Re: [PATCH v12 3/7] fpga: sec-mgr: expose sec-mgr update status

[Moritz Fischer <mdf@kernel.org>]

On Mon, May 03, 2021 at 02:35:42PM -0700, Russ Weight wrote:
> Extend the FPGA Security Manager class driver to
> include an update/status sysfs node that can be polled
> and read to monitor the progress of an ongoing secure
> update. Sysfs_notify() is used to signal transitions
> between different phases of the update process.
> 
> Signed-off-by: Russ Weight <russell.h.weight@intel.com>
> Reviewed-by: Tom Rix <trix@redhat.com>
> ---
> v12:
>   - Updated Date and KernelVersion fields in ABI documentation
>   - Changed syntax of sec_mgr_prog_str[] array definition from:
> 	"idle",			/* FPGA_SEC_PROG_IDLE */
>     to:
> 	[FPGA_SEC_PROG_IDLE]	    = "idle",
> v11:
>   - No change
> v10:
>   - Rebased to 5.12-rc2 next
>   - Updated Date and KernelVersion in ABI documentation
> v9:
>   - Updated Date and KernelVersion in ABI documentation
> v8:
>   - No change
> v7:
>   - Changed Date in documentation file to December 2020
> v6:
>   - No change
> v5:
>   - Use new function sysfs_emit() in the status_show() function
> v4:
>   - Changed from "Intel FPGA Security Manager" to FPGA Security Manager"
>     and removed unnecessary references to "Intel".
>   - Changed: iops -> sops, imgr -> smgr, IFPGA_ -> FPGA_, ifpga_ to fpga_
> v3:
>   - Use a local variable to read progress once in status_show()
>   - Use dev_err to report invalid progress status
> v2:
>   - Bumped documentation date and version
>   - Changed progress state "read_file" to "reading"
> ---
>  .../ABI/testing/sysfs-class-fpga-sec-mgr      | 11 +++++
>  drivers/fpga/fpga-sec-mgr.c                   | 42 +++++++++++++++++--
>  2 files changed, 49 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
> index 36d1b6ba8d76..b962ad2cf18d 100644
> --- a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
> +++ b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
> @@ -16,3 +16,14 @@ Description:	Write only. Write the filename of an image
>  		BMC images, BMC firmware, Static Region images,
>  		and Root Entry Hashes, and to cancel Code Signing
>  		Keys (CSK).
> +
> +What: 		/sys/class/fpga_sec_mgr/fpga_secX/update/status
> +Date:		June 2021
> +KernelVersion:	5.14
> +Contact:	Russ Weight <russell.h.weight@intel.com>
> +Description:	Read-only. Returns a string describing the current
> +		status of an update. The string will be one of the
> +		following: idle, reading, preparing, writing,
> +		programming. Userspace code can poll on this file,
> +		as it will be signaled by sysfs_notify() on each
> +		state change.
> diff --git a/drivers/fpga/fpga-sec-mgr.c b/drivers/fpga/fpga-sec-mgr.c
> index fe82feda6b3c..dec52c68fe16 100644
> --- a/drivers/fpga/fpga-sec-mgr.c
> +++ b/drivers/fpga/fpga-sec-mgr.c
> @@ -23,6 +23,13 @@ struct fpga_sec_mgr_devres {
>  
>  #define to_sec_mgr(d) container_of(d, struct fpga_sec_mgr, dev)
>  
> +static void update_progress(struct fpga_sec_mgr *smgr,
> +			    enum fpga_sec_prog new_progress)
> +{
> +	smgr->progress = new_progress;
> +	sysfs_notify(&smgr->dev.kobj, "update", "status");
> +}
> +
>  static void fpga_sec_dev_error(struct fpga_sec_mgr *smgr,
>  			       enum fpga_sec_err err_code)
>  {
> @@ -33,7 +40,7 @@ static void fpga_sec_dev_error(struct fpga_sec_mgr *smgr,
>  static void progress_complete(struct fpga_sec_mgr *smgr)
>  {
>  	mutex_lock(&smgr->lock);
> -	smgr->progress = FPGA_SEC_PROG_IDLE;
> +	update_progress(smgr, FPGA_SEC_PROG_IDLE);
>  	complete_all(&smgr->update_done);
>  	mutex_unlock(&smgr->lock);
>  }
> @@ -61,14 +68,14 @@ static void fpga_sec_mgr_update(struct work_struct *work)
>  		goto release_fw_exit;
>  	}
>  
> -	smgr->progress = FPGA_SEC_PROG_PREPARING;
> +	update_progress(smgr, FPGA_SEC_PROG_PREPARING);
>  	ret = smgr->sops->prepare(smgr);
>  	if (ret != FPGA_SEC_ERR_NONE) {
>  		fpga_sec_dev_error(smgr, ret);
>  		goto modput_exit;
>  	}
>  
> -	smgr->progress = FPGA_SEC_PROG_WRITING;
> +	update_progress(smgr, FPGA_SEC_PROG_WRITING);
>  	while (smgr->remaining_size) {
>  		ret = smgr->sops->write_blk(smgr, offset);
>  		if (ret != FPGA_SEC_ERR_NONE) {
> @@ -79,7 +86,7 @@ static void fpga_sec_mgr_update(struct work_struct *work)
>  		offset = fw->size - smgr->remaining_size;
>  	}
>  
> -	smgr->progress = FPGA_SEC_PROG_PROGRAMMING;
> +	update_progress(smgr, FPGA_SEC_PROG_PROGRAMMING);
>  	ret = smgr->sops->poll_complete(smgr);
>  	if (ret != FPGA_SEC_ERR_NONE)
>  		fpga_sec_dev_error(smgr, ret);
> @@ -107,6 +114,32 @@ static void fpga_sec_mgr_update(struct work_struct *work)
>  	progress_complete(smgr);
>  }
>  
> +static const char * const sec_mgr_prog_str[] = {
> +	[FPGA_SEC_PROG_IDLE]	    = "idle",
> +	[FPGA_SEC_PROG_READING]	    = "reading",
> +	[FPGA_SEC_PROG_PREPARING]   = "preparing",
> +	[FPGA_SEC_PROG_WRITING]	    = "writing",
> +	[FPGA_SEC_PROG_PROGRAMMING] = "programming"
> +};
> +
> +static ssize_t
> +status_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct fpga_sec_mgr *smgr = to_sec_mgr(dev);
> +	const char *status = "unknown-status";
> +	enum fpga_sec_prog progress;
> +
> +	progress = smgr->progress;
> +	if (progress < FPGA_SEC_PROG_MAX)
> +		status = sec_mgr_prog_str[progress];
> +	else
> +		dev_err(dev, "Invalid status during secure update: %d\n",
> +			progress);
> +
> +	return sysfs_emit(buf, "%s\n", status);
> +}
> +static DEVICE_ATTR_RO(status);
> +
>  static ssize_t filename_store(struct device *dev, struct device_attribute *attr,
>  			      const char *buf, size_t count)
>  {
> @@ -141,6 +174,7 @@ static DEVICE_ATTR_WO(filename);
>  
>  static struct attribute *sec_mgr_update_attrs[] = {
>  	&dev_attr_filename.attr,
> +	&dev_attr_status.attr,
>  	NULL,
>  };
>  
> -- 
> 2.25.1
> 
Looks good to me,

- Moritz