3 The protocol provides support to allocate, free, map and umap a DMA buffer
4 for bus master (e.g PciHostBridge). When SEV is enabled, the DMA operations
5 must be performed on unencrypted buffer hence we use a bounce buffer to map
6 the guest buffer into an unencrypted DMA buffer.
8 Copyright (c) 2017, AMD Inc. All rights reserved.<BR>
9 Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
11 This program and the accompanying materials are licensed and made available
12 under the terms and conditions of the BSD License which accompanies this
13 distribution. The full text of the license may be found at
14 http://opensource.org/licenses/bsd-license.php
16 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
17 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
21 #include "AmdSevIoMmu.h"
23 #define MAP_INFO_SIG SIGNATURE_64 ('M', 'A', 'P', '_', 'I', 'N', 'F', 'O')
28 EDKII_IOMMU_OPERATION Operation
;
31 EFI_PHYSICAL_ADDRESS CryptedAddress
;
32 EFI_PHYSICAL_ADDRESS PlainTextAddress
;
36 // List of the MAP_INFO structures that have been set up by IoMmuMap() and not
37 // yet torn down by IoMmuUnmap(). The list represents the full set of mappings
38 // currently in effect.
40 STATIC LIST_ENTRY mMapInfos
= INITIALIZE_LIST_HEAD_VARIABLE (mMapInfos
);
42 #define COMMON_BUFFER_SIG SIGNATURE_64 ('C', 'M', 'N', 'B', 'U', 'F', 'F', 'R')
45 // ASCII names for EDKII_IOMMU_OPERATION constants, for debug logging.
47 STATIC CONST CHAR8
* CONST
48 mBusMasterOperationName
[EdkiiIoMmuOperationMaximum
] = {
58 // The following structure enables Map() and Unmap() to perform in-place
59 // decryption and encryption, respectively, for BusMasterCommonBuffer[64]
60 // operations, without dynamic memory allocation or release.
62 // Both COMMON_BUFFER_HEADER and COMMON_BUFFER_HEADER.StashBuffer are allocated
63 // by AllocateBuffer() and released by FreeBuffer().
70 // Always allocated from EfiBootServicesData type memory, and always
76 // Followed by the actual common buffer, starting at the next page.
78 } COMMON_BUFFER_HEADER
;
82 Provides the controller-specific addresses required to access system memory
83 from a DMA bus master. On SEV guest, the DMA operations must be performed on
84 shared buffer hence we allocate a bounce buffer to map the HostAddress to a
85 DeviceAddress. The Encryption attribute is removed from the DeviceAddress
88 @param This The protocol instance pointer.
89 @param Operation Indicates if the bus master is going to read or
90 write to system memory.
91 @param HostAddress The system memory address to map to the PCI
93 @param NumberOfBytes On input the number of bytes to map. On output
94 the number of bytes that were mapped.
95 @param DeviceAddress The resulting map address for the bus master
96 PCI controller to use to access the hosts
98 @param Mapping A resulting value to pass to Unmap().
100 @retval EFI_SUCCESS The range was mapped for the returned
102 @retval EFI_UNSUPPORTED The HostAddress cannot be mapped as a common
104 @retval EFI_INVALID_PARAMETER One or more parameters are invalid.
105 @retval EFI_OUT_OF_RESOURCES The request could not be completed due to a
107 @retval EFI_DEVICE_ERROR The system hardware could not map the requested
114 IN EDKII_IOMMU_PROTOCOL
*This
,
115 IN EDKII_IOMMU_OPERATION Operation
,
116 IN VOID
*HostAddress
,
117 IN OUT UINTN
*NumberOfBytes
,
118 OUT EFI_PHYSICAL_ADDRESS
*DeviceAddress
,
124 EFI_ALLOCATE_TYPE AllocateType
;
125 COMMON_BUFFER_HEADER
*CommonBufferHeader
;
126 VOID
*DecryptionSource
;
130 "%a: Operation=%a Host=0x%p Bytes=0x%Lx\n",
133 Operation
< ARRAY_SIZE (mBusMasterOperationName
)) ?
134 mBusMasterOperationName
[Operation
] :
137 (UINT64
)((NumberOfBytes
== NULL
) ? 0 : *NumberOfBytes
)
140 if (HostAddress
== NULL
|| NumberOfBytes
== NULL
|| DeviceAddress
== NULL
||
142 return EFI_INVALID_PARAMETER
;
146 // Allocate a MAP_INFO structure to remember the mapping when Unmap() is
149 MapInfo
= AllocatePool (sizeof (MAP_INFO
));
150 if (MapInfo
== NULL
) {
151 Status
= EFI_OUT_OF_RESOURCES
;
156 // Initialize the MAP_INFO structure, except the PlainTextAddress field
158 ZeroMem (&MapInfo
->Link
, sizeof MapInfo
->Link
);
159 MapInfo
->Signature
= MAP_INFO_SIG
;
160 MapInfo
->Operation
= Operation
;
161 MapInfo
->NumberOfBytes
= *NumberOfBytes
;
162 MapInfo
->NumberOfPages
= EFI_SIZE_TO_PAGES (MapInfo
->NumberOfBytes
);
163 MapInfo
->CryptedAddress
= (UINTN
)HostAddress
;
166 // In the switch statement below, we point "MapInfo->PlainTextAddress" to the
167 // plaintext buffer, according to Operation. We also set "DecryptionSource".
169 MapInfo
->PlainTextAddress
= MAX_ADDRESS
;
170 AllocateType
= AllocateAnyPages
;
171 DecryptionSource
= (VOID
*)(UINTN
)MapInfo
->CryptedAddress
;
174 // For BusMasterRead[64] and BusMasterWrite[64] operations, a bounce buffer
175 // is necessary regardless of whether the original (crypted) buffer crosses
176 // the 4GB limit or not -- we have to allocate a separate plaintext buffer.
177 // The only variable is whether the plaintext buffer should be under 4GB.
179 case EdkiiIoMmuOperationBusMasterRead
:
180 case EdkiiIoMmuOperationBusMasterWrite
:
181 MapInfo
->PlainTextAddress
= BASE_4GB
- 1;
182 AllocateType
= AllocateMaxAddress
;
186 case EdkiiIoMmuOperationBusMasterRead64
:
187 case EdkiiIoMmuOperationBusMasterWrite64
:
189 // Allocate the implicit plaintext bounce buffer.
191 Status
= gBS
->AllocatePages (
194 MapInfo
->NumberOfPages
,
195 &MapInfo
->PlainTextAddress
197 if (EFI_ERROR (Status
)) {
203 // For BusMasterCommonBuffer[64] operations, a to-be-plaintext buffer and a
204 // stash buffer (for in-place decryption) have been allocated already, with
205 // AllocateBuffer(). We only check whether the address of the to-be-plaintext
206 // buffer is low enough for the requested operation.
208 case EdkiiIoMmuOperationBusMasterCommonBuffer
:
209 if ((MapInfo
->CryptedAddress
> BASE_4GB
) ||
210 (EFI_PAGES_TO_SIZE (MapInfo
->NumberOfPages
) >
211 BASE_4GB
- MapInfo
->CryptedAddress
)) {
213 // CommonBuffer operations cannot be remapped. If the common buffer is
214 // above 4GB, then it is not possible to generate a mapping, so return an
217 Status
= EFI_UNSUPPORTED
;
223 case EdkiiIoMmuOperationBusMasterCommonBuffer64
:
225 // The buffer at MapInfo->CryptedAddress comes from AllocateBuffer().
227 MapInfo
->PlainTextAddress
= MapInfo
->CryptedAddress
;
229 // Stash the crypted data.
231 CommonBufferHeader
= (COMMON_BUFFER_HEADER
*)(
232 (UINTN
)MapInfo
->CryptedAddress
- EFI_PAGE_SIZE
234 ASSERT (CommonBufferHeader
->Signature
== COMMON_BUFFER_SIG
);
236 CommonBufferHeader
->StashBuffer
,
237 (VOID
*)(UINTN
)MapInfo
->CryptedAddress
,
238 MapInfo
->NumberOfBytes
241 // Point "DecryptionSource" to the stash buffer so that we decrypt
242 // it to the original location, after the switch statement.
244 DecryptionSource
= CommonBufferHeader
->StashBuffer
;
249 // Operation is invalid
251 Status
= EFI_INVALID_PARAMETER
;
256 // Clear the memory encryption mask on the plaintext buffer.
258 Status
= MemEncryptSevClearPageEncMask (
260 MapInfo
->PlainTextAddress
,
261 MapInfo
->NumberOfPages
,
264 ASSERT_EFI_ERROR (Status
);
265 if (EFI_ERROR (Status
)) {
270 // If this is a read operation from the Bus Master's point of view,
271 // then copy the contents of the real buffer into the mapped buffer
272 // so the Bus Master can read the contents of the real buffer.
274 // For BusMasterCommonBuffer[64] operations, the CopyMem() below will decrypt
275 // the original data (from the stash buffer) back to the original location.
277 if (Operation
== EdkiiIoMmuOperationBusMasterRead
||
278 Operation
== EdkiiIoMmuOperationBusMasterRead64
||
279 Operation
== EdkiiIoMmuOperationBusMasterCommonBuffer
||
280 Operation
== EdkiiIoMmuOperationBusMasterCommonBuffer64
) {
282 (VOID
*) (UINTN
) MapInfo
->PlainTextAddress
,
284 MapInfo
->NumberOfBytes
289 // Track all MAP_INFO structures.
291 InsertHeadList (&mMapInfos
, &MapInfo
->Link
);
293 // Populate output parameters.
295 *DeviceAddress
= MapInfo
->PlainTextAddress
;
300 "%a: Mapping=0x%p Device(PlainText)=0x%Lx Crypted=0x%Lx Pages=0x%Lx\n",
303 MapInfo
->PlainTextAddress
,
304 MapInfo
->CryptedAddress
,
305 (UINT64
)MapInfo
->NumberOfPages
319 Completes the Map() operation and releases any corresponding resources.
321 This is an internal worker function that only extends the Map() API with
322 the MemoryMapLocked parameter.
324 @param This The protocol instance pointer.
325 @param Mapping The mapping value returned from Map().
326 @param MemoryMapLocked The function is executing on the stack of
327 gBS->ExitBootServices(); changes to the UEFI
328 memory map are forbidden.
330 @retval EFI_SUCCESS The range was unmapped.
331 @retval EFI_INVALID_PARAMETER Mapping is not a value that was returned by
333 @retval EFI_DEVICE_ERROR The data was not committed to the target system
340 IN EDKII_IOMMU_PROTOCOL
*This
,
342 IN BOOLEAN MemoryMapLocked
347 COMMON_BUFFER_HEADER
*CommonBufferHeader
;
348 VOID
*EncryptionTarget
;
352 "%a: Mapping=0x%p MemoryMapLocked=%d\n",
358 if (Mapping
== NULL
) {
359 return EFI_INVALID_PARAMETER
;
362 MapInfo
= (MAP_INFO
*)Mapping
;
365 // set CommonBufferHeader to suppress incorrect compiler/analyzer warnings
367 CommonBufferHeader
= NULL
;
370 // For BusMasterWrite[64] operations and BusMasterCommonBuffer[64] operations
371 // we have to encrypt the results, ultimately to the original place (i.e.,
372 // "MapInfo->CryptedAddress").
374 // For BusMasterCommonBuffer[64] operations however, this encryption has to
375 // land in-place, so divert the encryption to the stash buffer first.
377 EncryptionTarget
= (VOID
*)(UINTN
)MapInfo
->CryptedAddress
;
379 switch (MapInfo
->Operation
) {
380 case EdkiiIoMmuOperationBusMasterCommonBuffer
:
381 case EdkiiIoMmuOperationBusMasterCommonBuffer64
:
382 ASSERT (MapInfo
->PlainTextAddress
== MapInfo
->CryptedAddress
);
384 CommonBufferHeader
= (COMMON_BUFFER_HEADER
*)(
385 (UINTN
)MapInfo
->PlainTextAddress
- EFI_PAGE_SIZE
387 ASSERT (CommonBufferHeader
->Signature
== COMMON_BUFFER_SIG
);
388 EncryptionTarget
= CommonBufferHeader
->StashBuffer
;
393 case EdkiiIoMmuOperationBusMasterWrite
:
394 case EdkiiIoMmuOperationBusMasterWrite64
:
397 (VOID
*) (UINTN
) MapInfo
->PlainTextAddress
,
398 MapInfo
->NumberOfBytes
404 // nothing to encrypt after BusMasterRead[64] operations
410 // Restore the memory encryption mask on the area we used to hold the
413 Status
= MemEncryptSevSetPageEncMask (
415 MapInfo
->PlainTextAddress
,
416 MapInfo
->NumberOfPages
,
419 ASSERT_EFI_ERROR (Status
);
420 if (EFI_ERROR (Status
)) {
425 // For BusMasterCommonBuffer[64] operations, copy the stashed data to the
426 // original (now encrypted) location.
428 // For all other operations, fill the late bounce buffer (which existed as
429 // plaintext at some point) with zeros, and then release it (unless the UEFI
430 // memory map is locked).
432 if (MapInfo
->Operation
== EdkiiIoMmuOperationBusMasterCommonBuffer
||
433 MapInfo
->Operation
== EdkiiIoMmuOperationBusMasterCommonBuffer64
) {
435 (VOID
*)(UINTN
)MapInfo
->CryptedAddress
,
436 CommonBufferHeader
->StashBuffer
,
437 MapInfo
->NumberOfBytes
441 (VOID
*)(UINTN
)MapInfo
->PlainTextAddress
,
442 EFI_PAGES_TO_SIZE (MapInfo
->NumberOfPages
)
444 if (!MemoryMapLocked
) {
445 gBS
->FreePages (MapInfo
->PlainTextAddress
, MapInfo
->NumberOfPages
);
450 // Forget the MAP_INFO structure, then free it (unless the UEFI memory map is
453 RemoveEntryList (&MapInfo
->Link
);
454 if (!MemoryMapLocked
) {
462 Completes the Map() operation and releases any corresponding resources.
464 @param This The protocol instance pointer.
465 @param Mapping The mapping value returned from Map().
467 @retval EFI_SUCCESS The range was unmapped.
468 @retval EFI_INVALID_PARAMETER Mapping is not a value that was returned by
470 @retval EFI_DEVICE_ERROR The data was not committed to the target system
476 IN EDKII_IOMMU_PROTOCOL
*This
,
480 return IoMmuUnmapWorker (
483 FALSE
// MemoryMapLocked
488 Allocates pages that are suitable for an OperationBusMasterCommonBuffer or
489 OperationBusMasterCommonBuffer64 mapping.
491 @param This The protocol instance pointer.
492 @param Type This parameter is not used and must be ignored.
493 @param MemoryType The type of memory to allocate,
494 EfiBootServicesData or EfiRuntimeServicesData.
495 @param Pages The number of pages to allocate.
496 @param HostAddress A pointer to store the base system memory
497 address of the allocated range.
498 @param Attributes The requested bit mask of attributes for the
501 @retval EFI_SUCCESS The requested memory pages were allocated.
502 @retval EFI_UNSUPPORTED Attributes is unsupported. The only legal
503 attribute bits are MEMORY_WRITE_COMBINE and
505 @retval EFI_INVALID_PARAMETER One or more parameters are invalid.
506 @retval EFI_OUT_OF_RESOURCES The memory pages could not be allocated.
511 IoMmuAllocateBuffer (
512 IN EDKII_IOMMU_PROTOCOL
*This
,
513 IN EFI_ALLOCATE_TYPE Type
,
514 IN EFI_MEMORY_TYPE MemoryType
,
516 IN OUT VOID
**HostAddress
,
521 EFI_PHYSICAL_ADDRESS PhysicalAddress
;
523 UINTN CommonBufferPages
;
524 COMMON_BUFFER_HEADER
*CommonBufferHeader
;
528 "%a: MemoryType=%u Pages=0x%Lx Attributes=0x%Lx\n",
536 // Validate Attributes
538 if ((Attributes
& EDKII_IOMMU_ATTRIBUTE_INVALID_FOR_ALLOCATE_BUFFER
) != 0) {
539 return EFI_UNSUPPORTED
;
543 // Check for invalid inputs
545 if (HostAddress
== NULL
) {
546 return EFI_INVALID_PARAMETER
;
550 // The only valid memory types are EfiBootServicesData and
551 // EfiRuntimeServicesData
553 if (MemoryType
!= EfiBootServicesData
&&
554 MemoryType
!= EfiRuntimeServicesData
) {
555 return EFI_INVALID_PARAMETER
;
559 // We'll need a header page for the COMMON_BUFFER_HEADER structure.
561 if (Pages
> MAX_UINTN
- 1) {
562 return EFI_OUT_OF_RESOURCES
;
564 CommonBufferPages
= Pages
+ 1;
567 // Allocate the stash in EfiBootServicesData type memory.
569 // Map() will temporarily save encrypted data in the stash for
570 // BusMasterCommonBuffer[64] operations, so the data can be decrypted to the
571 // original location.
573 // Unmap() will temporarily save plaintext data in the stash for
574 // BusMasterCommonBuffer[64] operations, so the data can be encrypted to the
575 // original location.
577 // StashBuffer always resides in encrypted memory.
579 StashBuffer
= AllocatePages (Pages
);
580 if (StashBuffer
== NULL
) {
581 return EFI_OUT_OF_RESOURCES
;
584 PhysicalAddress
= (UINTN
)-1;
585 if ((Attributes
& EDKII_IOMMU_ATTRIBUTE_DUAL_ADDRESS_CYCLE
) == 0) {
587 // Limit allocations to memory below 4GB
589 PhysicalAddress
= SIZE_4GB
- 1;
591 Status
= gBS
->AllocatePages (
597 if (EFI_ERROR (Status
)) {
598 goto FreeStashBuffer
;
601 CommonBufferHeader
= (VOID
*)(UINTN
)PhysicalAddress
;
602 PhysicalAddress
+= EFI_PAGE_SIZE
;
604 CommonBufferHeader
->Signature
= COMMON_BUFFER_SIG
;
605 CommonBufferHeader
->StashBuffer
= StashBuffer
;
607 *HostAddress
= (VOID
*)(UINTN
)PhysicalAddress
;
611 "%a: Host=0x%Lx Stash=0x%p\n",
619 FreePages (StashBuffer
, Pages
);
624 Frees memory that was allocated with AllocateBuffer().
626 @param This The protocol instance pointer.
627 @param Pages The number of pages to free.
628 @param HostAddress The base system memory address of the allocated
631 @retval EFI_SUCCESS The requested memory pages were freed.
632 @retval EFI_INVALID_PARAMETER The memory range specified by HostAddress and
633 Pages was not allocated with AllocateBuffer().
639 IN EDKII_IOMMU_PROTOCOL
*This
,
644 UINTN CommonBufferPages
;
645 COMMON_BUFFER_HEADER
*CommonBufferHeader
;
649 "%a: Host=0x%p Pages=0x%Lx\n",
655 CommonBufferPages
= Pages
+ 1;
656 CommonBufferHeader
= (COMMON_BUFFER_HEADER
*)(
657 (UINTN
)HostAddress
- EFI_PAGE_SIZE
661 // Check the signature.
663 ASSERT (CommonBufferHeader
->Signature
== COMMON_BUFFER_SIG
);
664 if (CommonBufferHeader
->Signature
!= COMMON_BUFFER_SIG
) {
665 return EFI_INVALID_PARAMETER
;
669 // Free the stash buffer. This buffer was always encrypted, so no need to
672 FreePages (CommonBufferHeader
->StashBuffer
, Pages
);
675 // Release the common buffer itself. Unmap() has re-encrypted it in-place, so
676 // no need to zero it.
678 return gBS
->FreePages ((UINTN
)CommonBufferHeader
, CommonBufferPages
);
683 Set IOMMU attribute for a system memory.
685 If the IOMMU protocol exists, the system memory cannot be used
688 When a device requests a DMA access for a system memory,
689 the device driver need use SetAttribute() to update the IOMMU
690 attribute to request DMA access (read and/or write).
692 The DeviceHandle is used to identify which device submits the request.
693 The IOMMU implementation need translate the device path to an IOMMU device
694 ID, and set IOMMU hardware register accordingly.
695 1) DeviceHandle can be a standard PCI device.
696 The memory for BusMasterRead need set EDKII_IOMMU_ACCESS_READ.
697 The memory for BusMasterWrite need set EDKII_IOMMU_ACCESS_WRITE.
698 The memory for BusMasterCommonBuffer need set
699 EDKII_IOMMU_ACCESS_READ|EDKII_IOMMU_ACCESS_WRITE.
700 After the memory is used, the memory need set 0 to keep it being
702 2) DeviceHandle can be an ACPI device (ISA, I2C, SPI, etc).
703 The memory for DMA access need set EDKII_IOMMU_ACCESS_READ and/or
704 EDKII_IOMMU_ACCESS_WRITE.
706 @param[in] This The protocol instance pointer.
707 @param[in] DeviceHandle The device who initiates the DMA access
709 @param[in] Mapping The mapping value returned from Map().
710 @param[in] IoMmuAccess The IOMMU access.
712 @retval EFI_SUCCESS The IoMmuAccess is set for the memory range
713 specified by DeviceAddress and Length.
714 @retval EFI_INVALID_PARAMETER DeviceHandle is an invalid handle.
715 @retval EFI_INVALID_PARAMETER Mapping is not a value that was returned by
717 @retval EFI_INVALID_PARAMETER IoMmuAccess specified an illegal combination
719 @retval EFI_UNSUPPORTED DeviceHandle is unknown by the IOMMU.
720 @retval EFI_UNSUPPORTED The bit mask of IoMmuAccess is not supported
722 @retval EFI_UNSUPPORTED The IOMMU does not support the memory range
723 specified by Mapping.
724 @retval EFI_OUT_OF_RESOURCES There are not enough resources available to
725 modify the IOMMU access.
726 @retval EFI_DEVICE_ERROR The IOMMU device reported an error while
727 attempting the operation.
733 IN EDKII_IOMMU_PROTOCOL
*This
,
734 IN EFI_HANDLE DeviceHandle
,
736 IN UINT64 IoMmuAccess
739 return EFI_UNSUPPORTED
;
742 EDKII_IOMMU_PROTOCOL mAmdSev
= {
743 EDKII_IOMMU_PROTOCOL_REVISION
,
752 Notification function that is queued when gBS->ExitBootServices() signals the
753 EFI_EVENT_GROUP_EXIT_BOOT_SERVICES event group. This function signals another
754 event, received as Context, and returns.
756 Signaling an event in this context is safe. The UEFI spec allows
757 gBS->SignalEvent() to return EFI_SUCCESS only; EFI_OUT_OF_RESOURCES is not
758 listed, hence memory is not allocated. The edk2 implementation also does not
759 release memory (and we only have to care about the edk2 implementation
760 because EDKII_IOMMU_PROTOCOL is edk2-specific anyway).
762 @param[in] Event Event whose notification function is being invoked.
763 Event is permitted to request the queueing of this
764 function at TPL_CALLBACK or TPL_NOTIFY task
767 @param[in] EventToSignal Identifies the EFI_EVENT to signal. EventToSignal
768 is permitted to request the queueing of its
769 notification function only at TPL_CALLBACK level.
776 IN VOID
*EventToSignal
780 // (1) The NotifyFunctions of all the events in
781 // EFI_EVENT_GROUP_EXIT_BOOT_SERVICES will have been queued before
782 // AmdSevExitBoot() is entered.
784 // (2) AmdSevExitBoot() is executing minimally at TPL_CALLBACK.
786 // (3) AmdSevExitBoot() has been queued in unspecified order relative to the
787 // NotifyFunctions of all the other events in
788 // EFI_EVENT_GROUP_EXIT_BOOT_SERVICES whose NotifyTpl is the same as
793 // - If Event's NotifyTpl is TPL_CALLBACK, then some other NotifyFunctions
794 // queued at TPL_CALLBACK may be invoked after AmdSevExitBoot() returns.
796 // - If Event's NotifyTpl is TPL_NOTIFY, then some other NotifyFunctions
797 // queued at TPL_NOTIFY may be invoked after AmdSevExitBoot() returns; plus
798 // *all* NotifyFunctions queued at TPL_CALLBACK will be invoked strictly
799 // after all NotifyFunctions queued at TPL_NOTIFY, including
800 // AmdSevExitBoot(), have been invoked.
802 // - By signaling EventToSignal here, whose NotifyTpl is TPL_CALLBACK, we
803 // queue EventToSignal's NotifyFunction after the NotifyFunctions of *all*
804 // events in EFI_EVENT_GROUP_EXIT_BOOT_SERVICES.
806 DEBUG ((DEBUG_VERBOSE
, "%a\n", __FUNCTION__
));
807 gBS
->SignalEvent (EventToSignal
);
811 Notification function that is queued after the notification functions of all
812 events in the EFI_EVENT_GROUP_EXIT_BOOT_SERVICES event group. The same memory
813 map restrictions apply.
815 This function unmaps all currently existing IOMMU mappings.
817 @param[in] Event Event whose notification function is being invoked. Event
818 is permitted to request the queueing of this function
819 only at TPL_CALLBACK task priority level.
821 @param[in] Context Ignored.
826 AmdSevUnmapAllMappings (
832 LIST_ENTRY
*NextNode
;
835 DEBUG ((DEBUG_VERBOSE
, "%a\n", __FUNCTION__
));
838 // All drivers that had set up IOMMU mappings have halted their respective
839 // controllers by now; tear down the mappings.
841 for (Node
= GetFirstNode (&mMapInfos
); Node
!= &mMapInfos
; Node
= NextNode
) {
842 NextNode
= GetNextNode (&mMapInfos
, Node
);
843 MapInfo
= CR (Node
, MAP_INFO
, Link
, MAP_INFO_SIG
);
847 TRUE
// MemoryMapLocked
853 Initialize Iommu Protocol.
858 AmdSevInstallIoMmuProtocol (
863 EFI_EVENT UnmapAllMappingsEvent
;
864 EFI_EVENT ExitBootEvent
;
868 // Create the "late" event whose notification function will tear down all
869 // left-over IOMMU mappings.
871 Status
= gBS
->CreateEvent (
872 EVT_NOTIFY_SIGNAL
, // Type
873 TPL_CALLBACK
, // NotifyTpl
874 AmdSevUnmapAllMappings
, // NotifyFunction
875 NULL
, // NotifyContext
876 &UnmapAllMappingsEvent
// Event
878 if (EFI_ERROR (Status
)) {
883 // Create the event whose notification function will be queued by
884 // gBS->ExitBootServices() and will signal the event created above.
886 Status
= gBS
->CreateEvent (
887 EVT_SIGNAL_EXIT_BOOT_SERVICES
, // Type
888 TPL_CALLBACK
, // NotifyTpl
889 AmdSevExitBoot
, // NotifyFunction
890 UnmapAllMappingsEvent
, // NotifyContext
891 &ExitBootEvent
// Event
893 if (EFI_ERROR (Status
)) {
894 goto CloseUnmapAllMappingsEvent
;
898 Status
= gBS
->InstallMultipleProtocolInterfaces (
900 &gEdkiiIoMmuProtocolGuid
, &mAmdSev
,
903 if (EFI_ERROR (Status
)) {
904 goto CloseExitBootEvent
;
910 gBS
->CloseEvent (ExitBootEvent
);
912 CloseUnmapAllMappingsEvent
:
913 gBS
->CloseEvent (UnmapAllMappingsEvent
);