Files
system76-edk2/OvmfPkg/XenPlatformPei/AmdSev.c
Tom Lendacky 45388d046c OvmfPkg: Obtain SEV encryption mask with the new MemEncryptSevLib API
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. The new
MemEncryptSevGetEncryptionMask() interface provides access to this
validated value.

To ensure that we always use a validated encryption mask for an SEV-ES
guest, update all locations that use CPUID to calculate the encryption
mask to use the new interface.

Also, clean up some call areas where extra masking was being performed
and where a function call was being used instead of the local variable
that was just set using the function.

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: Brijesh Singh <brijesh.singh@amd.com>
Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Julien Grall <julien@xen.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <9de678c0d66443c6cc33e004a4cac0a0223c2ebc.1610045305.git.thomas.lendacky@amd.com>
2021-01-07 19:34:39 +00:00

57 lines
1.3 KiB
C

/**@file
Initialize Secure Encrypted Virtualization (SEV) support
Copyright (c) 2017 - 2020, Advanced Micro Devices. All rights reserved.<BR>
Copyright (c) 2019, Citrix Systems, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
//
// The package level header files this module uses
//
#include <Library/DebugLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Library/PcdLib.h>
#include <PiPei.h>
#include "Platform.h"
/**
Function checks if SEV support is available, if present then it sets
the dynamic PcdPteMemoryEncryptionAddressOrMask with memory encryption mask.
**/
VOID
AmdSevInitialize (
VOID
)
{
UINT64 EncryptionMask;
RETURN_STATUS PcdStatus;
//
// Check if SEV is enabled
//
if (!MemEncryptSevIsEnabled ()) {
return;
}
//
// Set Memory Encryption Mask PCD
//
EncryptionMask = MemEncryptSevGetEncryptionMask ();
PcdStatus = PcdSet64S (PcdPteMemoryEncryptionAddressOrMask, EncryptionMask);
ASSERT_RETURN_ERROR (PcdStatus);
DEBUG ((DEBUG_INFO, "SEV is enabled (mask 0x%lx)\n", EncryptionMask));
//
// Set Pcd to Deny the execution of option ROM when security
// violation.
//
PcdStatus = PcdSet32S (PcdOptionRomImageVerificationPolicy, 0x4);
ASSERT_RETURN_ERROR (PcdStatus);
}