why in units of 128 KiB?
I think UFS/eMMC RPMB spec suggests size of RPMB multiple of 128K
and NVMe spec suggests RPMB Data Area to be multiple of 128K as well.
+/**
+ * rpmb_dev_find_by_device() - retrieve rpmb device from the parent
device
+ * @parent: parent device of the rpmb device
+ * @target: RPMB target/region within the physical device
+ *
+ * Return: NULL if there is no rpmb device associated with the parent
device
+ */
Can an NVMe controller have multiple RPMB units? From the NVMe specification:
"The controller may support multiple RPMB targets."
That we have to figure, I see NVMe device can have upto 7 RPMB
targets/units
Can rpmb_dev_find_by_device() be used if multiple RPMB units are associated
with a single controller?
That's not finalised yet, but we some ideas from Optee folks on the other
replies.
+/**
+ * rpmb_dev_register - register RPMB partition with the RPMB subsystem
+ * @dev: storage device of the rpmb device
+ * @target: RPMB target/region within the physical device
+ * @ops: device specific operations
+ *
+ * Return: a pointer to rpmb device
+ */
+struct rpmb_dev *rpmb_dev_register(struct device *dev, u8 target,
+ const struct rpmb_ops *ops)
+{
+ struct rpmb_dev *rdev;
+ int id;
+ int ret;
+
+ if (!dev || !ops)
+ return ERR_PTR(-EINVAL);
+
+ if (!ops->program_key)
+ return ERR_PTR(-EINVAL);
+
+ if (!ops->get_capacity)
+ return ERR_PTR(-EINVAL);
+
+ if (!ops->get_write_counter)
+ return ERR_PTR(-EINVAL);
+
+ if (!ops->write_blocks)
+ return ERR_PTR(-EINVAL);
+
+ if (!ops->read_blocks)
+ return ERR_PTR(-EINVAL);
+
+ rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
+ if (!rdev)
+ return ERR_PTR(-ENOMEM);
+
+ id = ida_simple_get(&rpmb_ida, 0, 0, GFP_KERNEL);
+ if (id < 0) {
+ ret = id;
+ goto exit;
+ }
+
+ mutex_init(&rdev->lock);
+ rdev->ops = ops;
+ rdev->id = id;
+ rdev->target = target;
+
+ dev_set_name(&rdev->dev, "rpmb%d", id);
+ rdev->dev.class = &rpmb_class;
+ rdev->dev.parent = dev;
+
+ rpmb_cdev_prepare(rdev);
+
+ ret = device_register(&rdev->dev);
+ if (ret)
+ goto exit;
+
+ rpmb_cdev_add(rdev);
+
+ dev_dbg(&rdev->dev, "registered device\n");
+
+ return rdev;
+
+exit:
+ if (id >= 0)
+ ida_simple_remove(&rpmb_ida, id);
+ kfree(rdev);
+ return ERR_PTR(ret);
+}
How is user space software supposed to map an NVMe RPMB target ID to an RPMB
device name?
I am not sure, this driver aims to provide in kernel RPMB access APIs,
user space support may be added later on, but i will look if the current
RFC version has any implication on future user-space support.
+MODULE_AUTHOR("Intel Corporation");
Shouldn't this be the name of a person instead of the name of a company?
Thanks, I will address that in next iteration.
Please keep posted your reviews and feedback.
Best Regards,
Shyam
