[PATCH v2 14/14] qemu: arm64: Add documentation for capsule update

Sughosh Ganu sughosh.ganu at linaro.org
Tue Dec 22 07:10:38 CET 2020 

On Mon, 21 Dec 2020 at 23:21, Heinrich Schuchardt <xypron.glpk at gmx.de>
wrote:

> On 12/21/20 6:12 PM, Sughosh Ganu wrote:
> > On Mon, 21 Dec 2020 at 18:28, Heinrich Schuchardt <xypron.glpk at gmx.de>
> > wrote:
> >
> >> On 12/21/20 12:43 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>
> >>> ---
> >>>
> >>> Changes since V1:
> >>> * Change the documentation to reflect the usage of overlays for
> >>>     embedding the public key certs at runtime
> >>> * Fix the build for 'make htmldocs'
> >>>
> >>>    doc/board/emulation/qemu-arm.rst | 188
> +++++++++++++++++++++++++++++++
> >>
> >> Why do you put the information into doc/board/emulation/qemu-arm.rst?
> >>
> >> Isn't the same applicable to RISC-V QEMU?
> >>
> >
> > Where do you want me to put it. Currently, I do not see any common
> document
> > for qemu which can be shared between qemu-arm and qemu risc-v. Or do you
> > think a new document should be created under doc/board/emulation/
> > directory. Moreover, my series is adding support for capsule update
> feature
> > on the qemu arm64 platform, and i have only tested this feature on the
> qemu
> > arm64 platform. If someone wants to extend this on the qemu
> > risc-v platform, that work i think needs to be done separately, with
> > whatever changes that may be needed to get capsule updates working on
> qemu
> > risc-v. If you so prefer, I can move the changes made for mtdparts and
> > dfu(patches 4/14 and 5/14) under a common directory under
> board/emulation.
>
>
> I have started putting the documentation for shell commands into
> doc/usage. This is where a description of efidebug could be placed.
>
> Equally I think we should put the documentation of tools like
> mkeficapsule under doc/usage.
>
> The description on the usage of the UEFI firmware protocol would fit
> into doc/uefi/uefi.rst.
>
> When it comes to things that are really QEMU specific
> doc/board/emulation/ is the right folder.
>

Ok. I will create a Qemu specific file for capsule updates under the
doc/board/emulation/ directory.


>
> See more comments below.
>
> >
> > -sughosh
> >
> >
> >>
> >> Best regards
> >>
> >> Heinrich
> >>
> >>>    1 file changed, 188 insertions(+)
> >>>
> >>> diff --git a/doc/board/emulation/qemu-arm.rst
> >> b/doc/board/emulation/qemu-arm.rst
> >>> index 8d7fda10f1..11d91811b3 100644
> >>> --- a/doc/board/emulation/qemu-arm.rst
> >>> +++ b/doc/board/emulation/qemu-arm.rst
> >>> @@ -90,3 +90,191 @@ 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
>
> %s/uefi/UEFI/
>
> >>> +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).
>
> According to the UEFI spec the relevant directory is \EFI\UpdateCapsule.
> I think you should mentions this path.
>
> >>> +
> >>> +Currently, support has been added for updating the u-boot binary as a
>
> %s/u-boot/U-Boot/g
>
> >>> +raw image when the platform is booted in non-secure mode, i.e with
>
> %s/i.e/i.e./
>
> >>> +CONFIG_TFABOOT disabled. For this configuration, the qemu platform
>
> %s/qemu/QEMU/
>
> >>> +needs to be booted with 'secure=off'. The u-boot binary placed on the
>
> U-Boot
>
> >>> +first bank of the Nor Flash at offset 0x0. The u-boot environment is
>
> %s/Nor Flash/NOR flash/
>
> U-Boot
>
> >>> +placed on the second Nor Flash bank at offset 0x4000000.
>
> NOR flash
>
> >>> +
> >>> +The capsule update feature is enabled with the following configs::
>
> %s/configs/configuration settings/
>
> >>> +
> >>> +    CONFIG_MTD=y
> >>> +    CONFIG_FLASH_CFI_MTD=y
> >>> +    CONFIG_CMD_MTDPARTS=y
> >>> +    CONFIG_CMD_DFU=y
> >>> +    CONFIG_DFU_MTD=y
> >>> +    CONFIG_PCI_INIT_R=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::
>
> EDK II
>
> >>> +
> >>> +    $ ./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>
> >>> +
> >>> +As per the uefi specification, the capsule file needs to be placed on
>
> UEFI
>
> >>> +the EFI System Partition, under the EFI/UpdateCapsule/ directory. The
>
> \EFI\UpdateCapsule\ (see UEFI specification)
>
> >>> +EFI System Partition can be a virtio-blk-device.
> >>> +
> >>> +Before initiating the firmware update, the efi variables BootNext,
>
> %s/efi/UEFI/
>
> >>> +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
>
> Shouldn't OsIndications bit 2 be set by default when EFI capsule support
> is enabled? How about bit 3 (EFI_OS_INDICATIONS_FMP_CAPSULE_SUPPORTED)?
>

The OsIndications bit
2(EFI_OS_INDICATIONS_FILE_CAPSULE_DELIEVERY_SUPPORTED) should be set by the
OS through a SetVariable call. This is still work in progress though,
hence, for now, we are setting the bit in u-boot before invoking the
capsule update.

As for the bit 3(EFI_OS_INDICATIONS_FMP_CAPSULE_SUPPORTED), this has no
function in the OsIndications variable. This needs to be set in the
variable OsIndicationsSupported, which is being done in the function
efi_init_os_indications.

-sughosh


> >>> +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.
>
> U-Boot
>
> >>> +
> >>> +Enabling Capsule Authentication
> >>> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >>> +
> >>> +The uefi specification defines a way of authenticating the capsule to
>
> UEFI
>
> >>> +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.
> >>> +
> >>> +On the qemu virt platforms, the device-tree is generated on the fly
>
> QEMU
>
> >>> +based on the devices configured. This device tree is then passed on to
> >>> +the various software components booting on the platform, including
> >>> +u-boot. Therefore, on the qemu virt platform, the signatute is
>
> QEMU
>
> >>> +embedded on an overlay. This overlay is then applied at runtime to the
> >>> +base platform device-tree. Steps needed for embedding the esl file in
> >>> +the overlay are highlighted below.
> >>> +
> >>> +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 and private keys used for the signing process are generated
> >>> +and used by the steps highlighted below::
> >>> +
> >>> +    1. Install utility commands on your host
> >>> +       * openssl
>
> 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
> >>> +
> >>> +The capsule file can be generated by using the GenerateCapsule.py
> >>> +script in edk2::
>
> EDK II
>
> >>> +
> >>> +    $ ./BaseTools/BinWrappers/PosixLike/GenerateCapsule -e -o \
>
> Above you wrote GenerateCapsule.py. I understand that the binary wrapper
> shall be used. But somehow this should be explained.
>
> >>> +      <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>
> >>> +
> >>> +Place the capsule generated in the above step on the EFI System
> >>> +Partition under the EFI/UpdateCapsule directory
> >>> +
> >>> +For embedding the public key certificate, the following steps need to
> >>> +be followed::
> >>> +
> >>> +    1. Generate a skeleton overlay dts file, with a single fragment
> >>> +       node and an empty __overlay__ node
>
> A typical user will be lost here. Please, provide the content of the
> file here.
>
> >>> +
> >>> +    2. Convert the dts to a corresponding dtb with the following
> >>> +       command
> >>> +        ./scripts/dtc/dtc -@ -I dts -O dtb -o <ov_dtb_file_name> \
> >>> +        <dts_file>
> >>> +
> >>> +    3. Run the dtb file generated above through the mkeficapsule tool
> >>> +       in u-boot
> >>> +        ./tools/mkeficapsule -O <pub_key.esl> -D <ov_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. The '-O' option is to be used since the
> >>> +public key certificate(esl) file is being embedded in an overlay.
> >>> +
> >>> +The dtb file embedded with the certificate is now to be placed on an
> >>> +EFI System Partition. This would then be loaded and "merged" with the
> >>> +base platform fdt at runtime.
>
> %s/fdt/flattened device-tree (dtb)/
>
> >>> +
> >>> +Build u-boot with the following steps::
>
> U-Boot
>
> >>> +
> >>> +    $ make qemu_arm64_defconfig
> >>> +    $ make menuconfig
> >>> +        Disable CONFIG_TFABOOT
> >>> +        Enable CONFIG_EFI_CAPSULE_AUTHENTICATE
> >>> +        Enable all configs needed for capsule update(listed above)
> >>> +    $ make all
> >>> +
> >>> +Boot the platform and perform the following steps on the u-boot
> >>> +command line::
> >>> +
> >>> +    1. Enable capsule authentication by setting the following env
> >>> +       variable
> >>> +
> >>> +        => setenv capsule_authentication_enabled 1
> >>> +        => saveenv
> >>> +
> >>> +    2. Load the overlay dtb to memory and merge it with the base fdt
> >>> +
> >>> +        => fatload virtio 0:1 <$fdtovaddr> EFI/<ov_dtb_file>
> >>> +        => fdt addr $fdtcontroladdr
> >>> +        => fdt resize <size_of_ov_dtb_file>
> >>> +        => fdt apply <$fdtovaddr>
> >>> +
> >>> +    3. Set the following env and efi Boot variables
>
> environment and UEFI boot variables
>
> >>> +
> >>> +        => setenv -e -nv -bs -rt -v OsIndications =0x04
> >>> +        => efidebug boot add 0 Boot0000 virtio 0:1 <capsule_file_name>
> >>> +        => efidebug boot next 0
> >>> +        => saveenv
> >>> +
> >>> +    4. Finally, the capsule update can be initiated with the following
> >>> +       command
> >>> +
> >>> +        => efidebug capsule disk-update
> >>> +
> >>> +On subsequent reboot, the platform should boot the updated u-boot
>
> U-Boot
>
> Best regards
>
> Heinrich
>
> >> binary.
> >>>
> >>
> >>
> >
>
>

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