On 03/10/21 11:12, Ray Ni wrote:
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3199
>
> When Token points to mSmmStartupThisApToken, this routine is called
> from SmmStartupThisAp() in non-blocking mode due to
> PcdCpuSmmBlockStartupThisAp == FALSE.
>
> In this case, caller wants to startup AP procedure in non-blocking
> mode and cannot get the completion status from the Token because there
> is no way to return the Token to caller from SmmStartupThisAp().
> Caller needs to use its specific way to query the completion status.
>
> There is no need to allocate a token for such case so the 3 overheads
> can be avoided:
> 1. Call AllocateTokenBuffer() when there is no free token.
> 2. Get a free token from the token buffer.
> 3. Call ReleaseToken() in APHandler().
>
> Signed-off-by: Ray Ni <ray...@intel.com>
> Reviewed-by: Eric Dong <eric.d...@intel.com>
> Reviewed-by: Laszlo Ersek <ler...@redhat.com>
> Cc: Rahul Kumar <rahul1.ku...@intel.com>
> ---
> UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c | 30 ++++++++++++++++++++-------
> 1 file changed, 23 insertions(+), 7 deletions(-)
Thanks for the update, Ray!
Laszlo
>
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> index 6227b2428a..fd6583f9d1 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> @@ -1,7 +1,7 @@
> /** @file
> SMM MP service implementation
>
> -Copyright (c) 2009 - 2020, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) 2009 - 2021, Intel Corporation. All rights reserved.<BR>
> Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
>
> SPDX-License-Identifier: BSD-2-Clause-Patent
> @@ -22,6 +22,7 @@ UINTN mSemaphoreSize;
> SPIN_LOCK *mPFLock = NULL;
> SMM_CPU_SYNC_MODE mCpuSmmSyncMode;
> BOOLEAN mMachineCheckSupported = FALSE;
> +MM_COMPLETION mSmmStartupThisApToken;
>
> extern UINTN mSmmShadowStackSize;
>
> @@ -1240,9 +1241,26 @@ InternalSmmStartupThisAp (
> mSmmMpSyncData->CpuData[CpuIndex].Procedure = Procedure;
> mSmmMpSyncData->CpuData[CpuIndex].Parameter = ProcArguments;
> if (Token != NULL) {
> - ProcToken= GetFreeToken (1);
> - mSmmMpSyncData->CpuData[CpuIndex].Token = ProcToken;
> - *Token = (MM_COMPLETION)ProcToken->SpinLock;
> + if (Token != &mSmmStartupThisApToken) {
> + //
> + // When Token points to mSmmStartupThisApToken, this routine is called
> + // from SmmStartupThisAp() in non-blocking mode
> (PcdCpuSmmBlockStartupThisAp == FALSE).
> + //
> + // In this case, caller wants to startup AP procedure in non-blocking
> + // mode and cannot get the completion status from the Token because
> there
> + // is no way to return the Token to caller from SmmStartupThisAp().
> + // Caller needs to use its implementation specific way to query the
> completion status.
> + //
> + // There is no need to allocate a token for such case so the 3
> overheads
> + // can be avoided:
> + // 1. Call AllocateTokenBuffer() when there is no free token.
> + // 2. Get a free token from the token buffer.
> + // 3. Call ReleaseToken() in APHandler().
> + //
> + ProcToken = GetFreeToken (1);
> + mSmmMpSyncData->CpuData[CpuIndex].Token = ProcToken;
> + *Token = (MM_COMPLETION)ProcToken->SpinLock;
> + }
> }
> mSmmMpSyncData->CpuData[CpuIndex].Status = CpuStatus;
> if (mSmmMpSyncData->CpuData[CpuIndex].Status != NULL) {
> @@ -1474,8 +1492,6 @@ SmmStartupThisAp (
> IN OUT VOID *ProcArguments OPTIONAL
> )
> {
> - MM_COMPLETION Token;
> -
> gSmmCpuPrivate->ApWrapperFunc[CpuIndex].Procedure = Procedure;
> gSmmCpuPrivate->ApWrapperFunc[CpuIndex].ProcedureArgument = ProcArguments;
>
> @@ -1486,7 +1502,7 @@ SmmStartupThisAp (
> ProcedureWrapper,
> CpuIndex,
> &gSmmCpuPrivate->ApWrapperFunc[CpuIndex],
> - FeaturePcdGet (PcdCpuSmmBlockStartupThisAp) ? NULL : &Token,
> + FeaturePcdGet (PcdCpuSmmBlockStartupThisAp) ? NULL :
> &mSmmStartupThisApToken,
> 0,
> NULL
> );
>
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