From 5a751b7c76c8f9a0a328c4d33fa440e1f02c02e6 Mon Sep 17 00:00:00 2001
From: Liu Zixing <[email protected]>
Date: Fri, 25 Feb 2022 16:54:44 +0800
Subject: [PATCH 09/11] OvmfPkg/IoMmuDxe: Add CsvIoMmu protocol

Create the dedicated IoMmu protocol for CSV virtual machine.
And Install it during CSV VM boots up.

It calls the CsvSharedMemoryProtocol to allocate shared memory
for DMA operations.

- AllocateBuffer() allocates the shared memory.

- FreeBuffer() frees the shared memory.

- Map() does nothing when BusMasterCommonBuffer[64] is requested
  Otherwise, Map() allocates shared memory.

- Unmap() does nothing when cleaning up a BusMasterCommonBuffer[64]
  operation. Otherwise, Unmap() frees the shared memory.

Signed-off-by: Xin Jiang <[email protected]>
---
 OvmfPkg/IoMmuDxe/CsvIoMmu.c   | 592 ++++++++++++++++++++++++++++++++++
 OvmfPkg/IoMmuDxe/CsvIoMmu.h   |  29 ++
 OvmfPkg/IoMmuDxe/IoMmuDxe.c   |  10 +
 OvmfPkg/IoMmuDxe/IoMmuDxe.inf |   6 +-
 4 files changed, 636 insertions(+), 1 deletion(-)
 create mode 100644 OvmfPkg/IoMmuDxe/CsvIoMmu.c
 create mode 100644 OvmfPkg/IoMmuDxe/CsvIoMmu.h

diff --git a/OvmfPkg/IoMmuDxe/CsvIoMmu.c b/OvmfPkg/IoMmuDxe/CsvIoMmu.c
new file mode 100644
index 0000000..2a46e98
--- /dev/null
+++ b/OvmfPkg/IoMmuDxe/CsvIoMmu.c
@@ -0,0 +1,592 @@
+/** @file
+
+  The protocol provides support to allocate, free, map and umap a DMA buffer
+  for bus master (e.g PciHostBridge). When CSV is enabled, the DMA operations
+  must be performed on non-secure memory so we have to allocate the DMA buffer
+  from non-secure memory.
+
+  Copyright (c) 2022, HYGON. All rights reserved.<BR>
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Protocol/IoMmu.h>
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/CsvLib.h>
+#include <Protocol/CsvSharedMemory.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include "CsvIoMmu.h"
+
+#define MAP_INFO_SIG SIGNATURE_64 ('M', 'A', 'P', '_', 'I', 'N', 'F', 'O')
+
+typedef struct {
+  UINT64                                    Signature;
+  LIST_ENTRY                                Link;
+  EDKII_IOMMU_OPERATION                     Operation;
+  UINTN                                     NumberOfBytes;
+  UINTN                                     NumberOfPages;
+  EFI_PHYSICAL_ADDRESS                      SecureAddress;
+  EFI_PHYSICAL_ADDRESS                      UnSecureAddress;
+} MAP_INFO;
+
+//
+// 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);
+
+//
+// ASCII names for EDKII_IOMMU_OPERATION constants, for debug logging.
+//
+STATIC CONST CHAR8 * CONST
+mBusMasterOperationName[EdkiiIoMmuOperationMaximum] = {
+  "Read",
+  "Write",
+  "CommonBuffer",
+  "Read64",
+  "Write64",
+  "CommonBuffer64"
+};
+
+STATIC CSV_SHARED_MEMORY_PROTOCOL      *SharedMemory;
+STATIC
+EFI_STATUS
+EFIAPI
+CsvAllocSharedPage(
+  IN  UINTN                    Pages,
+  OUT EFI_PHYSICAL_ADDRESS     *Address
+  )
+{
+  EFI_STATUS    Status;
+
+  Status = SharedMemory->CsvAllocateSharedMemory (
+             SharedMemory,
+             Pages,
+             (UINT64*)Address
+             );
+
+  return Status;
+}
+
+STATIC
+EFI_STATUS
+EFIAPI
+CsvFreeSharedPage(
+  IN  UINTN                                    Pages,
+  IN  VOID                                     *HostAddress
+  )
+{
+  EFI_STATUS    Status;
+
+  Status = SharedMemory->CsvFreeSharedMemory (
+             SharedMemory,
+             Pages,
+             (UINTN)HostAddress
+             );
+
+  return Status;
+}
+
+/**
+  Provides the controller-specific addresses required to access system memory
+  from a DMA bus master.
+  On CSV guest, the DMA openerations must be done on non-secure memory which
+  is the shared memory between the guest and QEMU.
+
+  @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
+CsvIoMmuMap (
+  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;
+
+  DEBUG ((
+    DEBUG_VERBOSE,
+    "%a: Operation=%a Operation=%u Host=0x%p Bytes=0x%Lx\n",
+    __FUNCTION__,
+    ((Operation >= 0 &&
+      Operation < ARRAY_SIZE (mBusMasterOperationName)) ?
+     mBusMasterOperationName[Operation] :
+     "Invalid"),
+    Operation,
+    HostAddress,
+    (UINT64)((NumberOfBytes == NULL) ? 0 : *NumberOfBytes)
+    ));
+
+  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.
+  //
+  MapInfo = AllocatePool (sizeof (MAP_INFO));
+  if (MapInfo == NULL) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Failed;
+  }
+
+  ZeroMem (&MapInfo->Link, sizeof MapInfo->Link);
+  MapInfo->Operation         = Operation;
+  MapInfo->NumberOfBytes     = *NumberOfBytes;
+  MapInfo->NumberOfPages     = EFI_SIZE_TO_PAGES (MapInfo->NumberOfBytes);
+  MapInfo->Signature         = MAP_INFO_SIG;
+
+  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:
+    //
+    // fall through
+    //
+  case EdkiiIoMmuOperationBusMasterRead64:
+  case EdkiiIoMmuOperationBusMasterWrite64:
+    //
+    // Allocate the implicit plaintext bounce buffer.
+    //
+    Status = CsvAllocSharedPage (
+               MapInfo->NumberOfPages,
+               &MapInfo->UnSecureAddress
+               );
+    if (EFI_ERROR (Status)) {
+      goto FreeMapInfo;
+    }
+    MapInfo->SecureAddress = (UINTN)HostAddress;
+    if (Operation == EdkiiIoMmuOperationBusMasterRead ||
+        Operation == EdkiiIoMmuOperationBusMasterRead64) {
+      CopyMem (
+        (VOID *) (UINTN) MapInfo->UnSecureAddress,
+        (VOID *) (UINTN) MapInfo->SecureAddress,
+        MapInfo->NumberOfBytes
+        );
+    }
+    break;
+
+  //
+  // For BusMasterCommonBuffer[64] operations,
+  // AllocateBuffer already returns the plain-text,
+  // No need to decrypt the data.
+  //
+  case EdkiiIoMmuOperationBusMasterCommonBuffer:
+  case EdkiiIoMmuOperationBusMasterCommonBuffer64:
+    MapInfo->UnSecureAddress = (UINTN)HostAddress;
+    MapInfo->SecureAddress   = (UINTN)HostAddress;
+    break;
+
+  default:
+    //
+    // Operation is invalid
+    //
+    Status = EFI_INVALID_PARAMETER;
+    goto FreeMapInfo;
+  }
+
+  //
+  // Track all MAP_INFO structures.
+  //
+  InsertHeadList (&mMapInfos, &MapInfo->Link);
+  //
+  // Populate output parameters.
+  //
+  *DeviceAddress = MapInfo->UnSecureAddress;
+  *Mapping       = MapInfo;
+
+  DEBUG ((
+    DEBUG_VERBOSE,
+    "%a: Mapping=0x%p Device=0x%Lx Host=0x%Lx Pages=0x%Lx\n",
+    __FUNCTION__,
+    MapInfo,
+    MapInfo->UnSecureAddress,
+    MapInfo->SecureAddress,
+    (UINT64)MapInfo->NumberOfPages
+    ));
+
+  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
+CsvIoMmuUnmapWorker (
+  IN  EDKII_IOMMU_PROTOCOL                     *This,
+  IN  VOID                                     *Mapping,
+  IN  BOOLEAN                                  MemoryMapLocked
+  )
+{
+  MAP_INFO                 *MapInfo;
+  EDKII_IOMMU_OPERATION    Operation;
+
+  if (Mapping == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  MapInfo = (MAP_INFO *)Mapping;
+  Operation = MapInfo->Operation;
+
+  DEBUG ((
+    DEBUG_VERBOSE,
+    "%a: Mapping=0x%p MemoryMapLocked=%d Operation %a Operation %d\n",
+    __FUNCTION__,
+    Mapping,
+    MemoryMapLocked,
+    ((Operation >= 0 &&
+      Operation < ARRAY_SIZE (mBusMasterOperationName)) ?
+     mBusMasterOperationName[Operation] :
+     "Invalid"),
+     Operation
+    ));
+
+  switch (MapInfo->Operation) {
+  case EdkiiIoMmuOperationBusMasterWrite:
+  case EdkiiIoMmuOperationBusMasterWrite64:
+    CopyMem (
+      (VOID *) (UINTN) MapInfo->SecureAddress,
+      (VOID *) (UINTN) MapInfo->UnSecureAddress,
+      MapInfo->NumberOfBytes
+      );
+  case EdkiiIoMmuOperationBusMasterRead:
+  case EdkiiIoMmuOperationBusMasterRead64:
+    ZeroMem (
+      (VOID *)(UINTN)MapInfo->UnSecureAddress,
+      EFI_PAGES_TO_SIZE (MapInfo->NumberOfPages)
+      );
+    CsvFreeSharedPage(
+      MapInfo->NumberOfPages,
+      (VOID*)(UINTN)MapInfo->UnSecureAddress
+      );
+
+  default:
+    break;
+  }
+
+  //
+  // 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
+CsvIoMmuUnmap (
+  IN  EDKII_IOMMU_PROTOCOL                     *This,
+  IN  VOID                                     *Mapping
+  )
+{
+  return CsvIoMmuUnmapWorker (
+           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
+CsvIoMmuAllocateBuffer (
+  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;
+
+  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;
+  }
+
+  Status = CsvAllocSharedPage (Pages,&PhysicalAddress);
+  if (Status != EFI_SUCCESS){
+    goto error;
+  }
+
+
+  *HostAddress = (VOID *)(UINTN)PhysicalAddress;
+
+  return EFI_SUCCESS;
+
+error:
+  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
+CsvIoMmuFreeBuffer (
+  IN  EDKII_IOMMU_PROTOCOL                     *This,
+  IN  UINTN                                    Pages,
+  IN  VOID                                     *HostAddress
+  )
+{
+
+  EFI_STATUS                Status;
+
+  if (HostAddress == NULL || Pages == 0) {
+      return EFI_INVALID_PARAMETER;
+  }
+
+  DEBUG ((
+    DEBUG_VERBOSE,
+    "%a: Host=0x%p Pages=0x%Lx\n",
+    __FUNCTION__,
+    HostAddress,
+    (UINT64)Pages
+    ));
+
+  Status = CsvFreeSharedPage (Pages, HostAddress);
+
+  return Status;
+}
+
+
+/**
+  Set IOMMU attribute for a system memory.
+
+  @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
+CsvIoMmuSetAttribute (
+  IN EDKII_IOMMU_PROTOCOL  *This,
+  IN EFI_HANDLE            DeviceHandle,
+  IN VOID                  *Mapping,
+  IN UINT64                IoMmuAccess
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+EDKII_IOMMU_PROTOCOL  mCsv = {
+  EDKII_IOMMU_PROTOCOL_REVISION,
+  CsvIoMmuSetAttribute,
+  CsvIoMmuMap,
+  CsvIoMmuUnmap,
+  CsvIoMmuAllocateBuffer,
+  CsvIoMmuFreeBuffer,
+};
+
+/**
+  Initialize Iommu Protocol.
+
+**/
+EFI_STATUS
+EFIAPI
+CsvInstallIoMmuProtocol (
+  VOID
+  )
+{
+  EFI_STATUS  Status;
+  EFI_HANDLE  Handle;
+
+  Status = gBS->LocateProtocol (
+                  &gCsvSharedMemoryProtocolGuid,
+                  NULL,
+                  (VOID**)&SharedMemory
+                  );
+
+  if (EFI_ERROR (Status)) {
+    goto error;
+  }
+
+  Handle = NULL;
+  Status = gBS->InstallMultipleProtocolInterfaces (
+                  &Handle,
+                  &gEdkiiIoMmuProtocolGuid,
+                  &mCsv,
+                  NULL
+                  );
+  if (EFI_ERROR (Status)) {
+    goto error;
+  }
+
+  return EFI_SUCCESS;
+
+error:
+  return Status;
+}
diff --git a/OvmfPkg/IoMmuDxe/CsvIoMmu.h b/OvmfPkg/IoMmuDxe/CsvIoMmu.h
new file mode 100644
index 0000000..431d284
--- /dev/null
+++ b/OvmfPkg/IoMmuDxe/CsvIoMmu.h
@@ -0,0 +1,29 @@
+/** @file
+
+  The protocol provides support to allocate, free, map and umap a DMA buffer
+  for bus master (e.g PciHostBridge). When CSV is enabled, the DMA operations
+  must be performed on unencrypted buffer hence protocol clear the encryption
+  bit from the DMA buffer.
+
+  Copyright (c) 2022, HYGON. All rights reserved.<BR>
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#ifndef _CSV_IOMMU_H_
+#define _CSV_IOMMU_H_
+
+EFI_STATUS
+EFIAPI
+CsvInstallIoMmuProtocol (
+  VOID
+  );
+
+#endif
diff --git a/OvmfPkg/IoMmuDxe/IoMmuDxe.c b/OvmfPkg/IoMmuDxe/IoMmuDxe.c
index aab6d8b..cd03ca9 100644
--- a/OvmfPkg/IoMmuDxe/IoMmuDxe.c
+++ b/OvmfPkg/IoMmuDxe/IoMmuDxe.c
@@ -10,6 +10,8 @@
 **/
 
 #include "CcIoMmu.h"
+#include <Library/CsvLib.h>
+#include "CsvIoMmu.h"
 
 EFI_STATUS
 EFIAPI
@@ -21,6 +23,14 @@ IoMmuDxeEntryPoint (
   EFI_STATUS  Status;
   EFI_HANDLE  Handle;
 
+  if (CsvIsEnabled ()) {
+    Status = CsvInstallIoMmuProtocol ();
+    if (Status != EFI_SUCCESS) {
+      DEBUG((EFI_D_ERROR, "fail to install CSV IOMMU\n"));
+    }
+    return Status;
+  }
+
   //
   // When SEV or TDX is enabled, install IoMmu protocol otherwise install the
   // placeholder protocol so that other dependent module can run.
diff --git a/OvmfPkg/IoMmuDxe/IoMmuDxe.inf b/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
index 17fca52..37d0d81 100644
--- a/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
+++ b/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
@@ -22,6 +22,8 @@
   CcIoMmu.h
   IoMmuDxe.c
   IoMmuBuffer.c
+  CsvIoMmu.c
+  CsvIoMmu.h
 
 [Packages]
   MdePkg/MdePkg.dec
@@ -37,6 +39,7 @@
   MemoryAllocationLib
   UefiBootServicesTableLib
   UefiDriverEntryPoint
+  CsvLib
 
 [Pcd]
   gEfiMdePkgTokenSpaceGuid.PcdConfidentialComputingGuestAttr
@@ -44,6 +47,7 @@
 [Protocols]
   gEdkiiIoMmuProtocolGuid                     ## SOMETIME_PRODUCES
   gIoMmuAbsentProtocolGuid                    ## SOMETIME_PRODUCES
+  gCsvSharedMemoryProtocolGuid
 
 [Depex]
-  TRUE
+  gCsvSharedMemoryProtocolGuid
-- 
2.25.1