Reviewed-by: Ray Ni <[email protected]> > -----Original Message----- > From: Nikodem, Damian > Sent: Wednesday, September 11, 2019 1:23 AM > To: [email protected] > Cc: Nikodem, Damian <[email protected]>; Dong, Eric > <[email protected]>; Ni, Ray <[email protected]>; You, > Benjamin <[email protected]>; Laszlo Ersek <[email protected]>; Rusocki, > Krzysztof <[email protected]> > Subject: [PATCH v3] UefiCpuPkg: Fix potential spinLock issue in > SmmStartupThisAp > > Due to needs a tackling the deficiency of the AP API, is necessary to ensure > that in non-blocking mode > previous AP executed command is finished before start new one. > > To remedy above: > 1) execute AcquireSpinLock instead AcquireSpinLockOrFail - this will ensure > time "window" to eliminate potential > race condition beetwen BSP and AP spinLock release in non-blocking mode. > This also will eliminate possibility to start executing new AP function > before last is finished. > 2) remove returns EFI_STATUS - EFI_NOT_READY - in new scenario returned > status is not necessary to caller. > > Signed-off-by: Damian Nikodem <[email protected]> > Cc: Eric Dong <[email protected]> > Cc: Ray Ni <[email protected]> > Cc: Benjamin You <[email protected]> > Cc: Laszlo Ersek <[email protected]> > Cc: Krzysztof Rusocki <[email protected]> > > diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c > b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c > index d8d2b6f444..0685637c2b 100644 > --- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c > +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c > @@ -1235,14 +1235,9 @@ InternalSmmStartupThisAp ( > return EFI_INVALID_PARAMETER; > } > > - if (Token == NULL) { > - AcquireSpinLock (mSmmMpSyncData->CpuData[CpuIndex].Busy); > - } else { > - if (!AcquireSpinLockOrFail (mSmmMpSyncData->CpuData[CpuIndex].Busy)) { > - DEBUG((DEBUG_ERROR, "Can't acquire > mSmmMpSyncData->CpuData[%d].Busy\n", CpuIndex)); > - return EFI_NOT_READY; > - } > + AcquireSpinLock (mSmmMpSyncData->CpuData[CpuIndex].Busy); > > + if (Token != NULL) { > *Token = (MM_COMPLETION) CreateToken (); > }
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