OvmfPkg/MemEncryptSevLib: Add an interface to retrieve the encryption mask

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>
This commit is contained in:
Tom Lendacky
2021-01-07 12:48:16 -06:00
committed by mergify[bot]
parent 3b32be7e71
commit b97dc4b92b
12 changed files with 400 additions and 104 deletions

View File

@@ -135,4 +135,16 @@ MemEncryptSevLocateInitialSmramSaveStateMapPages (
OUT UINTN *BaseAddress,
OUT UINTN *NumberOfPages
);
/**
Returns the SEV encryption mask.
@return The SEV pagetable encryption mask
**/
UINT64
EFIAPI
MemEncryptSevGetEncryptionMask (
VOID
);
#endif // _MEM_ENCRYPT_SEV_LIB_H_