[edk2-devel] [PATCH v2 00/23] Provide SEV-SNP support for running under an SVSM

["Lendacky, Thomas via groups.io" <thomas.lendacky=amd.com@groups.io>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654

This series adds SEV-SNP support for running OVMF under an Secure VM
Service Module (SVSM) at a less privileged VM Privilege Level (VMPL).
By running at a less priviledged VMPL, the SVSM can be used to provide
services, e.g. a virtual TPM, for the guest OS within the SEV-SNP
confidential VM (CVM) rather than trust such services from the hypervisor.

Currently, OVMF expects to run at the highest VMPL, VMPL0, and there are
certain SNP related operations that require that VMPL level. Specifically,
the PVALIDATE instruction and the RMPADJUST instruction when setting the
the VMSA attribute of a page (used when starting APs).

If OVMF is to run at a less privileged VMPL, e.g. VMPL2, then it must
use an SVSM (which is running at VMPL0) to perform the operations that
it is no longer able to perform.

When running under an SVSM, OVMF must know the APIC IDs of the vCPUs that
it will be starting. As a result, the GHCB APIC ID retrieval action must
be performed. Since this service can also work with SEV-SNP running at
VMPL0, the patches to make use of this feature are near the beginning of
the series.

How OVMF interacts with and uses the SVSM is documented in the SVSM
specification [1] and the GHCB specification [2].

This support creates a new CcSvsmLib library that is used by MpInitLib.
This requires an update to the edk2-platform DSC files to add the new
library. The edk2-platform change would be needed after patch 12, but
before patch 15.

This series introduces support to run OVMF under an SVSM. It consists
of:
  - Retrieving the list of vCPU APIC IDs and starting up all APs without
    performing a broadcast SIPI
  - Reorganizing the page state change support to not directly use the
    GHCB buffer since an SVSM will use the calling area buffer, instead
  - Detecting the presence of an SVSM
  - When not running at VMPL0, invoking the SVSM for page validation and
    VMSA page creation/deletion
  - Detecting and allowing OVMF to run in a VMPL other than 0 when an
    SVSM is present

The series is based off of commit:

  2ca8d5597443 ("UefiCpuPkg/PiSmmCpuDxeSmm: Check BspIndex first before lock cmpxchg")

[1] https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/58019.pdf
[2] https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/56421.pdf

---

Changes in v2:
- Move the APIC IDs retrieval support to the beginning of the patch series
    - Use a GUIDed HOB to hold the APIC ID list instead of a PCD
- Split up Page State Change reorganization into multiple patches
- Created CcSvsmLib library instead of extending CcExitLib
    - This will require a corresponding update to edk2-platform DSC files
    - Removed Ray Ni's Acked-by since it is not a minor change
- Variable name changes and other misc changes

Tom Lendacky (23):
  OvmfPkg/BaseMemEncryptLib: Fix error check from AsmRmpAdjust()
  MdePkg: GHCB APIC ID retrieval support definitions
  OvmfPkg/PlatformPei: Retrieve APIC IDs from the hypervisor
  UefiCpuPkg/MpInitLib: Always use AP Create if PcdSevSnpApicIds is set
  OvmfPkg/BaseMemEncryptSevLib: Fix uncrustify errors
  OvmfPkg/BaseMemEncryptSevLib: Calculate memory size for Page State
    Change
  MdePkg: Avoid hardcoded value for number of Page State Change entries
  OvmfPkg/BaseMemEncryptSevLib: Re-organize page state change support
  OvmfPkg/BaseMemEncryptSevLib: Maximize Page State Change efficiency
  MdePkg/Register/Amd: Define the SVSM related information
  MdePkg/BaseLib: Add a new VMGEXIT instruction invocation for SVSM
  UefiCpuPkg/CcSvsmLib: Create the CcSvsmLib library to support an SVSM
  UefiPayloadPkg: Prepare UefiPayloadPkg to use the CcSvsmLib library
  Ovmfpkg/CcSvsmLib: Create CcSvsmLib to handle SVSM related services
  UefiCpuPkg/MpInitLib: Use CcSvsmSnpVmsaRmpAdjust() to set/clear VMSA
  OvmfPkg/BaseMemEncryptSevLib: Use CcSvsmSnpPvalidate() to validate
    pages
  OvmfPkg: Create a calling area used to communicate with the SVSM
  OvmfPkg/CcSvsmLib: Add support for the SVSM_CORE_PVALIDATE call
  OvmfPkg/BaseMemEncryptSevLib: Maximize Page State Change efficiency
  OvmfPkg/CcSvsmLib: Add support for the SVSM create/delete vCPU calls
  UefiCpuPkg/MpInitLib: AP creation support under an SVSM
  Ovmfpkg/CcExitLib: Provide SVSM discovery support
  OvmfPkg/BaseMemEncryptLib: Check for presence of an SVSM when not at
    VMPL0

 MdePkg/MdePkg.dec                                                     |   5 +-
 OvmfPkg/OvmfPkg.dec                                                   |   4 +
 UefiCpuPkg/UefiCpuPkg.dec                                             |   5 +-
 OvmfPkg/AmdSev/AmdSevX64.dsc                                          |   1 +
 OvmfPkg/Bhyve/BhyveX64.dsc                                            |   1 +
 OvmfPkg/CloudHv/CloudHvX64.dsc                                        |   1 +
 OvmfPkg/IntelTdx/IntelTdxX64.dsc                                      |   1 +
 OvmfPkg/Microvm/MicrovmX64.dsc                                        |   1 +
 OvmfPkg/OvmfPkgIa32.dsc                                               |   1 +
 OvmfPkg/OvmfPkgIa32X64.dsc                                            |   3 +-
 OvmfPkg/OvmfPkgX64.dsc                                                |   1 +
 OvmfPkg/OvmfXen.dsc                                                   |   1 +
 UefiCpuPkg/UefiCpuPkg.dsc                                             |   4 +-
 UefiPayloadPkg/UefiPayloadPkg.dsc                                     |   1 +
 OvmfPkg/AmdSev/AmdSevX64.fdf                                          |   9 +-
 OvmfPkg/OvmfPkgX64.fdf                                                |   3 +
 MdePkg/Library/BaseLib/BaseLib.inf                                    |   2 +
 OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf          |   3 +-
 OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf          |   3 +-
 OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf          |   3 +-
 OvmfPkg/Library/CcExitLib/CcExitLib.inf                               |   3 +-
 OvmfPkg/Library/CcExitLib/SecCcExitLib.inf                            |   3 +-
 OvmfPkg/Library/CcSvsmLib/CcSvsmLib.inf                               |  38 ++
 OvmfPkg/PlatformPei/PlatformPei.inf                                   |   3 +
 OvmfPkg/ResetVector/ResetVector.inf                                   |   2 +
 UefiCpuPkg/Library/CcSvsmLibNull/CcSvsmLibNull.inf                    |  27 ++
 UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf                         |   2 +
 UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf                         |   2 +
 MdePkg/Include/Library/BaseLib.h                                      |  39 ++
 MdePkg/Include/Register/Amd/Fam17Msr.h                                |  19 +-
 MdePkg/Include/Register/Amd/Ghcb.h                                    |  23 +-
 MdePkg/Include/Register/Amd/Msr.h                                     |   3 +-
 MdePkg/Include/Register/Amd/Svsm.h                                    | 101 ++++
 MdePkg/Include/Register/Amd/SvsmMsr.h                                 |  35 ++
 OvmfPkg/Include/WorkArea.h                                            |   9 +-
 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChange.h         |   6 +-
 UefiCpuPkg/Include/Library/CcSvsmLib.h                                | 101 ++++
 UefiCpuPkg/Library/MpInitLib/MpLib.h                                  |  29 +-
 OvmfPkg/Library/BaseMemEncryptSevLib/X64/DxeSnpSystemRamValidate.c    |  11 +-
 OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c        |  27 +-
 OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c    |  22 +-
 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecSnpSystemRamValidate.c    |  31 +-
 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c | 206 ++++----
 OvmfPkg/Library/CcExitLib/CcExitVcHandler.c                           |  29 +-
 OvmfPkg/Library/CcSvsmLib/CcSvsmLib.c                                 | 500 ++++++++++++++++++++
 OvmfPkg/PlatformPei/AmdSev.c                                          | 102 +++-
 UefiCpuPkg/Library/CcSvsmLibNull/CcSvsmLibNull.c                      | 108 +++++
 UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c                            |  21 +-
 UefiCpuPkg/Library/MpInitLib/MpLib.c                                  |   9 +-
 UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c                             | 134 ++++--
 MdePkg/Library/BaseLib/Ia32/VmgExitSvsm.nasm                          |  39 ++
 MdePkg/Library/BaseLib/X64/VmgExitSvsm.nasm                           |  94 ++++
 OvmfPkg/ResetVector/ResetVector.nasmb                                 |   6 +-
 OvmfPkg/ResetVector/X64/OvmfSevMetadata.asm                           |  11 +-
 UefiCpuPkg/Library/CcSvsmLibNull/CcSvsmLibNull.uni                    |  13 +
 55 files changed, 1628 insertions(+), 233 deletions(-)
 create mode 100644 OvmfPkg/Library/CcSvsmLib/CcSvsmLib.inf
 create mode 100644 UefiCpuPkg/Library/CcSvsmLibNull/CcSvsmLibNull.inf
 create mode 100644 MdePkg/Include/Register/Amd/Svsm.h
 create mode 100644 MdePkg/Include/Register/Amd/SvsmMsr.h
 create mode 100644 UefiCpuPkg/Include/Library/CcSvsmLib.h
 create mode 100644 OvmfPkg/Library/CcSvsmLib/CcSvsmLib.c
 create mode 100644 UefiCpuPkg/Library/CcSvsmLibNull/CcSvsmLibNull.c
 create mode 100644 MdePkg/Library/BaseLib/Ia32/VmgExitSvsm.nasm
 create mode 100644 MdePkg/Library/BaseLib/X64/VmgExitSvsm.nasm
 create mode 100644 UefiCpuPkg/Library/CcSvsmLibNull/CcSvsmLibNull.uni

-- 
2.42.0



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