On Fri, 9 Aug 2024 at 03:56, Caleb Connolly <[email protected]> wrote: > > Document how platforms can generate GUIDs at runtime rather than > maintaining a list of UUIDs per-board. > > Reviewed-by: Ilias Apalodimas <[email protected]> > Signed-off-by: Caleb Connolly <[email protected]> > --- > doc/develop/uefi/uefi.rst | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst > index d450b12bf801..b64009cc2256 100644 > --- a/doc/develop/uefi/uefi.rst > +++ b/doc/develop/uefi/uefi.rst > @@ -448,8 +448,35 @@ the location of the firmware updates is not a very secure > practice. Getting this information from the firmware itself is more > secure, assuming the firmware has been verified by a previous stage > boot loader. > > +Dynamic Firmware Update GUIDs > +***************************** > + > +The image_type_id contains a GUID value which is specific to the image > +and board being updated, that is to say it should uniquely identify the > +board model (and revision if relevant) and image pair. Traditionally, > +these GUIDs are generated manually and hardcoded on a per-board basis, > +however this scheme makes it difficult to scale up to support many > +boards. > + > +To address this, v5 GUIDs can be used to generate board-specific GUIDs > +at runtime, based on the board's devicetree root compatible > +(e.g. "qcom,qrb5165-rb5"). > + > +These strings are combined with the fw_image name to generate GUIDs for > +each image. Support for dynamic UUIDs can be enabled by generating a new > +namespace UUID and setting EFI_CAPSULE_NAMESPACE_GUID to it. Dynamic GUID > +generation is only enabled if the image_type_id property is unset for your > +firmware images, this is to avoid breaking existing boards with hardcoded > +GUIDs. > + > +The mkeficapsule tool can be used to determine the GUIDs for a particular > +board and image. It can be found in the tools directory. > + > +Firmware update images > +********************** > + > The firmware images structure defines the GUID values, image index > values and the name of the images that are to be updated through > the capsule update feature. These values are to be defined as part of > an array. These GUID values would be used by the Firmware Management > > -- > 2.46.0 >
Reviewed-by: Ilias Apalodimas <[email protected]>
