Reviewed-by: Ray Ni <ray...@intel.com>
Thanks,
Ray
> -----Original Message-----
> From: Wu, Jiaxin <jiaxin...@intel.com>
> Sent: Tuesday, December 26, 2023 12:21 AM
> To: devel@edk2.groups.io
> Cc: Laszlo Ersek <ler...@redhat.com>; Dong, Eric <eric.d...@intel.com>; Ni,
> Ray <ray...@intel.com>; Zeng, Star <star.z...@intel.com>; Gerd Hoffmann
> <kra...@redhat.com>; Kumar, Rahul R <rahul.r.ku...@intel.com>
> Subject: [PATCH v2 4/6] UefiCpuPkg/PiSmmCpuDxeSmm: Align BSP and AP
> sync logic for SMI exit
>
> Below piece of code is the BSP and AP sync logic for SMI exit.
> 1. AP after finish the scheduled procedure:
> if (SmmCpuFeaturesNeedConfigureMtrrs ()) {
> SmmCpuSyncReleaseBsp ();
> SmmCpuSyncWaitForBsp ();
> ...
> }
> SmmCpuSyncReleaseBsp ();
> SmmCpuSyncWaitForBsp ();
> SmmCpuSyncReleaseBsp ();
>
> 2. BSP after return from SmmCoreEntry:
> SmmCpuSyncWaitForAPs ();
> if (SmmCpuFeaturesNeedConfigureMtrrs ()) {
> ReleaseAllAPs ();
> ...
> SmmCpuSyncWaitForAPs ();
> }
> ReleaseAllAPs ();
> SmmCpuSyncWaitForAPs();
>
> This patch is to make BSP same as AP sync logic:
> if (SmmCpuFeaturesNeedConfigureMtrrs ()) {
> SmmCpuSyncWaitForAPs ();
> ReleaseAllAPs ();
> ...
> }
> SmmCpuSyncWaitForAPs ();
> ReleaseAllAPs ();
> SmmCpuSyncWaitForAPs();
>
> With the change, it will be easy to understand the sync flow as
> below:
> BSP: SmmCpuSyncWaitForAPs <-- AP: SmmCpuSyncReleaseBsp
> BSP: ReleaseAllAPs --> AP: SmmCpuSyncWaitForBsp
>
> This patch doesn't have function impact.
>
> Cc: Laszlo Ersek <ler...@redhat.com>
> Cc: Eric Dong <eric.d...@intel.com>
> Cc: Ray Ni <ray...@intel.com>
> Cc: Zeng Star <star.z...@intel.com>
> Cc: Gerd Hoffmann <kra...@redhat.com>
> Cc: Rahul Kumar <rahul1.ku...@intel.com>
> Signed-off-by: Jiaxin Wu <jiaxin...@intel.com>
> ---
> UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> index 324e85d6b5..bd2c9f841b 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> @@ -625,33 +625,33 @@ BSPHandler (
> // Notify all APs to exit
> //
> *mSmmMpSyncData->InsideSmm = FALSE;
> ReleaseAllAPs ();
>
> - //
> - // Wait for all APs to complete their pending tasks
> - //
> - SmmCpuSyncWaitForAPs (mSmmMpSyncData->SyncContext, ApCount,
> CpuIndex);
> -
> if (SmmCpuFeaturesNeedConfigureMtrrs ()) {
> + //
> + // Wait for all APs the readiness to program MTRRs
> + //
> + SmmCpuSyncWaitForAPs (mSmmMpSyncData->SyncContext, ApCount,
> CpuIndex);
> +
> //
> // Signal APs to restore MTRRs
> //
> ReleaseAllAPs ();
>
> //
> // Restore OS MTRRs
> //
> SmmCpuFeaturesReenableSmrr ();
> MtrrSetAllMtrrs (&Mtrrs);
> -
> - //
> - // Wait for all APs to complete MTRR programming
> - //
> - SmmCpuSyncWaitForAPs (mSmmMpSyncData->SyncContext, ApCount,
> CpuIndex);
> }
>
> + //
> + // Wait for all APs to complete their pending tasks including MTRR
> programming if needed.
> + //
> + SmmCpuSyncWaitForAPs (mSmmMpSyncData->SyncContext, ApCount,
> CpuIndex);
> +
> if (mSmmDebugAgentSupport) {
> //
> // Stop source level debug in BSP handler, the code below will not be
> // debugged.
> //
> --
> 2.16.2.windows.1
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