[edk2-devel] [PATCH V3 00/10] Add Intel TDX support in OvmfPkg/ResetVector

Tue Jul 27 05:42:17 UTC 2021

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3429

Intel's Trust Domain Extensions (Intel TDX) refers to an Intel technology
that extends Virtual Machines Extensions (VMX) and Multi-Key Total Memory
Encryption (MKTME) with a new kind of virutal machines guest called a 
Trust Domain (TD). A TD is desinged to run in a CPU mode that protects the
confidentiality of TD memory contents and the TD's CPU state from other
software, including the hosting Virtual-Machine Monitor (VMM), unless
explicitly shared by the TD itself.

The patch-sets to support Intel TDX in OvmfPkg is split into several
waves. This is wave1 which adds Intel TDX support in OvmfPkg/ResetVector.
Note: TDX only works in X64.

According to the comments in https://edk2.groups.io/g/devel/message/78152
and https://edk2.groups.io/g/devel/message/78151, PageTables64.asm and
Flat32ToFlat64.asm are refined. SEV and TDX related routines are separated
to AmdSev.asm and IntelTdx.asm.

Patch 1 add the PCDs of BFV/CFV. BFV is the code part of the image. CFV is
the configuration part. BFV is measured by VMM and CFV is measured by TDVF
itself.

Patch 2 add TdxMetadata in OvmfPkg/ResetVector. It describes the
information about the image so that VMM can do the initialization and
measurement based on these information.

Patch 3 set the initial value of Td mailbox and its related macros used in
ResetVector.

Patch 4 define macro of TDX_PT_ADDR which indicates the Tdx extra page
tables.

Patch 5 is IntelTdx.asm which includes below routines used in ResetVector.
 - IsTdx
 - InitTdx
 - PostSetCr3PageTables64Tdx

Patch 6 is AmdSev.asm which includes SEV routines. These routines are
extracted from the previous PageTables64.asm/Flat32ToFlat64.asm.

Patch 7 load the GDT and set CR0, then jump to Flat32 protected mode. This
is because GDT is not set in the initial stage of ResetVector.

Patch 8 is Init32.asm. It is the entry point of doing the 32-bit protected
mode initialization. ReloadFlat32 and InitTdx are called. In the future if
SEV has something to initialize, InitSev (for example) can be called in
turn.

Patch 9 create Main.asm in OvmfPkg/ResetVector. It is based on the
suggestion in https://edk2.groups.io/g/devel/message/78152. In this commit
it is simply copied from UefiCpuPkg. In the next commit this Main.asm is
updated to add a new Entry (Main32) to support Tdx.

In Patch 10, all above are put together. Init32.asm call ReloadFlat32
to jump to 32-bit protected mode, then InitTdx initialize TDX_WORK_AREA
to record 'TDXG' flags. After that page tables are built and set, then
jump to SecEntry.

[TDX]: https://software.intel.com/content/dam/develop/external/us/en/
documents/tdx-whitepaper-final9-17.pdf

[TDVF]: https://software.intel.com/content/dam/develop/external/us/en/
documents/tdx-virtual-firmware-design-guide-rev-1.pdf

[ReviewComment-1]: https://edk2.groups.io/g/devel/message/78151

[ReviewComment-2]: https://edk2.groups.io/g/devel/message/78152

Code is at https://github.com/mxu9/edk2/tree/tdvf_wave1.v3

v3 changes:
 - Refine PageTables64.asm and Flat32ToFlat64.asm based on the review
   comments in [ReviewComment-1] and [ReviewComment-2].
 - SEV codes are in AmdSev.asm
 - TDX codes are in IntelTdx.asm
 - Main.asm is created in OvmfPkg/ResetVector. The one in
   UefiCpuPkg/ResetVector/Vtf0 is not used.
 - Init32.asm/ReloadFlat32.asm in UefiCpuPkg/ResetVector/Vtf0/Ia32 are
   deleted. They're moved to OvmfPkg/ResetVector/Ia32.
 - InitTdx.asm is renamed to InteTdx.asm

v2 changes:
 - Move InitTdx.asm and ReloadFlat32.asm from UefiCpuPkg/ResetVector/Vtf0
   to OvmfPkg/ResetVector. Init32.asm is created which is a null stub of
   32-bit initialization. In Main32 just simply call Init32. It makes
   the Main.asm in UefiCpuPkg/ResetVector clean and clear.
 - Init32.asm/InitTdx.asm/ReloadFlat32.asm are created under
   OvmfPkg/ResetVector/Ia32.
 - Update some descriptions of the patch-sets.
 - Update the REF link in cover letter.
 - Add Ard Biesheuvel in Cc list.

v1: https://edk2.groups.io/g/devel/message/77675

Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
Cc: Jordan Justen <jordan.l.justen at intel.com>
Cc: Brijesh Singh <brijesh.singh at amd.com>
Cc: Erdem Aktas <erdemaktas at google.com>
Cc: James Bottomley <jejb at linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao at intel.com>
Cc: Tom Lendacky <thomas.lendacky at amd.com>
Signed-off-by: Min Xu <min.m.xu at intel.com>

Min Xu (10):
  OvmfPkg: Add Tdx BFV/CFV PCDs and PcdOvmfImageSizeInKb
  OvmfPkg: Add Tdx metadata
  OvmfPkg: Set TdMailbox initial value and macros
  OvmfPkg: Add TDX_PT_ADDR defition in ResetVector.nasmb
  OvmfPkg: Add IntelTdx.asm in ResetVector
  OvmfPkg: Add AmdSev.asm in ResetVector
  OvmfPkg: Add ReloadFlat32
  OvmfPkg: Add Init32
  OvmfPkg: Create Main.asm in ResetVector
  OvmfPkg: Update ResetVector to support Tdx

 OvmfPkg/OvmfPkg.dec                          |  13 +
 OvmfPkg/OvmfPkgDefines.fdf.inc               |  12 +-
 OvmfPkg/OvmfPkgX64.fdf                       |   6 +
 OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm |  38 ++
 OvmfPkg/ResetVector/Ia32/AmdSev.asm          | 526 +++++++++++++++++++
 OvmfPkg/ResetVector/Ia32/Flat32ToFlat64.asm  | 110 +---
 OvmfPkg/ResetVector/Ia32/Init32.asm          |  32 ++
 OvmfPkg/ResetVector/Ia32/IntelTdx.asm        | 172 ++++++
 OvmfPkg/ResetVector/Ia32/PageTables64.asm    | 478 +++--------------
 OvmfPkg/ResetVector/Ia32/ReloadFlat32.asm    |  44 ++
 OvmfPkg/ResetVector/Main.asm                 | 119 +++++
 OvmfPkg/ResetVector/ResetVector.inf          |  11 +-
 OvmfPkg/ResetVector/ResetVector.nasmb        |  66 ++-
 OvmfPkg/ResetVector/X64/TdxMetadata.asm      |  97 ++++
 14 files changed, 1224 insertions(+), 500 deletions(-)
 create mode 100644 OvmfPkg/ResetVector/Ia32/AmdSev.asm
 create mode 100644 OvmfPkg/ResetVector/Ia32/Init32.asm
 create mode 100644 OvmfPkg/ResetVector/Ia32/IntelTdx.asm
 create mode 100644 OvmfPkg/ResetVector/Ia32/ReloadFlat32.asm
 create mode 100644 OvmfPkg/ResetVector/Main.asm
 create mode 100644 OvmfPkg/ResetVector/X64/TdxMetadata.asm

-- 
2.29.2.windows.2

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