[edk2-devel] [PATCH V2 0/2] OvmfPkg: Update TdVmCall to handle the retry for MapGPA

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

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4572

According to section 3.2 of the [GHCI] spec, if the result is 
"TDG.VP.VMCALL_RETRY" for TDG.VP.VMCALL.MapGPA, TD must retry the
mapping for the pages in the region starting at the GPA specified in r11.

Currently, TDVF does not properly handle the retry results of MapGPA.
For this, TDVF should update the TdVmCall to return the value in R11
and must retry the mapping for the pages by the value.

How to verify the retry for MapGPA in TDVF:
Note: Since the range size of MapGPA in QEMU is limited to 64MB and
TDVF always maps 1.5GB( 2GB~3.5GB) MMIO to shared-memory for TD guest, 
the retry action is triggered always.
Pre-Config:
QEMU:
https://github.com/intel/qemu-tdx/tree/tdx-qemu-upstream | tag: tdx-qemu-upstream-2023.10.20-v8.1.0
KERNEL:
https://github.com/intel/tdx/tree/kvm-upstream-2023.10.16-v6.6-rc2

Step:
Boot with TD guest and check the log with TdVmcall(MAPGPA), as below:
TdxDxe:SetMemorySharedOrPrivate: Cr3Base=0x0 Physical=0x80000000 Length=0x60000000 Mode=Shared
SetOrClearSharedBit: TdVmcall(MAPGPA) Retry PhysicalAddress is 8000080000000, MapGpaRetryaddr is 8000084000000

Reference:
[GHCI]: TDX Guest-Host-Communication Interface v1.0
https://cdrdv2.intel.com/v1/dl/getContent/726790

v2 changes:
  - Update the code based on the comments of v1 reviewer
  - Update TdVmcall to instead of the extra API file

code: https://github.com/sunceping/edk2/tree/handleRetryMapGPA.v2

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>
Signed-off-by: Ceping Sun <cepingx.sun@intel.com>

Ceping Sun (2):
  MdePkg/BaseLib: Update TdVmcall to always output the value in R11
  OvmfPkg/BaseMemEncryptTdxLib: Handle retry result of MapGPA

 MdePkg/Library/BaseLib/X64/TdVmcall.nasm      |  4 +-
 .../BaseMemEncryptTdxLib/MemoryEncryption.c   | 43 ++++++++++++++++++-
 2 files changed, 43 insertions(+), 4 deletions(-)

-- 
2.34.1



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