Re: [edk2-devel] [PATCH 11/13] OvmfPkg/PlatformBootManagerLib: switch to QemuLoadImageLib

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

On 03/02/20 08:29, Ard Biesheuvel wrote:
> Replace the open coded sequence to load Linux on x86 with a short and
> generic sequence invoking QemuLoadImageLib, which can be provided by
> a generic version that only supports the LoadImage and StartImage boot
> services, and one that incorporates the entire legacy loading sequence
> as well.
> 
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2566
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf |   2 +-
>  OvmfPkg/Library/PlatformBootManagerLib/QemuKernel.c               | 157 +++-----------------
>  2 files changed, 24 insertions(+), 135 deletions(-)
> 
> diff --git a/OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf b/OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
> index f89cce187942..40ac5dd7f9d5 100644
> --- a/OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
> +++ b/OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
> @@ -48,7 +48,7 @@ [LibraryClasses]
>    NvVarsFileLib
>    QemuFwCfgLib
>    QemuFwCfgS3Lib
> -  LoadLinuxLib
> +  QemuLoadImageLib
>    QemuBootOrderLib
>    ReportStatusCodeLib
>    UefiLib
> diff --git a/OvmfPkg/Library/PlatformBootManagerLib/QemuKernel.c b/OvmfPkg/Library/PlatformBootManagerLib/QemuKernel.c
> index ddfef925edd3..a15b48d360d2 100644
> --- a/OvmfPkg/Library/PlatformBootManagerLib/QemuKernel.c
> +++ b/OvmfPkg/Library/PlatformBootManagerLib/QemuKernel.c
> @@ -9,11 +9,8 @@
>  
>  #include <Library/BaseLib.h>
>  #include <Library/DebugLib.h>
> -#include <Library/LoadLinuxLib.h>
> -#include <Library/MemoryAllocationLib.h>
> -#include <Library/QemuFwCfgLib.h>
> +#include <Library/QemuLoadImageLib.h>
>  #include <Library/ReportStatusCodeLib.h>
> -#include <Library/UefiBootServicesTableLib.h>
>  #include <Library/UefiLib.h>
>  
>  
> @@ -23,146 +20,38 @@ TryRunningQemuKernel (
>    )
>  {
>    EFI_STATUS                Status;
> -  UINTN                     KernelSize;
> -  UINTN                     KernelInitialSize;
> -  VOID                      *KernelBuf;
> -  UINTN                     SetupSize;
> -  VOID                      *SetupBuf;
> -  UINTN                     CommandLineSize;
> -  CHAR8                     *CommandLine;
> -  UINTN                     InitrdSize;
> -  VOID*                     InitrdData;
> -
> -  SetupBuf = NULL;
> -  SetupSize = 0;
> -  KernelBuf = NULL;
> -  KernelInitialSize = 0;
> -  CommandLine = NULL;
> -  CommandLineSize = 0;
> -  InitrdData = NULL;
> -  InitrdSize = 0;
> -
> -  if (!QemuFwCfgIsAvailable ()) {
> -    return EFI_NOT_FOUND;
> -  }
> -
> -  QemuFwCfgSelectItem (QemuFwCfgItemKernelSize);
> -  KernelSize = (UINTN) QemuFwCfgRead64 ();
> -
> -  QemuFwCfgSelectItem (QemuFwCfgItemKernelSetupSize);
> -  SetupSize = (UINTN) QemuFwCfgRead64 ();
> -
> -  if (KernelSize == 0 || SetupSize == 0) {
> -    DEBUG ((EFI_D_INFO, "qemu -kernel was not used.\n"));
> -    return EFI_NOT_FOUND;
> -  }
> -
> -  SetupBuf = LoadLinuxAllocateKernelSetupPages (EFI_SIZE_TO_PAGES (SetupSize));
> -  if (SetupBuf == NULL) {
> -    DEBUG ((EFI_D_ERROR, "Unable to allocate memory for kernel setup!\n"));
> -    return EFI_OUT_OF_RESOURCES;
> -  }
> -
> -  DEBUG ((EFI_D_INFO, "Setup size: 0x%x\n", (UINT32) SetupSize));
> -  DEBUG ((EFI_D_INFO, "Reading kernel setup image ..."));
> -  QemuFwCfgSelectItem (QemuFwCfgItemKernelSetupData);
> -  QemuFwCfgReadBytes (SetupSize, SetupBuf);
> -  DEBUG ((EFI_D_INFO, " [done]\n"));
> -
> -  Status = LoadLinuxCheckKernelSetup (SetupBuf, SetupSize);
> -  if (EFI_ERROR (Status)) {
> -    goto FreeAndReturn;
> -  }
> -
> -  Status = LoadLinuxInitializeKernelSetup (SetupBuf);
> -  if (EFI_ERROR (Status)) {
> -    goto FreeAndReturn;
> -  }
> -
> -  KernelInitialSize = LoadLinuxGetKernelSize (SetupBuf, KernelSize);
> -  if (KernelInitialSize == 0) {
> -    Status = EFI_UNSUPPORTED;
> -    goto FreeAndReturn;
> -  }
> -
> -  KernelBuf = LoadLinuxAllocateKernelPages (
> -                SetupBuf,
> -                EFI_SIZE_TO_PAGES (KernelInitialSize));
> -  if (KernelBuf == NULL) {
> -    DEBUG ((EFI_D_ERROR, "Unable to allocate memory for kernel!\n"));
> -    Status = EFI_OUT_OF_RESOURCES;
> -    goto FreeAndReturn;
> -  }
> -
> -  DEBUG ((EFI_D_INFO, "Kernel size: 0x%x\n", (UINT32) KernelSize));
> -  DEBUG ((EFI_D_INFO, "Reading kernel image ..."));
> -  QemuFwCfgSelectItem (QemuFwCfgItemKernelData);
> -  QemuFwCfgReadBytes (KernelSize, KernelBuf);
> -  DEBUG ((EFI_D_INFO, " [done]\n"));
> -
> -  QemuFwCfgSelectItem (QemuFwCfgItemCommandLineSize);
> -  CommandLineSize = (UINTN) QemuFwCfgRead64 ();
> -
> -  if (CommandLineSize > 0) {
> -    CommandLine = LoadLinuxAllocateCommandLinePages (
> -                    EFI_SIZE_TO_PAGES (CommandLineSize));
> -    QemuFwCfgSelectItem (QemuFwCfgItemCommandLineData);
> -    QemuFwCfgReadBytes (CommandLineSize, CommandLine);
> -  } else {
> -    CommandLine = NULL;
> -  }
> -
> -  Status = LoadLinuxSetCommandLine (SetupBuf, CommandLine);
> -  if (EFI_ERROR (Status)) {
> -    goto FreeAndReturn;
> -  }
> -
> -  QemuFwCfgSelectItem (QemuFwCfgItemInitrdSize);
> -  InitrdSize = (UINTN) QemuFwCfgRead64 ();
> -
> -  if (InitrdSize > 0) {
> -    InitrdData = LoadLinuxAllocateInitrdPages (
> -                   SetupBuf,
> -                   EFI_SIZE_TO_PAGES (InitrdSize)
> -                   );
> -    DEBUG ((EFI_D_INFO, "Initrd size: 0x%x\n", (UINT32) InitrdSize));
> -    DEBUG ((EFI_D_INFO, "Reading initrd image ..."));
> -    QemuFwCfgSelectItem (QemuFwCfgItemInitrdData);
> -    QemuFwCfgReadBytes (InitrdSize, InitrdData);
> -    DEBUG ((EFI_D_INFO, " [done]\n"));
> -  } else {
> -    InitrdData = NULL;
> -  }
> -
> -  Status = LoadLinuxSetInitrd (SetupBuf, InitrdData, InitrdSize);
> -  if (EFI_ERROR (Status)) {
> -    goto FreeAndReturn;
> +  EFI_HANDLE                KernelImageHandle;
> +
> +  Status = QemuLoadKernelImage (&KernelImageHandle);
> +  if (EFI_ERROR (Status)) {
> +    if (Status != EFI_SECURITY_VIOLATION) {

(1) This special treatment should disappear, once QemuLoadKernelImage()
keeps EFI_SECURITY_VIOLATION inside.

> +      return Status;
> +    }
> +    //
> +    // From the resource allocation perspective, EFI_SECURITY_VIOLATION means
> +    // "success", so we must roll back the image loading.
> +    //
> +    goto UnloadKernelImage;
>    }
>  
>    //
> -  // Signal the EVT_SIGNAL_READY_TO_BOOT event
> +  // Signal the EFI_EVENT_GROUP_READY_TO_BOOT event.
>    //
>    EfiSignalEventReadyToBoot();
>  
>    REPORT_STATUS_CODE (EFI_PROGRESS_CODE,
>      (EFI_SOFTWARE_DXE_BS_DRIVER | EFI_SW_DXE_BS_PC_READY_TO_BOOT_EVENT));
>  
> -  Status = LoadLinux (KernelBuf, SetupBuf);
> +  //
> +  // Start the image.
> +  //
> +  Status = QemuStartKernelImage (KernelImageHandle);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((EFI_D_ERROR, "%a: StartImage(): %r\n", __FUNCTION__, Status));
> +  }

(2) Please run "PatchCheck.py" on the series; it will reject "EFI_D_ERROR".

Thanks,
Laszlo


>  
> -FreeAndReturn:
> -  if (SetupBuf != NULL) {
> -    FreePages (SetupBuf, EFI_SIZE_TO_PAGES (SetupSize));
> -  }
> -  if (KernelBuf != NULL) {
> -    FreePages (KernelBuf, EFI_SIZE_TO_PAGES (KernelInitialSize));
> -  }
> -  if (CommandLine != NULL) {
> -    FreePages (CommandLine, EFI_SIZE_TO_PAGES (CommandLineSize));
> -  }
> -  if (InitrdData != NULL) {
> -    FreePages (InitrdData, EFI_SIZE_TO_PAGES (InitrdSize));
> -  }
> +UnloadKernelImage:
> +  QemuUnloadKernelImage (KernelImageHandle);
>  
>    return Status;
>  }
> -
>