mirror of https://github.com/acidanthera/audk.git
156 lines
3.8 KiB
C
156 lines
3.8 KiB
C
/** @file
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Secure Encrypted Virtualization (SEV) library helper function
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Copyright (c) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Library/BaseLib.h>
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#include <Library/DebugLib.h>
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#include <Library/MemEncryptSevLib.h>
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#include <Library/PcdLib.h>
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#include <Register/Amd/Cpuid.h>
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#include <Register/Amd/Msr.h>
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#include <Register/Cpuid.h>
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#include <Uefi/UefiBaseType.h>
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/**
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Reads and sets the status of SEV features.
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**/
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STATIC
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UINT32
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EFIAPI
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InternalMemEncryptSevStatus (
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VOID
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)
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{
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UINT32 RegEax;
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CPUID_MEMORY_ENCRYPTION_INFO_EAX Eax;
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BOOLEAN ReadSevMsr;
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SEC_SEV_ES_WORK_AREA *SevEsWorkArea;
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ReadSevMsr = FALSE;
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SevEsWorkArea = (SEC_SEV_ES_WORK_AREA *) FixedPcdGet32 (PcdSevEsWorkAreaBase);
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if (SevEsWorkArea != NULL && SevEsWorkArea->EncryptionMask != 0) {
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//
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// The MSR has been read before, so it is safe to read it again and avoid
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// having to validate the CPUID information.
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//
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ReadSevMsr = TRUE;
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} else {
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//
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// Check if memory encryption leaf exist
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//
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AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
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if (RegEax >= CPUID_MEMORY_ENCRYPTION_INFO) {
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//
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// CPUID Fn8000_001F[EAX] Bit 1 (Sev supported)
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//
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AsmCpuid (CPUID_MEMORY_ENCRYPTION_INFO, &Eax.Uint32, NULL, NULL, NULL);
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if (Eax.Bits.SevBit) {
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ReadSevMsr = TRUE;
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}
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}
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}
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return ReadSevMsr ? AsmReadMsr32 (MSR_SEV_STATUS) : 0;
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}
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/**
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Returns a boolean to indicate whether SEV-ES is enabled.
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@retval TRUE SEV-ES is enabled
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@retval FALSE SEV-ES is not enabled
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**/
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BOOLEAN
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EFIAPI
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MemEncryptSevEsIsEnabled (
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VOID
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)
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{
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MSR_SEV_STATUS_REGISTER Msr;
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Msr.Uint32 = InternalMemEncryptSevStatus ();
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return Msr.Bits.SevEsBit ? TRUE : FALSE;
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}
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/**
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Returns a boolean to indicate whether SEV is enabled.
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@retval TRUE SEV is enabled
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@retval FALSE SEV is not enabled
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**/
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BOOLEAN
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EFIAPI
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MemEncryptSevIsEnabled (
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VOID
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)
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{
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MSR_SEV_STATUS_REGISTER Msr;
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Msr.Uint32 = InternalMemEncryptSevStatus ();
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return Msr.Bits.SevBit ? TRUE : FALSE;
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}
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/**
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Returns the SEV encryption mask.
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@return The SEV pagtable encryption mask
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**/
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UINT64
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EFIAPI
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MemEncryptSevGetEncryptionMask (
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VOID
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)
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{
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CPUID_MEMORY_ENCRYPTION_INFO_EBX Ebx;
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SEC_SEV_ES_WORK_AREA *SevEsWorkArea;
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UINT64 EncryptionMask;
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SevEsWorkArea = (SEC_SEV_ES_WORK_AREA *) FixedPcdGet32 (PcdSevEsWorkAreaBase);
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if (SevEsWorkArea != NULL) {
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EncryptionMask = SevEsWorkArea->EncryptionMask;
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} else {
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//
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// CPUID Fn8000_001F[EBX] Bit 0:5 (memory encryption bit position)
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//
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AsmCpuid (CPUID_MEMORY_ENCRYPTION_INFO, NULL, &Ebx.Uint32, NULL, NULL);
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EncryptionMask = LShiftU64 (1, Ebx.Bits.PtePosBits);
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}
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return EncryptionMask;
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}
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/**
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Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
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Save State Map.
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@param[out] BaseAddress The base address of the lowest-address page that
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covers the initial SMRAM Save State Map.
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@param[out] NumberOfPages The number of pages in the page range that covers
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the initial SMRAM Save State Map.
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@retval RETURN_SUCCESS BaseAddress and NumberOfPages have been set on
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output.
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@retval RETURN_UNSUPPORTED SMM is unavailable.
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**/
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RETURN_STATUS
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EFIAPI
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MemEncryptSevLocateInitialSmramSaveStateMapPages (
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OUT UINTN *BaseAddress,
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OUT UINTN *NumberOfPages
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)
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{
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return RETURN_UNSUPPORTED;
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}
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