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/** @file
Secure Encrypted Virtualization (SEV) library helper function
Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Library/PcdLib.h>
#include <Register/Amd/Cpuid.h>
#include <Register/Amd/Msr.h>
#include <Register/Cpuid.h>
#include <Uefi/UefiBaseType.h>
#include <ConfidentialComputingGuestAttr.h>
STATIC UINT64 mCurrentAttr = 0;
STATIC BOOLEAN mCurrentAttrRead = FALSE;
STATIC UINT64 mSevEncryptionMask = 0;
STATIC BOOLEAN mSevEncryptionMaskSaved = FALSE;
/**
The function check if the specified Attr is set.
@param[in] CurrentAttr The current attribute.
@param[in] Attr The attribute to check.
@retval TRUE The specified Attr is set.
@retval FALSE The specified Attr is not set.
**/
STATIC
BOOLEAN
AmdMemEncryptionAttrCheck (
IN UINT64 CurrentAttr,
IN CONFIDENTIAL_COMPUTING_GUEST_ATTR Attr
)
{
switch (Attr) {
case CCAttrAmdSev:
//
// SEV is automatically enabled if SEV-ES or SEV-SNP is active.
//
return CurrentAttr >= CCAttrAmdSev;
case CCAttrAmdSevEs:
//
// SEV-ES is automatically enabled if SEV-SNP is active.
//
return CurrentAttr >= CCAttrAmdSevEs;
case CCAttrAmdSevSnp:
return CurrentAttr == CCAttrAmdSevSnp;
default:
return FALSE;
}
}
/**
Check if the specified confidential computing attribute is active.
@param[in] Attr The attribute to check.
@retval TRUE The specified Attr is active.
@retval FALSE The specified Attr is not active.
**/
STATIC
BOOLEAN
EFIAPI
ConfidentialComputingGuestHas (
IN CONFIDENTIAL_COMPUTING_GUEST_ATTR Attr
)
{
//
// Get the current CC attribute.
//
// We avoid reading the PCD on every check because this routine could be indirectly
// called during the virtual pointer conversion. And its not safe to access the
// PCDs during the virtual pointer conversion.
//
if (!mCurrentAttrRead) {
mCurrentAttr = PcdGet64 (PcdConfidentialComputingGuestAttr);
mCurrentAttrRead = TRUE;
}
//
// If attr is for the AMD group then call AMD specific checks.
//
if (((RShiftU64 (mCurrentAttr, 8)) & 0xff) == 1) {
return AmdMemEncryptionAttrCheck (mCurrentAttr, Attr);
}
return (mCurrentAttr == Attr);
}
/**
Returns a boolean to indicate whether SEV-SNP is enabled.
@retval TRUE SEV-SNP is enabled
@retval FALSE SEV-SNP is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevSnpIsEnabled (
VOID
)
{
return ConfidentialComputingGuestHas (CCAttrAmdSevSnp);
}
/**
Returns a boolean to indicate whether SEV-ES is enabled.
@retval TRUE SEV-ES is enabled
@retval FALSE SEV-ES is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevEsIsEnabled (
VOID
)
{
return ConfidentialComputingGuestHas (CCAttrAmdSevEs);
}
/**
Returns a boolean to indicate whether SEV is enabled.
@retval TRUE SEV is enabled
@retval FALSE SEV is not enabled
**/
BOOLEAN
EFIAPI
MemEncryptSevIsEnabled (
VOID
)
{
return ConfidentialComputingGuestHas (CCAttrAmdSev);
}
/**
Returns the SEV encryption mask.
@return The SEV pagtable encryption mask
**/
UINT64
EFIAPI
MemEncryptSevGetEncryptionMask (
VOID
)
{
if (!mSevEncryptionMaskSaved) {
mSevEncryptionMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask);
mSevEncryptionMaskSaved = TRUE;
}
return mSevEncryptionMask;
}
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