Re: [PATCH v1 07/12] fpga: expose sec-mgr update status

Tom Rix
2020-09-06T16:16:50Z

On 9/4/20 4:53 PM, Russ Weight wrote:
> Extend the Intel 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: Wu Hao <hao.wu@intel.com>
> ---
> .../ABI/testing/sysfs-class-ifpga-sec-mgr | 11 ++++++
> drivers/fpga/ifpga-sec-mgr.c | 34 ++++++++++++++++---
> 2 files changed, 41 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr b/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
> index a476504b7ae9..849ccb2802f8 100644
> --- a/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
> +++ b/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
> @@ -86,3 +86,14 @@ Description: Write only. Write the filename of an Intel image
> BMC images, BMC firmware, Static Region images,
> and Root Entry Hashes, and to cancel Code Signing
> Keys (CSK).
> +
> +What: /sys/class/ifpga_sec_mgr/ifpga_secX/update/status
> +Date: Sep 2020
> +KernelVersion: 5.10
> +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, read_file, preparing, writing,
For consistency, read_file -> reading
> + 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/ifpga-sec-mgr.c b/drivers/fpga/ifpga-sec-mgr.c
> index 73173badbe96..5fe3d85e2963 100644
> --- a/drivers/fpga/ifpga-sec-mgr.c
> +++ b/drivers/fpga/ifpga-sec-mgr.c
> @@ -139,6 +139,13 @@ static struct attribute *sec_mgr_security_attrs[] = {
> NULL,
> };
>
> +static void update_progress(struct ifpga_sec_mgr *imgr,
> + enum ifpga_sec_prog new_progress)
> +{
> + imgr->progress = new_progress;
> + sysfs_notify(&imgr->dev.kobj, "update", "status");
> +}
> +
> static void ifpga_sec_dev_error(struct ifpga_sec_mgr *imgr,
> enum ifpga_sec_err err_code)
> {
> @@ -149,7 +156,7 @@ static void ifpga_sec_dev_error(struct ifpga_sec_mgr *imgr,
> static void progress_complete(struct ifpga_sec_mgr *imgr)
> {
> mutex_lock(&imgr->lock);
> - imgr->progress = IFPGA_SEC_PROG_IDLE;
> + update_progress(imgr, IFPGA_SEC_PROG_IDLE);
> complete_all(&imgr->update_done);
> mutex_unlock(&imgr->lock);
> }
> @@ -177,14 +184,14 @@ static void ifpga_sec_mgr_update(struct work_struct *work)
> goto release_fw_exit;
> }
>
> - imgr->progress = IFPGA_SEC_PROG_PREPARING;
> + update_progress(imgr, IFPGA_SEC_PROG_PREPARING);
> ret = imgr->iops->prepare(imgr);
> if (ret) {
> ifpga_sec_dev_error(imgr, ret);
> goto modput_exit;
> }
>
> - imgr->progress = IFPGA_SEC_PROG_WRITING;
> + update_progress(imgr, IFPGA_SEC_PROG_WRITING);
> size = imgr->remaining_size;
> while (size) {
> blk_size = min_t(u32, size, WRITE_BLOCK_SIZE);
> @@ -199,7 +206,7 @@ static void ifpga_sec_mgr_update(struct work_struct *work)
> offset += blk_size;
> }
>
> - imgr->progress = IFPGA_SEC_PROG_PROGRAMMING;
> + update_progress(imgr, IFPGA_SEC_PROG_PROGRAMMING);
> ret = imgr->iops->poll_complete(imgr);
> if (ret) {
> ifpga_sec_dev_error(imgr, ret);
> @@ -251,6 +258,24 @@ static struct attribute_group sec_mgr_security_attr_group = {
> .is_visible = sec_mgr_visible,
> };
>
> +static const char * const sec_mgr_prog_str[] = {
> + "idle", /* IFPGA_SEC_PROG_IDLE */
> + "read_file", /* IFPGA_SEC_PROG_READ_FILE */
"reading"
> + "preparing", /* IFPGA_SEC_PROG_PREPARING */
> + "writing", /* IFPGA_SEC_PROG_WRITING */
> + "programming" /* IFPGA_SEC_PROG_PROGRAMMING */
> +};
> +
> +static ssize_t
> +status_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> + struct ifpga_sec_mgr *imgr = to_sec_mgr(dev);
> +
> + return sprintf(buf, "%s\n", (imgr->progress < IFPGA_SEC_PROG_MAX) ?
> + sec_mgr_prog_str[imgr->progress] : "unknown-status");

when imgr->progress is unknown, should there be a dev_warn ?

Tom

> +}
> +static DEVICE_ATTR_RO(status);
> +
> static ssize_t filename_store(struct device *dev, struct device_attribute *attr,
> const char *buf, size_t count)
> {
> @@ -288,6 +313,7 @@ static DEVICE_ATTR_WO(filename);
>
> static struct attribute *sec_mgr_update_attrs[] = {
> &dev_attr_filename.attr,
> + &dev_attr_status.attr,
> NULL,
> };
>