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

["dann frazier" <dann.frazier@canonical.com>]

On Tue, May 17, 2022 at 12:47:21PM +0000, Yao, Jiewen wrote:
> Question: Does this patch need catch release 202205 release?

It does fix a regression since 202202, so I'd hope so :)

  -dann

> 
> 
> > -----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
>