[edk2-devel] [RFC PATCH v4 00/27] Add AMD Secure Nested Paging (SEV-SNP) support
Yao, Jiewen
jiewen.yao at intel.com
Wed Jul 28 08:16:46 UTC 2021
Hi Brijesh
I reviewed the patch set. I have some basic questions.
Please help me understand before I post my comment
If a platform supports SEV-SNP, can we assume SEV-ES is supported?
Or is it a valid case that SecSnp==YES, SevEs==NO?
I am trying to understand how many cases we need support.
I think we want to support below:
+------------------------+
| SEV | SEV_ES | SEV_SNP |
+------------------------+
| 0 | 0 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
| 1 | 1 | 1 |
+------------------------+
Any other combination we need support? Such as below:
+------------------------+
| SEV | SEV_ES | SEV_SNP |
+------------------------+
| 0 | 1 | 0 |
| 0 | 0 | 1 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
+------------------------+
Thank you
Yao Jiewen
> -----Original Message-----
> From: Brijesh Singh <brijesh.singh at amd.com>
> Sent: Tuesday, June 29, 2021 1:42 AM
> To: devel at edk2.groups.io
> Cc: James Bottomley <jejb at linux.ibm.com>; Xu, Min M <min.m.xu at intel.com>;
> Yao, Jiewen <jiewen.yao at intel.com>; Tom Lendacky
> <thomas.lendacky at amd.com>; Justen, Jordan L <jordan.l.justen at intel.com>;
> Ard Biesheuvel <ardb+tianocore at kernel.org>; Laszlo Ersek
> <lersek at redhat.com>; Erdem Aktas <erdemaktas at google.com>; Dong, Eric
> <eric.dong at intel.com>; Ni, Ray <ray.ni at intel.com>; Kumar, Rahul1
> <rahul1.kumar at intel.com>; Kinney, Michael D <michael.d.kinney at intel.com>;
> Liming Gao <gaoliming at byosoft.com.cn>; Liu, Zhiguang
> <zhiguang.liu at intel.com>; Michael Roth <Michael.Roth at amd.com>; Brijesh
> Singh <brijesh.singh at amd.com>
> Subject: [RFC PATCH v4 00/27] Add AMD Secure Nested Paging (SEV-SNP)
> support
>
> 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
>
> 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-4
>
> GHCB spec:
> https://developer.amd.com/wp-content/resources/56421.pdf
>
> SEV-SNP firmware specification:
> https://www.amd.com/system/files/TechDocs/56860.pdf
>
> Brijesh Singh (26):
> OvmfPkg/ResetVector: move SEV specific code in a separate file
> OvmfPkg/ResetVector: add the macro to invoke MSR protocol based
> VMGEXIT
> OvmfPkg/ResetVector: add the macro to request guest termination
> OvmfPkg: reserve SNP secrets page
> OvmfPkg: reserve CPUID page for SEV-SNP
> OvmfPkg/ResetVector: introduce SEV-SNP boot block GUID
> OvmfPkg/ResetVector: pre-validate the data pages used in SEC phase
> OvmfPkg/ResetVector: invalidate the GHCB page
> UefiCpuPkg: Define the SEV-SNP specific dynamic PCDs
> 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/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/PlatformPei: set the SEV-SNP enabled PCD
> 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
>
> Tom Lendacky (1):
> UefiCpuPkg/MpInitLib: Use SEV-SNP AP Creation NAE event to launch APs
>
> OvmfPkg/OvmfPkg.dec | 24 +
> UefiCpuPkg/UefiCpuPkg.dec | 11 +
> OvmfPkg/AmdSev/AmdSevX64.dsc | 5 +-
> OvmfPkg/Bhyve/BhyveX64.dsc | 5 +-
> OvmfPkg/OvmfPkgIa32.dsc | 1 +
> OvmfPkg/OvmfPkgIa32X64.dsc | 6 +-
> OvmfPkg/OvmfPkgX64.dsc | 5 +-
> OvmfPkg/OvmfXen.dsc | 5 +-
> OvmfPkg/OvmfPkgX64.fdf | 14 +-
> OvmfPkg/AmdSevDxe/AmdSevDxe.inf | 7 +
> .../DxeMemEncryptSevLib.inf | 3 +
> .../PeiMemEncryptSevLib.inf | 7 +
> .../SecMemEncryptSevLib.inf | 3 +
> OvmfPkg/PlatformPei/PlatformPei.inf | 8 +
> OvmfPkg/ResetVector/ResetVector.inf | 6 +
> 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/MemEncryptSevLib.h | 26 ++
> .../X64/SnpPageStateChange.h | 31 ++
> .../BaseMemEncryptSevLib/X64/VirtualMemory.h | 19 +
> UefiCpuPkg/Library/MpInitLib/MpLib.h | 19 +
> 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 | 126 ++++++
> .../X64/SecSnpSystemRamValidate.c | 36 ++
> .../X64/SnpPageStateChangeInternal.c | 295 +++++++++++++
> OvmfPkg/PlatformPei/AmdSev.c | 192 ++++++++
> OvmfPkg/PlatformPei/MemDetect.c | 21 +
> OvmfPkg/Sec/SecMain.c | 111 +++++
> UefiCpuPkg/Library/MpInitLib/DxeMpLib.c | 11 +-
> .../MpInitLib/Ia32/SevSnpRmpAdjustInternal.c | 31 ++
> UefiCpuPkg/Library/MpInitLib/MpLib.c | 275 +++++++++++-
> .../MpInitLib/X64/SevSnpRmpAdjustInternal.c | 44 ++
> OvmfPkg/FvmainCompactScratchEnd.fdf.inc | 5 +
> OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm | 27 ++
> .../Ia32/{PageTables64.asm => AmdSev.asm} | 415 +++++++++---------
> OvmfPkg/ResetVector/Ia32/PageTables64.asm | 404 +----------------
> OvmfPkg/ResetVector/ResetVector.nasmb | 7 +
> UefiCpuPkg/Library/MpInitLib/MpEqu.inc | 1 +
> UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm | 51 +++
> 48 files changed, 1978 insertions(+), 630 deletions(-)
> 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
> UefiCpuPkg/Library/MpInitLib/Ia32/SevSnpRmpAdjustInternal.c
> create mode 100644
> UefiCpuPkg/Library/MpInitLib/X64/SevSnpRmpAdjustInternal.c
> copy OvmfPkg/ResetVector/Ia32/{PageTables64.asm => AmdSev.asm} (67%)
>
> --
> 2.17.1
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