[edk2-devel] [PATCH RFC v2 00/28] Add AMD Secure Nested Paging (SEV-SNP) support
Brijesh Singh
brijesh.singh at amd.com
Fri Apr 30 11:51:20 UTC 2021
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.
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
--
2.17.1
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