Reviewed-by: Eric Dong <[email protected]> > -----Original Message----- > From: Wang, Jian J > Sent: Friday, July 13, 2018 1:54 PM > To: [email protected] > Cc: Dong, Eric <[email protected]>; Laszlo Ersek <[email protected]>; > Yao, Jiewen <[email protected]>; Zeng, Star <[email protected]> > Subject: [PATCH] UefiCpuPkg/CpuDxe: fix incorrect check of SMM mode > > Current IsInSmm() method makes use of gEfiSmmBase2ProtocolGuid.InSmm() > to check if current processor is in SMM mode or not. But this is not correct > because gEfiSmmBase2ProtocolGuid.InSmm() can only detect if the caller is > running in SMRAM or from SMM driver. It cannot guarantee if the caller is > running in SMM mode. Because SMM mode will load its own page table, > adding an extra check of saved DXE page table base address against current > CR3 register value can help to get the correct answer for sure (in SMM mode > or not in SMM mode). > > This is an issue caused by check-in at > > d106cf71eabaacff63c14626a4a87346b93074dd > > Cc: Eric Dong <[email protected]> > Cc: Laszlo Ersek <[email protected]> > Cc: Jiewen Yao <[email protected]> > Cc: Star Zeng <[email protected]> > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Jian J Wang <[email protected]> > --- > UefiCpuPkg/CpuDxe/CpuPageTable.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/UefiCpuPkg/CpuDxe/CpuPageTable.c > b/UefiCpuPkg/CpuDxe/CpuPageTable.c > index 850eed60e7..df021798c0 100644 > --- a/UefiCpuPkg/CpuDxe/CpuPageTable.c > +++ b/UefiCpuPkg/CpuDxe/CpuPageTable.c > @@ -136,7 +136,14 @@ IsInSmm ( > mSmmBase2->InSmm (mSmmBase2, &InSmm); > } > > - return InSmm; > + // > + // mSmmBase2->InSmm() can only detect if the caller is running in > + SMRAM // or from SMM driver. It cannot tell if the caller is running in > SMM mode. > + // Check page table base address to guarantee that because SMM mode > + willl // load its own page table. > + // > + return (InSmm && > + mPagingContext.ContextData.X64.PageTableBase != > + (UINT64)AsmReadCr3()); > } > > /** > -- > 2.16.2.windows.1
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