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[PATCH v2 00/21] hw/uefi: add uefi variable service


From: Gerd Hoffmann
Subject: [PATCH v2 00/21] hw/uefi: add uefi variable service
Date: Tue, 7 Jan 2025 16:33:27 +0100

This patch adds a virtual device to qemu which the uefi firmware can use
to store variables.  This moves the UEFI variable management from
privileged guest code (managing vars in pflash) to the host.  Main
advantage is that the need to have privilege separation in the guest
goes away.

On x86 privileged guest code runs in SMM.  It's supported by kvm, but
not liked much by various stakeholders in cloud space due to the
complexity SMM emulation brings.

On arm privileged guest code runs in el3 (aka secure world).  This is
not supported by kvm, which is unlikely to change anytime soon given
that even el2 support (nested virt) is being worked on for years and is
not yet in mainline.

The design idea is to reuse the request serialization protocol edk2 uses
for communication between SMM and non-SMM code, so large chunks of the
edk2 variable driver stack can be used unmodified.  Only the driver
which traps into SMM mode must be replaced by a driver which talks to
qemu instead.

A edk2 test branch can be found here (build with "-D QEMU_VARS=TRUE").
https://github.com/kraxel/edk2/commits/devel/secure-boot-external-vars

The uefi-vars device re-implements the privileged edk2 protocols
(i.e. the code running in SMM mode).

v2 changes:
 - fully implement authenticated variables.
 - various cleanups and fixes.

enjoy & take care,
  Gerd

Gerd Hoffmann (21):
  hw/uefi: add include/hw/uefi/var-service-api.h
  hw/uefi: add include/hw/uefi/var-service-edk2.h
  hw/uefi: add include/hw/uefi/var-service.h
  hw/uefi: add var-service-guid.c
  hw/uefi: add var-service-utils.c
  hw/uefi: add var-service-vars.c
  hw/uefi: add var-service-auth.c
  hw/uefi: add var-service-policy.c
  hw/uefi: add var-service-core.c
  hw/uefi: add var-service-pkcs7.c
  hw/uefi: add var-service-pkcs7-stub.c
  hw/uefi: add var-service-siglist.c
  hw/uefi: add var-service-json.c + qapi for NV vars.
  hw/uefi: add trace-events
  hw/uefi: add UEFI_VARS to Kconfig
  hw/uefi: add to meson
  hw/uefi: add uefi-vars-sysbus device
  hw/uefi: add uefi-vars-isa device
  hw/arm: add uefi variable support to virt machine type
  docs: add uefi variable service documentation
  hw/uefi: add MAINTAINERS entry

 include/hw/arm/virt.h              |   2 +
 include/hw/uefi/var-service-api.h  |  40 ++
 include/hw/uefi/var-service-edk2.h | 227 +++++++++
 include/hw/uefi/var-service.h      | 186 ++++++++
 hw/arm/virt.c                      |  41 ++
 hw/uefi/var-service-auth.c         | 361 ++++++++++++++
 hw/uefi/var-service-core.c         | 237 ++++++++++
 hw/uefi/var-service-guid.c         |  99 ++++
 hw/uefi/var-service-isa.c          |  91 ++++
 hw/uefi/var-service-json.c         | 242 ++++++++++
 hw/uefi/var-service-pkcs7-stub.c   |  16 +
 hw/uefi/var-service-pkcs7.c        | 436 +++++++++++++++++
 hw/uefi/var-service-policy.c       | 370 +++++++++++++++
 hw/uefi/var-service-siglist.c      | 212 +++++++++
 hw/uefi/var-service-sysbus.c       |  90 ++++
 hw/uefi/var-service-utils.c        | 241 ++++++++++
 hw/uefi/var-service-vars.c         | 725 +++++++++++++++++++++++++++++
 MAINTAINERS                        |   6 +
 docs/devel/index-internals.rst     |   1 +
 docs/devel/uefi-vars.rst           |  66 +++
 hw/Kconfig                         |   1 +
 hw/meson.build                     |   1 +
 hw/uefi/Kconfig                    |   9 +
 hw/uefi/LIMITATIONS.md             |   7 +
 hw/uefi/meson.build                |  24 +
 hw/uefi/trace-events               |  17 +
 meson.build                        |   1 +
 qapi/meson.build                   |   1 +
 qapi/qapi-schema.json              |   1 +
 qapi/uefi.json                     |  45 ++
 30 files changed, 3796 insertions(+)
 create mode 100644 include/hw/uefi/var-service-api.h
 create mode 100644 include/hw/uefi/var-service-edk2.h
 create mode 100644 include/hw/uefi/var-service.h
 create mode 100644 hw/uefi/var-service-auth.c
 create mode 100644 hw/uefi/var-service-core.c
 create mode 100644 hw/uefi/var-service-guid.c
 create mode 100644 hw/uefi/var-service-isa.c
 create mode 100644 hw/uefi/var-service-json.c
 create mode 100644 hw/uefi/var-service-pkcs7-stub.c
 create mode 100644 hw/uefi/var-service-pkcs7.c
 create mode 100644 hw/uefi/var-service-policy.c
 create mode 100644 hw/uefi/var-service-siglist.c
 create mode 100644 hw/uefi/var-service-sysbus.c
 create mode 100644 hw/uefi/var-service-utils.c
 create mode 100644 hw/uefi/var-service-vars.c
 create mode 100644 docs/devel/uefi-vars.rst
 create mode 100644 hw/uefi/Kconfig
 create mode 100644 hw/uefi/LIMITATIONS.md
 create mode 100644 hw/uefi/meson.build
 create mode 100644 hw/uefi/trace-events
 create mode 100644 qapi/uefi.json

-- 
2.47.1




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