On 07/09/20 03:56, Guomin Jiang wrote:
> From: Michael Kubacki <michael.a.kuba...@intel.com>
>
> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1614
>
> Moves the GDT and IDT to permanent memory in a memory discovered
> callback. This is done to ensure the GDT and IDT authenticated in
> pre-memory is not fetched from outside a verified location after
> the permanent memory transition.
>
> Cc: Eric Dong <eric.d...@intel.com>
> Cc: Ray Ni <ray...@intel.com>
> Cc: Laszlo Ersek <ler...@redhat.com>
> Cc: Rahul Kumar <rahul1.ku...@intel.com>
> Signed-off-by: Michael Kubacki <michael.a.kuba...@intel.com>
> Reviewed-by: Laszlo Ersek <ler...@redhat.com>
> ---
> UefiCpuPkg/CpuMpPei/CpuMpPei.inf | 1 +
> UefiCpuPkg/CpuMpPei/CpuMpPei.h | 12 +++++++++++
> UefiCpuPkg/CpuMpPei/CpuMpPei.c | 37 ++++++++++++++++++++++++++++++++
> UefiCpuPkg/CpuMpPei/CpuPaging.c | 12 +++++++++--
> 4 files changed, 60 insertions(+), 2 deletions(-)
sorry, a question -- the subject line and the commit message reference
the IDT, not just the GDT. But the code handles the GDT only. Is this
intentional? Should the code handle the IDT, or should we remove the IDT
mentions from the subject and the commit message?
Thanks
Laszlo
> diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
> b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
> index caead3ce34d4..f4d11b861f77 100644
> --- a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
> +++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
> @@ -63,6 +63,7 @@ [Pcd]
> gUefiCpuPkgTokenSpaceGuid.PcdCpuStackSwitchExceptionList ##
> SOMETIMES_CONSUMES
> gUefiCpuPkgTokenSpaceGuid.PcdCpuKnownGoodStackSize ##
> SOMETIMES_CONSUMES
> gUefiCpuPkgTokenSpaceGuid.PcdCpuApStackSize ##
> SOMETIMES_CONSUMES
> + gEfiMdeModulePkgTokenSpaceGuid.PcdMigrateTemporaryRamFirmwareVolumes ##
> CONSUMES
>
> [Depex]
> TRUE
> diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.h b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
> index 7d5c527d6006..309478cbe14c 100644
> --- a/UefiCpuPkg/CpuMpPei/CpuMpPei.h
> +++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
> @@ -397,6 +397,18 @@ SecPlatformInformation2 (
> OUT EFI_SEC_PLATFORM_INFORMATION_RECORD2 *PlatformInformationRecord2
> );
>
> +/**
> + Migrates the Global Descriptor Table (GDT) to permanent memory.
> +
> + @retval EFI_SUCCESS The GDT was migrated successfully.
> + @retval EFI_OUT_OF_RESOURCES The GDT could not be migrated due to lack
> of available memory.
> +
> +**/
> +EFI_STATUS
> +MigrateGdt (
> + VOID
> + );
> +
> /**
> Initializes MP and exceptions handlers.
>
> diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.c b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
> index 07ccbe7c6a91..d07540cf7471 100644
> --- a/UefiCpuPkg/CpuMpPei/CpuMpPei.c
> +++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.c
> @@ -429,6 +429,43 @@ GetGdtr (
> AsmReadGdtr ((IA32_DESCRIPTOR *)Buffer);
> }
>
> +/**
> + Migrates the Global Descriptor Table (GDT) to permanent memory.
> +
> + @retval EFI_SUCCESS The GDT was migrated successfully.
> + @retval EFI_OUT_OF_RESOURCES The GDT could not be migrated due to lack
> of available memory.
> +
> +**/
> +EFI_STATUS
> +MigrateGdt (
> + VOID
> + )
> +{
> + EFI_STATUS Status;
> + UINTN GdtBufferSize;
> + IA32_DESCRIPTOR Gdtr;
> + VOID *GdtBuffer;
> +
> + AsmReadGdtr ((IA32_DESCRIPTOR *) &Gdtr);
> + GdtBufferSize = sizeof (IA32_SEGMENT_DESCRIPTOR) -1 + Gdtr.Limit + 1;
> +
> + Status = PeiServicesAllocatePool (
> + GdtBufferSize,
> + &GdtBuffer
> + );
> + ASSERT (GdtBuffer != NULL);
> + if (EFI_ERROR (Status)) {
> + return EFI_OUT_OF_RESOURCES;
> + }
> +
> + GdtBuffer = ALIGN_POINTER (GdtBuffer, sizeof (IA32_SEGMENT_DESCRIPTOR));
> + CopyMem (GdtBuffer, (VOID *) Gdtr.Base, Gdtr.Limit + 1);
> + Gdtr.Base = (UINTN) GdtBuffer;
> + AsmWriteGdtr (&Gdtr);
> +
> + return EFI_SUCCESS;
> +}
> +
> /**
> Initializes CPU exceptions handlers for the sake of stack switch
> requirement.
>
> diff --git a/UefiCpuPkg/CpuMpPei/CpuPaging.c b/UefiCpuPkg/CpuMpPei/CpuPaging.c
> index a462e7ee1e38..3bf0574b34c6 100644
> --- a/UefiCpuPkg/CpuMpPei/CpuPaging.c
> +++ b/UefiCpuPkg/CpuMpPei/CpuPaging.c
> @@ -602,8 +602,16 @@ MemoryDiscoveredPpiNotifyCallback (
> IN VOID *Ppi
> )
> {
> - EFI_STATUS Status;
> - BOOLEAN InitStackGuard;
> + EFI_STATUS Status;
> + BOOLEAN InitStackGuard;
> + BOOLEAN InterruptState;
> +
> + if (PcdGetBool (PcdMigrateTemporaryRamFirmwareVolumes)) {
> + InterruptState = SaveAndDisableInterrupts ();
> + Status = MigrateGdt ();
> + ASSERT_EFI_ERROR (Status);
> + SetInterruptState (InterruptState);
> + }
>
> //
> // Paging must be setup first. Otherwise the exception TSS setup during MP
>
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