Date:   Wed, 22 Dec 2021 18:16:00 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Chen Yu <yu.c.chen@...el.com>
Cc:     ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Ard Biesheuvel <ardb@...nel.org>, Len Brown <lenb@...nel.org>,
        Ashok Raj <ashok.raj@...el.com>,
        Andy Shevchenko <andriy.shevchenko@...el.com>,
        Mike Rapoport <rppt@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v13 0/4] Introduce Platform Firmware Runtime Update and
 Telemetry drivers

On Wed, Dec 22, 2021 at 5:27 AM Chen Yu <yu.c.chen@...el.com> wrote:
>
> The PFRUT(Platform Firmware Runtime Update and Telemetry) kernel interface
> is designed to interact with the platform firmware interface defined in the
> `Management Mode Firmware Runtime Update
> <https://uefi.org/sites/default/files/resources/Intel_MM_OS_Interface_Spec_Rev100.pdf>`
> specification. The primary function of PFRUT is to carry out runtime
> updates of the platform firmware, which doesn't require the system to
> be restarted. It also allows telemetry data to be retrieved from the
> platform firmware.
>
> =============
> - Change from v12 to v13:
>   - Print the _DSM failure result if invalid EFI capsule is provided.
>     (Hongyu Ning)
> - Change from v11 to v12:
>   - Rename the driver from pfru_update to pfr_update, and the
>     telemetry part to pfr_telementry for symmetry.
>     (Rafael J. Wysocki)
>   - Rename the "capsule file" to "EFI capsule".
>     (Rafael J. Wysocki)
>   - Revise the commit log. (Rafael J. Wysocki)
>   - Add the reason in the commit log that explains why it is
>     a good idea to add this driver to the kernel.
>     (Rafael J. Wysocki)
>   - Rename pfru.h to pfrut.h (Rafael J. Wysocki)
>   - Rename the CONFIG_ACPI_PFRU to CONFIG_ACPI_PFRUT
>     (Rafael J. Wysocki)
>   - Rename the Kconfig name to "ACPI Platform Firmware Runtime
>     Update and Telemetry"
>     (Rafael J. Wysocki)
>   - Revise the Kconfig help message (Rafael J. Wysocki)
>   - Describe what the driver is for briefly in the beginning of
>     the source code file.
>     (Rafael J. Wysocki)
>   - Add a comment pointing to the definitions of the GUIDs and
>     explain briefly what they are for.
>     (Rafael J. Wysocki)
>   - Reduce redundant memory updates by doing all of the checks
>     upfront. (Rafael J. Wysocki)
>   - Rename valid_version() to applicable_image(), and revise the
>     comment.(Rafael J. Wysocki)
>   - Remove Redundant else in applicable_image().(Rafael J. Wysocki)
>   - Rename dump_update_result() to print_ipdate_debug_info().
>     (Rafael J. Wysocki)
>   - Rename start_acpi_update() to start_update()(Rafael J. Wysocki)
>     Add a blank line before each "case xxx:"(Rafael J. Wysocki)
>   - Move status check into query_capability() and returns -EBUSY if
>     fails(Rafael J. Wysocki)
>   - Rename the device node name from "acpi_pfru%d" to "acpi_pfr_update%d"
>     (Rafael J. Wysocki)
>   - Rename the drive name from "pfru_update" to "pfr_update"
>     (Rafael J. Wysocki)
>   - Rename PFRU_MAGIC_FOR_IOCTL to PFRUT_IOCTL_MAGIC(Rafael J. Wysocki)
>     Fix grammar errors in the comments.(Rafael J. Wysocki)
> - Change from v10 to v11:
>   - Revise the commit log to explain why version check is introduced
>     in kernel rather than letting Management Mode to do it.
>     (Rafael J. Wysocki)
>   - Revise the commit log to better describe the pack attribute.
>     (Rafael J. Wysocki)
>   - Refine the comment for hw_ins and capsule_support.
>     (Rafael J. Wysocki)
> - Change from v9 to v10:
>   - Remove the explicit assignment of the last item of enum.
>     (Andy Shevchenko)
> - Change from v8 to v9:
>   - Use GUID_INIT() instead of guid_parse() during boot up.
>     (Andy Shevchenko)
>   - Drop uuid, code_uuid, drv_uuid in struct pfru_device as they
>     are not needed. (Andy Shevchenko)
>   - Drop type casting from void * in valid_version().
>     (Andy Shevchenko)
>   - Use kfree() instead of ACPI_FREE() in non-ACPICA usage.
>     (Andy Shevchenko)
>   - Use sizeof(rev) instead of sizeof(u32) in copy_from_user().
>     (Andy Shevchenko)
>   - Generate physical address from MSB part to LSB.
>     (Andy Shevchenko)
>   - Use devm_add_action_or_reset() to add ida release into dev resource
>     management. (Andy Shevchenko)
>   - Use devm_kasprintf() instead of kasprintf() to format the
>     pfru_dev name.(Andy Shevchenko)
>   - Remove redundant 0 in acpi_pfru_ids. (Andy Shevchenko)
>   - Adjust the order of included headers in pfru.h.
>     (Andy Shevchenko)
>   - Replace PFRU_MAGIC with PFRU_MAGIC_FOR_IOCTL in uapi file.
>     (Andy Shevchenko)
>     Use devm_kasprintf() instead of kasprintf() to format the
>     pfru_log_dev name.(Andy Shevchenko)
>     Remove redundant 0 in acpi_pfru_log_ids. (Andy Shevchenko)
> - Change from v7 to v8:
>   - Remove the variable-length array in struct pfru_update_cap_info, and
>     copy the non-variable-length struct pfru_update_cap_info to userspace
>     directly. (Greg Kroah-Hartman)
>   - Use efi_guid_t instead of guid_t when parsing capsule file.
>     (Andy Shevchenko)
>   - Change the type of rev_id from int to u32, because this data will
>     be copied between kernel and userspace. (Greg Kroah-Hartman)
>   - Add a prefix for dev in struct pfru_device to parent_dev, so as
>     to indicate that this filed is the parent of the created miscdev.
>     (Greg Kroah-Hartman)
>   - Use blank lines between different macro sections. (Greg Kroah-Hartman)
>     Illusatrate the possible errno for each ioctl interface.
>     (Greg Kroah-Hartman)
>   - Remove pfru_valid_revid() from uapi header to avoid poluting the global
>     namespace.(Greg Kroah-Hartman)
>   - Assign the value to the enum type explicitly.(Greg Kroah-Hartman)
>   - Change the guid_t to efi_guid_t when parsing image header in get_image_type()
>     (Greg Kroah-Hartman)
>   - Remove the void * to other type casting in valid_version(). (Andy Shevchenko)
>   - Combined the assignment of variables with definitions. (Andy Shevchenko)
>   - Define this magic for revision ID. (Andy Shevchenko)
>   - Make the labeling consistent for error handling. (Andy Shevchenko)
>   - Replace the UUID_SIZE in uapi with 16 directly. (Andy Shevchenko)
>   - Add blank line between generic include header and uapi header.
>     (Andy Shevchenko)
>   - Arrange the order between devm_kzalloc() and normal allocation in
>     acpi_pfru_probe() that, the former should always be ahead of the
>     latter. (Andy Shevchenko)
> - Change from v6 to v7:
>   - Use __packed instead of pragma pack(1).
>     (Greg Kroah-Hartman, Ard Biesheuve)
>   - Use ida_alloc() to allocate a ID, and release the ID when
>     device is removed. (Greg Kroah-Hartman)
>   - Check the _DSM method at early stage, before allocate or parse
>     anything in acpi_pfru_[log_]probe(). (Greg Kroah-Hartman)
>   - Set the parent of the misc device. (Greg Kroah-Hartman)
>   - Use module_platform_driver() instead of platform_driver_register()
>     in module_init(). Separate pfru driver and pfru_telemetry driver
>     to two files. (Greg Kroah-Hartman)
> - Change from v5 to v6:
>   - Use Link: tag to add the specification download address.
>     (Andy Shevchenko)
>   - Drop comma for each terminator entry in the enum structure.
>     (Andy Shevchenko)
>   - Remove redundant 'else' in get_image_type().
>     (Andy Shevchenko)
>   - Directly return results from the switch cases in adjust_efi_size()
>     and pfru_ioctl().(Andy Shevchenko)
>   - Keep comment style consistency by removing the period for
>     one line comment.
>     (Andy Shevchenko)
>   - Remove devm_kfree() if .probe() failed.
>     (Andy Shevchenko)
>   - Remove linux/uuid.h and use raw buffers to contain uuid.
>     (Andy Shevchenko)
>   - Include types.h in pfru.h. (Andy Shevchenko)
>   - Use __u8[16] instead of uuid_t. (Andy Shevchenko)
>   - Replace enum in pfru.h with __u32 as enum size is not the
>     same size on all possible architectures.
>     (Andy Shevchenko)
>   - Simplify the userspace tool to use while loop for getopt_long().
>     (Andy Shevchenko)
> - Change from v4 to v5:
>   - Remove Documentation/ABI/pfru, and move the content to kernel doc
>     in include/uapi/linux/pfru.h (Greg Kroah-Hartman)
>   - Shrink the range of ioctl numbers declared in
>     Documentation/userspace-api/ioctl/ioctl-number.rst
>     from 16 to 8. (Greg Kroah-Hartman)
>   - Change global variable struct pfru_device *pfru_dev to
>     per PFRU device. (Greg Kroah-Hartman)
>   - Unregister the misc device in acpi_pfru_remove().
>     (Greg Kroah-Hartman)
>   - Convert the kzalloc() to devm_kzalloc() in the driver so
>     as to avoid freeing the memory. (Greg Kroah-Hartman)
>   - Fix the compile warning by declaring the pfru_log_ioctl() as
>     static. (kernel test robot LKP)
>   - Change to global variable misc_device to per PFRU device.
>     (Greg Kroah-Hartman)
>   - Remove the telemetry output in commit log. (Greg Kroah-Hartman)
>   - Add link for corresponding userspace tool in the commit log.
>     (Greg Kroah-Hartman)
>   - Replace the telemetry .read() with .mmap() so that the userspace
>     could mmap once, and read multiple times. (Greg Kroah-Hartman)
> - Change from v3 to v4:
>   - Add Documentation/ABI/testing/pfru to document the ABI and
>     remove Documentation/x86/pfru.rst (Rafael J. Wysocki)
>   - Replace all pr_err() with dev_dbg() (Greg Kroah-Hartman,
>     Rafael J. Wysocki)
>   - returns ENOTTY rather than ENOIOCTLCMD if invalid ioctl command
>     is provided. (Greg Kroah-Hartman)
>   - Remove compat ioctl. (Greg Kroah-Hartman)
>   - Rename /dev/pfru/pfru_update to /dev/acpi_pfru (Greg Kroah-Hartman)
>   - Simplify the check for element of the package in query_capability()
>     (Rafael J. Wysocki)
>   - Remove the loop in query_capability(), query_buffer() and query
>     the package elemenet directly. (Rafael J. Wysocki)
>   - Check the number of elements in case the number of package
>     elements is too small. (Rafael J. Wysocki)
>   - Doing the assignment as initialization in get_image_type().
>     Meanwhile, returns the type or a negative error code in
>     get_image_type(). (Rafael J. Wysocki)
>   - Put the comments inside the function. (Rafael J. Wysocki)
>   - Returns the size or a negative error code in adjust_efi_size()
>     (Rafael J. Wysocki)
>   - Fix the return value from EFAULT to EINVAL if pfru_valid_revid()
>     does not pass. (Rafael J. Wysocki)
>   - Change the write() to be the code injection/update, the read() to
>     be telemetry retrieval and all of the rest to be ioctl()s under
>     one special device file.(Rafael J. Wysocki)
>   - Remove redundant parens. (Rafael J. Wysocki)
>   - Putting empty code lines after an if () statement that is not
>     followed by a block. (Rafael J. Wysocki)
>   - Remove "goto" tags to make the code more readable. (Rafael J. Wysocki)
> - Change from v2 to v3:
>   - Use valid types for structures that cross the user/kernel boundary
>     in the uapi header. (Greg Kroah-Hartman)
>   - Rename the structure in uapi to start with a prefix pfru so as
>     to avoid confusing in the global namespace. (Greg Kroah-Hartman)
> - Change from v1 to v2:
>   - Add a spot in index.rst so it becomes part of the docs build
>     (Jonathan Corbet).
>   - Sticking to the 80-column limit(Jonathan Corbet).
>   - Underline lengths should match the title text(Jonathan Corbet).
>   - Use literal blocks for the code samples(Jonathan Corbet).
>   - Add sanity check for duplicated instance of ACPI device.
>   - Update the driver to work with allocated pfru_device objects.
>     (Mike Rapoport)
>   - For each switch case pair, get rid of the magic case numbers
>     and add a default clause with the error handling.(Mike Rapoport)
>   - Move the obj->type checks outside the switch to reduce redundancy.
>     (Mike Rapoport)
>   - Parse the code_inj_id and drv_update_id at driver initialization time
>     to reduce the re-parsing at runtime. (Mike Rapoport)
>   - Explain in detail how the size needs to be adjusted when doing
>     version check. (Mike Rapoport)
>   - Rename parse_update_result() to dump_update_result()
>     (Mike Rapoport)
>   - Remove redundant return.(Mike Rapoport)
>   - Do not expose struct capsulate_buf_info to uapi, since it is
>     not needed in userspace. (Mike Rapoport)
>   - Do not allow non-root user to run this test.(Shuah Khan)
>   - Test runs on platform without pfru_telemetry should skip
>     instead of reporting failure/error.(Shuah Khan)
>   - Reuse uapi/linux/pfru.h instead of copying it into the test
>     directory. (Mike Rapoport)
>
> Chen Yu (4):
>   efi: Introduce EFI_FIRMWARE_MANAGEMENT_CAPSULE_HEADER and
>     corresponding structures
>   drivers/acpi: Introduce Platform Firmware Runtime Update device driver
>   drivers/acpi: Introduce Platform Firmware Runtime Telemetry
>   tools: Introduce power/acpi/tools/pfrut
>
>  .../userspace-api/ioctl/ioctl-number.rst      |   1 +
>  drivers/acpi/Kconfig                          |  22 +
>  drivers/acpi/Makefile                         |   1 +
>  drivers/acpi/pfr_telemetry.c                  | 434 +++++++++++++
>  drivers/acpi/pfr_update.c                     | 575 ++++++++++++++++++
>  include/linux/efi.h                           |  46 ++
>  include/uapi/linux/pfrut.h                    | 262 ++++++++
>  tools/power/acpi/.gitignore                   |   1 +
>  tools/power/acpi/Makefile                     |  16 +-
>  tools/power/acpi/Makefile.rules               |   2 +-
>  tools/power/acpi/man/pfrut.8                  | 137 +++++
>  tools/power/acpi/tools/pfrut/Makefile         |  23 +
>  tools/power/acpi/tools/pfrut/pfrut.c          | 424 +++++++++++++
>  13 files changed, 1935 insertions(+), 9 deletions(-)
>  create mode 100644 drivers/acpi/pfr_telemetry.c
>  create mode 100644 drivers/acpi/pfr_update.c
>  create mode 100644 include/uapi/linux/pfrut.h
>  create mode 100644 tools/power/acpi/man/pfrut.8
>  create mode 100644 tools/power/acpi/tools/pfrut/Makefile
>  create mode 100644 tools/power/acpi/tools/pfrut/pfrut.c
>
> --

I have one comment regarding the second patch (I'll send it
separately), but generally I'm inclined to pick up the patches in
their current form, barring any objections from Greg.

Thanks!

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