> -----Original Message----- > From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of > Dong, Eric > Sent: Wednesday, April 22, 2020 4:23 PM > To: Ni, Ray <ray...@intel.com>; devel@edk2.groups.io > Cc: Laszlo Ersek <ler...@redhat.com>; Kumar, Chandana C > <chandana.c.ku...@intel.com> > Subject: Re: [edk2-devel] [PATCH 1/2] UefiCpuPkg/MpInitLib: Restore IDT > context for APs. > > > -----Original Message----- > > From: Ni, Ray > > Sent: Wednesday, April 22, 2020 3:54 PM > > To: Dong, Eric <eric.d...@intel.com>; devel@edk2.groups.io > > Cc: Laszlo Ersek <ler...@redhat.com>; Kumar, Chandana C > > <chandana.c.ku...@intel.com> > > Subject: RE: [PATCH 1/2] UefiCpuPkg/MpInitLib: Restore IDT context for > APs. > > > > Please check my comments in below. > > > > > -----Original Message----- > > > From: Dong, Eric <eric.d...@intel.com> > > > Sent: Wednesday, April 22, 2020 9:35 AM > > > To: devel@edk2.groups.io > > > Cc: Ni, Ray <ray...@intel.com>; Laszlo Ersek <ler...@redhat.com>; > > > Kumar, Chandana C <chandana.c.ku...@intel.com> > > > Subject: [PATCH 1/2] UefiCpuPkg/MpInitLib: Restore IDT context for APs. > > > > > > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2683 > > > > > > > > > > > > This patch used to fix a ASSERT because AP can't find the CpuMpData. > > > > 1. This patch fixes an assertion because AP can't find the CpuMpData. > > > > > > > > > > > When AP been waked up through Init-Sipi-Sipi, the IDT should been > > > restore to preallcated buffer to make it can get the CpuMpData > > > through IDT base address. > > > Not when CpuMpData->InitFlag is ApInitReconfig or ApInitConfig, AP > > > will be wake up through Init-Sipi-Sipi. Current code already has > > > logic to handle ApInitConfig, but miss the handler for > > > ApInitReconfig. This patch fixes this gap. > > > > 2. When AP is waken up through Init-Sipi-Sipi, AP's IDT should be > > restored to pre-allocated buffer so AP can get the CpuMpData through > > the IDT base address. > > Current code already has logic to handle this when CpuMpData-> > > InitFlag is ApInitConfig but misses the logic when CpuMpData->InitFlag > > is ApInitReconfig. > > This patch fixes this gap. > > > > > > > > > > > > Cc: Ray Ni <ray...@intel.com> > > > Cc: Laszlo Ersek <ler...@redhat.com> > > > Cc: Chandana Kumar <chandana.c.ku...@intel.com> > > > Signed-off-by: Eric Dong <eric.d...@intel.com> > > > --- > > > UefiCpuPkg/Library/MpInitLib/MpLib.c | 15 +++++++++++++-- > > > 1 file changed, 13 insertions(+), 2 deletions(-) > > > > > > diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c > > > b/UefiCpuPkg/Library/MpInitLib/MpLib.c > > > index 64a4c3546e..ac7f92fd48 100644 > > > --- a/UefiCpuPkg/Library/MpInitLib/MpLib.c > > > +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c > > > @@ -664,8 +664,9 @@ ApWakeupFunction ( > > > BistData = *(UINT32 *) ((UINTN) ApTopOfStack - sizeof > > > (UINTN)); > > > > > > // > > > > > > // CpuMpData->CpuData[0].VolatileRegisters is initialized > > > based on BSP environment, > > > > > > - // to initialize AP in InitConfig path. > > > > > > - // NOTE: IDTR.BASE stored in CpuMpData- > > >CpuData[0].VolatileRegisters > > > points to a different IDT shared by all APs. > > > > > > + // to initialize AP in InitConfig/ApInitReconfig path. > > > > > > + // NOTE: IDTR.BASE stored in CpuMpData- > > >CpuData[0].VolatileRegisters > > > points to a > > > > > > + // different IDT shared by all APs. > > > > > > // > > > > > > RestoreVolatileRegisters > > > (&CpuMpData->CpuData[0].VolatileRegisters, > > > FALSE); > > > > > > InitializeApData (CpuMpData, ProcessorNumber, BistData, > > > ApTopOfStack); > > > > > > @@ -673,6 +674,16 @@ ApWakeupFunction ( > > > > > > > > > InterlockedDecrement ((UINT32 *) &CpuMpData- > > >MpCpuExchangeInfo- > > > >NumApsExecuting); > > > > > > } else { > > > > > > + if ((CpuMpData->InitFlag == ApInitReconfig) && (CpuMpData- > > > >ApLoopMode != ApInHltLoop)) { > > > > > > + // > > > > > > + // CpuMpData->CpuData[0].VolatileRegisters is initialized > > > + based on > > > BSP environment, > > > > > > + // to initialize AP in InitConfig/ApInitReconfig path. > > > > 3. > > Initialize AP volatile registers in ApInitReconfig path. > > ApInitReconfig happens when: > > 1. AP is re-enabled after it's disabled, in either PEI or DXE phase. > > 2. AP is initialized in DXE phase. > > > > > > > > + // NOTE: IDTR.BASE stored in CpuMpData- > > > >CpuData[0].VolatileRegisters points to a > > > > > > + // different IDT shared by all APs. > > > > > > + // > > > > > > + RestoreVolatileRegisters (&CpuMpData- > > >CpuData[0].VolatileRegisters, > > > FALSE); > > > > 4. Is it possible to combine this function call with the restoration code > below? > > >
I move the code into the else of " if (CpuMpData->ApLoopMode == ApInHltLoop)", it's truly better than original. Please see my v2 change. Thanks, Eric > New logic changes code flow when CpuMpData->InitFlag == ApInitReconfig. > In original flow, the code does RestoreVolatileRegisters and CpuFlushTlb, but > new code only does CpuFlushTlb. > Is CpuFlushTlb not needs if wake up through Init-Sipi-Sipi? I prefer to not > change this code flow. > > Thanks, > Eric > > > if (CpuMpData->InitFlag == ApInitReconfig) { > > // > > // ApInitReconfig happens when: > > // 1. AP is re-enabled after it's disabled, in either PEI or DXE > > phase. > > // 2. AP is initialized in DXE phase. > > // In either case, use the volatile registers value derived from > > BSP. > > // NOTE: IDTR.BASE stored in > > CpuMpData->CpuData[0].VolatileRegisters > > points to a > > // different IDT shared by all APs. > > // > > RestoreVolatileRegisters > > (&CpuMpData->CpuData[0].VolatileRegisters, > > FALSE); > > } else { > > if (CpuMpData->ApLoopMode == ApInHltLoop) { > > // > > // Restore AP's volatile registers saved before AP is halted > > // > > RestoreVolatileRegisters (&CpuMpData- > > >CpuData[ProcessorNumber].VolatileRegisters, TRUE); > > } else { > > // > > // The CPU driver might not flush TLB for APs on spot after > > updating > > // page attributes. AP in mwait loop mode needs to take care of it > when > > // woken up. > > // > > CpuFlushTlb (); > > } > > } > > > > > > + } > > > > > > + > > > > > > // > > > > > > // Execute AP function if AP is ready > > > > > > // > > > > > > -- > > > 2.23.0.windows.1 > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#57793): https://edk2.groups.io/g/devel/message/57793 Mute This Topic: https://groups.io/mt/73187416/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-