Thanks. SMRR is used to prevent cache poisoning attack. IMHO, the assumption is valid.
Reviewed-by: jiewen....@intel.com > -----Original Message----- > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of Ni, > Ruiyu > Sent: Tuesday, October 30, 2018 10:51 AM > To: edk2-devel@lists.01.org > Cc: Kinney, Michael D <michael.d.kin...@intel.com>; Yao, Jiewen > <jiewen....@intel.com> > Subject: [edk2] [PATCH v3] MdeModulePkg/PiSmmIpl: Do not reset SMRAM > to UC when CPU driver runs > > Today's PiSmmIpl implementation initially sets SMRAM to WB to speed > up the SMM core/modules loading before SMM CPU driver runs. > When SMM CPU driver runs, PiSmmIpl resets the SMRAM to UC. It's done > in SmmIplDxeDispatchEventNotify(). > COMM_BUFFER_SMM_DISPATCH_RESTART > is returned from SMM core that SMM CPU driver is just dispatched. > > Since now the SMRR is widely used to control the SMRAM cache setting. > It's not needed to reset the SMRAM to UC anymore. > > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Ruiyu Ni <ruiyu...@intel.com> > Cc: Jiewen Yao <jiewen....@intel.com> > Cc: Michael Kinney <michael.d.kin...@intel.com> > --- > MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c | 15 ++------------- > 1 file changed, 2 insertions(+), 13 deletions(-) > > diff --git a/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c > b/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c > index f8cbe1704b..2fb877127b 100644 > --- a/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c > +++ b/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c > @@ -672,21 +672,10 @@ SmmIplDxeDispatchEventNotify ( > return; > } > > - // > - // Attempt to reset SMRAM cacheability to UC > - // Assume CPU AP is available at this time > - // > - Status = gDS->SetMemorySpaceAttributes( > - mSmramCacheBase, > - mSmramCacheSize, > - EFI_MEMORY_UC > - ); > - if (EFI_ERROR (Status)) { > - DEBUG ((DEBUG_WARN, "SMM IPL failed to reset SMRAM window > to EFI_MEMORY_UC\n")); > - } > - > // > // Close all SMRAM ranges to protect SMRAM > + // NOTE: SMRR is enabled by CPU SMM driver by calling > SmmCpuFeaturesInitializeProcessor() from SmmCpuFeaturesLib > + // so no need to reset the SMRAM to UC in MTRR. > // > Status = mSmmAccess->Close (mSmmAccess); > ASSERT_EFI_ERROR (Status); > -- > 2.16.1.windows.1 > > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
