Yes. With below "Cr2 !=0" removed from final commit, Reviewed-by: Ray Ni <ray...@intel.com> > > +RestoreCr2 ( > > + UINTN Cr2 > > + ) > > +{ > > + if ((!mCpuSmmStaticPageTable) && (Cr2 != 0)) { > > + AsmWriteCr2 (Cr2); > > + } > > +}
> -----Original Message----- > From: Vanguput, Narendra K <narendra.k.vangu...@intel.com> > Sent: Friday, March 29, 2019 5:32 PM > To: Ni, Ray <ray...@intel.com>; edk2-devel@lists.01.org > Cc: Yao, Jiewen <jiewen....@intel.com>; Dong, Eric <eric.d...@intel.com>; > Laszlo Ersek <ler...@redhat.com> > Subject: RE: [edk2] [PATCH v6] UefiCpuPkg\CpuSmm: Save & restore CR2 on- > demand paging in SMM > > Hi Ray, > > While programming, I thought this cannot be 0 as in SDM, it says page-fault > linear address. > >> CR2 - Contains the page-fault linear address (the linear address that > caused a page fault). > > So added a check for 0. > > Now as the function is changed like program into CR2 register based on input > parameter and checking for 0 is up to caller of this function. And also we > don't need to require for checking 0 means, will remove it. Please confirm. > > Thanks, > Naren > > -----Original Message----- > From: Ni, Ray > Sent: Friday, March 29, 2019 10:40 AM > To: Vanguput, Narendra K <narendra.k.vangu...@intel.com>; edk2- > de...@lists.01.org > Cc: Yao, Jiewen <jiewen....@intel.com>; Dong, Eric <eric.d...@intel.com>; > Laszlo Ersek <ler...@redhat.com> > Subject: RE: [edk2] [PATCH v6] UefiCpuPkg\CpuSmm: Save & restore CR2 on- > demand paging in SMM > > > + if ((!mCpuSmmStaticPageTable) && (Cr2 != 0)) { > > Can the "Cr2 != 0" be removed? > > > -----Original Message----- > > From: edk2-devel <edk2-devel-boun...@lists.01.org> On Behalf Of > > nkvangup > > Sent: Friday, March 29, 2019 12:58 PM > > To: edk2-devel@lists.01.org > > Cc: Yao, Jiewen <jiewen....@intel.com>; Dong, Eric > > <eric.d...@intel.com>; Laszlo Ersek <ler...@redhat.com> > > Subject: [edk2] [PATCH v6] UefiCpuPkg\CpuSmm: Save & restore CR2 on- > > demand paging in SMM > > > > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1593 > > > > For every SMI occurrence, save and restore CR2 register only when SMM > > on- demand paging support is enabled in 64 bit operation mode. > > This is not a bug but to have better improvement of code. > > > > Patch5 is updated with separate functions for Save and Restore of CR2 > > based on review feedback. > > > > Contributed-under: TianoCore Contribution Agreement 1.1 > > Signed-off-by: Vanguput Narendra K <narendra.k.vangu...@intel.com> > > Cc: Eric Dong <eric.d...@intel.com> > > Cc: Ray Ni <ray...@intel.com> > > Cc: Laszlo Ersek <ler...@redhat.com> > > Cc: Yao Jiewen <jiewen....@intel.com> > > --- > > UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c | 26 > > ++++++++++++++++++++++++++ > > UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c | 9 ++++++--- > > UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h | 22 > > ++++++++++++++++++++++ > > UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c | 30 > > ++++++++++++++++++++++++++++++ > > 4 files changed, 84 insertions(+), 3 deletions(-) > > > > diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c > > b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c > > index b734a1ea8c..af96e42982 100644 > > --- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c > > +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c > > @@ -316,3 +316,29 @@ SetPageTableAttributes ( > > > > return ; > > } > > + > > +/** > > + This function returns with no action for 32 bit. > > + > > + @param[in] *Cr2 Pointer to variable to hold CR2 register value > > +**/ VOID > > +SaveCr2 ( > > + UINTN *Cr2 > > + ) > > +{ > > + return ; > > +} > > + > > +/** > > + This function returns with no action for 32 bit. > > + > > + @param[in] Cr2 Value to write into CR2 register **/ VOID > > +RestoreCr2 ( > > + UINTN Cr2 > > + ) > > +{ > > + return ; > > +} > > diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c > > b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c > > index 3b0b3b52ac..ce70f77709 100644 > > --- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c > > +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c > > @@ -1112,9 +1112,11 @@ SmiRendezvous ( > > ASSERT(CpuIndex < mMaxNumberOfCpus); > > > > // > > - // Save Cr2 because Page Fault exception in SMM may override its > > value > > + // Save Cr2 because Page Fault exception in SMM may override its > > + value, // when using on-demand paging for above 4G memory. > > // > > - Cr2 = AsmReadCr2 (); > > + Cr2 = 0; > > + SaveCr2 (&Cr2); > > > > // > > // Perform CPU specific entry hooks @@ -1253,10 +1255,11 @@ > > SmiRendezvous ( > > > > Exit: > > SmmCpuFeaturesRendezvousExit (CpuIndex); > > + > > // > > // Restore Cr2 > > // > > - AsmWriteCr2 (Cr2); > > + RestoreCr2 (Cr2); > > } > > > > /** > > diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h > > b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h > > index 84efb22981..c9d147c8a1 100644 > > --- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h > > +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h > > @@ -1243,4 +1243,26 @@ EFIAPI > > PiSmmCpuSmiEntryFixupAddress ( > > ); > > > > +/** > > + This function reads CR2 register when on-demand paging is enabled > > + for 64 bit and no action for 32 bit. > > + > > + @param[in] *Cr2 Pointer to variable to hold CR2 register value > > +**/ VOID > > +SaveCr2 ( > > + UINTN *Cr2 > > + ); > > + > > +/** > > + This function writes into CR2 register when on-demand paging is > > +enabled > > + for 64 bit and no action for 32 bit. > > + > > + @param[in] Cr2 Value to write into CR2 register **/ VOID > > +RestoreCr2 ( > > + UINTN Cr2 > > + ); > > + > > #endif > > diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c > > b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c > > index 2c77cb47a4..6cb44fbbe5 100644 > > --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c > > +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c > > @@ -1053,3 +1053,33 @@ SetPageTableAttributes ( > > > > return ; > > } > > + > > +/** > > + This function reads CR2 register when on-demand paging is enabled > > + > > + @param[in] *Cr2 Pointer to variable to hold CR2 register value > > +**/ VOID > > +SaveCr2 ( > > + UINTN *Cr2 > > + ) > > +{ > > + if (!mCpuSmmStaticPageTable) { > > + *Cr2 = AsmReadCr2 (); > > + } > > +} > > + > > +/** > > + This function restores CR2 register when on-demand paging is > > +enabled > > + > > + @param[in] Cr2 Value to write into CR2 register **/ VOID > > +RestoreCr2 ( > > + UINTN Cr2 > > + ) > > +{ > > + if ((!mCpuSmmStaticPageTable) && (Cr2 != 0)) { > > + AsmWriteCr2 (Cr2); > > + } > > +} > > -- > > 2.16.2.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