Re: [edk2-devel] [PATCH v13 00/32] Add AMD Secure Nested Paging (SEV-SNP) support

["Brijesh Singh" <brijesh.singh@amd.com>]

Hi Edk2 Maintainers,

The SNP support development finished almost two months ago. I have 
addressed all the feedback from the Ovmf maintainer, and the patches are 
ready to be merged. We are waiting for UefiCpuPkg maintainers to ack the 
patches as it touches a few areas in the EDK2 core. As defined, I've 
been following the edk2 process; I have kept sending the gentle ping one 
after another every other week without results. As a contributor, I am 
not sure what I am missing. Can I ask ovmf maintainer to reach out 
directly to UefiCpuPkg maintainer to understand what is blocking? Other 
cleanups/optimization depends on this series; I would like to keep 
improving the code and make OVMF ready for the confidential computing 
use case and not be discouraged by the lack of responses.

Thanks
Brijesh

On 11/26/21 9:21 AM, Brijesh Singh via groups.io wrote:
> Hi Ray,
> 
> Can you please ack the remaining patches so that it can be merged?
> 
> thanks
> 
> On 11/12/21 11:39 AM, Brijesh Singh wrote:
>> ---------------------------------------------------------------------------
>> Hi Ray,
>>    
>> Thanks for your reviews and continuous support; I have updated a couple of patches
>> to address your comment. As I said in my previous reply, I will working on a
>> follow-up series to group some of those Sev specific variables in CpuData.
>>        
>> I hope that is okay with you.
>>           
>> thanks
>> ----------------------------------------------------------------------------
>>
>> BZ: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.tianocore.org%2Fshow_bug.cgi%3Fid%3D3275&data=04%7C01%7Cbrijesh.singh%40amd.com%7C12c8f5b9e6e74f316eb808d9b0f079b0%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637735371437948485%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=MaxkCh6bBq%2BxjR3c7YBaczFmSBNlp6CJfsM6UKEl%2BdE%3D&reserved=0
>>
>> SEV-SNP builds upon existing SEV and SEV-ES functionality while adding
>> new hardware-based memory protections. SEV-SNP adds strong memory integrity
>> protection to help prevent malicious hypervisor-based attacks like data
>> replay, memory re-mapping and more in order to create an isolated memory
>> encryption environment.
>>   
>> This series provides the basic building blocks to support booting the SEV-SNP
>> VMs, it does not cover all the security enhancement introduced by the SEV-SNP
>> such as interrupt protection.
>>
>> Many of the integrity guarantees of SEV-SNP are enforced through a new
>> structure called the Reverse Map Table (RMP). Adding a new page to SEV-SNP
>> VM requires a 2-step process. First, the hypervisor assigns a page to the
>> guest using the new RMPUPDATE instruction. This transitions the page to
>> guest-invalid. Second, the guest validates the page using the new PVALIDATE
>> instruction. The SEV-SNP VMs can use the new "Page State Change Request NAE"
>> defined in the GHCB specification to ask hypervisor to add or remove page
>> from the RMP table.
>>
>> Each page assigned to the SEV-SNP VM can either be validated or unvalidated,
>> as indicated by the Validated flag in the page's RMP entry. There are two
>> approaches that can be taken for the page validation: Pre-validation and
>> Lazy Validation.
>>
>> Under pre-validation, the pages are validated prior to first use. And under
>> lazy validation, pages are validated when first accessed. An access to a
>> unvalidated page results in a #VC exception, at which time the exception
>> handler may validate the page. Lazy validation requires careful tracking of
>> the validated pages to avoid validating the same GPA more than once. The
>> recently introduced "Unaccepted" memory type can be used to communicate the
>> unvalidated memory ranges to the Guest OS.
>>
>> At this time we only support the pre-validation. OVMF detects all the available
>> system RAM in the PEI phase. When SEV-SNP is enabled, the memory is validated
>> before it is made available to the EDK2 core.
>>
>> Now that series contains all the basic support required to launch SEV-SNP
>> guest. We are still missing the Interrupt security feature provided by the
>> SNP. The feature will be added after the base support is accepted.
>>
>> Additional resources
>> ---------------------
>> SEV-SNP whitepaper
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.amd.com%2Fsystem%2Ffiles%2FTechDocs%2FSEV-SNP-strengthening-vm-isolation-with-integrity-protection-and-more.pdf&data=04%7C01%7Cbrijesh.singh%40amd.com%7C12c8f5b9e6e74f316eb808d9b0f079b0%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637735371437948485%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=IscTAPfML8wT7L37UY7xZWLU7sINgvcw3dTAn1ge0I8%3D&reserved=0
>>
>> APM 2: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.amd.com%2Fsystem%2Ffiles%2FTechDocs%2F24593.pdf&data=04%7C01%7Cbrijesh.singh%40amd.com%7C12c8f5b9e6e74f316eb808d9b0f079b0%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637735371437948485%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=nnxB790ZvinJeAL2FDhi2VvHDbdSXAtyJNhWMcY%2F6cg%3D&reserved=0 (section 15.36)
>>
>> The complete source is available at
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FAMDESE%2Fovmf%2Ftree%2Fsnp-v13&data=04%7C01%7Cbrijesh.singh%40amd.com%7C12c8f5b9e6e74f316eb808d9b0f079b0%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637735371437948485%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=3KQX6nOiXKGba16EarC%2FGBv%2B5qb5DoqyZ5PwQoKzqVM%3D&reserved=0
>>
>> GHCB spec:
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdeveloper.amd.com%2Fwp-content%2Fresources%2F56421.pdf&data=04%7C01%7Cbrijesh.singh%40amd.com%7C12c8f5b9e6e74f316eb808d9b0f079b0%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637735371437948485%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=lruiWt%2FKo2q%2FO6YEvOuEYPLcIikoKM3xkJndZP9ri8M%3D&reserved=0
>>
>> SEV-SNP firmware specification:
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.amd.com%2Fsystem%2Ffiles%2FTechDocs%2F56860.pdf&data=04%7C01%7Cbrijesh.singh%40amd.com%7C12c8f5b9e6e74f316eb808d9b0f079b0%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637735371437948485%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=gM6YIvx3LyH98I0jBEb2RFh7Vv1NAgyxd3td6wcwyAI%3D&reserved=0
>>
>> Change since v12:
>>   * MpLib: Add comment to clarify that SEV-SNP enabled implicitly means SEV and SEV-ES are active.
>>   * MpLib: Move the extended topology initialization in AmdSev.c
>>
>> Change since v11:
>>   * rebase to the latest
>>   * fix the UefiCpuPkg PCD definition patch header.
>>
>> Change since v10:
>>   * fix 'unresolved external symbol __allshl' link error when building I32 for VS2017.
>>
>> Changes since v9:
>>   * Move CCAttrs Pcd define in MdePkg
>>   * Add comment to indicate that allocating the identity map PT is temporary until we get lazy validation
>>
>> Changes since v8:
>>   * drop the generic metadata and make it specific to SEV.
>>
>> Changes since v7:
>>   * Move SEV specific changes in MpLib in AmdSev file
>>   * Update the GHCB register function to not restore the GHCB MSR because
>>     we were already in the MSR protocol mode.
>>   * Drop the SNP name from PcdSnpSecPreValidate.
>>   * Add new section for GHCB memory in the OVMF metadata.
>>
>> Change since v6:
>>   * Drop the SNP boot block GUID and switch to using the Metadata guided structure
>>     proposed by Min in TDX series.
>>   * Exclude the GHCB page from the pre-validated region. It simplifies the reset
>>     vector code where we do not need to unvalidate the GHCB page.
>>   * Now that GHCB page is not validated so move the VMPL check from reset vector
>>     code to the MemEncryptSevLib on the first page validation.
>>   * Introduce the ConfidentialComputingGuestAttr PCD to communicate which
>>     memory encryption is active so that MpInitLib can make use of it.
>>   * Drop the SEVES specific PCD as the information can be communicated via
>>     the ConfidentialComputingGuestAttr.
>>   * Move the SNP specific AP creation function in AmdSev.c.
>>   * Define the SNP Blob GUID in a new file.
>>
>> Change since v5:
>>   * When possible use the CPUID value from CPUID page
>>   * Move the SEV specific functions from SecMain.c in AmdSev.c
>>   * Rebase to the latest code
>>   * Add the review feedback from Yao.
>>
>> Change since v4:
>>   * Use the correct MSR for the SEV_STATUS
>>   * Add VMPL-0 check
>>
>> Change since v3:
>>   * ResetVector: move all SEV specific code in AmdSev.asm and add macros to keep
>>     the code readable.
>>   * Drop extending the EsWorkArea to contain SNP specific state.
>>   * Drop the GhcbGpa library and call the VmgExit directly to register GHCB GPA.
>>   * Install the CC blob config table from AmdSevDxe instead of extending the
>>     AmdSev/SecretsDxe for it.
>>   * Add the separate PCDs for the SNP Secrets.
>>
>> Changes since v2:
>>   * Add support for the AP creation.
>>   * Use the module-scoping override to make AmdSevDxe use the IO port for PCI reads.
>>   * Use the reserved memory type for CPUID and Secrets page.
>>   *
>> Changes since v1:
>>   * Drop the interval tree support to detect the pre-validated overlap region.
>>   * Use an array to keep track of pre-validated regions.
>>   * Add support to query the Hypervisor feature and verify that SNP feature is supported.
>>   * Introduce MemEncryptSevClearMmioPageEncMask() to clear the C-bit from MMIO ranges.
>>   * Pull the SevSecretDxe and SevSecretPei into OVMF package build.
>>   * Extend the SevSecretDxe to expose confidential computing blob location through
>>     EFI configuration table.
>>
>> Brijesh Singh (28):
>>    OvmfPkg/SecMain: move SEV specific routines in AmdSev.c
>>    UefiCpuPkg/MpInitLib: move SEV specific routines in AmdSev.c
>>    OvmfPkg/ResetVector: move clearing GHCB in SecMain
>>    OvmfPkg/ResetVector: introduce SEV metadata descriptor for VMM use
>>    OvmfPkg: reserve SNP secrets page
>>    OvmfPkg: reserve CPUID page
>>    OvmfPkg/ResetVector: pre-validate the data pages used in SEC phase
>>    OvmfPkg/MemEncryptSevLib: add MemEncryptSevSnpEnabled()
>>    OvmfPkg/SecMain: register GHCB gpa for the SEV-SNP guest
>>    OvmfPkg/PlatformPei: register GHCB gpa for the SEV-SNP guest
>>    OvmfPkg/AmdSevDxe: do not use extended PCI config space
>>    OvmfPkg/MemEncryptSevLib: add support to validate system RAM
>>    OvmfPkg/MemEncryptSevLib: add function to check the VMPL0
>>    OvmfPkg/BaseMemEncryptSevLib: skip the pre-validated system RAM
>>    OvmfPkg/MemEncryptSevLib: add support to validate > 4GB memory in PEI
>>      phase
>>    OvmfPkg/SecMain: validate the memory used for decompressing Fv
>>    OvmfPkg/PlatformPei: validate the system RAM when SNP is active
>>    MdePkg: Define ConfidentialComputingGuestAttr
>>    OvmfPkg/PlatformPei: set PcdConfidentialComputingAttr when SEV is
>>      active
>>    UefiCpuPkg/MpInitLib: use PcdConfidentialComputingAttr to check SEV
>>      status
>>    UefiCpuPkg: add PcdGhcbHypervisorFeatures
>>    OvmfPkg/PlatformPei: set the Hypervisor Features PCD
>>    MdePkg/GHCB: increase the GHCB protocol max version
>>    UefiCpuPkg/MpLib: add support to register GHCB GPA when SEV-SNP is
>>      enabled
>>    OvmfPkg/MemEncryptSevLib: change the page state in the RMP table
>>    OvmfPkg/MemEncryptSevLib: skip page state change for Mmio address
>>    OvmfPkg/PlatformPei: mark cpuid and secrets memory reserved in EFI map
>>    OvmfPkg/AmdSev: expose the SNP reserved pages through configuration
>>      table
>>
>> Michael Roth (3):
>>    OvmfPkg/ResetVector: use SEV-SNP-validated CPUID values
>>    OvmfPkg/VmgExitLib: use SEV-SNP-validated CPUID values
>>    UefiCpuPkg/MpInitLib: use BSP to do extended topology check
>>
>> Tom Lendacky (1):
>>    UefiCpuPkg/MpInitLib: Use SEV-SNP AP Creation NAE event to launch APs
>>
>>   MdePkg/MdePkg.dec                             |   4 +
>>   OvmfPkg/OvmfPkg.dec                           |  19 +
>>   UefiCpuPkg/UefiCpuPkg.dec                     |   5 +
>>   OvmfPkg/AmdSev/AmdSevX64.dsc                  |   8 +-
>>   OvmfPkg/Bhyve/BhyveX64.dsc                    |   5 +-
>>   OvmfPkg/OvmfPkgIa32.dsc                       |   4 +
>>   OvmfPkg/OvmfPkgIa32X64.dsc                    |   9 +-
>>   OvmfPkg/OvmfPkgX64.dsc                        |   8 +-
>>   OvmfPkg/OvmfXen.dsc                           |   5 +-
>>   OvmfPkg/OvmfPkgX64.fdf                        |   6 +
>>   OvmfPkg/AmdSevDxe/AmdSevDxe.inf               |   7 +
>>   .../DxeMemEncryptSevLib.inf                   |   3 +
>>   .../PeiMemEncryptSevLib.inf                   |   7 +
>>   .../SecMemEncryptSevLib.inf                   |   3 +
>>   OvmfPkg/Library/VmgExitLib/SecVmgExitLib.inf  |   2 +
>>   OvmfPkg/Library/VmgExitLib/VmgExitLib.inf     |   3 +
>>   OvmfPkg/PlatformPei/PlatformPei.inf           |   7 +
>>   OvmfPkg/ResetVector/ResetVector.inf           |   5 +
>>   OvmfPkg/Sec/SecMain.inf                       |   4 +
>>   UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf |   6 +-
>>   UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf |   6 +-
>>   .../Include/ConfidentialComputingGuestAttr.h  |  25 +
>>   MdePkg/Include/Register/Amd/Ghcb.h            |   2 +-
>>   .../Guid/ConfidentialComputingSevSnpBlob.h    |  33 ++
>>   OvmfPkg/Include/Library/MemEncryptSevLib.h    |  26 +
>>   .../X64/SnpPageStateChange.h                  |  36 ++
>>   .../BaseMemEncryptSevLib/X64/VirtualMemory.h  |  24 +
>>   OvmfPkg/PlatformPei/Platform.h                |   5 +
>>   OvmfPkg/Sec/AmdSev.h                          |  95 ++++
>>   UefiCpuPkg/Library/MpInitLib/MpLib.h          | 103 ++++
>>   OvmfPkg/AmdSevDxe/AmdSevDxe.c                 |  23 +
>>   .../DxeMemEncryptSevLibInternal.c             |  27 ++
>>   .../Ia32/MemEncryptSevLib.c                   |  17 +
>>   .../PeiMemEncryptSevLibInternal.c             |  27 ++
>>   .../SecMemEncryptSevLibInternal.c             |  19 +
>>   .../X64/DxeSnpSystemRamValidate.c             |  40 ++
>>   .../X64/PeiDxeVirtualMemory.c                 | 167 ++++++-
>>   .../X64/PeiSnpSystemRamValidate.c             | 127 +++++
>>   .../X64/SecSnpSystemRamValidate.c             |  82 ++++
>>   .../X64/SnpPageStateChangeInternal.c          | 294 ++++++++++++
>>   OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 444 ++++++++++++++++--
>>   OvmfPkg/PlatformPei/AmdSev.c                  | 231 +++++++++
>>   OvmfPkg/PlatformPei/MemDetect.c               |   2 +
>>   OvmfPkg/Sec/AmdSev.c                          | 298 ++++++++++++
>>   OvmfPkg/Sec/SecMain.c                         | 158 +------
>>   UefiCpuPkg/Library/MpInitLib/AmdSev.c         | 260 ++++++++++
>>   UefiCpuPkg/Library/MpInitLib/DxeMpLib.c       |  16 +-
>>   UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c    |  70 +++
>>   UefiCpuPkg/Library/MpInitLib/MpLib.c          | 347 +++++---------
>>   UefiCpuPkg/Library/MpInitLib/PeiMpLib.c       |   4 +-
>>   UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c     | 261 ++++++++++
>>   OvmfPkg/FvmainCompactScratchEnd.fdf.inc       |   5 +
>>   OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm  |  14 +
>>   OvmfPkg/ResetVector/Ia32/AmdSev.asm           |  86 +++-
>>   OvmfPkg/ResetVector/ResetVector.nasmb         |  18 +
>>   OvmfPkg/ResetVector/X64/OvmfSevMetadata.asm   |  74 +++
>>   UefiCpuPkg/Library/MpInitLib/MpEqu.inc        |   2 +
>>   UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm  | 200 ++++++++
>>   UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm | 100 +---
>>   59 files changed, 3360 insertions(+), 528 deletions(-)
>>   create mode 100644 MdePkg/Include/ConfidentialComputingGuestAttr.h
>>   create mode 100644 OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h
>>   create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChange.h
>>   create mode 100644 OvmfPkg/Sec/AmdSev.h
>>   create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/DxeSnpSystemRamValidate.c
>>   create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiSnpSystemRamValidate.c
>>   create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecSnpSystemRamValidate.c
>>   create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
>>   create mode 100644 OvmfPkg/Sec/AmdSev.c
>>   create mode 100644 UefiCpuPkg/Library/MpInitLib/AmdSev.c
>>   create mode 100644 UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
>>   create mode 100644 UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
>>   create mode 100644 OvmfPkg/ResetVector/X64/OvmfSevMetadata.asm
>>   create mode 100644 UefiCpuPkg/Library/MpInitLib/X64/AmdSev.nasm
>>
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