[edk2-devel] [PATCH RFC v2 00/28] Add AMD Secure Nested Paging (SEV-SNP) support
Laszlo Ersek
lersek at redhat.com
Fri Apr 30 16:49:34 UTC 2021
Hi,
On 04/30/21 13:51, Brijesh Singh wrote:
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275
>
> 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.
I've added this to my review queue.
Thanks
Laszlo
>
> 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.
>
> This series does not implements the following SEV-SNP features yet:
>
> * CPUID filtering
> * AP bring up using the new SEV-SNP NAE
> * Lazy validation
> * Interrupt security
>
> The series is based on commit:
> 01c0ab90be (origin/master, origin/HEAD, master) AzurePipelines: Add support for ArmPlatformPkg
>
> Additional resources
> ---------------------
> SEV-SNP whitepaper
> https://www.amd.com/system/files/TechDocs/SEV-SNP-strengthening-vm-isolation-with-integrity-protection-and-more.pdf
>
> APM 2: https://www.amd.com/system/files/TechDocs/24593.pdf (section 15.36)
>
> The complete source is available at
> https://github.com/AMDESE/ovmf/tree/sev-snp-rfc-2
>
> GHCB spec:
> https://developer.amd.com/wp-content/resources/56421.pdf
>
> SEV-SNP firmware specification:
> https://developer.amd.com/sev/
>
> Cc: James Bottomley <jejb at linux.ibm.com>
> Cc: Min Xu <min.m.xu at intel.com>
> Cc: Jiewen Yao <jiewen.yao at intel.com>
> Cc: Tom Lendacky <thomas.lendacky at amd.com>
> Cc: Jordan Justen <jordan.l.justen at intel.com>
> Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
> Cc: Laszlo Ersek <lersek at redhat.com>
> Cc: Erdem Aktas <erdemaktas at google.com>
>
> 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):
> MdePkg: Expand the SEV MSR to include the SNP definition
> MdePkg: Define the GHCB Hypervisor features
> MdePkg: Define the GHCB GPA structure
> MdePkg: Define the Page State Change VMGEXIT structures
> MdePkg: Add AsmPvalidate() support
> OvmfPkg/BaseMemEncryptSevLib: Introduce
> MemEncryptSevClearMmioPageEncMask()
> OvmfPkg: Use MemEncryptSevClearMmioPageEncMask() to clear EncMask from
> Mmio
> OvmfPkg/BaseMemEncryptSevLib: Remove CacheFlush parameter
> OvmfPkg/VmgExitLib: Allow PMBASE register access in Dxe phase
> OvmfPkg/MemEncryptSevLib: add MemEncryptSevSnpEnabled()
> OvmfPkg: Reserve Secrets page in MEMFD
> OvmfPkg: Reserve CPUID page for the SEV-SNP guest
> OvmfPkg: Validate the data pages used in the Reset vector and SEC
> phase
> UefiCpuPkg: Define the SEV-SNP specific dynamic PCDs
> OvmfPkg/MemEncryptSevLib: extend the workarea to include SNP enabled
> field
> OvmfPkg/MemEncryptSevLib: Extend Es Workarea to include hv features
> OvmfPkg/ResetVector: Invalidate the GHCB page
> OvmfPkg: Add a library to support registering GHCB GPA
> OvmfPkg: register GHCB gpa for the SEV-SNP guest
> UefiCpuPkg/MpLib: add support to register GHCB GPA when SEV-SNP is
> enabled
> OvmfPkg/MemEncryptSevLib: Add support to validate system RAM
> OvmfPkg/BaseMemEncryptSevLib: Skip the pre-validated system RAM
> OvmfPkg/MemEncryptSevLib: Add support to validate > 4GB memory in PEI
> phase
> OvmfPkg/SecMain: Pre-validate the memory used for decompressing Fv
> OvmfPkg/PlatformPei: Validate the system RAM when SNP is active
> OvmfPkg/MemEncryptSevLib: Change the page state in the RMP table
> OvmfPkg/AmdSev: Expose the SNP reserved pages through configuration
> table
> MdePkg/GHCB: Increase the GHCB protocol max version
>
> MdePkg/Include/Library/BaseLib.h | 37 +++
> MdePkg/Include/Register/Amd/Fam17Msr.h | 36 ++-
> MdePkg/Include/Register/Amd/Ghcb.h | 37 ++-
> MdePkg/Library/BaseLib/BaseLib.inf | 1 +
> MdePkg/Library/BaseLib/X64/Pvalidate.nasm | 43 +++
> OvmfPkg/AmdSev/SecretDxe/SecretDxe.c | 21 ++
> OvmfPkg/AmdSev/SecretDxe/SecretDxe.inf | 4 +
> OvmfPkg/AmdSev/SecretPei/SecretPei.c | 16 +-
> OvmfPkg/AmdSev/SecretPei/SecretPei.inf | 1 +
> OvmfPkg/AmdSevDxe/AmdSevDxe.c | 13 +-
> OvmfPkg/FvmainCompactScratchEnd.fdf.inc | 5 +
> .../Guid/ConfidentialComputingSecret.h | 17 ++
> OvmfPkg/Include/Library/GhcbRegisterLib.h | 27 ++
> OvmfPkg/Include/Library/MemEncryptSevLib.h | 66 ++++-
> OvmfPkg/IoMmuDxe/AmdSevIoMmu.c | 6 +-
> .../DxeMemEncryptSevLib.inf | 3 +
> .../DxeMemEncryptSevLibInternal.c | 27 ++
> .../Ia32/MemEncryptSevLib.c | 58 +++-
> .../PeiMemEncryptSevLib.inf | 7 +
> .../PeiMemEncryptSevLibInternal.c | 27 ++
> .../SecMemEncryptSevLib.inf | 3 +
> .../SecMemEncryptSevLibInternal.c | 19 ++
> .../X64/DxeSnpSystemRamValidate.c | 40 +++
> .../X64/MemEncryptSevLib.c | 49 +++-
> .../X64/PeiDxeVirtualMemory.c | 203 +++++++++++++-
> .../X64/PeiSnpSystemRamValidate.c | 126 +++++++++
> .../X64/SecSnpSystemRamValidate.c | 36 +++
> .../X64/SecVirtualMemory.c | 8 +-
> .../X64/SnpPageStateChange.h | 31 +++
> .../X64/SnpPageStateChangeInternal.c | 261 ++++++++++++++++++
> .../BaseMemEncryptSevLib/X64/VirtualMemory.h | 52 +++-
> .../Library/GhcbRegisterLib/GhcbRegisterLib.c | 97 +++++++
> .../GhcbRegisterLib/GhcbRegisterLib.inf | 33 +++
> .../SmmCpuFeaturesLib/SmmCpuFeaturesLib.c | 3 +-
> OvmfPkg/Library/VmgExitLib/SecVmgExitLib.inf | 4 +
> OvmfPkg/Library/VmgExitLib/VmgExitLib.inf | 7 +
> OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 45 +++
> OvmfPkg/OvmfPkg.dec | 21 ++
> OvmfPkg/OvmfPkgIa32.dsc | 2 +
> OvmfPkg/OvmfPkgIa32X64.dsc | 2 +
> OvmfPkg/OvmfPkgX64.dsc | 3 +
> OvmfPkg/OvmfPkgX64.fdf | 17 +-
> OvmfPkg/PlatformPei/AmdSev.c | 84 +++++-
> OvmfPkg/PlatformPei/MemDetect.c | 13 +
> OvmfPkg/PlatformPei/PlatformPei.inf | 5 +
> .../FwBlockServiceDxe.c | 5 +-
> .../QemuFlashSmm.c | 5 +-
> OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm | 23 ++
> OvmfPkg/ResetVector/Ia32/PageTables64.asm | 216 +++++++++++++++
> OvmfPkg/ResetVector/ResetVector.inf | 4 +
> OvmfPkg/ResetVector/ResetVector.nasmb | 6 +
> OvmfPkg/Sec/SecMain.c | 103 +++++++
> OvmfPkg/Sec/SecMain.inf | 3 +
> UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf | 1 +
> UefiCpuPkg/Library/MpInitLib/MpEqu.inc | 1 +
> UefiCpuPkg/Library/MpInitLib/MpLib.c | 2 +
> UefiCpuPkg/Library/MpInitLib/MpLib.h | 2 +
> UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf | 1 +
> UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm | 51 ++++
> UefiCpuPkg/UefiCpuPkg.dec | 11 +
> 60 files changed, 1970 insertions(+), 80 deletions(-)
> create mode 100644 MdePkg/Library/BaseLib/X64/Pvalidate.nasm
> create mode 100644 OvmfPkg/Include/Library/GhcbRegisterLib.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/SnpPageStateChange.h
> create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChangeInternal.c
> create mode 100644 OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.c
> create mode 100644 OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf
>
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