Re: [edk2-devel] [PATCH 02/13] OvmfPkg: export abstract QEMU blob filesystem in standalone driver

["Laszlo Ersek" <lersek@redhat.com>]

On 03/02/20 08:29, Ard Biesheuvel wrote:
> Expose the existing implementation of an abstract filesystem exposing
> the blobs passed to QEMU via the command line via a standalone DXE
> driver.

"git show --find-copies-harder" works wonders while reviewing this patch :)

> 
> Notable difference with the original code is the switch to a new vendor
> GUIDed media device path, as opposed to a vendor GUID hardware device
> path, which is not entirely appropriate for pure software constructs.

Good point!

> 
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2566
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c   | 979 ++++++++++++++++++++
>  OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.inf |  48 +
>  2 files changed, 1027 insertions(+)
> 
> diff --git a/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
> new file mode 100644
> index 000000000000..efecbd817da1
> --- /dev/null
> +++ b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
> @@ -0,0 +1,979 @@
> +/** @file
> +  DXE driver to expose the 'kernel', 'initrd' and 'cmdline' blobs
> +  provided by QEMU as file in an abstract file system

(1) s/file/files/

[...]

> diff --git a/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.inf b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.inf
> new file mode 100644
> index 000000000000..f4b50c265027
> --- /dev/null
> +++ b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.inf
> @@ -0,0 +1,48 @@
> +##  @file
> +#  DXE driver to expose the 'kernel', 'initrd' and 'cmdline' blobs
> +#  provided by QEMU as file in an abstract file system

(2) same as (1)

> +#
> +#  Copyright (C) 2014-2016, Red Hat, Inc.
> +#  Copyright (C) 2020, Arm, Limited.
> +#
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 1.27
> +  BASE_NAME                      = QemuKernelLoaderFsDxe
> +  FILE_GUID                      = 806040ca-dad9-4978-a3b4-2d2ab0c8a48f
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 1.0
> +  ENTRY_POINT                    = QemuKernelLoaderFsDxeEntrypoint
> +
> +[Sources]
> +  QemuKernelLoaderFsDxe.c
> +
> +[Packages]
> +  MdeModulePkg/MdeModulePkg.dec
> +  MdePkg/MdePkg.dec
> +  OvmfPkg/OvmfPkg.dec
> +
> +[LibraryClasses]
> +  BaseLib
> +  BaseMemoryLib
> +  DebugLib
> +  MemoryAllocationLib
> +  UefiBootServicesTableLib
> +  QemuFwCfgLib

(3) slight disorder

> +  UefiDriverEntryPoint
> +  UefiRuntimeServicesTableLib
> +
> +[Guids]
> +  gEfiFileInfoGuid
> +  gEfiFileSystemInfoGuid
> +  gEfiFileSystemVolumeLabelInfoIdGuid
> +  gQemuKernelLoaderFsMediaGuid
> +
> +[Protocols]
> +  gEfiDevicePathProtocolGuid                ## PRODUCES
> +  gEfiSimpleFileSystemProtocolGuid          ## PRODUCES
> +
> +[Depex]
> +  gEfiRealTimeClockArchProtocolGuid
> 

Good point about the depex; per PI vol 2, 12.6 Real Time Clock
Architectural Protocol, we need this for gRT->GetTime(). The previous
implementation can tage GetTime for granted, because it is linked into
BdsDxe, which ensures that all the architectural protocols have been
installed.

(4) Can you please add a short note about this (the depex) in the commit
message?

With (1) to (4) addressed:

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks!
Laszlo