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

Russ Weight
2020-09-22T22:31:16Z

On 9/6/20 9:16 AM, Tom Rix wrote:
> 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
Yes - I'll make the change.
>> + 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"
yes
>> + "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 ?
Yes, this is a case that should not happen so it probably warrants something in
the kernel log. I'll add that.
>
> 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,
>> };
>>