[edk2-devel] RFC: Universal Payload Interface

[Ni, Ray]

Laszlo,
Thank you for the comments.
Reply inline.

> -----Original Message-----
> From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Laszlo
> Ersek
> Sent: Tuesday, October 27, 2020 10:21 PM
> To: devel at edk2.groups.io; Ni, Ray <ray.ni at intel.com>
> Cc: Zimmer, Vincent <vincent.zimmer at intel.com>; Ma, Maurice
> <maurice.ma at intel.com>; Rangarajan, Ravi P <ravi.p.rangarajan at intel.com>;
> Dong, Guo <guo.dong at intel.com>; Hau, Tze-ming <tze-ming.hau at intel.com>
> Subject: Re: [edk2-devel] RFC: Universal Payload Interface
> 
> On 10/23/20 03:18, Ni, Ray wrote:
> > With the fact that there are many different firmware implementations, we
> tried to decouple today's monolithic UEFI firmware binary to two independent
> components: bootloader and payload.
> 
> (1) "Bootloader" is an extremely loaded word. Regardless of everything
> else in this topic, I strongly suggest picking a different name.
> 
> We already have "Platform Init" or "PI"; maybe use "Silicon Init" or "SI"?
I am a UEFI guy for many years. So your suggestion "PI" looks very friendly to me.
But I am not sure if the audiences include broader people, like coreboot, SBL developers,
do they like the names.

Personally I am open to any name as long as the concept is not changed: the binary blob
is responsible to initialize the silicon.


> 
> 
> (2) What is the *exact* use case (or workflow) that the proposed
> interface enables, or improves?
> What groups of people (what roles) are supposed to benefit from the
> proposed interface?

1. Unified UEFI Payload Binary.
By standardizing the bootloader->payload interface, we keep in mind to move all
platform/silicon specific implementation to bootloader and all the specific info is
passed to payload through the standard interface such that the payload doesn't need
to deal with concrete hardware but just the abstracted info. It gives possibility to create
the unified UEFI payload binary that can run in any platform/silicon (off course, one binary
per one CPU arch). Just like today's UEFI Shell.
It's a huge save on validation side to every company that uses UEFI as boot solution for
hardware.
People may argue maintaining such a binary causes additional overhead. I agree.
But I am optimistic on such direction. 
(The code will be still in open source.)

2. Bootloaders
It shows an attitude of EDKII community that it doesn't restrict to use EDKII PEI as the
only acknowledged silicon code execution environment. The standard interface as a promise
allows any compliant bootloader to work with EDKII UEFI Payload.

3. Payloads
I saw different tries to change EDKII DXE environment for different hardware/OS.
It may cause defragmentation of UEFI spec. The standard interface also allows any
compliant payload to be created.

> 
> Thanks
> Laszlo
> 
> >
> > Basically, bootloader initializes the silicon hardware and payload prepares
> the OS required data and services. Bootloader passes control to payload.
> >
> > https://universalpayload.github.io/documentation/spec/spec.html defines the
> universal interface between bootloader and payload. So that different
> bootloaders can work with different payloads, initializing different hardware
> and booting different OSes.
> > The interface document is in very draft phase. Any feedback is welcome.
> >
> > We also developed the POC code to demonstrate the idea. Please use below
> steps to get the code that uses SBL as the bootloader and EDKII UEFI Payload as
> the payload. This POC is being developed for QEMU Q35 virtual machine.
> >
> >   1.  Run "git clone https://github.com/universalpayload/tools.git payload"
> >
> > This step downloads the initial tools that will setup the dev environment.
> >
> >   1.  Run "py -3 clone_and_build_sbl_with_uefipayload.py" in the "payload"
> directory
> >
> > This script downloads branched SBL
> (https://github.com/universalpayload/slimbootloader.git) and edk2
> (https://github.com/universalpayload/edk2.git).
> >
> > Then it builds the firmware binary "SlimBootloader.bin" in "codeworkspace"
> directory.
> >
> >   1.  Boot QEMU by running "qemu-system-x86_64.exe -machine q35 -pflash
> codeworkspace\SlimBootloader.bin  -serial file:test.log"
> >
> > Because the code is under active development, please contact us when you
> cannot build or boot successfully.
> >
> > Besides the SBL, we modified coreboot
> (https://github.com/universalpayload/coreboot.git) to let it conform to the
> universal interface as a bootloader.
> > Besides the EDK2 UEFI Payload, we created a payload
> (https://github.com/universalpayload/linuxpayload.git) that can boot Linux.
> >
> > Thanks,
> > Ray
> >
> >
> >
> >
> >
> >
> >
> 
> 
> 
> 
> 



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