EFI_STATUS
EFIAPI
AmdSevDxeEntryPoint (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
EFI_GCD_MEMORY_SPACE_DESCRIPTOR *AllDescMap;
UINTN NumEntries;
UINTN Index;
//
// Do nothing when SEV is not enabled
//
if (!MemEncryptSevIsEnabled ()) {
return EFI_UNSUPPORTED;
}
//
// Iterate through the GCD map and clear the C-bit from MMIO and NonExistent
// memory space. The NonExistent memory space will be used for mapping the MMIO
// space added later (eg PciRootBridge). By clearing both known MMIO and
// NonExistent memory space can gurantee that current and furture MMIO adds
// will have C-bit cleared.
//
Status = gDS->GetMemorySpaceMap (&NumEntries, &AllDescMap);
if (!EFI_ERROR (Status)) {
for (Index = 0; Index < NumEntries; Index++) {
CONST EFI_GCD_MEMORY_SPACE_DESCRIPTOR *Desc;
Desc = &AllDescMap[Index];
if (Desc->GcdMemoryType == EfiGcdMemoryTypeMemoryMappedIo ||
Desc->GcdMemoryType == EfiGcdMemoryTypeNonExistent) {
Status = MemEncryptSevClearPageEncMask (0,
Desc->BaseAddress,
EFI_SIZE_TO_PAGES(Desc->Length),
FALSE);
ASSERT_EFI_ERROR (Status);
}
}
FreePool (AllDescMap);
}
return EFI_SUCCESS;
}
/**
Provides the controller-specific addresses required to access system memory
from a DMA bus master. On SEV guest, the DMA operations must be performed on
shared buffer hence we allocate a bounce buffer to map the HostAddress to a
DeviceAddress. The Encryption attribute is removed from the DeviceAddress
buffer.
@param This The protocol instance pointer.
@param Operation Indicates if the bus master is going to read or
write to system memory.
@param HostAddress The system memory address to map to the PCI
controller.
@param NumberOfBytes On input the number of bytes to map. On output
the number of bytes that were mapped.
@param DeviceAddress The resulting map address for the bus master
PCI controller to use to access the hosts
HostAddress.
@param Mapping A resulting value to pass to Unmap().
@retval EFI_SUCCESS The range was mapped for the returned
NumberOfBytes.
@retval EFI_UNSUPPORTED The HostAddress cannot be mapped as a common
buffer.
@retval EFI_INVALID_PARAMETER One or more parameters are invalid.
@retval EFI_OUT_OF_RESOURCES The request could not be completed due to a
lack of resources.
@retval EFI_DEVICE_ERROR The system hardware could not map the requested
address.
**/
EFI_STATUS
EFIAPI
IoMmuMap (
IN EDKII_IOMMU_PROTOCOL *This,
IN EDKII_IOMMU_OPERATION Operation,
IN VOID *HostAddress,
IN OUT UINTN *NumberOfBytes,
OUT EFI_PHYSICAL_ADDRESS *DeviceAddress,
OUT VOID **Mapping
)
{
EFI_STATUS Status;
LIST_ENTRY *RecycledMapInfo;
MAP_INFO *MapInfo;
EFI_ALLOCATE_TYPE AllocateType;
COMMON_BUFFER_HEADER *CommonBufferHeader;
VOID *DecryptionSource;
if (HostAddress == NULL || NumberOfBytes == NULL || DeviceAddress == NULL ||
Mapping == NULL) {
return EFI_INVALID_PARAMETER;
}
//
// Allocate a MAP_INFO structure to remember the mapping when Unmap() is
// called later.
//
RecycledMapInfo = GetFirstNode (&mRecycledMapInfos);
if (RecycledMapInfo == &mRecycledMapInfos) {
//
// No recycled MAP_INFO structure, allocate a new one.
//
MapInfo = AllocatePool (sizeof (MAP_INFO));
if (MapInfo == NULL) {
Status = EFI_OUT_OF_RESOURCES;
goto Failed;
}
} else {
MapInfo = CR (RecycledMapInfo, MAP_INFO, Link, MAP_INFO_SIG);
RemoveEntryList (RecycledMapInfo);
}
//
// Initialize the MAP_INFO structure, except the PlainTextAddress field
//
ZeroMem (&MapInfo->Link, sizeof MapInfo->Link);
MapInfo->Signature = MAP_INFO_SIG;
MapInfo->Operation = Operation;
MapInfo->NumberOfBytes = *NumberOfBytes;
MapInfo->NumberOfPages = EFI_SIZE_TO_PAGES (MapInfo->NumberOfBytes);
MapInfo->CryptedAddress = (UINTN)HostAddress;
//
// In the switch statement below, we point "MapInfo->PlainTextAddress" to the
// plaintext buffer, according to Operation. We also set "DecryptionSource".
//
MapInfo->PlainTextAddress = MAX_ADDRESS;
AllocateType = AllocateAnyPages;
DecryptionSource = (VOID *)(UINTN)MapInfo->CryptedAddress;
switch (Operation) {
//
// For BusMasterRead[64] and BusMasterWrite[64] operations, a bounce buffer
// is necessary regardless of whether the original (crypted) buffer crosses
// the 4GB limit or not -- we have to allocate a separate plaintext buffer.
// The only variable is whether the plaintext buffer should be under 4GB.
//
case EdkiiIoMmuOperationBusMasterRead:
case EdkiiIoMmuOperationBusMasterWrite:
MapInfo->PlainTextAddress = BASE_4GB - 1;
AllocateType = AllocateMaxAddress;
//
// fall through
//
case EdkiiIoMmuOperationBusMasterRead64:
case EdkiiIoMmuOperationBusMasterWrite64:
//
// Allocate the implicit plaintext bounce buffer.
//
Status = gBS->AllocatePages (
AllocateType,
EfiBootServicesData,
MapInfo->NumberOfPages,
&MapInfo->PlainTextAddress
);
if (EFI_ERROR (Status)) {
goto FreeMapInfo;
}
break;
//
// For BusMasterCommonBuffer[64] operations, a to-be-plaintext buffer and a
// stash buffer (for in-place decryption) have been allocated already, with
// AllocateBuffer(). We only check whether the address of the to-be-plaintext
// buffer is low enough for the requested operation.
//
case EdkiiIoMmuOperationBusMasterCommonBuffer:
if ((MapInfo->CryptedAddress > BASE_4GB) ||
(EFI_PAGES_TO_SIZE (MapInfo->NumberOfPages) >
BASE_4GB - MapInfo->CryptedAddress)) {
//
// CommonBuffer operations cannot be remapped. If the common buffer is
// above 4GB, then it is not possible to generate a mapping, so return an
// error.
//
Status = EFI_UNSUPPORTED;
goto FreeMapInfo;
}
//
// fall through
//
case EdkiiIoMmuOperationBusMasterCommonBuffer64:
//
// The buffer at MapInfo->CryptedAddress comes from AllocateBuffer().
//
MapInfo->PlainTextAddress = MapInfo->CryptedAddress;
//
// Stash the crypted data.
//
CommonBufferHeader = (COMMON_BUFFER_HEADER *)(
(UINTN)MapInfo->CryptedAddress - EFI_PAGE_SIZE
);
ASSERT (CommonBufferHeader->Signature == COMMON_BUFFER_SIG);
CopyMem (
CommonBufferHeader->StashBuffer,
(VOID *)(UINTN)MapInfo->CryptedAddress,
MapInfo->NumberOfBytes
);
//
// Point "DecryptionSource" to the stash buffer so that we decrypt
// it to the original location, after the switch statement.
//
DecryptionSource = CommonBufferHeader->StashBuffer;
break;
default:
//
// Operation is invalid
//
Status = EFI_INVALID_PARAMETER;
goto FreeMapInfo;
}
//
// Clear the memory encryption mask on the plaintext buffer.
//
Status = MemEncryptSevClearPageEncMask (
0,
MapInfo->PlainTextAddress,
MapInfo->NumberOfPages,
TRUE
);
ASSERT_EFI_ERROR (Status);
if (EFI_ERROR (Status)) {
CpuDeadLoop ();
}
//
// If this is a read operation from the Bus Master's point of view,
// then copy the contents of the real buffer into the mapped buffer
// so the Bus Master can read the contents of the real buffer.
//
// For BusMasterCommonBuffer[64] operations, the CopyMem() below will decrypt
// the original data (from the stash buffer) back to the original location.
//
if (Operation == EdkiiIoMmuOperationBusMasterRead ||
Operation == EdkiiIoMmuOperationBusMasterRead64 ||
Operation == EdkiiIoMmuOperationBusMasterCommonBuffer ||
Operation == EdkiiIoMmuOperationBusMasterCommonBuffer64) {
CopyMem (
(VOID *) (UINTN) MapInfo->PlainTextAddress,
DecryptionSource,
MapInfo->NumberOfBytes
);
}
//
// Populate output parameters.
//
*DeviceAddress = MapInfo->PlainTextAddress;
*Mapping = MapInfo;
DEBUG ((
DEBUG_VERBOSE,
"%a PlainText 0x%Lx Crypted 0x%Lx Pages 0x%Lx Bytes 0x%Lx\n",
__FUNCTION__,
MapInfo->PlainTextAddress,
MapInfo->CryptedAddress,
(UINT64)MapInfo->NumberOfPages,
(UINT64)MapInfo->NumberOfBytes
));
return EFI_SUCCESS;
FreeMapInfo:
FreePool (MapInfo);
Failed:
*NumberOfBytes = 0;
return Status;
}
