[edk2-devel] [PATCH V1 0/3] OvmfPkg: Update TDVMCALL to avoid leaking secrets to the VMM

["sunceping" <cepingx.sun@intel.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4696

According to section 2.4.1 of [GHCI] spec,
RBP register is usually used as a frame pointer according to the C language calling convention. 
The software should not use RBP as an input/output parameter and should clear BIT5 (RBP) in
the GPR mask in RCX.

Reference:
[GHCI]: TDX Guest-Host-Communication Interface v1.5
https://cdrdv2.intel.com/v1/dl/getContent/726792


Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Ceping Sun <cepingx.sun@intel.com>

Ceping Sun (3):
  MdePkg/BaseLib: Update TDVMCALL_EXPOSE_REGS_MASK
  OvmfPkg/CcExitLib: Update TDVMCALL_EXPOSE_REGS_MASK
  OvmfPkg/TdxDxe: Clear the registers before tdcall

 MdePkg/Library/BaseLib/X64/TdVmcall.nasm      |  2 +-
 .../Library/CcExitLib/X64/TdVmcallCpuid.nasm  |  2 +-
 OvmfPkg/TdxDxe/X64/ApRunLoop.nasm             | 30 ++++++++++++++++---
 3 files changed, 28 insertions(+), 6 deletions(-)

-- 
2.34.1



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