BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3108
To ensure that we always use a validated encryption mask for an SEV-ES
guest, create a new interface in the MemEncryptSevLib library to return
the encryption mask. This can be used in place of the multiple locations
where CPUID is used to retrieve the value (which would require validation
again) and allows the validated mask to be returned.
The PEI phase will use the value from the SEV-ES work area. Since the
SEV-ES work area isn't valid in the DXE phase, the DXE phase will use the
PcdPteMemoryEncryptionAddressOrMask PCD which is set during PEI.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Rebecca Cran <rebecca@bsdio.com>
Cc: Peter Grehan <grehan@freebsd.org>
Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Julien Grall <julien@xen.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <e12044dc01b21e6fc2e9535760ddf3a38a142a71.1610045305.git.thomas.lendacky@amd.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3108
The early assembler code performs validation for some of the SEV-related
information, specifically the encryption bit position. To avoid having to
re-validate the encryption bit position as the system proceeds through its
boot phases, save the validated encryption bit position in the SEV-ES work
area for use by later phases.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <2609724859cf21f0c6d45bc323e94465dca4e621.1610045305.git.thomas.lendacky@amd.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3108
To help mitigate against ROP attacks, add some checks to validate the
encryption bit position that is reported by the hypervisor.
The first check is to ensure that the hypervisor reports a bit position
above bit 31. After extracting the encryption bit position from the CPUID
information, the code checks that the value is above 31. If the value is
not above 31, then the bit position is not valid, so the code enters a
HLT loop.
The second check is specific to SEV-ES guests and is a two step process.
The first step will obtain random data using RDRAND and store that data to
memory before paging is enabled. When paging is not enabled, all writes to
memory are encrypted. The random data is maintained in registers, which
are protected. The second step is that, after enabling paging, the random
data in memory is compared to the register contents. If they don't match,
then the reported bit position is not valid, so the code enters a HLT
loop.
The third check is after switching to 64-bit long mode. Use the fact that
instruction fetches are automatically decrypted, while a memory fetch is
decrypted only if the encryption bit is set in the page table. By
comparing the bytes of an instruction fetch against a memory read of that
same instruction, the encryption bit position can be validated. If the
compare is not equal, then SEV/SEV-ES is active but the reported bit
position is not valid, so the code enters a HLT loop.
To keep the changes local to the OvmfPkg, an OvmfPkg version of the
Flat32ToFlat64.asm file has been created based on the UefiCpuPkg file
UefiCpuPkg/ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <cb9c5ab23ab02096cd964ed64115046cc706ce67.1610045305.git.thomas.lendacky@amd.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3108
In order to allow for the SEV-ES workarea to be used for other purposes
and by other files, move the definition into the BaseMemEncryptSevLib
header file, MemEncryptSevLib.h.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <07d66f3384bd54da97d540e89b9f3473a6d17231.1610045305.git.thomas.lendacky@amd.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
Create a function that can be used to determine if the VM is running
as an SEV-ES guest.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
In the next three patches, we're going to modify three modules under
OvmfPkg. When OVMF is built with -D SMM_REQUIRE and runs in an SEV guest,
each affected module will have to know the page range that covers the
initial (pre-SMBASE relocation) SMRAM save state map. Add a helper
function to MemEncryptSevLib that calculates the "base address" and
"number of pages" constants for this page range.
(In a RELEASE build -- i.e., with assertions disabled and optimization
enabled --, the helper function can be compiled to store two constants
determined at compile time.)
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
The declaration and the definition(s) of the function should have
identical leading comments and/or identical parameter lists. Replace any
leftover "clear" references to the C-bit with "set" references. Also
remove any excess space in the comment block, and unindent the trailing
"**/" if necessary. Correct several parameter references.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
The declaration and the definition(s) of the function should have
identical leading comments and/or identical parameter lists. Also remove
any excess space in the comment block, and unindent the trailing "**/" if
necessary. Correct several parameter references.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
The declaration and the definition(s) of the function should have
identical leading comments and/or identical parameter lists. Also remove
any excess space in the comment block, and unindent the trailing "**/" if
necessary.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
There are many overlong lines; it's hard to work with the library like
this. Rewrap all files to 79 columns.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Add Secure Encrypted Virtualization (SEV) helper library.
The library provides the routines to:
- set or clear memory encryption bit for a given memory region.
- query whether SEV is enabled.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Jordan Justen <jordan.l.justen@intel.com>
Tom Lendacky
Michael D Kinney
Laszlo Ersek
Brijesh Singh