Re: [PATCH V6 06/42] UefiCpuPkg/CpuExceptionHandler: Add base support for the #VE exception

["Min Xu" <min.m.xu@intel.com>]

Hi, Ray & Eric
I am doing the TDVF upstreaming and this commit is in UefiCpuPkg. You're the maintainer/reviewer of UefiCpuPkg. 
Your comments to this patch is great helpful.
The complete code is at: https://github.com/mxu9/edk2/tree/tdvf_wave2.v6

Thanks
Min

> RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
> 
> Add base support to handle #VE exceptions. Update the common exception
> handlers to invoke the VmTdExitHandleVe () function of the VmgExitLib
> library when a #VE is encountered. A non-zero return code will propagate to
> the targeted exception handler.
> 
> Cc: Brijesh Singh <brijesh.singh@amd.com>
> Cc: Erdem Aktas <erdemaktas@google.com>
> Cc: James Bottomley <jejb@linux.ibm.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Rahul Kumar <rahul1.kumar@intel.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Acked-by: Gerd Hoffmann <kraxel@redhat.com>
> Signed-off-by: Min Xu <min.m.xu@intel.com>
> ---
>  .../PeiDxeSmmCpuException.c                    | 17 +++++++++++++++++
>  .../SecPeiCpuException.c                       | 18 ++++++++++++++++++
>  2 files changed, 35 insertions(+)
> 
> diff --git
> a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c
> index 762ea2460f91..4fa3f8202a33 100644
> ---
> a/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c
> +++
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiDxeSmmCpuException.c
> @@ -45,6 +45,23 @@ CommonExceptionHandlerWorker (
>      }
>    }
> 
> +  if (ExceptionType == VE_EXCEPTION) {
> +    EFI_STATUS  Status;
> +    //
> +    // #VE needs to be handled immediately upon enabling exception
> handling
> +    // and therefore can't use the RegisterCpuInterruptHandler() interface.
> +    //
> +    // Handle the #VE:
> +    //   On EFI_SUCCESS - Exception has been handled, return
> +    //   On other       - ExceptionType contains (possibly new) exception
> +    //                    value
> +    //
> +    Status = VmTdExitHandleVe (&ExceptionType, SystemContext);
> +    if (!EFI_ERROR (Status)) {
> +      return;
> +    }
> +  }
> +
>    ExceptionHandlerContext  = (EXCEPTION_HANDLER_CONTEXT
> *)(UINTN)(SystemContext.SystemContextIa32);
>    ReservedVectors          = ExceptionHandlerData->ReservedVectors;
>    ExternalInterruptHandler = ExceptionHandlerData-
> >ExternalInterruptHandler;
> diff --git
> a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
> b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
> index c614d5b0b6f1..148d89011721 100644
> --- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
> +++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/SecPeiCpuException.c
> @@ -43,6 +43,24 @@ CommonExceptionHandler (
>      }
>    }
> 
> +  if (ExceptionType == VE_EXCEPTION) {
> +    EFI_STATUS  Status;
> +    //
> +    // #VE needs to be handled immediately upon enabling exception
> handling
> +    // and therefore can't use the RegisterCpuInterruptHandler() interface
> +    // (which isn't supported under Sec and Pei anyway).
> +    //
> +    // Handle the #VE:
> +    //   On EFI_SUCCESS - Exception has been handled, return
> +    //   On other       - ExceptionType contains (possibly new) exception
> +    //                    value
> +    //
> +    Status = VmTdExitHandleVe (&ExceptionType, SystemContext);
> +    if (!EFI_ERROR (Status)) {
> +      return;
> +    }
> +  }
> +
>    //
>    // Initialize the serial port before dumping.
>    //
> --
> 2.29.2.windows.2