[edk2-devel] [RFC PATCH 00/19] Add AMD Secure Nested Paging (SEV-SNP) support
Brijesh Singh
brijesh.singh at amd.com
Wed Mar 24 15:31:56 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:
e542e05d4f UefiCpuPkg/SmmCpuFeaturesLib: Abstract PcdCpuMaxLogicalProcessorNumber
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-1
GHCB spec v2:
The draft specification is posted on AMD-SEV-SNP mailing list:
https://lists.suse.com/mailman/private/amd-sev-snp/
Copy of the spec is also available at
https://github.com/AMDESE/AMDSEV/blob/sev-snp-devel/docs/56421-Guest_Hypervisor_Communication_Block_Standardization.pdf
GHCB spec v1:
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>
Brijesh Singh (19):
OvmfPkg: Reserve the Secrets and Cpuid page for the SEV-SNP guest
OvmfPkg: validate the data pages used in the SEC phase
MdePkg: Expand the SEV MSR to include the SNP definition
OvmfPkg/MemEncryptSevLib: add MemEncryptSevSnpEnabled()
MdePkg: Define the GHCB GPA structure
UefiCpuPkg/MpLib: add support to register GHCB GPA when SEV-SNP is
enabled
OvmfPkg: Add a library to support registering GHCB GPA
OvmfPkg: register GHCB gpa for the SEV-SNP guest
MdePkg: Add AsmPvalidate() support
OvmfPkg: Define the Page State Change VMGEXIT structures
OvmfPkg/ResetVector: Invalidate the GHCB page
OvmfPkg/MemEncryptSevLib: Add support to validate system RAM
OvmfPkg/SecMain: Validate the data/code pages used for the PEI phase
OvmfPkg/MemEncryptSevLib: Add support to validate RAM in PEI phase
OvmfPkg/PlatformPei: Validate the system RAM when SNP is active
OvmfPkg/MemEncryptSevLib: Add support to validate > 4GB memory in PEI
phase
OvmfPkg/VmgExitLib: Allow PMBASE register access in Dxe phase
OvmfPkg/MemEncryptSevLib: Validate the memory during set or clear enc
attribute
OvmfPkg/MemEncryptSevLib: Skip page state change for non RAM region
MdePkg/Include/Library/BaseLib.h | 37 +++
MdePkg/Include/Register/Amd/Fam17Msr.h | 31 ++-
MdePkg/Include/Register/Amd/Ghcb.h | 39 ++-
MdePkg/Library/BaseLib/BaseLib.inf | 1 +
MdePkg/Library/BaseLib/X64/Pvalidate.nasm | 43 +++
OvmfPkg/Include/Library/GhcbRegisterLib.h | 27 ++
OvmfPkg/Include/Library/MemEncryptSevLib.h | 30 +++
.../DxeMemEncryptSevLib.inf | 7 +
.../DxeMemEncryptSevLibInternal.c | 27 ++
.../Ia32/SnpPageStateChange.c | 17 ++
.../PeiMemEncryptSevLib.inf | 9 +
.../PeiMemEncryptSevLibInternal.c | 47 ++++
.../SecMemEncryptSevLib.inf | 4 +
.../SecMemEncryptSevLibInternal.c | 39 +++
.../BaseMemEncryptSevLib/SnpPageStateChange.h | 37 +++
.../X64/PeiDxeSnpSetPageState.c | 63 +++++
.../X64/PeiDxeVirtualMemory.c | 151 ++++++++++-
.../X64/PeiSnpSystemRamValidate.c | 129 +++++++++
.../X64/SecSnpSystemRamValidate.c | 23 ++
.../X64/SnpPageStateChangeInternal.c | 254 ++++++++++++++++++
.../X64/SnpPageStateTrack.c | 119 ++++++++
.../X64/SnpPageStateTrack.h | 36 +++
.../X64/SnpSetPageState.h | 27 ++
.../BaseMemEncryptSevLib/X64/VirtualMemory.h | 19 ++
.../Library/GhcbRegisterLib/GhcbRegisterLib.c | 97 +++++++
.../GhcbRegisterLib/GhcbRegisterLib.inf | 33 +++
OvmfPkg/Library/VmgExitLib/SecVmgExitLib.inf | 4 +
OvmfPkg/Library/VmgExitLib/VmgExitLib.inf | 7 +
OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 45 ++++
OvmfPkg/OvmfPkg.dec | 12 +
OvmfPkg/OvmfPkgX64.dsc | 1 +
OvmfPkg/OvmfPkgX64.fdf | 33 ++-
OvmfPkg/PlatformPei/AmdSev.c | 52 ++++
OvmfPkg/PlatformPei/PlatformPei.inf | 2 +
OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm | 24 ++
OvmfPkg/ResetVector/Ia32/PageTables64.asm | 106 ++++++++
OvmfPkg/ResetVector/ResetVector.inf | 5 +
OvmfPkg/ResetVector/ResetVector.nasmb | 4 +
OvmfPkg/Sec/SecMain.c | 102 +++++++
OvmfPkg/Sec/SecMain.inf | 2 +
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 | 6 +
47 files changed, 1790 insertions(+), 19 deletions(-)
create mode 100644 MdePkg/Library/BaseLib/X64/Pvalidate.nasm
create mode 100644 OvmfPkg/Include/Library/GhcbRegisterLib.h
create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/SnpPageStateChange.c
create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/SnpPageStateChange.h
create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeSnpSetPageState.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/BaseMemEncryptSevLib/X64/SnpPageStateTrack.c
create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpPageStateTrack.h
create mode 100644 OvmfPkg/Library/BaseMemEncryptSevLib/X64/SnpSetPageState.h
create mode 100644 OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.c
create mode 100644 OvmfPkg/Library/GhcbRegisterLib/GhcbRegisterLib.inf
--
2.17.1
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#73216): https://edk2.groups.io/g/devel/message/73216
Mute This Topic: https://groups.io/mt/81584576/1813853
Group Owner: devel+owner at edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [edk2-devel-archive at redhat.com]
-=-=-=-=-=-=-=-=-=-=-=-
More information about the edk2-devel-archive
mailing list