OvmfPkg: Update IoMmuDxe to support TDX

RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429

The IOMMU protocol driver provides capabilities to set a DMA access
attribute and methods to allocate, free, map and unmap the DMA memory
for the PCI Bus devices.

The current IoMmuDxe driver supports DMA operations inside SEV guest.
To support DMA operation in TDX guest,
CC_GUEST_IS_XXX (PcdConfidentialComputingGuestAttr) is used to determine
if it is SEV guest or TDX guest.

Due to security reasons all DMA operations inside the SEV/TDX guest must
be performed on shared pages. The IOMMU protocol driver for the SEV/TDX
guest uses a bounce buffer to map guest DMA buffer to shared pages in
order to provide the support for DMA operations inside SEV/TDX guest.

The call of SEV or TDX specific function to set/clear EncMask/SharedBit
is determined by CC_GUEST_IS_XXX (PcdConfidentialComputingGuestAttr).

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

4 files changed, 78 insertions, 42 deletions

diff --git a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
index 16b5b4eac8..6b65897f03 100644
--- a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
+++ b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
@@ -1,9 +1,9 @@
 /** @file

 

   The protocol provides support to allocate, free, map and umap a DMA buffer

-  for bus master (e.g PciHostBridge). When SEV 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.

+  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>

@@ -12,6 +12,8 @@
 

 **/

 

+#include <Library/PcdLib.h>

+#include <ConfidentialComputingGuestAttr.h>

 #include "AmdSevIoMmu.h"

 

 #define MAP_INFO_SIG  SIGNATURE_64 ('M', 'A', 'P', '_', 'I', 'N', 'F', 'O')

@@ -74,7 +76,7 @@ typedef struct {
 

 /**

   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

+  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.

@@ -250,14 +252,28 @@ IoMmuMap (
       goto FreeMapInfo;

   }

 

-  //

-  // Clear the memory encryption mask on the plaintext buffer.

-  //

-  Status = MemEncryptSevClearPageEncMask (

-             0,

-             MapInfo->PlainTextAddress,

-             MapInfo->NumberOfPages

-             );

+  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 ();

@@ -358,7 +374,7 @@ IoMmuUnmapWorker (
   }

 

   MapInfo = (MAP_INFO *)Mapping;

-

+  Status  = EFI_SUCCESS;

   //

   // set CommonBufferHeader to suppress incorrect compiler/analyzer warnings

   //

@@ -404,15 +420,30 @@ IoMmuUnmapWorker (
       break;

   }

 

-  //

-  // Restore the memory encryption mask on the area we used to hold the

-  // plaintext.

-  //

-  Status = MemEncryptSevSetPageEncMask (

-             0,

-             MapInfo->PlainTextAddress,

-             MapInfo->NumberOfPages

-             );

+  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 ();

@@ -739,7 +770,7 @@ IoMmuSetAttribute (
   return EFI_UNSUPPORTED;

 }

 

-EDKII_IOMMU_PROTOCOL  mAmdSev = {

+EDKII_IOMMU_PROTOCOL  mIoMmu = {

   EDKII_IOMMU_PROTOCOL_REVISION,

   IoMmuSetAttribute,

   IoMmuMap,

@@ -771,7 +802,7 @@ EDKII_IOMMU_PROTOCOL  mAmdSev = {
 STATIC

 VOID

 EFIAPI

-AmdSevExitBoot (

+IoMmuExitBoot (

   IN EFI_EVENT  Event,

   IN VOID       *EventToSignal

   )

@@ -779,11 +810,11 @@ AmdSevExitBoot (
   //

   // (1) The NotifyFunctions of all the events in

   //     EFI_EVENT_GROUP_EXIT_BOOT_SERVICES will have been queued before

-  //     AmdSevExitBoot() is entered.

+  //     IoMmuExitBoot() is entered.

   //

-  // (2) AmdSevExitBoot() is executing minimally at TPL_CALLBACK.

+  // (2) IoMmuExitBoot() is executing minimally at TPL_CALLBACK.

   //

-  // (3) AmdSevExitBoot() has been queued in unspecified order relative to the

+  // (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.

@@ -791,13 +822,13 @@ AmdSevExitBoot (
   // Consequences:

   //

   // - If Event's NotifyTpl is TPL_CALLBACK, then some other NotifyFunctions

-  //   queued at TPL_CALLBACK may be invoked after AmdSevExitBoot() returns.

+  //   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 AmdSevExitBoot() returns; plus

+  //   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

-  //   AmdSevExitBoot(), have been invoked.

+  //   IoMmuExitBoot(), have been invoked.

   //

   // - By signaling EventToSignal here, whose NotifyTpl is TPL_CALLBACK, we

   //   queue EventToSignal's NotifyFunction after the NotifyFunctions of *all*

@@ -823,7 +854,7 @@ AmdSevExitBoot (
 STATIC

 VOID

 EFIAPI

-AmdSevUnmapAllMappings (

+IoMmuUnmapAllMappings (

   IN EFI_EVENT  Event,

   IN VOID       *Context

   )

@@ -842,7 +873,7 @@ AmdSevUnmapAllMappings (
     NextNode = GetNextNode (&mMapInfos, Node);

     MapInfo  = CR (Node, MAP_INFO, Link, MAP_INFO_SIG);

     IoMmuUnmapWorker (

-      &mAmdSev, // This

+      &mIoMmu,  // This

       MapInfo,  // Mapping

       TRUE      // MemoryMapLocked

       );

@@ -855,7 +886,7 @@ AmdSevUnmapAllMappings (
 **/

 EFI_STATUS

 EFIAPI

-AmdSevInstallIoMmuProtocol (

+InstallIoMmuProtocol (

   VOID

   )

 {

@@ -871,7 +902,7 @@ AmdSevInstallIoMmuProtocol (
   Status = gBS->CreateEvent (

                   EVT_NOTIFY_SIGNAL,      // Type

                   TPL_CALLBACK,           // NotifyTpl

-                  AmdSevUnmapAllMappings, // NotifyFunction

+                  IoMmuUnmapAllMappings,  // NotifyFunction

                   NULL,                   // NotifyContext

                   &UnmapAllMappingsEvent  // Event

                   );

@@ -886,7 +917,7 @@ AmdSevInstallIoMmuProtocol (
   Status = gBS->CreateEvent (

                   EVT_SIGNAL_EXIT_BOOT_SERVICES, // Type

                   TPL_CALLBACK,                  // NotifyTpl

-                  AmdSevExitBoot,                // NotifyFunction

+                  IoMmuExitBoot,                 // NotifyFunction

                   UnmapAllMappingsEvent,         // NotifyContext

                   &ExitBootEvent                 // Event

                   );

@@ -898,7 +929,7 @@ AmdSevInstallIoMmuProtocol (
   Status = gBS->InstallMultipleProtocolInterfaces (

                   &Handle,

                   &gEdkiiIoMmuProtocolGuid,

-                  &mAmdSev,

+                  &mIoMmu,

                   NULL

                   );

   if (EFI_ERROR (Status)) {

diff --git a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.h b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.h
index 8244f28b57..8fdfa99685 100644
--- a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.h
+++ b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.h
@@ -21,17 +21,17 @@
 #include <Library/BaseMemoryLib.h>

 #include <Library/DebugLib.h>

 #include <Library/MemEncryptSevLib.h>

+#include <Library/MemEncryptTdxLib.h>

 #include <Library/MemoryAllocationLib.h>

 #include <Library/UefiBootServicesTableLib.h>

 

 /**

-  Install IOMMU protocol to provide the DMA support for PciHostBridge and

-  MemEncryptSevLib.

+  Install IOMMU protocol to provide the DMA support for PciHostBridge.

 

 **/

 EFI_STATUS

 EFIAPI

-AmdSevInstallIoMmuProtocol (

+InstallIoMmuProtocol (

   VOID

   );

 

diff --git a/OvmfPkg/IoMmuDxe/IoMmuDxe.c b/OvmfPkg/IoMmuDxe/IoMmuDxe.c
index bca8c14c40..86777dd05c 100644
--- a/OvmfPkg/IoMmuDxe/IoMmuDxe.c
+++ b/OvmfPkg/IoMmuDxe/IoMmuDxe.c
@@ -22,11 +22,11 @@ IoMmuDxeEntryPoint (
   EFI_HANDLE  Handle;

 

   //

-  // When SEV is enabled, install IoMmu protocol otherwise install the

+  // When SEV or TDX is enabled, install IoMmu protocol otherwise install the

   // placeholder protocol so that other dependent module can run.

   //

-  if (MemEncryptSevIsEnabled ()) {

-    Status = AmdSevInstallIoMmuProtocol ();

+  if (MemEncryptSevIsEnabled () || MemEncryptTdxIsEnabled ()) {

+    Status = InstallIoMmuProtocol ();

   } else {

     Handle = NULL;

 

diff --git a/OvmfPkg/IoMmuDxe/IoMmuDxe.inf b/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
index 2ebd74e555..e10be1dcff 100644
--- a/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
+++ b/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
@@ -26,16 +26,21 @@
   MdePkg/MdePkg.dec

   MdeModulePkg/MdeModulePkg.dec

   OvmfPkg/OvmfPkg.dec

+#  UefiCpuPkg/UefiCpuPkg.dec

 

 [LibraryClasses]

   BaseLib

   BaseMemoryLib

   DebugLib

   MemEncryptSevLib

+  MemEncryptTdxLib

   MemoryAllocationLib

   UefiBootServicesTableLib

   UefiDriverEntryPoint

 

+[Pcd]

+  gEfiMdePkgTokenSpaceGuid.PcdConfidentialComputingGuestAttr

+

 [Protocols]

   gEdkiiIoMmuProtocolGuid                     ## SOMETIME_PRODUCES

   gIoMmuAbsentProtocolGuid                    ## SOMETIME_PRODUCES