UefiPayloadPkg: Add support for Firmware Volume Block ProtocolHEADmaster

This adds support for FVB in order to support a platform-independent
non-volatile variable store on UefiPayloadPkg. The variable store makes
use of the SmmStoreLib to provide an unauthenticated variable store.

Since commit bc744f5893fc4d53275ed26dd8d968011c6a09c1 coreboot supports
the SMMSTORE v2 feature. It implements an SMI handler that is able to
write, read and erase pages in the boot media (SPI flash).
The communication is done using a fixed communication buffer that is
allocated in CBMEM. The existence of this optional feature is advertised
by a coreboot table. When the SMMSTORE feature is not available, the
variable emulation is used by setting PcdEmuVariableNvModeEnable to
TRUE.

The DXE component provides runtime services and takes care of virtual to
physical mapping the communication buffers between SMM and OS.

The contents of the variable store can be accessed and modified by any
privileged application. As authentication is done by runtime services
only the store shouldn't be used to store authenticated variables.

Tested on Linux and Windows on a variety of real hardware.
This can also be tested in QEMU starting with coreboot 24.12 using
qemu-q35 board.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>

0 files changed, 0 insertions, 0 deletions