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Message-ID: <YJlvOD9BlX9dxWE9@epycbox.lan>
Date: Mon, 10 May 2021 10:36:56 -0700
From: Moritz Fischer <mdf@...nel.org>
To: Russ Weight <russell.h.weight@...el.com>
Cc: mdf@...nel.org, linux-fpga@...r.kernel.org,
linux-kernel@...r.kernel.org, trix@...hat.com, lgoncalv@...hat.com,
yilun.xu@...el.com, hao.wu@...el.com, matthew.gerlach@...el.com,
richard.gong@...el.com
Subject: Re: [PATCH v12 3/7] fpga: sec-mgr: expose sec-mgr update status
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@...el.com>
> Reviewed-by: Tom Rix <trix@...hat.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@...el.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
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