Hi Pierre,

Thanks for sending the update. I tested on QEMU with this change (no 
TRNG from TFA), it works for me.
Tested-by: Kun Qin <kun.qin@microsoft.com>

Please note that the change below is still needed to avoid data abortion 
exception. It will be helpful if one
of the maintainers can help merging it.
[PATCH v2 1/1] SecurityPkg: RngDxe: Fixing mAvailableAlgoArray allocator 
(groups.io) <https://edk2.groups.io/g/devel/message/106547>

Regards,
Kun

On 7/6/2023 1:51 AM, pierre.gondois@arm.com wrote:
> From: Pierre Gondois<pierre.gondois@arm.com>
>
> v3:
> - As the unsafe algorithm GUID will not be added to the UEFI
>    specification, rename:
>    - gEfiRngAlgorithmUnSafe to gEdkiiRngAlgorithmUnSafe
>    - EFI_RNG_ALGORITHM_UNSAFE to EDKII_RNG_ALGORITHM_UNSAFE
>
> v2:
> [1/8] MdePkg/ArmTrngLib: Remove ASSERTs in Null implementation
> - Dropped
> [2/8] MdePkg/MdePkg.dec: Move PcdCpuRngSupportedAlgorithm to MdePkg
> - Change gEfiMdePkgTokenSpaceGuid.PcdCpuRngSupportedAlgorithm
>    token number
> - Rename to SecurityPkg/SecurityPkg.dec: Move
>    PcdCpuRngSupportedAlgorithm to MdePkg
> [5/8] MdePkg/Rng: Add GetRngGuid() to RngLib
> - Remove gEfiRngAlgorithmUnSafe from inf file
> - Split Guids definitions in arch specific sections
> [6/8] SecurityPkg/RngDxe: Use GetRngGuid() when probing RngLib
> - Remove RngFindDefaultAlgo() and change logic accordingly.
> [7/8] SecurityPkg/RngDxe: Select safe default Rng algorithm
> - Dropped due to changes in [6/8]
>
> This patch also requires the following patch on top of the serie:
> -https://edk2.groups.io/g/devel/message/106546
>
> This patchset follows the 'code first' approach and relates to [1].
> This patchset follows the thread at [3] that aims to solve [2].
> [1] and [2] are bound and this patchset aims to solve both.
>
> In this patchset:
> a-
> The RngDxe can rely on the RngLib. However the RngLib has no
> interface allowing to describe which Rng algorithm is implemented.
> The RngDxe must advertise the algorithm that are available through
> the RngGetInfo() callback.
> Add a GetRngGuid() for interface to the RngLib.
>
> b-
> The Arm Architecture states the RNDR that the DRBG algorithm should
> be compliant with NIST SP800-90A, while not mandating a particular
> algorithm, so as to be inclusive of different geographies.
> The RngLib can rely on this Arm RNDR instruction. In order to
> accurately describe the implementation using the RNDR instruction,
> add a EFI_RNG_ALGORITHM_ARM_RNDR GUID [1].
>
> c-
> For the same reason as a/b, add a GUID describing unsafe RNG
> algorithms, allowing to accurately describe the BaseRngLibTimerLib.
>
> d-
> Use a/b/c mechanisms/GUIDs to select a safe Rng algorithm in the
> Arm implementation of the RngDxe.
>
> [1] BZ:https://bugzilla.tianocore.org/show_bug.cgi?id=4441
> [2] BZ:https://bugzilla.tianocore.org/show_bug.cgi?id=4151
> [3]https://edk2.groups.io/g/devel/message/100806
>
> Pierre Gondois (6):
>    SecurityPkg/SecurityPkg.dec: Move PcdCpuRngSupportedAlgorithm to
>      MdePkg
>    MdePkg/DxeRngLib: Request raw algorithm instead of default
>    MdePkg/Rng: Add GUIDs to describe Rng algorithms
>    MdePkg/Rng: Add GetRngGuid() to RngLib
>    SecurityPkg/RngDxe: Use GetRngGuid() when probing RngLib
>    SecurityPkg/RngDxe: Simplify Rng algorithm selection for Arm
>
>   MdePkg/Include/Library/RngLib.h               | 17 ++++++
>   MdePkg/Include/Protocol/Rng.h                 | 20 +++++++
>   MdePkg/Library/BaseRngLib/AArch64/Rndr.c      | 42 +++++++++++++++
>   MdePkg/Library/BaseRngLib/BaseRngLib.inf      | 10 ++++
>   MdePkg/Library/BaseRngLib/Rand/RdRand.c       | 26 +++++++++
>   .../Library/BaseRngLibNull/BaseRngLibNull.c   | 22 ++++++++
>   .../BaseRngLibTimerLib/BaseRngLibTimerLib.inf |  3 ++
>   .../Library/BaseRngLibTimerLib/RngLibTimer.c  | 28 ++++++++++
>   MdePkg/Library/DxeRngLib/DxeRngLib.c          | 36 ++++++++++++-
>   MdePkg/MdePkg.dec                             |  7 +++
>   .../RngDxe/AArch64/AArch64Algo.c              | 54 +++++++++++++------
>   .../RandomNumberGenerator/RngDxe/ArmRngDxe.c  | 23 ++++----
>   .../RandomNumberGenerator/RngDxe/RngDxe.inf   |  5 +-
>   SecurityPkg/SecurityPkg.dec                   |  2 -
>   14 files changed, 258 insertions(+), 37 deletions(-)
>