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audk/OvmfPkg/IoMmuDxe/CcIoMmu.c

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/** @file
The protocol provides support to allocate, free, map and umap a DMA buffer
for bus master (e.g PciHostBridge). When SEV or TDX is enabled, the DMA
operations must be performed on unencrypted buffer hence we use a bounce
buffer to map the guest buffer into an unencrypted DMA buffer.
Copyright (c) 2017, AMD Inc. All rights reserved.<BR>
Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/PcdLib.h>
#include <ConfidentialComputingGuestAttr.h>
#include "CcIoMmu.h"
#include "IoMmuInternal.h"
//
// List of the MAP_INFO structures that have been set up by IoMmuMap() and not
// yet torn down by IoMmuUnmap(). The list represents the full set of mappings
// currently in effect.
//
STATIC LIST_ENTRY mMapInfos = INITIALIZE_LIST_HEAD_VARIABLE (mMapInfos);
//
// Indicate if the feature of reserved memory is supported in DMA operation.
//
BOOLEAN mReservedSharedMemSupported = FALSE;
//
// ASCII names for EDKII_IOMMU_OPERATION constants, for debug logging.
//
STATIC CONST CHAR8 *CONST
mBusMasterOperationName[EdkiiIoMmuOperationMaximum] = {
"Read",
"Write",
"CommonBuffer",
"Read64",
"Write64",
"CommonBuffer64"
};
/**
Provides the controller-specific addresses required to access system memory
from a DMA bus master. On SEV/TDX 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;
MAP_INFO *MapInfo;
EFI_ALLOCATE_TYPE AllocateType;
COMMON_BUFFER_HEADER *CommonBufferHeader;
VOID *DecryptionSource;
DEBUG ((
DEBUG_VERBOSE,
"%a: Operation=%a Host=0x%p Bytes=0x%Lx\n",
__FUNCTION__,
((Operation >= 0 &&
Operation < ARRAY_SIZE (mBusMasterOperationName)) ?
mBusMasterOperationName[Operation] :
"Invalid"),
HostAddress,
(UINT64)((NumberOfBytes == NULL) ? 0 : *NumberOfBytes)
));
if ((HostAddress == NULL) || (NumberOfBytes == NULL) || (DeviceAddress == NULL) ||
(Mapping == NULL))
{
return EFI_INVALID_PARAMETER;
}
Status = EFI_SUCCESS;
//
// Allocate a MAP_INFO structure to remember the mapping when Unmap() is
// called later.
//
MapInfo = AllocatePool (sizeof (MAP_INFO));
if (MapInfo == NULL) {
Status = EFI_OUT_OF_RESOURCES;
goto Failed;
}
//
// 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;
MapInfo->ReservedMemBitmap = 0;
//
// 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 = IoMmuAllocateBounceBuffer (
AllocateType,
EfiBootServicesData,
MapInfo
);
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;
MapInfo->ReservedMemBitmap = CommonBufferHeader->ReservedMemBitmap;
break;
default:
//
// Operation is invalid
//
Status = EFI_INVALID_PARAMETER;
goto FreeMapInfo;
}
if (MapInfo->ReservedMemBitmap == 0) {
//
// If MapInfo->ReservedMemBitmap is 0, it means the bounce buffer is not allocated
// from the pre-allocated shared memory, so it must be converted to shared memory here.
//
if (CC_GUEST_IS_SEV (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
//
// Clear the memory encryption mask on the plaintext buffer.
//
Status = MemEncryptSevClearPageEncMask (
0,
MapInfo->PlainTextAddress,
MapInfo->NumberOfPages
);
} else if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
//
// Set the memory shared bit.
//
Status = MemEncryptTdxSetPageSharedBit (
0,
MapInfo->PlainTextAddress,
MapInfo->NumberOfPages
);
} else {
ASSERT (FALSE);
}
}
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
);
}
//
// Track all MAP_INFO structures.
//
InsertHeadList (&mMapInfos, &MapInfo->Link);
//
// Populate output parameters.
//
*DeviceAddress = MapInfo->PlainTextAddress;
*Mapping = MapInfo;
DEBUG ((
DEBUG_VERBOSE,
"%a: Mapping=0x%p Device(PlainText)=0x%Lx Crypted=0x%Lx Pages=0x%Lx, ReservedMemBitmap=0x%Lx\n",
__FUNCTION__,
MapInfo,
MapInfo->PlainTextAddress,
MapInfo->CryptedAddress,
(UINT64)MapInfo->NumberOfPages,
MapInfo->ReservedMemBitmap
));
return EFI_SUCCESS;
FreeMapInfo:
FreePool (MapInfo);
Failed:
*NumberOfBytes = 0;
return Status;
}
/**
Completes the Map() operation and releases any corresponding resources.
This is an internal worker function that only extends the Map() API with
the MemoryMapLocked parameter.
@param This The protocol instance pointer.
@param Mapping The mapping value returned from Map().
@param MemoryMapLocked The function is executing on the stack of
gBS->ExitBootServices(); changes to the UEFI
memory map are forbidden.
@retval EFI_SUCCESS The range was unmapped.
@retval EFI_INVALID_PARAMETER Mapping is not a value that was returned by
Map().
@retval EFI_DEVICE_ERROR The data was not committed to the target system
memory.
**/
STATIC
EFI_STATUS
EFIAPI
IoMmuUnmapWorker (
IN EDKII_IOMMU_PROTOCOL *This,
IN VOID *Mapping,
IN BOOLEAN MemoryMapLocked
)
{
MAP_INFO *MapInfo;
EFI_STATUS Status;
COMMON_BUFFER_HEADER *CommonBufferHeader;
VOID *EncryptionTarget;
DEBUG ((
DEBUG_VERBOSE,
"%a: Mapping=0x%p MemoryMapLocked=%d\n",
__FUNCTION__,
Mapping,
MemoryMapLocked
));
if (Mapping == NULL) {
return EFI_INVALID_PARAMETER;
}
MapInfo = (MAP_INFO *)Mapping;
Status = EFI_SUCCESS;
//
// set CommonBufferHeader to suppress incorrect compiler/analyzer warnings
//
CommonBufferHeader = NULL;
//
// For BusMasterWrite[64] operations and BusMasterCommonBuffer[64] operations
// we have to encrypt the results, ultimately to the original place (i.e.,
// "MapInfo->CryptedAddress").
//
// For BusMasterCommonBuffer[64] operations however, this encryption has to
// land in-place, so divert the encryption to the stash buffer first.
//
EncryptionTarget = (VOID *)(UINTN)MapInfo->CryptedAddress;
switch (MapInfo->Operation) {
case EdkiiIoMmuOperationBusMasterCommonBuffer:
case EdkiiIoMmuOperationBusMasterCommonBuffer64:
ASSERT (MapInfo->PlainTextAddress == MapInfo->CryptedAddress);
CommonBufferHeader = (COMMON_BUFFER_HEADER *)(
(UINTN)MapInfo->PlainTextAddress - EFI_PAGE_SIZE
);
ASSERT (CommonBufferHeader->Signature == COMMON_BUFFER_SIG);
EncryptionTarget = CommonBufferHeader->StashBuffer;
//
// fall through
//
case EdkiiIoMmuOperationBusMasterWrite:
case EdkiiIoMmuOperationBusMasterWrite64:
CopyMem (
EncryptionTarget,
(VOID *)(UINTN)MapInfo->PlainTextAddress,
MapInfo->NumberOfBytes
);
break;
default:
//
// nothing to encrypt after BusMasterRead[64] operations
//
break;
}
if (MapInfo->ReservedMemBitmap == 0) {
if (CC_GUEST_IS_SEV (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
//
// Restore the memory encryption mask on the area we used to hold the
// plaintext.
//
Status = MemEncryptSevSetPageEncMask (
0,
MapInfo->PlainTextAddress,
MapInfo->NumberOfPages
);
} else if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
//
// Restore the memory shared bit mask on the area we used to hold the
// plaintext.
//
Status = MemEncryptTdxClearPageSharedBit (
0,
MapInfo->PlainTextAddress,
MapInfo->NumberOfPages
);
} else {
ASSERT (FALSE);
}
}
ASSERT_EFI_ERROR (Status);
if (EFI_ERROR (Status)) {
CpuDeadLoop ();
}
//
// For BusMasterCommonBuffer[64] operations, copy the stashed data to the
// original (now encrypted) location.
//
// For all other operations, fill the late bounce buffer (which existed as
// plaintext at some point) with zeros, and then release it (unless the UEFI
// memory map is locked).
//
if ((MapInfo->Operation == EdkiiIoMmuOperationBusMasterCommonBuffer) ||
(MapInfo->Operation == EdkiiIoMmuOperationBusMasterCommonBuffer64))
{
CopyMem (
(VOID *)(UINTN)MapInfo->CryptedAddress,
CommonBufferHeader->StashBuffer,
MapInfo->NumberOfBytes
);
} else {
ZeroMem (
(VOID *)(UINTN)MapInfo->PlainTextAddress,
EFI_PAGES_TO_SIZE (MapInfo->NumberOfPages)
);
if (!MemoryMapLocked) {
IoMmuFreeBounceBuffer (MapInfo);
}
}
//
// Forget the MAP_INFO structure, then free it (unless the UEFI memory map is
// locked).
//
RemoveEntryList (&MapInfo->Link);
if (!MemoryMapLocked) {
FreePool (MapInfo);
}
return EFI_SUCCESS;
}
/**
Completes the Map() operation and releases any corresponding resources.
@param This The protocol instance pointer.
@param Mapping The mapping value returned from Map().
@retval EFI_SUCCESS The range was unmapped.
@retval EFI_INVALID_PARAMETER Mapping is not a value that was returned by
Map().
@retval EFI_DEVICE_ERROR The data was not committed to the target system
memory.
**/
EFI_STATUS
EFIAPI
IoMmuUnmap (
IN EDKII_IOMMU_PROTOCOL *This,
IN VOID *Mapping
)
{
return IoMmuUnmapWorker (
This,
Mapping,
FALSE // MemoryMapLocked
);
}
/**
Allocates pages that are suitable for an OperationBusMasterCommonBuffer or
OperationBusMasterCommonBuffer64 mapping.
@param This The protocol instance pointer.
@param Type This parameter is not used and must be ignored.
@param MemoryType The type of memory to allocate,
EfiBootServicesData or EfiRuntimeServicesData.
@param Pages The number of pages to allocate.
@param HostAddress A pointer to store the base system memory
address of the allocated range.
@param Attributes The requested bit mask of attributes for the
allocated range.
@retval EFI_SUCCESS The requested memory pages were allocated.
@retval EFI_UNSUPPORTED Attributes is unsupported. The only legal
attribute bits are MEMORY_WRITE_COMBINE and
MEMORY_CACHED.
@retval EFI_INVALID_PARAMETER One or more parameters are invalid.
@retval EFI_OUT_OF_RESOURCES The memory pages could not be allocated.
**/
EFI_STATUS
EFIAPI
IoMmuAllocateBuffer (
IN EDKII_IOMMU_PROTOCOL *This,
IN EFI_ALLOCATE_TYPE Type,
IN EFI_MEMORY_TYPE MemoryType,
IN UINTN Pages,
IN OUT VOID **HostAddress,
IN UINT64 Attributes
)
{
EFI_STATUS Status;
EFI_PHYSICAL_ADDRESS PhysicalAddress;
VOID *StashBuffer;
UINTN CommonBufferPages;
COMMON_BUFFER_HEADER *CommonBufferHeader;
UINT32 ReservedMemBitmap;
DEBUG ((
DEBUG_VERBOSE,
"%a: MemoryType=%u Pages=0x%Lx Attributes=0x%Lx\n",
__FUNCTION__,
(UINT32)MemoryType,
(UINT64)Pages,
Attributes
));
//
// Validate Attributes
//
if ((Attributes & EDKII_IOMMU_ATTRIBUTE_INVALID_FOR_ALLOCATE_BUFFER) != 0) {
return EFI_UNSUPPORTED;
}
//
// Check for invalid inputs
//
if (HostAddress == NULL) {
return EFI_INVALID_PARAMETER;
}
//
// The only valid memory types are EfiBootServicesData and
// EfiRuntimeServicesData
//
if ((MemoryType != EfiBootServicesData) &&
(MemoryType != EfiRuntimeServicesData))
{
return EFI_INVALID_PARAMETER;
}
//
// We'll need a header page for the COMMON_BUFFER_HEADER structure.
//
if (Pages > MAX_UINTN - 1) {
return EFI_OUT_OF_RESOURCES;
}
CommonBufferPages = Pages + 1;
//
// Allocate the stash in EfiBootServicesData type memory.
//
// Map() will temporarily save encrypted data in the stash for
// BusMasterCommonBuffer[64] operations, so the data can be decrypted to the
// original location.
//
// Unmap() will temporarily save plaintext data in the stash for
// BusMasterCommonBuffer[64] operations, so the data can be encrypted to the
// original location.
//
// StashBuffer always resides in encrypted memory.
//
StashBuffer = AllocatePages (Pages);
if (StashBuffer == NULL) {
return EFI_OUT_OF_RESOURCES;
}
PhysicalAddress = (UINTN)-1;
if ((Attributes & EDKII_IOMMU_ATTRIBUTE_DUAL_ADDRESS_CYCLE) == 0) {
//
// Limit allocations to memory below 4GB
//
PhysicalAddress = SIZE_4GB - 1;
}
Status = IoMmuAllocateCommonBuffer (
MemoryType,
CommonBufferPages,
&PhysicalAddress,
&ReservedMemBitmap
);
if (EFI_ERROR (Status)) {
goto FreeStashBuffer;
}
CommonBufferHeader = (VOID *)(UINTN)PhysicalAddress;
PhysicalAddress += EFI_PAGE_SIZE;
CommonBufferHeader->Signature = COMMON_BUFFER_SIG;
CommonBufferHeader->StashBuffer = StashBuffer;
CommonBufferHeader->ReservedMemBitmap = ReservedMemBitmap;
*HostAddress = (VOID *)(UINTN)PhysicalAddress;
DEBUG ((
DEBUG_VERBOSE,
"%a: Host=0x%Lx Stash=0x%p\n",
__FUNCTION__,
PhysicalAddress,
StashBuffer
));
return EFI_SUCCESS;
FreeStashBuffer:
FreePages (StashBuffer, Pages);
return Status;
}
/**
Frees memory that was allocated with AllocateBuffer().
@param This The protocol instance pointer.
@param Pages The number of pages to free.
@param HostAddress The base system memory address of the allocated
range.
@retval EFI_SUCCESS The requested memory pages were freed.
@retval EFI_INVALID_PARAMETER The memory range specified by HostAddress and
Pages was not allocated with AllocateBuffer().
**/
EFI_STATUS
EFIAPI
IoMmuFreeBuffer (
IN EDKII_IOMMU_PROTOCOL *This,
IN UINTN Pages,
IN VOID *HostAddress
)
{
UINTN CommonBufferPages;
COMMON_BUFFER_HEADER *CommonBufferHeader;
DEBUG ((
DEBUG_VERBOSE,
"%a: Host=0x%p Pages=0x%Lx\n",
__FUNCTION__,
HostAddress,
(UINT64)Pages
));
CommonBufferPages = Pages + 1;
CommonBufferHeader = (COMMON_BUFFER_HEADER *)(
(UINTN)HostAddress - EFI_PAGE_SIZE
);
//
// Check the signature.
//
ASSERT (CommonBufferHeader->Signature == COMMON_BUFFER_SIG);
if (CommonBufferHeader->Signature != COMMON_BUFFER_SIG) {
return EFI_INVALID_PARAMETER;
}
//
// Free the stash buffer. This buffer was always encrypted, so no need to
// zero it.
//
FreePages (CommonBufferHeader->StashBuffer, Pages);
//
// Release the common buffer itself. Unmap() has re-encrypted it in-place, so
// no need to zero it.
//
return IoMmuFreeCommonBuffer (CommonBufferHeader, CommonBufferPages);
}
/**
Set IOMMU attribute for a system memory.
If the IOMMU protocol exists, the system memory cannot be used
for DMA by default.
When a device requests a DMA access for a system memory,
the device driver need use SetAttribute() to update the IOMMU
attribute to request DMA access (read and/or write).
The DeviceHandle is used to identify which device submits the request.
The IOMMU implementation need translate the device path to an IOMMU device
ID, and set IOMMU hardware register accordingly.
1) DeviceHandle can be a standard PCI device.
The memory for BusMasterRead need set EDKII_IOMMU_ACCESS_READ.
The memory for BusMasterWrite need set EDKII_IOMMU_ACCESS_WRITE.
The memory for BusMasterCommonBuffer need set
EDKII_IOMMU_ACCESS_READ|EDKII_IOMMU_ACCESS_WRITE.
After the memory is used, the memory need set 0 to keep it being
protected.
2) DeviceHandle can be an ACPI device (ISA, I2C, SPI, etc).
The memory for DMA access need set EDKII_IOMMU_ACCESS_READ and/or
EDKII_IOMMU_ACCESS_WRITE.
@param[in] This The protocol instance pointer.
@param[in] DeviceHandle The device who initiates the DMA access
request.
@param[in] Mapping The mapping value returned from Map().
@param[in] IoMmuAccess The IOMMU access.
@retval EFI_SUCCESS The IoMmuAccess is set for the memory range
specified by DeviceAddress and Length.
@retval EFI_INVALID_PARAMETER DeviceHandle is an invalid handle.
@retval EFI_INVALID_PARAMETER Mapping is not a value that was returned by
Map().
@retval EFI_INVALID_PARAMETER IoMmuAccess specified an illegal combination
of access.
@retval EFI_UNSUPPORTED DeviceHandle is unknown by the IOMMU.
@retval EFI_UNSUPPORTED The bit mask of IoMmuAccess is not supported
by the IOMMU.
@retval EFI_UNSUPPORTED The IOMMU does not support the memory range
specified by Mapping.
@retval EFI_OUT_OF_RESOURCES There are not enough resources available to
modify the IOMMU access.
@retval EFI_DEVICE_ERROR The IOMMU device reported an error while
attempting the operation.
**/
EFI_STATUS
EFIAPI
IoMmuSetAttribute (
IN EDKII_IOMMU_PROTOCOL *This,
IN EFI_HANDLE DeviceHandle,
IN VOID *Mapping,
IN UINT64 IoMmuAccess
)
{
return EFI_UNSUPPORTED;
}
EDKII_IOMMU_PROTOCOL mIoMmu = {
EDKII_IOMMU_PROTOCOL_REVISION,
IoMmuSetAttribute,
IoMmuMap,
IoMmuUnmap,
IoMmuAllocateBuffer,
IoMmuFreeBuffer,
};
/**
Notification function that is queued when gBS->ExitBootServices() signals the
EFI_EVENT_GROUP_EXIT_BOOT_SERVICES event group. This function signals another
event, received as Context, and returns.
Signaling an event in this context is safe. The UEFI spec allows
gBS->SignalEvent() to return EFI_SUCCESS only; EFI_OUT_OF_RESOURCES is not
listed, hence memory is not allocated. The edk2 implementation also does not
release memory (and we only have to care about the edk2 implementation
because EDKII_IOMMU_PROTOCOL is edk2-specific anyway).
@param[in] Event Event whose notification function is being invoked.
Event is permitted to request the queueing of this
function at TPL_CALLBACK or TPL_NOTIFY task
priority level.
@param[in] EventToSignal Identifies the EFI_EVENT to signal. EventToSignal
is permitted to request the queueing of its
notification function only at TPL_CALLBACK level.
**/
STATIC
VOID
EFIAPI
IoMmuExitBoot (
IN EFI_EVENT Event,
IN VOID *EventToSignal
)
{
//
// (1) The NotifyFunctions of all the events in
// EFI_EVENT_GROUP_EXIT_BOOT_SERVICES will have been queued before
// IoMmuExitBoot() is entered.
//
// (2) IoMmuExitBoot() is executing minimally at TPL_CALLBACK.
//
// (3) IoMmuExitBoot() has been queued in unspecified order relative to the
// NotifyFunctions of all the other events in
// EFI_EVENT_GROUP_EXIT_BOOT_SERVICES whose NotifyTpl is the same as
// Event's.
//
// Consequences:
//
// - If Event's NotifyTpl is TPL_CALLBACK, then some other NotifyFunctions
// queued at TPL_CALLBACK may be invoked after IoMmuExitBoot() returns.
//
// - If Event's NotifyTpl is TPL_NOTIFY, then some other NotifyFunctions
// queued at TPL_NOTIFY may be invoked after IoMmuExitBoot() returns; plus
// *all* NotifyFunctions queued at TPL_CALLBACK will be invoked strictly
// after all NotifyFunctions queued at TPL_NOTIFY, including
// IoMmuExitBoot(), have been invoked.
//
// - By signaling EventToSignal here, whose NotifyTpl is TPL_CALLBACK, we
// queue EventToSignal's NotifyFunction after the NotifyFunctions of *all*
// events in EFI_EVENT_GROUP_EXIT_BOOT_SERVICES.
//
DEBUG ((DEBUG_VERBOSE, "%a\n", __FUNCTION__));
gBS->SignalEvent (EventToSignal);
}
/**
Notification function that is queued after the notification functions of all
events in the EFI_EVENT_GROUP_EXIT_BOOT_SERVICES event group. The same memory
map restrictions apply.
This function unmaps all currently existing IOMMU mappings.
@param[in] Event Event whose notification function is being invoked. Event
is permitted to request the queueing of this function
only at TPL_CALLBACK task priority level.
@param[in] Context Ignored.
**/
STATIC
VOID
EFIAPI
IoMmuUnmapAllMappings (
IN EFI_EVENT Event,
IN VOID *Context
)
{
LIST_ENTRY *Node;
LIST_ENTRY *NextNode;
MAP_INFO *MapInfo;
DEBUG ((DEBUG_VERBOSE, "%a\n", __FUNCTION__));
//
// All drivers that had set up IOMMU mappings have halted their respective
// controllers by now; tear down the mappings.
//
for (Node = GetFirstNode (&mMapInfos); Node != &mMapInfos; Node = NextNode) {
NextNode = GetNextNode (&mMapInfos, Node);
MapInfo = CR (Node, MAP_INFO, Link, MAP_INFO_SIG);
IoMmuUnmapWorker (
&mIoMmu, // This
MapInfo, // Mapping
TRUE // MemoryMapLocked
);
}
//
// Release the reserved shared memory as well.
//
IoMmuReleaseReservedSharedMem (TRUE);
}
/**
Initialize Iommu Protocol.
**/
EFI_STATUS
EFIAPI
InstallIoMmuProtocol (
VOID
)
{
EFI_STATUS Status;
EFI_EVENT UnmapAllMappingsEvent;
EFI_EVENT ExitBootEvent;
EFI_HANDLE Handle;
//
// Create the "late" event whose notification function will tear down all
// left-over IOMMU mappings.
//
Status = gBS->CreateEvent (
EVT_NOTIFY_SIGNAL, // Type
TPL_CALLBACK, // NotifyTpl
IoMmuUnmapAllMappings, // NotifyFunction
NULL, // NotifyContext
&UnmapAllMappingsEvent // Event
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Create the event whose notification function will be queued by
// gBS->ExitBootServices() and will signal the event created above.
//
Status = gBS->CreateEvent (
EVT_SIGNAL_EXIT_BOOT_SERVICES, // Type
TPL_CALLBACK, // NotifyTpl
IoMmuExitBoot, // NotifyFunction
UnmapAllMappingsEvent, // NotifyContext
&ExitBootEvent // Event
);
if (EFI_ERROR (Status)) {
goto CloseUnmapAllMappingsEvent;
}
Handle = NULL;
Status = gBS->InstallMultipleProtocolInterfaces (
&Handle,
&gEdkiiIoMmuProtocolGuid,
&mIoMmu,
NULL
);
if (EFI_ERROR (Status)) {
goto CloseExitBootEvent;
}
//
// For CC guests, use reserved shared memory for DMA operation.
//
mReservedSharedMemSupported = TRUE;
Status = IoMmuInitReservedSharedMem ();
if (EFI_ERROR (Status)) {
mReservedSharedMemSupported = FALSE;
} else {
DEBUG ((DEBUG_INFO, "%a: Feature of reserved memory for DMA is supported.\n", __FUNCTION__));
}
return EFI_SUCCESS;
CloseExitBootEvent:
gBS->CloseEvent (ExitBootEvent);
CloseUnmapAllMappingsEvent:
gBS->CloseEvent (UnmapAllMappingsEvent);
return Status;
}
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