On 10/09/18 04:15, Ni, Ruiyu wrote: > On 10/9/2018 10:05 AM, Dong, Eric wrote: >> Add BZ link for this issue: >> https://bugzilla.tianocore.org/show_bug.cgi?id=1232 >> >> Thanks, >> Eric >> >>> -----Original Message----- >>> From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of >>> Eric Dong >>> Sent: Tuesday, October 9, 2018 9:51 AM >>> To: edk2-devel@lists.01.org >>> Cc: Ni, Ruiyu <ruiyu...@intel.com>; Laszlo Ersek <ler...@redhat.com> >>> Subject: [edk2] [Patch] UefiCpuPkg/S3Resume2Pei: disable paging before >>> creating new page table. >>> >>> PEI Stack Guard needs to enable paging. This might cause #GP in the >>> transition from 32-bit PEI to 64-bit SMM due to the code trying to >>> write CR3 >>> register with PML4 page table while the processor is enabled with PAE >>> paging. >>> >>> Simply disabling paging before updating CR3 can solve this conflict. >>> >>> Change-Id: I99bfdba5daa48a95a4c4ef97eeca1af086558957 >>> Cc: Ruiyu Ni <ruiyu...@intel.com> >>> Cc: Laszlo Ersek <ler...@redhat.com> >>> Cc: Jian J Wang <jian.j.w...@intel.com> >>> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off- >>> by:Eric Dong <eric.d...@intel.com> >>> Signed-off-by: Eric Dong <eric.d...@intel.com> >>> --- >>> UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c | 7 +++++++ >>> UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf | 1 + >>> 2 files changed, 8 insertions(+) >>> >>> diff --git a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c >>> b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c >>> index f164c1713b..b3bf56e13d 100644 >>> --- a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c >>> +++ b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c >>> @@ -1105,6 +1105,13 @@ S3RestoreConfig2 ( >>> // >>> SetInterruptState (InterruptStatus); >>> >>> + if (PcdGetBool (PcdCpuStackGuard)) { >>> + // >>> + // Paging already been enabled, to avoid conflict >>> configuration, >>> + // disable paging first anyway. >>> + // >>> + AsmWriteCr0 (AsmReadCr0 () & (~BIT31)); >>> + } > > Two comments: > 1. We'd better not map the PcdCpuStackGuard to paging-enable. Maybe some > other feature also enables the paging in PEI phase but the > PcdCpuStackGuard is FALSE.
I think I agree. > 2. When PEI is in 64bit mode, disabling paging may not work because > paging-enable is a must in 64bit mode. I think this case is academic. S3Resume2Pei does not support 64-bit PEI with SMM enabled. This is why we have commit 5133d1f1d297 ("OvmfPkg: replace README fine print about X64 SMM S3 with PlatformPei check", 2015-11-30) in OVMF. Anyway, I'm making this comment in the general sense only. I'm not suggesting that we disable paging unconditionally. Actually, I believe, I will suggest (under the v3 posting) restricting the write to CR0 even more. Thanks! Laszlo > >>> AsmWriteCr3 ((UINTN)SmmS3ResumeState->SmmS3Cr3); >>> >>> // >>> diff --git a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf >>> b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf >>> index 6ce1bf944c..0f131d19df 100644 >>> --- a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf >>> +++ b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf >>> @@ -90,6 +90,7 @@ >>> [Pcd] >>> gEfiMdeModulePkgTokenSpaceGuid.PcdUse1GPageTable ## >>> SOMETIMES_CONSUMES >>> >>> gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrM >>> ask ## CONSUMES >>> + >>> gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard ## >>> CONSUMES >>> >>> [Depex] >>> TRUE >>> -- >>> 2.15.0.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