[RFC PATCH v1 14/30] ArmVirtPkg: Add library for Arm CCA helper functions

["Sami Mujawar" <sami.mujawar@arm.com>]

Introduce ArmCcaLib library that implements helper
functions to:
- probe if the code is executing in a Realm context
- configure the protection attribute in page tables
  for the memory regions shared with the host
- get the IPA width of the Realm which was stored in
  the GUID HOB gArmCcaIpaWidthGuid.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
---
 ArmVirtPkg/ArmVirtPkg.dec                  |   1 +
 ArmVirtPkg/Include/Library/ArmCcaLib.h     | 114 ++++++++++++
 ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.c   | 190 ++++++++++++++++++++
 ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.inf |  34 ++++
 4 files changed, 339 insertions(+)

diff --git a/ArmVirtPkg/ArmVirtPkg.dec b/ArmVirtPkg/ArmVirtPkg.dec
index c270d4a1ee268fb57a5338fd71487ed54699f496..c61ed9c492e97aa00ba9dbab1a5544354b6e7de7 100644
--- a/ArmVirtPkg/ArmVirtPkg.dec
+++ b/ArmVirtPkg/ArmVirtPkg.dec
@@ -27,6 +27,7 @@ [Includes.common]
 
 [LibraryClasses]
   ArmCcaInitPeiLib|Include/Library/ArmCcaInitPeiLib.h
+  ArmCcaLib|Include/Library/ArmCcaLib.h
   ArmCcaRsiLib|Include/Library/ArmCcaRsiLib.h
   ArmVirtMemInfoLib|Include/Library/ArmVirtMemInfoLib.h
 
diff --git a/ArmVirtPkg/Include/Library/ArmCcaLib.h b/ArmVirtPkg/Include/Library/ArmCcaLib.h
new file mode 100644
index 0000000000000000000000000000000000000000..a47e14b507f1bfd1feece636063eb2ba83357a5b
--- /dev/null
+++ b/ArmVirtPkg/Include/Library/ArmCcaLib.h
@@ -0,0 +1,114 @@
+/** @file
+  Library that implements the Arm CCA helper functions.
+
+  Copyright (c) 2022 - 2023, Arm Ltd. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+    - Rsi or RSI   - Realm Service Interface
+    - IPA          - Intermediate Physical Address
+    - RIPAS        - Realm IPA state
+**/
+
+#ifndef ARM_CCA_LIB_
+#define ARM_CCA_LIB_
+
+#include <Base.h>
+#include <Uefi/UefiBaseType.h>
+
+/**
+  Check if running in a Realm.
+
+    @retval TRUE    The execution is within the context of a Realm.
+    @retval FALSE   The execution is not within the context of a Realm.
+**/
+BOOLEAN
+EFIAPI
+IsRealm (
+  VOID
+  );
+
+/**
+  Configure the protection attribute for the page tables
+  describing the memory region.
+
+  The IPA space of a Realm is divided into two halves:
+    - Protected IPA space and
+    - Unprotected IPA space.
+
+  Software in a Realm should treat the most significant bit of an
+  IPA as a protection attribute.
+
+  A Protected IPA is an address in the lower half of a Realms IPA
+  space. The most significant bit of a Protected IPA is 0.
+
+  An Unprotected IPA is an address in the upper half of a Realms
+  IPA space. The most significant bit of an Unprotected IPA is 1.
+
+  Note:
+  - Configuring the memory region as Unprotected IPA enables the
+    Realm to share the memory region with the Host.
+  - This function updates the page table entries to reflect the
+    protection attribute.
+  - A separate call to transition the memory range using the Realm
+    Service Interface (RSI) RSI_IPA_STATE_SET command is additionally
+    required and is expected to be done outside this function.
+
+    @param [in]  BaseAddress  Base address of the memory region.
+    @param [in]  Length       Length of the memory region.
+    @param [in]  IpaWidth     IPA width of the Realm.
+    @param [in]  Share        If TRUE, set the most significant
+                              bit of the IPA to configure the memory
+                              region as Unprotected IPA.
+                              If FALSE, clear the most significant
+                              bit of the IPA to configure the memory
+                              region as Protected IPA.
+
+    @retval RETURN_SUCCESS            IPA protection attribute updated.
+    @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+    @retval RETURN_UNSUPPORTED        The request is not initiated in a
+                                      Realm.
+**/
+RETURN_STATUS
+EFIAPI
+ArmCcaSetMemoryProtectAttribute (
+  IN EFI_PHYSICAL_ADDRESS  BaseAddress,
+  IN UINT64                Length,
+  IN UINT64                IpaWidth,
+  IN BOOLEAN               Share
+  );
+
+/**
+  Return the IPA width of the Realm.
+
+  The IPA width of the Realm is used to configure the protection attribute
+  for memory regions, see ArmCcaSetMemoryProtectAttribute().
+
+  The IPA width of the Realm is present in the Realm config which is read
+  when the ArmCcaInitPeiLib library hook function ArmCcaInitialize () is
+  called in the PrePi phase. ArmCcaInitialize () stores the IPA width of
+  the Realm in a GUID HOB gArmCcaIpaWidthGuid.
+
+  This function searches the GUID HOB gArmCcaIpaWidthGuid and returns the
+  IPA width value stored therein.
+
+  Note:
+  - This function must only be called after ArmCcaInitialize () has setup
+    the GUID HOB gArmCcaIpaWidthGuid.
+
+    @param [out] IpaWidth  IPA width of the Realm.
+
+    @retval RETURN_SUCCESS            Success.
+    @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+    @retval RETURN_NOT_FOUND          The GUID HOB gArmCcaIpaWidthGuid is not
+                                      found and could mean that this function
+                                      was called before ArmCcaInitialize ()
+                                      has created and initialised the GUID
+                                      HOB gArmCcaIpaWidthGuid.
+**/
+RETURN_STATUS
+EFIAPI
+GetIpaWidth (
+  OUT UINT64  *IpaWidth
+  );
+
+#endif // ARM_CCA_LIB_
diff --git a/ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.c b/ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.c
new file mode 100644
index 0000000000000000000000000000000000000000..32cfcbcadea261d0fa616b0e0b75ede47bd0f747
--- /dev/null
+++ b/ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.c
@@ -0,0 +1,190 @@
+/** @file
+  Library that implements the Arm CCA helper functions.
+
+  Copyright (c) 2022 - 2023, Arm Limited. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+  @par Glossary:
+    - Rsi or RSI   - Realm Service Interface
+    - IPA          - Intermediate Physical Address
+    - RIPAS        - Realm IPA state
+**/
+#include <Base.h>
+
+#include <Chipset/AArch64.h>
+#include <Library/ArmCcaLib.h>
+#include <Library/ArmCcaRsiLib.h>
+#include <Library/ArmMmuLib.h>
+#include <Library/BaseLib.h>
+
+#include <Uefi/UefiMultiPhase.h>
+#include <Pi/PiBootMode.h>
+#include <Pi/PiHob.h>
+#include <Library/HobLib.h>
+
+/**
+  Check if running in a Realm.
+
+    @retval TRUE    The execution is within the context of a Realm.
+    @retval FALSE   The execution is not within the context of a Realm.
+**/
+BOOLEAN
+EFIAPI
+IsRealm (
+  VOID
+  )
+{
+  RETURN_STATUS  Status;
+  UINT16         Major;
+  UINT16         Minor;
+
+  if (ArmHasRme ()) {
+    Status = RsiGetVersion (&Major, &Minor);
+    if (!RETURN_ERROR (Status)) {
+      return TRUE;
+    }
+  }
+
+  return FALSE;
+}
+
+/**
+  Configure the protection attribute for the page tables
+  describing the memory region.
+
+  The IPA space of a Realm is divided into two halves:
+    - Protected IPA space and
+    - Unprotected IPA space.
+
+  Software in a Realm should treat the most significant bit of an
+  IPA as a protection attribute.
+
+  A Protected IPA is an address in the lower half of a Realms IPA
+  space. The most significant bit of a Protected IPA is 0.
+
+  An Unprotected IPA is an address in the upper half of a Realms
+  IPA space. The most significant bit of an Unprotected IPA is 1.
+
+  Note:
+  - Configuring the memory region as Unprotected IPA enables the
+    Realm to share the memory region with the Host.
+  - This function updates the page table entries to reflect the
+    protection attribute.
+  - A separate call to transition the memory range using the Realm
+    Service Interface (RSI) RSI_IPA_STATE_SET command is additionally
+    required and is expected to be done outside this function.
+
+    @param [in]  BaseAddress  Base address of the memory region.
+    @param [in]  Length       Length of the memory region.
+    @param [in]  IpaWidth     IPA width of the Realm.
+    @param [in]  Share        If TRUE, set the most significant
+                              bit of the IPA to configure the memory
+                              region as Unprotected IPA.
+                              If FALSE, clear the most significant
+                              bit of the IPA to configure the memory
+                              region as Protected IPA.
+
+    @retval RETURN_SUCCESS            IPA protection attribute updated.
+    @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+    @retval RETURN_UNSUPPORTED        The request is not initiated in a
+                                      Realm.
+**/
+RETURN_STATUS
+EFIAPI
+ArmCcaSetMemoryProtectAttribute (
+  IN EFI_PHYSICAL_ADDRESS  BaseAddress,
+  IN UINT64                Length,
+  IN UINT64                IpaWidth,
+  IN BOOLEAN               Share
+  )
+{
+  UINT64  Val;
+  UINT64  Mask;
+  UINT64  ProtectionAttributeMask;
+
+  if (!IsRealm ()) {
+    return RETURN_UNSUPPORTED;
+  }
+
+  if (IpaWidth == 0) {
+    return RETURN_INVALID_PARAMETER;
+  }
+
+  /* Software in a Realm should treat the most significant bit of an
+     IPA as a protection attribute.
+  */
+  ProtectionAttributeMask = 1ULL << (IpaWidth - 1);
+
+  if (Share) {
+    Val  = ProtectionAttributeMask;
+    Mask = ~TT_ADDRESS_MASK_BLOCK_ENTRY;
+  } else {
+    Val  = 0;
+    Mask = ~(TT_ADDRESS_MASK_BLOCK_ENTRY | ProtectionAttributeMask);
+  }
+
+  return SetMemoryRegionAttribute (
+           BaseAddress,
+           Length,
+           Val,
+           Mask
+           );
+}
+
+/**
+  Return the IPA width of the Realm.
+
+  The IPA width of the Realm is used to configure the protection attribute
+  for memory regions, see ArmCcaSetMemoryProtectAttribute().
+
+  The IPA width of the Realm is present in the Realm config which is read
+  when the ArmCcaInitPeiLib library hook function ArmCcaInitialize () is
+  called in the PrePi phase. ArmCcaInitialize () stores the IPA width of
+  the Realm in a GUID HOB gArmCcaIpaWidthGuid.
+
+  This function searches the GUID HOB gArmCcaIpaWidthGuid and returns the
+  IPA width value stored therein.
+
+  Note:
+  - This function must only be called after ArmCcaInitialize () has setup
+    the GUID HOB gArmCcaIpaWidthGuid.
+
+    @param [out] IpaWidth  IPA width of the Realm.
+
+    @retval RETURN_SUCCESS            Success.
+    @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+    @retval RETURN_NOT_FOUND          The GUID HOB gArmCcaIpaWidthGuid is not
+                                      found and could mean that this function
+                                      was called before ArmCcaInitialize ()
+                                      has created and initialised the GUID
+                                      HOB gArmCcaIpaWidthGuid.
+**/
+RETURN_STATUS
+EFIAPI
+GetIpaWidth (
+  OUT UINT64  *IpaWidth
+  )
+{
+  VOID    *Hob;
+  UINT64  *CcaIpaWidth;
+
+  if (IpaWidth == NULL) {
+    return RETURN_INVALID_PARAMETER;
+  }
+
+  Hob = GetFirstGuidHob (&gArmCcaIpaWidthGuid);
+  if ((Hob == NULL) ||
+      (GET_GUID_HOB_DATA_SIZE (Hob) != sizeof (UINT64)))
+  {
+    return RETURN_NOT_FOUND;
+  }
+
+  CcaIpaWidth = GET_GUID_HOB_DATA (Hob);
+  if ((UINT64)*CcaIpaWidth == 0) {
+    return RETURN_NOT_FOUND;
+  }
+
+  *IpaWidth = *CcaIpaWidth;
+
+  return RETURN_SUCCESS;
+}
diff --git a/ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.inf b/ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.inf
new file mode 100644
index 0000000000000000000000000000000000000000..7d90b4535d69c12672af5de3d7cab63a3cd528a6
--- /dev/null
+++ b/ArmVirtPkg/Library/ArmCcaLib/ArmCcaLib.inf
@@ -0,0 +1,34 @@
+## @file
+#  Library that implements the Arm CCA helper functions.
+#
+#  Copyright (c) 2022 - 2023, Arm Limited. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001B
+  BASE_NAME                      = ArmCcaLib
+  FILE_GUID                      = 11C18743-52F9-405E-B35B-D7BE91A26F9F
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = ArmCcaLib
+
+[Sources]
+  ArmCcaLib.c
+
+[Packages]
+  ArmPkg/ArmPkg.dec
+  ArmVirtPkg/ArmVirtPkg.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  ArmCcaRsiLib
+  ArmLib
+  ArmMmuLib
+  BaseLib
+  HobLib
+
+[Guids]
+  gArmCcaIpaWidthGuid
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'