[edk2-devel] [RESEND PATCH RFC v3 00/22] Add AMD Secure Nested Paging (SEV-SNP) support
Laszlo Ersek
lersek at redhat.com
Thu May 27 09:42:24 UTC 2021
On 05/27/21 01:10, Brijesh Singh wrote:
> (I missed adding devel at edk2.groups.io, resending the series)
>
> 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
> * Lazy validation
> * Interrupt security
>
> The series builds on SNP pre-patch posted here: https://tinyurl.com/pu6admks
>
> 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 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 (21):
> UefiCpuPkg: Define the SEV-SNP specific dynamic PCDs
> OvmfPkg/MemEncryptSevLib: add MemEncryptSevSnpEnabled()
> OvmfPkg/MemEncryptSevLib: extend the workarea to include SNP enabled
> field
> OvmfPkg/MemEncryptSevLib: extend Es Workarea to include hv features
> OvmfPkg: reserve Secrets page in MEMFD
> OvmfPkg: reserve CPUID page for the SEV-SNP guest
> OvmfPkg/ResetVector: validate the data pages used in SEC phase
> OvmfPkg/ResetVector: invalidate the GHCB page
> OvmfPkg: add library to support registering GHCB GPA
> OvmfPkg/PlatformPei: register GHCB gpa for the SEV-SNP guest
> UefiCpuPkg/MpLib: add support to register GHCB GPA when SEV-SNP is
> enabled
> OvmfPkg/AmdSevDxe: do not use extended PCI config space
> 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/MemEncryptSevLib: skip page state change for Mmio address
> OvmfPkg/AmdSev: expose the SNP reserved pages through configuration
> table
> MdePkg/GHCB: increase the GHCB protocol max version
>
> Tom Lendacky (1):
> UefiCpuPkg/MpInitLib: Use SEV-SNP AP Creation NAE event to launch APs
>
> OvmfPkg/OvmfPkg.dec | 21 ++
> UefiCpuPkg/UefiCpuPkg.dec | 11 +
> OvmfPkg/AmdSev/AmdSevX64.dsc | 5 +-
> OvmfPkg/Bhyve/BhyveX64.dsc | 5 +-
> OvmfPkg/OvmfPkgIa32.dsc | 2 +
> OvmfPkg/OvmfPkgIa32X64.dsc | 7 +-
> OvmfPkg/OvmfPkgX64.dsc | 8 +-
> OvmfPkg/OvmfXen.dsc | 5 +-
> OvmfPkg/OvmfPkgX64.fdf | 17 +-
> OvmfPkg/AmdSev/SecretDxe/SecretDxe.inf | 4 +
> OvmfPkg/AmdSev/SecretPei/SecretPei.inf | 1 +
> .../DxeMemEncryptSevLib.inf | 3 +
> .../PeiMemEncryptSevLib.inf | 7 +
> .../SecMemEncryptSevLib.inf | 3 +
> .../GhcbRegisterLib/GhcbRegisterLib.inf | 33 +++
> OvmfPkg/PlatformPei/PlatformPei.inf | 5 +
> OvmfPkg/ResetVector/ResetVector.inf | 4 +
> OvmfPkg/Sec/SecMain.inf | 3 +
> UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf | 4 +
> UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf | 4 +
> MdePkg/Include/Register/Amd/Ghcb.h | 2 +-
> .../Guid/ConfidentialComputingSecret.h | 18 ++
> OvmfPkg/Include/Library/GhcbRegisterLib.h | 27 ++
> OvmfPkg/Include/Library/MemEncryptSevLib.h | 31 +-
> .../X64/SnpPageStateChange.h | 31 ++
> .../BaseMemEncryptSevLib/X64/VirtualMemory.h | 19 ++
> UefiCpuPkg/Library/MpInitLib/MpLib.h | 19 ++
> OvmfPkg/AmdSev/SecretDxe/SecretDxe.c | 22 ++
> OvmfPkg/AmdSev/SecretPei/SecretPei.c | 15 +-
> .../DxeMemEncryptSevLibInternal.c | 27 ++
> .../Ia32/MemEncryptSevLib.c | 17 ++
> .../PeiMemEncryptSevLibInternal.c | 27 ++
> .../SecMemEncryptSevLibInternal.c | 19 ++
> .../X64/DxeSnpSystemRamValidate.c | 40 +++
> .../X64/PeiDxeVirtualMemory.c | 167 ++++++++++-
> .../X64/PeiSnpSystemRamValidate.c | 126 ++++++++
> .../X64/SecSnpSystemRamValidate.c | 36 +++
> .../X64/SnpPageStateChangeInternal.c | 230 +++++++++++++++
> .../Library/GhcbRegisterLib/GhcbRegisterLib.c | 97 +++++++
> OvmfPkg/PlatformPei/AmdSev.c | 81 ++++++
> OvmfPkg/PlatformPei/MemDetect.c | 12 +
> OvmfPkg/Sec/SecMain.c | 106 +++++++
> UefiCpuPkg/Library/MpInitLib/DxeMpLib.c | 11 +-
> .../MpInitLib/Ia32/SevSnpRmpAdjustInternal.c | 31 ++
> UefiCpuPkg/Library/MpInitLib/MpLib.c | 274 ++++++++++++++++--
> .../MpInitLib/X64/SevSnpRmpAdjustInternal.c | 44 +++
> OvmfPkg/FvmainCompactScratchEnd.fdf.inc | 5 +
> OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm | 23 ++
> OvmfPkg/ResetVector/Ia32/PageTables64.asm | 227 +++++++++++++++
> OvmfPkg/ResetVector/ResetVector.nasmb | 6 +
> UefiCpuPkg/Library/MpInitLib/MpEqu.inc | 1 +
> UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm | 51 ++++
> 52 files changed, 1956 insertions(+), 38 deletions(-)
> create mode 100644 OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf
> create mode 100644 OvmfPkg/Include/Library/GhcbRegisterLib.h
> create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateChange.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/Library/GhcbRegisterLib/GhcbRegisterLib.c
> create mode 100644 UefiCpuPkg/Library/MpInitLib/Ia32/SevSnpRmpAdjustInternal.c
> create mode 100644 UefiCpuPkg/Library/MpInitLib/X64/SevSnpRmpAdjustInternal.c
>
I'm confirming that this series is in my review queue.
However, I may need unusually long time to get to it. Thanks for your
patience.
Thanks
Laszlo
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