[PATCH 8/8] qemu: arm64: Add documentation for capsule update

[Heinrich Schuchardt]

On 4/30/20 7:36 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>

UEFI capsule updates should be architecture independent. I would expect
that the submitted code should work for x86, ARM, and RISC-V. Why does
this documentation live under the ARM emulation tree?

Best regards

Heinrich

> ---
>  doc/board/emulation/qemu-arm.rst | 112 +++++++++++++++++++++++++++++++
>  1 file changed, 112 insertions(+)
>
> diff --git a/doc/board/emulation/qemu-arm.rst b/doc/board/emulation/qemu-arm.rst
> index ca751d4af4..8649d593ed 100644
> --- a/doc/board/emulation/qemu-arm.rst
> +++ b/doc/board/emulation/qemu-arm.rst
> @@ -80,3 +80,115 @@ can be enabled with the following command line parameters:
>      -drive if=none,file=disk.img,id=mydisk -device nvme,drive=mydisk,serial=foo
>
>  These have been tested in QEMU 2.9.0 but should work in at least 2.5.0 as well.
> +
> +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 the arm64
> +target booting with arm trusted firmware. The This feature is enabled
> +with the following configs::
> +
> +    CONFIG_EFI_CAPSULE_ON_DISK=y
> +    CONFIG_EFI_FIRMWARE_MANAGEMENT_PROTOCOL=y
> +    CONFIG_CMD_EFIDEBUG=y
> +
> +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 \
> +    fb90808a-ba9a-4d42-b9a2-a7a937144aee --verbose --update-image-index \
> +    <val> --verbose <u-boot.bin>
> +
> +
> +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 and
> +BootXXXX need to be set. The BootXXXX variable needs to be pointing to
> +the EFI System Partition which contains the capsule file. The
> +BootNext and BootXXXX variables can be set using the efidebug
> +command::
> +
> +    => efidebug boot add 0 Boot0000 virtio 0:1 <capsule_file_name>
> +    => efidebug boot next 0
> +
> +The OsIndications efi variable needs to be set with the
> +EFI_OS_INDICATIONS_FILE_CAPSULE_DELIVERY_SUPPORTED flag set::
> +
> +    => setenv -e -nv -bs -rt OsIndications =0x04
> +    => saveenv
> +
> +The capsule update function will be invoked on subsequent boot as part
> +of the main_loop function. 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 stored as an
> +efi variable.
> +
> +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 esl file can be generated as follows:
> +
> +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 an efi variable::
> +
> +        => fatload virtio 0:1 <load_addr> EFI/CRT.esl
> +        => setenv -e -nv -bs -rt -i <load_addr>,$filesize CRT
> +
> +        => setenv capsule_authentication_enabled 1
> +        => setenv -e -nv -bs -rt OsIndication =0x04
> +        => saveenv
> +
> +Setting the environment variable capsule_authentication_enabled
> +enables the capsule authentication.
> +
> +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 \
> +	fb90808a-ba9a-4d42-b9a2-a7a937144aee --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
> +and subsequently to initiate the update.
>