[PATCH 14/14] qemu: arm64: Add documentation for capsule update

[Heinrich Schuchardt]

On 11/26/20 7:41 PM, Sughosh Ganu wrote:
> Add documentation highlighting the steps for using the uefi capsule
> update feature for updating the u-boot firmware image.
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> ---
>   doc/board/emulation/qemu-arm.rst | 157 +++++++++++++++++++++++++++++++

Thank you for carefully documenting your enhancement.

Unfortunately this does not build with 'make htmldocs'. (You will need
python3-sphinx with a version < 3 for building due to incompatible
changes in python3-sphinx.)

Warning, treated as error:
doc/board/emulation/qemu-arm.rst:137:Unexpected indentation.
make[1]: *** [doc/Makefile:69: htmldocs] Error 2
make: *** [Makefile:2167: htmldocs] Error 2

Please, run your series through Travis CI before resubmitting.

Takahiro's patches have been added to origin/next. So this is what your
series should be based on until the next is merged into master in January.

I am missing a documentation for mkeficapsule. Could you, please, try to
set one up together with Takahiro. I guess we should create a new
directory doc/tools/.

Best regards

Heinrich

>   1 file changed, 157 insertions(+)
>
> diff --git a/doc/board/emulation/qemu-arm.rst b/doc/board/emulation/qemu-arm.rst
> index 8d7fda10f1..3978c13269 100644
> --- a/doc/board/emulation/qemu-arm.rst
> +++ b/doc/board/emulation/qemu-arm.rst
> @@ -90,3 +90,160 @@ The debug UART on the ARM virt board uses these settings::
>       CONFIG_DEBUG_UART_PL010=y
>       CONFIG_DEBUG_UART_BASE=0x9000000
>       CONFIG_DEBUG_UART_CLOCK=0
> +
> +Enabling Uefi Capsule Update feature
> +------------------------------------
> +
> +Support has been added for the uefi capsule update feature which
> +enables updating the u-boot image using the uefi firmware management
> +protocol (fmp). The capsules are not passed to the firmware through
> +the UpdateCapsule runtime service. Instead, capsule-on-disk
> +functionality is used for fetching the capsule from the EFI System
> +Partition (ESP).
> +
> +Currently, support has been added for updating the u-boot binary as a
> +raw image when the platform is booted in non-secure mode, i.e with
> +CONFIG_TFABOOT disabled. For this configuration, the qemu platform
> +needs to be booted with 'secure=off'. The u-boot binary placed on the
> +first bank of the Nor Flash at offset 0x0. The u-boot environment is
> +placed on the second Nor Flash bank at offset 0x4000000.
> +
> +The capsule update feature is enabled with the following configs::
> +
> +    CONFIG_MTD=y
> +    CONFIG_FLASH_CFI_MTD=y
> +    CONFIG_CMD_MTDPARTS=y
> +    CONFIG_CMD_DFU=y
> +    CONFIG_DFU_MTD=y
> +    CONFIG_EFI_CAPSULE_ON_DISK=y
> +    CONFIG_EFI_CAPSULE_FIRMWARE_MANAGEMENT=y
> +    CONFIG_EFI_CAPSULE_FIRMWARE=y
> +    CONFIG_EFI_CAPSULE_FIRMWARE_RAW=y
> +    CONFIG_EFI_CAPSULE_FMP_HEADER=y
> +
> +In addition, the following config needs to be disabled::
> +    CONFIG_TFABOOT
> +
> +The capsule file can be generated by using the GenerateCapsule.py
> +script in edk2::
> +
> +    $ ./BaseTools/BinWrappers/PosixLike/GenerateCapsule -e -o \
> +    <capsule_file_name> --fw-version <val> --lsv <val> --guid \
> +    e2bb9c06-70e9-4b14-97a3-5a7913176e3f --verbose --update-image-index \
> +    <val> --verbose <u-boot.bin>
> +
> +If the above edk2 script is being used for generating the capsule, the
> +following additional config needs to be enabled::
> +    CONFIG_EFI_CAPSULE_FMP_HEADER=y
> +
> +As per the uefi specification, the capsule file needs to be placed on
> +the EFI System Partition, under the EFI/UpdateCapsule/ directory. The
> +EFI System Partition can be a virtio-blk-device.
> +
> +Before initiating the firmware update, the efi variables BootNext,
> +BootXXXX and OsIndications need to be set. The BootXXXX variable needs
> +to be pointing to the EFI System Partition which contains the capsule
> +file. The BootNext, BootXXXX and OsIndications variables can be set
> +using the following commands::
> +
> +    => efidebug boot add 0 Boot0000 virtio 0:1 <capsule_file_name>
> +    => efidebug boot next 0
> +    => setenv -e -nv -bs -rt -v OsIndications =0x04
> +    => saveenv
> +
> +Finally, the capsule update can be initiated with the following
> +command::
> +
> +    => efidebug capsule disk-update
> +
> +The updated u-boot image will be booted on subsequent boot.
> +
> +Enabling Capsule Authentication
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +The uefi specification defines a way of authenticating the capsule to
> +be updated by verifying the capsule signature. The capsule signature
> +is computed and prepended to the capsule payload at the time of
> +capsule generation. This signature is then verified by using the
> +public key stored as part of the X509 certificate. This certificate is
> +in the form of an efi signature list (esl) file, which is embedded as
> +part of the platform's device tree blob using the mkeficapsule
> +utility.
> +
> +The capsule authentication feature can be enabled through the
> +following config, in addition to the configs listed above for capsule
> +update::
> +
> +    CONFIG_EFI_CAPSULE_AUTHENTICATE=y
> +
> +The public key esl file can be embedded in the dtb with the following
> +command::
> +    ./tools/mkeficapsule -K <pub_key.esl> -D <dtb>
> +
> +Running the above command results in the creation of a 'signature'
> +node in the dtb, under which the public key is stored as a
> +'capsule-key' property.
> +
> +Once the esl file has been embedded as part of the dtb, the platform
> +needs to be be booted with this dtb. This can be done by disabling the
> +CONFIG_OF_BOARD option, and then, passing the above dtb file to the
> +u-boot build.
> +
> +The capsule update with authentication can be enabled on the platform
> +with the following steps
> +
> +1. Install utility commands on your host
> +    * openssl
> +    * efitools
> +
> +2. Create signing keys and certificate files on your host::
> +
> +        $ openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=CRT/ \
> +                -keyout CRT.key -out CRT.crt -nodes -days 365
> +        $ cert-to-efi-sig-list CRT.crt CRT.esl
> +
> +        $ openssl x509 -in CRT.crt -out CRT.cer -outform DER
> +        $ openssl x509 -inform DER -in CRT.cer -outform PEM -out CRT.pub.pem
> +
> +        $ openssl pkcs12 -export -out CRT.pfx -inkey CRT.key -in CRT.crt
> +        $ openssl pkcs12 -in CRT.pfx -nodes -out CRT.pem
> +
> +3. Store the esl file generated above as part of the dtb::
> +
> +        $ ./tools/mkeficapsule -K <pub_key.esl> -D <dtb>
> +
> +4. The capsule file can be generated by using the GenerateCapsule.py
> +   script in edk2::
> +
> +        $ ./BaseTools/BinWrappers/PosixLike/GenerateCapsule -e -o \
> +	<capsule_file_name> --monotonic-count <val> --fw-version \
> +	<val> --lsv <val> --guid \
> +	e2bb9c06-70e9-4b14-97a3-5a7913176e3f --verbose \
> +	--update-image-index <val> --signer-private-cert \
> +	/path/to/CRT.pem --trusted-public-cert \
> +	/path/to/CRT.pub.pem --other-public-cert /path/to/CRT.pub.pem \
> +	<u-boot.bin>
> +
> +Once the capsule has been generated, use the same instructions as
> +mentioned above for placing the capsule on the EFI System Partition
> +
> +5. Building u-boot with the following steps::
> +
> +       $ make qemu_arm64_defconfig
> +       $ make menuconfig
> +            Disable CONFIG_OF_BOARD and CONFIG_TFABOOT
> +       $ make EXT_DTB=<dtb> all
> +
> +6. Enable capsule authentication by setting the following env
> +   variable::
> +
> +        => setenv capsule_authentication_enabled 1
> +        => saveenv
> +
> +Setting the environment variable capsule_authentication_enabled
> +enables the capsule authentication.
> +
> +Once the capsule has been placed on the EFI System Partition and the
> +above env variable has been set, along with the BootXXXX and the
> +BootNext variables, the capsule update can be initiated
> +using the same command as that shown above.
>