diff mbox series

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

Message ID 20201221114314.25588-15-sughosh.ganu@linaro.org
State Superseded, archived
Delegated to: Heinrich Schuchardt
Headers show
Series qemu: arm64: Add support for uefi capsule update on qemu arm platform | expand

Commit Message

Sughosh Ganu Dec. 21, 2020, 11:43 a.m. UTC
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@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 +++++++++++++++++++++++++++++++
 1 file changed, 188 insertions(+)

Comments

Heinrich Schuchardt Dec. 21, 2020, 12:58 p.m. UTC | #1
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@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?

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
> +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_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::
> +
> +    $ ./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
> +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.
> +
> +On the qemu virt platforms, the device-tree is generated on the fly
> +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
> +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
> +       * 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::
> +
> +    $ ./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>
> +
> +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
> +
> +    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.
> +
> +Build u-boot with the following steps::
> +
> +    $ 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
> +
> +        => 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 binary.
>
Sughosh Ganu Dec. 21, 2020, 5:12 p.m. UTC | #2
On Mon, 21 Dec 2020 at 18:28, Heinrich Schuchardt <xypron.glpk@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@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.

-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
> > +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_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::
> > +
> > +    $ ./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
> > +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.
> > +
> > +On the qemu virt platforms, the device-tree is generated on the fly
> > +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
> > +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
> > +       * 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::
> > +
> > +    $ ./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>
> > +
> > +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
> > +
> > +    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.
> > +
> > +Build u-boot with the following steps::
> > +
> > +    $ 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
> > +
> > +        => 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
> binary.
> >
>
>
Heinrich Schuchardt Dec. 21, 2020, 5:51 p.m. UTC | #3
On 12/21/20 6:12 PM, Sughosh Ganu wrote:
> On Mon, 21 Dec 2020 at 18:28, Heinrich Schuchardt <xypron.glpk@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@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.

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)?

>>> +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.
>>>
>>
>>
>
Sughosh Ganu Dec. 22, 2020, 6:10 a.m. UTC | #4
On Mon, 21 Dec 2020 at 23:21, Heinrich Schuchardt <xypron.glpk@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@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@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.
> >>>
> >>
> >>
> >
>
>
diff mbox series

Patch

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
+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_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::
+
+    $ ./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
+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.
+
+On the qemu virt platforms, the device-tree is generated on the fly
+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
+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
+       * 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::
+
+    $ ./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>
+
+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
+
+    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.
+
+Build u-boot with the following steps::
+
+    $ 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
+
+        => 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 binary.