OvmfPkg/MemEncryptSevLib: Address range encryption state interface

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3108

Update the MemEncryptSevLib library to include an interface that can
report the encryption state on a range of memory. The values will
represent the range as being unencrypted, encrypted, a mix of unencrypted
and encrypted, and error (e.g. ranges that aren't mapped).

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <0d98f4d42a2b67310c29bac7bcdcf1eda6835847.1610045305.git.thomas.lendacky@amd.com>

9 files changed, 335 insertions, 12 deletions

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf
index 4480e4cc7c..8e3b8ddd5a 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf
@@ -36,6 +36,7 @@
 [Sources.X64]

   X64/MemEncryptSevLib.c

   X64/PeiDxeVirtualMemory.c

+  X64/VirtualMemory.c

   X64/VirtualMemory.h

 

 [Sources.IA32]

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
index b4f6e5738e..12a5bf495b 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
@@ -2,7 +2,7 @@
 

   Secure Encrypted Virtualization (SEV) library helper function

 

-  Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>

+  Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>

 

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

@@ -82,3 +82,32 @@ MemEncryptSevSetPageEncMask (
   //

   return RETURN_UNSUPPORTED;

 }

+

+/**

+  Returns the encryption state of the specified virtual address range.

+

+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use

+                                      current CR3)

+  @param[in]  BaseAddress             Base address to check

+  @param[in]  Length                  Length of virtual address range

+

+  @retval MemEncryptSevAddressRangeUnencrypted  Address range is mapped

+                                                unencrypted

+  @retval MemEncryptSevAddressRangeEncrypted    Address range is mapped

+                                                encrypted

+  @retval MemEncryptSevAddressRangeMixed        Address range is mapped mixed

+  @retval MemEncryptSevAddressRangeError        Address range is not mapped

+**/

+MEM_ENCRYPT_SEV_ADDRESS_RANGE_STATE

+EFIAPI

+MemEncryptSevGetAddressRangeState (

+  IN PHYSICAL_ADDRESS         Cr3BaseAddress,

+  IN PHYSICAL_ADDRESS         BaseAddress,

+  IN UINTN                    Length

+  )

+{

+  //

+  // Memory is always encrypted in 32-bit mode

+  //

+  return MemEncryptSevAddressRangeEncrypted;

+}

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
index 0697f1dab5..03a78c32df 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/PeiMemEncryptSevLib.inf
@@ -36,6 +36,7 @@
 [Sources.X64]

   X64/MemEncryptSevLib.c

   X64/PeiDxeVirtualMemory.c

+  X64/VirtualMemory.c

   X64/VirtualMemory.h

 

 [Sources.IA32]

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf b/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf
index 7cd0111fe4..279c38bfbc 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/SecMemEncryptSevLib.inf
@@ -35,6 +35,7 @@
 [Sources.X64]

   X64/MemEncryptSevLib.c

   X64/SecVirtualMemory.c

+  X64/VirtualMemory.c

   X64/VirtualMemory.h

 

 [Sources.IA32]

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
index cf0921e214..4fea6a6be0 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
@@ -2,7 +2,7 @@
 

   Secure Encrypted Virtualization (SEV) library helper function

 

-  Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>

+  Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>

 

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

@@ -88,3 +88,33 @@ MemEncryptSevSetPageEncMask (
            Flush

            );

 }

+

+/**

+  Returns the encryption state of the specified virtual address range.

+

+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use

+                                      current CR3)

+  @param[in]  BaseAddress             Base address to check

+  @param[in]  Length                  Length of virtual address range

+

+  @retval MemEncryptSevAddressRangeUnencrypted  Address range is mapped

+                                                unencrypted

+  @retval MemEncryptSevAddressRangeEncrypted    Address range is mapped

+                                                encrypted

+  @retval MemEncryptSevAddressRangeMixed        Address range is mapped mixed

+  @retval MemEncryptSevAddressRangeError        Address range is not mapped

+**/

+MEM_ENCRYPT_SEV_ADDRESS_RANGE_STATE

+EFIAPI

+MemEncryptSevGetAddressRangeState (

+  IN PHYSICAL_ADDRESS         Cr3BaseAddress,

+  IN PHYSICAL_ADDRESS         BaseAddress,

+  IN UINTN                    Length

+  )

+{

+  return InternalMemEncryptSevGetAddressRangeState (

+           Cr3BaseAddress,

+           BaseAddress,

+           Length

+           );

+}

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
index 3a5bab657b..d3455e812b 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
@@ -28,14 +28,14 @@ typedef enum {
 } MAP_RANGE_MODE;

 

 /**

-  Get the memory encryption mask

+  Return the pagetable memory encryption mask.

 

-  @param[out]      EncryptionMask        contains the pte mask.

+  @return  The pagetable memory encryption mask.

 

 **/

-STATIC

 UINT64

-GetMemEncryptionAddressMask (

+EFIAPI

+InternalGetMemEncryptionAddressMask (

   VOID

   )

 {

@@ -200,7 +200,7 @@ Split2MPageTo4K (
 

   PageTableEntry1 = PageTableEntry;

 

-  AddressEncMask = GetMemEncryptionAddressMask ();

+  AddressEncMask = InternalGetMemEncryptionAddressMask ();

 

   ASSERT (PageTableEntry != NULL);

   ASSERT (*PageEntry2M & AddressEncMask);

@@ -286,7 +286,7 @@ SetPageTablePoolReadOnly (
   LevelSize[3] = SIZE_1GB;

   LevelSize[4] = SIZE_512GB;

 

-  AddressEncMask  = GetMemEncryptionAddressMask();

+  AddressEncMask  = InternalGetMemEncryptionAddressMask();

   PageTable       = (UINT64 *)(UINTN)PageTableBase;

   PoolUnitSize    = PAGE_TABLE_POOL_UNIT_SIZE;

 

@@ -431,7 +431,7 @@ Split1GPageTo2M (
 

   PageDirectoryEntry = AllocatePageTableMemory(1);

 

-  AddressEncMask = GetMemEncryptionAddressMask ();

+  AddressEncMask = InternalGetMemEncryptionAddressMask ();

   ASSERT (PageDirectoryEntry != NULL);

   ASSERT (*PageEntry1G & AddressEncMask);

   //

@@ -485,7 +485,7 @@ SetOrClearCBit(
 {

   UINT64      AddressEncMask;

 

-  AddressEncMask = GetMemEncryptionAddressMask ();

+  AddressEncMask = InternalGetMemEncryptionAddressMask ();

 

   if (Mode == SetCBit) {

     *PageTablePointer |= AddressEncMask;

@@ -527,6 +527,7 @@ DisableReadOnlyPageWriteProtect (
 /**

  Enable Write Protect on pages marked as read-only.

 **/

+STATIC

 VOID

 EnableReadOnlyPageWriteProtect (

   VOID

@@ -605,7 +606,7 @@ SetMemoryEncDec (
   //

   // Check if we have a valid memory encryption mask

   //

-  AddressEncMask = GetMemEncryptionAddressMask ();

+  AddressEncMask = InternalGetMemEncryptionAddressMask ();

   if (!AddressEncMask) {

     return RETURN_ACCESS_DENIED;

   }

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
index 5c337ea0b8..bca5e3febb 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
@@ -14,6 +14,26 @@
 #include "VirtualMemory.h"

 

 /**

+  Return the pagetable memory encryption mask.

+

+  @return  The pagetable memory encryption mask.

+

+**/

+UINT64

+EFIAPI

+InternalGetMemEncryptionAddressMask (

+  VOID

+  )

+{

+  UINT64                            EncryptionMask;

+

+  EncryptionMask = MemEncryptSevGetEncryptionMask ();

+  EncryptionMask &= PAGING_1G_ADDRESS_MASK_64;

+

+  return EncryptionMask;

+}

+

+/**

   This function clears memory encryption bit for the memory region specified by

   PhysicalAddress and Length from the current page table context.

 

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.c
new file mode 100644
index 0000000000..36aabcf556
--- /dev/null
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.c
@@ -0,0 +1,207 @@
+/** @file

+

+  Virtual Memory Management Services to test an address range encryption state

+

+  Copyright (c) 2020, AMD Incorporated. All rights reserved.<BR>

+

+  SPDX-License-Identifier: BSD-2-Clause-Patent

+

+**/

+

+#include <Library/CpuLib.h>

+#include <Library/MemEncryptSevLib.h>

+

+#include "VirtualMemory.h"

+

+/**

+  Returns the (updated) address range state based upon the page table

+  entry.

+

+  @param[in]  CurrentState            The current address range state

+  @param[in]  PageDirectoryEntry      The page table entry to check

+  @param[in]  AddressEncMask          The encryption mask

+

+  @retval MemEncryptSevAddressRangeUnencrypted  Address range is mapped

+                                                unencrypted

+  @retval MemEncryptSevAddressRangeEncrypted    Address range is mapped

+                                                encrypted

+  @retval MemEncryptSevAddressRangeMixed        Address range is mapped mixed

+**/

+STATIC

+MEM_ENCRYPT_SEV_ADDRESS_RANGE_STATE

+UpdateAddressState (

+  IN MEM_ENCRYPT_SEV_ADDRESS_RANGE_STATE  CurrentState,

+  IN UINT64                               PageDirectoryEntry,

+  IN UINT64                               AddressEncMask

+  )

+{

+  if (CurrentState == MemEncryptSevAddressRangeEncrypted) {

+    if ((PageDirectoryEntry & AddressEncMask) == 0) {

+      CurrentState = MemEncryptSevAddressRangeMixed;

+    }

+  } else if (CurrentState == MemEncryptSevAddressRangeUnencrypted) {

+    if ((PageDirectoryEntry & AddressEncMask) != 0) {

+      CurrentState = MemEncryptSevAddressRangeMixed;

+    }

+  } else if (CurrentState == MemEncryptSevAddressRangeError) {

+    //

+    // First address check, set initial state

+    //

+    if ((PageDirectoryEntry & AddressEncMask) == 0) {

+      CurrentState = MemEncryptSevAddressRangeUnencrypted;

+    } else {

+      CurrentState = MemEncryptSevAddressRangeEncrypted;

+    }

+  }

+

+  return CurrentState;

+}

+

+/**

+  Returns the encryption state of the specified virtual address range.

+

+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use

+                                      current CR3)

+  @param[in]  BaseAddress             Base address to check

+  @param[in]  Length                  Length of virtual address range

+

+  @retval MemEncryptSevAddressRangeUnencrypted  Address range is mapped

+                                                unencrypted

+  @retval MemEncryptSevAddressRangeEncrypted    Address range is mapped

+                                                encrypted

+  @retval MemEncryptSevAddressRangeMixed        Address range is mapped mixed

+  @retval MemEncryptSevAddressRangeError        Address range is not mapped

+**/

+MEM_ENCRYPT_SEV_ADDRESS_RANGE_STATE

+EFIAPI

+InternalMemEncryptSevGetAddressRangeState (

+  IN PHYSICAL_ADDRESS  Cr3BaseAddress,

+  IN PHYSICAL_ADDRESS  BaseAddress,

+  IN UINTN             Length

+  )

+{

+  PAGE_MAP_AND_DIRECTORY_POINTER       *PageMapLevel4Entry;

+  PAGE_MAP_AND_DIRECTORY_POINTER       *PageUpperDirectoryPointerEntry;

+  PAGE_MAP_AND_DIRECTORY_POINTER       *PageDirectoryPointerEntry;

+  PAGE_TABLE_1G_ENTRY                  *PageDirectory1GEntry;

+  PAGE_TABLE_ENTRY                     *PageDirectory2MEntry;

+  PAGE_TABLE_4K_ENTRY                  *PageTableEntry;

+  UINT64                               AddressEncMask;

+  UINT64                               PgTableMask;

+  PHYSICAL_ADDRESS                     Address;

+  PHYSICAL_ADDRESS                     AddressEnd;

+  MEM_ENCRYPT_SEV_ADDRESS_RANGE_STATE  State;

+

+  //

+  // If Cr3BaseAddress is not specified then read the current CR3

+  //

+  if (Cr3BaseAddress == 0) {

+    Cr3BaseAddress = AsmReadCr3();

+  }

+

+  AddressEncMask = MemEncryptSevGetEncryptionMask ();

+  AddressEncMask &= PAGING_1G_ADDRESS_MASK_64;

+

+  PgTableMask = AddressEncMask | EFI_PAGE_MASK;

+

+  State = MemEncryptSevAddressRangeError;

+

+  //

+  // Encryption is on a page basis, so start at the beginning of the

+  // virtual address page boundary and walk page-by-page.

+  //

+  Address = (PHYSICAL_ADDRESS) (UINTN) BaseAddress & ~EFI_PAGE_MASK;

+  AddressEnd = (PHYSICAL_ADDRESS)

+                 (UINTN) (BaseAddress + Length);

+

+  while (Address < AddressEnd) {

+    PageMapLevel4Entry = (VOID*) (Cr3BaseAddress & ~PgTableMask);

+    PageMapLevel4Entry += PML4_OFFSET (Address);

+    if (!PageMapLevel4Entry->Bits.Present) {

+      return MemEncryptSevAddressRangeError;

+    }

+

+    PageDirectory1GEntry = (VOID *) (

+                             (PageMapLevel4Entry->Bits.PageTableBaseAddress <<

+                              12) & ~PgTableMask

+                             );

+    PageDirectory1GEntry += PDP_OFFSET (Address);

+    if (!PageDirectory1GEntry->Bits.Present) {

+      return MemEncryptSevAddressRangeError;

+    }

+

+    //

+    // If the MustBe1 bit is not 1, it's not actually a 1GB entry

+    //

+    if (PageDirectory1GEntry->Bits.MustBe1) {

+      //

+      // Valid 1GB page

+      //

+      State = UpdateAddressState (

+                State,

+                PageDirectory1GEntry->Uint64,

+                AddressEncMask

+                );

+

+      Address += BIT30;

+      continue;

+    }

+

+    //

+    // Actually a PDP

+    //

+    PageUpperDirectoryPointerEntry =

+      (PAGE_MAP_AND_DIRECTORY_POINTER *) PageDirectory1GEntry;

+    PageDirectory2MEntry =

+      (VOID *) (

+        (PageUpperDirectoryPointerEntry->Bits.PageTableBaseAddress <<

+         12) & ~PgTableMask

+        );

+    PageDirectory2MEntry += PDE_OFFSET (Address);

+    if (!PageDirectory2MEntry->Bits.Present) {

+      return MemEncryptSevAddressRangeError;

+    }

+

+    //

+    // If the MustBe1 bit is not a 1, it's not a 2MB entry

+    //

+    if (PageDirectory2MEntry->Bits.MustBe1) {

+      //

+      // Valid 2MB page

+      //

+      State = UpdateAddressState (

+                State,

+                PageDirectory2MEntry->Uint64,

+                AddressEncMask

+                );

+

+      Address += BIT21;

+      continue;

+    }

+

+    //

+    // Actually a PMD

+    //

+    PageDirectoryPointerEntry =

+      (PAGE_MAP_AND_DIRECTORY_POINTER *)PageDirectory2MEntry;

+    PageTableEntry =

+      (VOID *)(

+        (PageDirectoryPointerEntry->Bits.PageTableBaseAddress <<

+         12) & ~PgTableMask

+        );

+    PageTableEntry += PTE_OFFSET (Address);

+    if (!PageTableEntry->Bits.Present) {

+      return MemEncryptSevAddressRangeError;

+    }

+

+    State = UpdateAddressState (

+              State,

+              PageTableEntry->Uint64,

+              AddressEncMask

+              );

+

+    Address += EFI_PAGE_SIZE;

+  }

+

+  return State;

+}

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
index 26d26cd922..996f94f07e 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
@@ -3,7 +3,7 @@
   Virtual Memory Management Services to set or clear the memory encryption bit

 

   Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>

-  Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>

+  Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>

 

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

@@ -178,7 +178,17 @@ typedef struct {
   UINTN           FreePages;

 } PAGE_TABLE_POOL;

 

+/**

+  Return the pagetable memory encryption mask.

 

+  @return  The pagetable memory encryption mask.

+

+**/

+UINT64

+EFIAPI

+InternalGetMemEncryptionAddressMask (

+  VOID

+  );

 

 /**

   This function clears memory encryption bit for the memory region specified by

@@ -234,4 +244,27 @@ InternalMemEncryptSevSetMemoryEncrypted (
   IN  BOOLEAN                 Flush

   );

 

+/**

+  Returns the encryption state of the specified virtual address range.

+

+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use

+                                      current CR3)

+  @param[in]  BaseAddress             Base address to check

+  @param[in]  Length                  Length of virtual address range

+

+  @retval MemEncryptSevAddressRangeUnencrypted  Address range is mapped

+                                                unencrypted

+  @retval MemEncryptSevAddressRangeEncrypted    Address range is mapped

+                                                encrypted

+  @retval MemEncryptSevAddressRangeMixed        Address range is mapped mixed

+  @retval MemEncryptSevAddressRangeError        Address range is not mapped

+**/

+MEM_ENCRYPT_SEV_ADDRESS_RANGE_STATE

+EFIAPI

+InternalMemEncryptSevGetAddressRangeState (

+  IN PHYSICAL_ADDRESS         Cr3BaseAddress,

+  IN PHYSICAL_ADDRESS         BaseAddress,

+  IN UINTN                    Length

+  );

+

 #endif