Re: [PATCH] OvmfPkg/OvmfPkgX64: Use different CcProbeLib when SMM is on or off

["Yao, Jiewen" <jiewen.yao@intel.com>]

Question: Does this patch need catch release 202205 release?



> -----Original Message-----
> From: Xu, Min M <min.m.xu@intel.com>
> Sent: Tuesday, May 17, 2022 8:43 PM
> To: devel@edk2.groups.io
> Cc: Xu, Min M <min.m.xu@intel.com>; dann frazier
> <dann.frazier@canonical.com>; Aktas, Erdem <erdemaktas@google.com>;
> James Bottomley <jejb@linux.ibm.com>; Yao, Jiewen <jiewen.yao@intel.com>;
> Tom Lendacky <thomas.lendacky@amd.com>
> Subject: [PATCH] OvmfPkg/OvmfPkgX64: Use different CcProbeLib when SMM is
> on or off
> 
> CcProbeLib is designed to check the vm guest type. The OvmfPkg/CcProbeLib
> reads the OvmfWorkArea (0x80B000) to get the vm guest type which is
> written by each guest (SEV or TDX guest). But in SMM drivers the access
> to OvmfWorkArea is illegal. PiSmmCpuDxeSmm.inf is an example. It uses
> IoLib which in OvmfPkgX64 BaseIoLibIntrinsicSev.inf is included. The
> IoLib probes if the working guest is td guest by calling CcProbe().
> 
> So CcProbeLibNull will be included when SMM_REQUIRE is set. Currently
> only TDVF uses CcProbe to check the guest type, and TDVF doesn't
> support SMM, so this fix has no side-effect.
> 
> Cc: dann frazier <dann.frazier@canonical.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>
> Signed-off-by: Min Xu <min.m.xu@intel.com>
> ---
>  OvmfPkg/OvmfPkgX64.dsc | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
> index 71526bba31..db7f4def7a 100644
> --- a/OvmfPkg/OvmfPkgX64.dsc
> +++ b/OvmfPkg/OvmfPkgX64.dsc
> @@ -171,7 +171,6 @@
>    PciCapLib|OvmfPkg/Library/BasePciCapLib/BasePciCapLib.inf
> 
> PciCapPciSegmentLib|OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapP
> ciSegmentLib.inf
>    PciCapPciIoLib|OvmfPkg/Library/UefiPciCapPciIoLib/UefiPciCapPciIoLib.inf
> -  CcProbeLib|OvmfPkg/Library/CcProbeLib/CcProbeLib.inf
>    IoLib|MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsicSev.inf
> 
> OemHookStatusCodeLib|MdeModulePkg/Library/OemHookStatusCodeLibNull/
> OemHookStatusCodeLibNull.inf
>    SerialPortLib|PcAtChipsetPkg/Library/SerialIoLib/SerialIoLib.inf
> @@ -198,6 +197,9 @@
> 
>  !if $(SMM_REQUIRE) == FALSE
>    LockBoxLib|OvmfPkg/Library/LockBoxLib/LockBoxBaseLib.inf
> +  CcProbeLib|OvmfPkg/Library/CcProbeLib/CcProbeLib.inf
> +!else
> +  CcProbeLib|MdePkg/Library/CcProbeLibNull/CcProbeLibNull.inf
>  !endif
> 
> CustomizedDisplayLib|MdeModulePkg/Library/CustomizedDisplayLib/Customize
> dDisplayLib.inf
> 
> FrameBufferBltLib|MdeModulePkg/Library/FrameBufferBltLib/FrameBufferBltLi
> b.inf
> --
> 2.29.2.windows.2