Re: [PATCH v2 4/8] OvmfPkg: introduce FlashNvStorageAddressLib

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 30 November 2017 at 16:30, Laszlo Ersek <lersek@redhat.com> wrote:
> An OVMF binary built with
>
>   -D SMM_REQUIRE
>
> or with
>
>   -D MEM_VARSTORE_EMU_ENABLE=FALSE
>
> requires flash to be present at the expected (build-time determined)
> location; falling back to the emulated varstore is not possible.
>
> In such builds, we can replace the settings of the
> - varstore,
> - FTW working block,
> - and FTW spare area
> address PCDs in QemuFlashFvbServicesRuntimeDxe with identical settings in
> a new plug-in (NULL class) library, to be linked into variable-related
> PEIMs.
>
> This will enable such builds to access variables during the PEI phase,
> without dynamic flash detection and without ordering constraints against
> other PEIMs.
>

Why can't we set these at build time in this case?

> Cc: Anthony Perard <anthony.perard@citrix.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Cc: Julien Grall <julien.grall@linaro.org>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
>  OvmfPkg/Library/FlashNvStorageAddressLib/FlashNvStorageAddressLib.inf | 48 ++++++++++++++++++
>  OvmfPkg/Library/FlashNvStorageAddressLib/FlashNvStorageAddressLib.c   | 53 ++++++++++++++++++++
>  2 files changed, 101 insertions(+)
>
> diff --git a/OvmfPkg/Library/FlashNvStorageAddressLib/FlashNvStorageAddressLib.inf b/OvmfPkg/Library/FlashNvStorageAddressLib/FlashNvStorageAddressLib.inf
> new file mode 100644
> index 000000000000..f79194f80de9
> --- /dev/null
> +++ b/OvmfPkg/Library/FlashNvStorageAddressLib/FlashNvStorageAddressLib.inf
> @@ -0,0 +1,48 @@
> +## @file
> +#
> +# A hook-in library for variable-related PEIMs, in order to set
> +# - gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase64,
> +# - gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingBase,
> +# - gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareBase,
> +# from their gUefiOvmfPkgTokenSpaceGuid counterparts, just before those PEIMs
> +# consume them.
> +#
> +# Copyright (C) 2017, Red Hat, Inc.
> +#
> +# This program and the accompanying materials are licensed and made available
> +# under the terms and conditions of the BSD License which accompanies this
> +# distribution. The full text of the license may be found at
> +# http://opensource.org/licenses/bsd-license.php
> +#
> +# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
> +# WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 1.25
> +  BASE_NAME                      = FlashNvStorageAddressLib
> +  FILE_GUID                      = 5FF5A9F9-D01E-49EC-9A17-1682FC85122F
> +  MODULE_TYPE                    = BASE
> +  VERSION_STRING                 = 1.0
> +  LIBRARY_CLASS                  = FlashNvStorageAddressLib|PEIM
> +  CONSTRUCTOR                    = SetFlashNvStorageAddresses
> +
> +[Sources]
> +  FlashNvStorageAddressLib.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +  OvmfPkg/OvmfPkg.dec
> +
> +[LibraryClasses]
> +  PcdLib
> +
> +[Pcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareBase
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingBase
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase64
> +  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfFlashNvStorageFtwSpareBase
> +  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfFlashNvStorageFtwWorkingBase
> +  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfFlashNvStorageVariableBase
> diff --git a/OvmfPkg/Library/FlashNvStorageAddressLib/FlashNvStorageAddressLib.c b/OvmfPkg/Library/FlashNvStorageAddressLib/FlashNvStorageAddressLib.c
> new file mode 100644
> index 000000000000..dc1280cc23f1
> --- /dev/null
> +++ b/OvmfPkg/Library/FlashNvStorageAddressLib/FlashNvStorageAddressLib.c
> @@ -0,0 +1,53 @@
> +/** @file
> +
> +  A hook-in library for variable-related PEIMs, in order to set
> +  - gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase64,
> +  - gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingBase,
> +  - gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareBase,
> +  from their gUefiOvmfPkgTokenSpaceGuid counterparts, just before those PEIMs
> +  consume them.
> +
> +  Copyright (C) 2017, Red Hat, Inc.
> +
> +  This program and the accompanying materials are licensed and made available
> +  under the terms and conditions of the BSD License which accompanies this
> +  distribution. The full text of the license may be found at
> +  http://opensource.org/licenses/bsd-license.php
> +
> +  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
> +  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +#include <Library/PcdLib.h>
> +
> +RETURN_STATUS
> +EFIAPI
> +SetFlashNvStorageAddresses (
> +  VOID
> +  )
> +{
> +  RETURN_STATUS PcdStatus;
> +
> +  PcdStatus = PcdSet64S (
> +                PcdFlashNvStorageVariableBase64,
> +                PcdGet32 (PcdOvmfFlashNvStorageVariableBase)
> +                );
> +  if (RETURN_ERROR (PcdStatus)) {
> +    return PcdStatus;
> +  }
> +
> +  PcdStatus = PcdSet32S (
> +                PcdFlashNvStorageFtwWorkingBase,
> +                PcdGet32 (PcdOvmfFlashNvStorageFtwWorkingBase)
> +                );
> +  if (RETURN_ERROR (PcdStatus)) {
> +    return PcdStatus;
> +  }
> +
> +  PcdStatus = PcdSet32S (
> +                PcdFlashNvStorageFtwSpareBase,
> +                PcdGet32 (PcdOvmfFlashNvStorageFtwSpareBase)
> +                );
> +  return PcdStatus;
> +}
> --
> 2.14.1.3.gb7cf6e02401b
>
>