[edk2-devel] [edk2-platforms][PATCH V1 08/20] StandaloneMmPkg: Add backwards compatible support to detect FF-A v1.1

Oliver Smith-Denny osde at linux.microsoft.com
Wed Jul 12 20:31:50 UTC 2023


On 7/11/2023 7:36 AM, Nishant Sharma wrote:
> From: Achin Gupta <achin.gupta at arm.com>
> 
> For better or worse, an StMM SP can communicate with the SPM through one
> of these interfaces.
> 
> 1. SPM_MM interface
> 2. FF-A v1.0 interface
> 3. FF-A v1.1 interface
> 
> 2) implements only minimal FF-A support. It reuses the initialisation ABI
> defined by 1) and wraps the remaining communicaton in
> FFA_MSG_SEND_DIRECT_REQ/RESP ABIs.
> 3) uses FF-A ABIs from the spec for both initialisation and communication.
> 
> Detecting these variations in the GetSpmVersion() function is tedious. This
> patch restores the original function that discovered configuration
> 1). It defines a new function to discover presence of FF-A and
> differentiate between v1.0 and v1.1.
> 
> Signed-off-by: Achin Gupta <achin.gupta at arm.com>
> Signed-off-by: Nishant Sharma <nishant.sharma at arm.com>
> ---
>   StandaloneMmPkg/Library/StandaloneMmCoreEntryPoint/Arm/StandaloneMmCoreEntryPoint.c | 132 +++++++++++++-------
>   1 file changed, 87 insertions(+), 45 deletions(-)
> 
> diff --git a/StandaloneMmPkg/Library/StandaloneMmCoreEntryPoint/Arm/StandaloneMmCoreEntryPoint.c b/StandaloneMmPkg/Library/StandaloneMmCoreEntryPoint/Arm/StandaloneMmCoreEntryPoint.c
> index 682b55b5478a..9f6af55c86c4 100644
> --- a/StandaloneMmPkg/Library/StandaloneMmCoreEntryPoint/Arm/StandaloneMmCoreEntryPoint.c
> +++ b/StandaloneMmPkg/Library/StandaloneMmCoreEntryPoint/Arm/StandaloneMmCoreEntryPoint.c
> @@ -32,13 +32,9 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
>   #define SPM_MAJOR_VER_MASK   0xFFFF0000
>   #define SPM_MINOR_VER_MASK   0x0000FFFF
>   #define SPM_MAJOR_VER_SHIFT  16
> -#define FFA_NOT_SUPPORTED    -1
>   
> -STATIC CONST UINT32  mSpmMajorVer = SPM_MAJOR_VERSION;
> -STATIC CONST UINT32  mSpmMinorVer = SPM_MINOR_VERSION;
> -
> -STATIC CONST UINT32  mSpmMajorVerFfa = SPM_MAJOR_VERSION_FFA;
> -STATIC CONST UINT32  mSpmMinorVerFfa = SPM_MINOR_VERSION_FFA;
> +#define SPM_MAJOR_VER     0
> +#define SPM_MINOR_VER     1
>   
>   #define BOOT_PAYLOAD_VERSION  1
>   
> @@ -110,6 +106,70 @@ GetAndPrintBootinformation (
>     }
>   
>     return PayloadBootInfo;
> +
> +/**
> +  An StMM SP implements partial support for FF-A v1.0. The FF-A ABIs are used to
> +  get and set permissions of memory pages in collaboration with the SPMC and
> +  signalling completion of initialisation. The original Arm MM communication
> +  interface is used for communication with the Normal world. A TF-A specific
> +  interface is used for initialising the SP.
> +
> +  With FF-A v1.1, the StMM SP uses only FF-A ABIs for initialisation and
> +  communication. This is subject to support for FF-A v1.1 in the SPMC. If this
> +  is not the case, the StMM implementation reverts to the FF-A v1.0
> +  behaviour. Any of this is applicable only if the feature flag PcdFfaEnable is
> +  TRUE.

This should now be if the FixedAtBuild PcdFfaEnable is 1.

Thanks,
Oliver

> +
> +  This function helps the caller determine whether FF-A v1.1 or v1.0 are
> +  available and if only FF-A ABIs can be used at runtime.
> +**/
> +STATIC
> +EFI_STATUS
> +CheckFfaCompatibility (BOOLEAN *UseOnlyFfaAbis)
> +{
> +  UINT16       SpmcMajorVer;
> +  UINT16       SpmcMinorVer;
> +  UINT32       SpmcVersion;
> +  ARM_SVC_ARGS SpmcVersionArgs = {0};
> +
> +  // Sanity check in case of a spurious call.
> +  if (FixedPcdGet32 (PcdFfaEnable) == 0) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  // Send the SPMC our version to see whether it supports the same or not.
> +  SpmcVersionArgs.Arg0 = ARM_SVC_ID_FFA_VERSION_AARCH32;
> +  SpmcVersionArgs.Arg1 = FFA_VERSION_COMPILED;
> +
> +  ArmCallSvc (&SpmcVersionArgs);
> +  SpmcVersion = SpmcVersionArgs.Arg0;
> +
> +  // If the SPMC barfs then bail.
> +  if (SpmcVersion == ARM_FFA_SPM_RET_NOT_SUPPORTED) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  // Extract the SPMC version
> +  SpmcMajorVer = (SpmcVersion >> FFA_VERSION_MAJOR_SHIFT) & FFA_VERSION_MAJOR_MASK;
> +  SpmcMinorVer = (SpmcVersion >> FFA_VERSION_MINOR_SHIFT) & FFA_VERSION_MINOR_MASK;
> +
> +  // If the major versions differ then all bets are off.
> +  if (SpmcMajorVer != SPM_MAJOR_VERSION_FFA) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  // We advertised v1.1 as our version. If the SPMC supports it, it must return
> +  // the same or a compatible version. If it does not then FF-A ABIs cannot be
> +  // used for all communication.
> +  if (SpmcMinorVer >= SPM_MINOR_VERSION_FFA) {
> +    *UseOnlyFfaAbis = TRUE;
> +  } else {
> +    *UseOnlyFfaAbis = FALSE;
> +  }
> +
> +  // We have validated that there is a compatible FF-A
> +  // implementation. So. return success.
> +  return EFI_SUCCESS;
>   }
>   
>   /**
> @@ -219,34 +279,19 @@ GetSpmVersion (
>     )
>   {
>     EFI_STATUS    Status;
> -  UINT16        CalleeSpmMajorVer;
> -  UINT16        CallerSpmMajorVer;
> -  UINT16        CalleeSpmMinorVer;
> -  UINT16        CallerSpmMinorVer;
> +  UINT16        SpmMajorVersion;
> +  UINT16        SpmMinorVersion;
>     UINT32        SpmVersion;
>     ARM_SVC_ARGS  SpmVersionArgs;
>   
> -  if (FixedPcdGet32 (PcdFfaEnable) != 0) {
> -    SpmVersionArgs.Arg0  = ARM_SVC_ID_FFA_VERSION_AARCH32;
> -    SpmVersionArgs.Arg1  = mSpmMajorVerFfa << SPM_MAJOR_VER_SHIFT;
> -    SpmVersionArgs.Arg1 |= mSpmMinorVerFfa;
> -    CallerSpmMajorVer    = mSpmMajorVerFfa;
> -    CallerSpmMinorVer    = mSpmMinorVerFfa;
> -  } else {
> -    SpmVersionArgs.Arg0 = ARM_SVC_ID_SPM_VERSION_AARCH32;
> -    CallerSpmMajorVer   = mSpmMajorVer;
> -    CallerSpmMinorVer   = mSpmMinorVer;
> -  }
> +  SpmVersionArgs.Arg0 = ARM_SVC_ID_SPM_VERSION_AARCH32;
>   
>     ArmCallSvc (&SpmVersionArgs);
>   
>     SpmVersion = SpmVersionArgs.Arg0;
> -  if (SpmVersion == FFA_NOT_SUPPORTED) {
> -    return EFI_UNSUPPORTED;
> -  }
>   
> -  CalleeSpmMajorVer = ((SpmVersion & SPM_MAJOR_VER_MASK) >> SPM_MAJOR_VER_SHIFT);
> -  CalleeSpmMinorVer = ((SpmVersion & SPM_MINOR_VER_MASK) >> 0);
> +  SpmMajorVersion = ((SpmVersion & SPM_MAJOR_VER_MASK) >> SPM_MAJOR_VER_SHIFT);
> +  SpmMinorVersion = ((SpmVersion & SPM_MINOR_VER_MASK) >> 0);
>   
>     // Different major revision values indicate possibly incompatible functions.
>     // For two revisions, A and B, for which the major revision values are
> @@ -255,25 +300,17 @@ GetSpmVersion (
>     // revision A must work in a compatible way with revision B.
>     // However, it is possible for revision B to have a higher
>     // function count than revision A.
> -  if ((CalleeSpmMajorVer == CallerSpmMajorVer) &&
> -      (CalleeSpmMinorVer >= CallerSpmMinorVer))
> -  {
> -    DEBUG ((
> -      DEBUG_INFO,
> -      "SPM Version: Major=0x%x, Minor=0x%x\n",
> -      CalleeSpmMajorVer,
> -      CalleeSpmMinorVer
> -      ));
> +  if ((SpmMajorVersion == SPM_MAJOR_VER) &&
> +      (SpmMinorVersion >= SPM_MINOR_VER)) {
> +    DEBUG ((DEBUG_INFO, "SPM Version: Major=0x%x, Minor=0x%x\n",
> +           SpmMajorVersion, SpmMinorVersion));
>       Status = EFI_SUCCESS;
>     } else {
> -    DEBUG ((
> -      DEBUG_INFO,
> -      "Incompatible SPM Versions.\n Callee Version: Major=0x%x, Minor=0x%x.\n Caller: Major=0x%x, Minor>=0x%x.\n",
> -      CalleeSpmMajorVer,
> -      CalleeSpmMinorVer,
> -      CallerSpmMajorVer,
> -      CallerSpmMinorVer
> -      ));
> +    DEBUG ((DEBUG_INFO, "Incompatible SPM Versions.\n"));
> +    DEBUG ((DEBUG_INFO, "Current Version: Major=0x%x, Minor=0x%x.\n",
> +            SpmMajorVersion, SpmMinorVersion));
> +    DEBUG ((DEBUG_INFO, "Expected: Major=0x%x, Minor>=0x%x.\n",
> +            SPM_MAJOR_VER, SPM_MINOR_VER));
>       Status = EFI_UNSUPPORTED;
>     }
>   
> @@ -335,9 +372,14 @@ ModuleEntryPoint (
>     VOID                            *TeData;
>     UINTN                           TeDataSize;
>     EFI_PHYSICAL_ADDRESS            ImageBase;
> +  BOOLEAN                         UseOnlyFfaAbis = FALSE;
>   
> -  // Get Secure Partition Manager Version Information
> -  Status = GetSpmVersion ();
> +  if (FixedPcdGet32 (PcdFfaEnable) != 0) {
> +    Status = CheckFfaCompatibility (&UseOnlyFfaAbis);
> +  } else {
> +    // Get Secure Partition Manager Version Information
> +    Status = GetSpmVersion ();
> +  }
>     if (EFI_ERROR (Status)) {
>       goto finish;
>     }


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