Re: [PATCH v1 2/2] StandaloneMmPkg: Fix HOB space and heap space conflicted issue

["Ard Biesheuvel" <ardb@kernel.org>]

On Wed, 9 Feb 2022 at 13:26, Ming Huang <huangming@linux.alibaba.com> wrote:
>
> The heap space will be rewrote if a StandloneMmPkg module create HOB
> by BuildGuidHob() interface and write data to HOB space.

Can you elaborate? What is supposed to happen and why, and what is
happening instead?

> Add a PCD PcdMemoryHobSize for pre-allocation a space to create HOB to
> fix this issue.
>
> Signed-off-by: Ming Huang <huangming@linux.alibaba.com>
> ---
>  StandaloneMmPkg/Core/StandaloneMmCore.c   | 17 ++++++++++++++++-
>  StandaloneMmPkg/Core/StandaloneMmCore.inf |  3 +++
>  StandaloneMmPkg/StandaloneMmPkg.dec       |  2 ++
>  3 files changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.c b/StandaloneMmPkg/Core/StandaloneMmCore.c
> index d221f1d111..1cf259d946 100644
> --- a/StandaloneMmPkg/Core/StandaloneMmCore.c
> +++ b/StandaloneMmPkg/Core/StandaloneMmCore.c
> @@ -512,6 +512,9 @@ StandaloneMmMain (
>    EFI_MMRAM_DESCRIPTOR            *MmramRanges;
>    UINTN                           MmramRangeCount;
>    EFI_HOB_FIRMWARE_VOLUME         *BfvHob;
> +  EFI_HOB_HANDOFF_INFO_TABLE      *HandOffHobNew;
> +  EFI_HOB_HANDOFF_INFO_TABLE      *HandOffHobOrg;
> +  UINT64                          MaxHobSize = PcdGet64 (PcdMemoryHobSize);
>
>    ProcessLibraryConstructorList (HobStart, &gMmCoreMmst);
>
> @@ -619,10 +622,22 @@ StandaloneMmMain (
>    //
>    HobSize = GetHobListSize (HobStart);
>    DEBUG ((DEBUG_INFO, "HobSize - 0x%x\n", HobSize));
> -  MmHobStart = AllocatePool (HobSize);
> +  ASSERT (HobSize <= MaxHobSize);
> +  MmHobStart = AllocatePool (MaxHobSize);
>    DEBUG ((DEBUG_INFO, "MmHobStart - 0x%x\n", MmHobStart));
>    ASSERT (MmHobStart != NULL);
>    CopyMem (MmHobStart, HobStart, HobSize);
> +  //
> +  // Initlialize the new HOB table
> +  //
> +  HandOffHobOrg = (EFI_HOB_HANDOFF_INFO_TABLE *)HobStart;
> +  HandOffHobNew = (EFI_HOB_HANDOFF_INFO_TABLE *)MmHobStart;
> +  HandOffHobNew->EfiEndOfHobList = (EFI_PHYSICAL_ADDRESS)MmHobStart +
> +    (HandOffHobOrg->EfiEndOfHobList - (EFI_PHYSICAL_ADDRESS)HobStart);
> +  HandOffHobNew->EfiFreeMemoryBottom = HandOffHobNew->EfiEndOfHobList +
> +                                       sizeof (EFI_HOB_GENERIC_HEADER);
> +  HandOffHobNew->EfiFreeMemoryTop = (EFI_PHYSICAL_ADDRESS)MmHobStart + MaxHobSize;
> +
>    Status = MmInstallConfigurationTable (&gMmCoreMmst, &gEfiHobListGuid, MmHobStart, HobSize);
>    ASSERT_EFI_ERROR (Status);
>
> diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.inf b/StandaloneMmPkg/Core/StandaloneMmCore.inf
> index c44b9ff333..37e6135d73 100644
> --- a/StandaloneMmPkg/Core/StandaloneMmCore.inf
> +++ b/StandaloneMmPkg/Core/StandaloneMmCore.inf
> @@ -76,6 +76,9 @@
>    gEfiEventExitBootServicesGuid
>    gEfiEventReadyToBootGuid
>
> +[FixedPcd]
> +  gStandaloneMmPkgTokenSpaceGuid.PcdMemoryHobSize
> +
>  #
>  # This configuration fails for CLANGPDB, which does not support PIE in the GCC
>  # sense. Such however is required for ARM family StandaloneMmCore
> diff --git a/StandaloneMmPkg/StandaloneMmPkg.dec b/StandaloneMmPkg/StandaloneMmPkg.dec
> index 46784d94e4..cf554676e2 100644
> --- a/StandaloneMmPkg/StandaloneMmPkg.dec
> +++ b/StandaloneMmPkg/StandaloneMmPkg.dec
> @@ -48,3 +48,5 @@
>    gEfiStandaloneMmNonSecureBufferGuid      = { 0xf00497e3, 0xbfa2, 0x41a1, { 0x9d, 0x29, 0x54, 0xc2, 0xe9, 0x37, 0x21, 0xc5 }}
>    gEfiArmTfCpuDriverEpDescriptorGuid       = { 0x6ecbd5a1, 0xc0f8, 0x4702, { 0x83, 0x01, 0x4f, 0xc2, 0xc5, 0x47, 0x0a, 0x51 }}
>
> +[PcdsFixedAtBuild]
> +  gStandaloneMmPkgTokenSpaceGuid.PcdMemoryHobSize|0x00000000|UINT64|0x00000004
> --
> 2.17.1
>