[RFC PATCH v1 09/30] ArmVirtPkg: ArmCcaRsiLib: Add interfaces to get/extend REMs

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

The Section A2.1.3 Realm attributes, RMM Specification, version A-bet0
introduces the concept of REMs as described below:
  DGRFCS - A Realm Extensible Measurement (REM) is a measurement value
           which can be extended during the lifetime of a Realm.
  IFMPYL - Attributes of a Realm include an array of measurement values.
           The first entry in this array is a RIM. The remaining entries
           in this array are REMs.

The Realm Service Interface commands defined in section
B4.3.7 RSI_MEASUREMENT_READ and B4.3.6 RSI_MEASUREMENT_EXTEND
specify the interfaces to read and extend measurements to REMs.

Therefore, update ArmCcaRsiLib to add interfaces to get and extend REMs.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
---
 ArmVirtPkg/Include/Library/ArmCcaRsiLib.h      | 53 ++++++++++++
 ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsi.h    |  2 +
 ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c | 91 ++++++++++++++++++++
 3 files changed, 146 insertions(+)

diff --git a/ArmVirtPkg/Include/Library/ArmCcaRsiLib.h b/ArmVirtPkg/Include/Library/ArmCcaRsiLib.h
index fe176d83c4b11d3f7bb35c97ec8ef00a4f47f981..51527071ab87aa82efa9ddc3064bb88803d5ba13 100644
--- a/ArmVirtPkg/Include/Library/ArmCcaRsiLib.h
+++ b/ArmVirtPkg/Include/Library/ArmCcaRsiLib.h
@@ -7,6 +7,8 @@
     - Rsi or RSI   - Realm Service Interface
     - IPA          - Intermediate Physical Address
     - RIPAS        - Realm IPA state
+    - RIM          - Realm Initial Measurement
+    - REM          - Realm Extensible Measurement
 
   @par Reference(s):
    - Realm Management Monitor (RMM) Specification, version A-bet0
@@ -44,6 +46,21 @@
 */
 #define MIN_CHALLENGE_DATA_SIZE_BITS  256
 
+/* Maximum measurement data size in bytes.
+  See Section C1.11 RmmRealmMeasurement type, RMM Specification, version A-bet0
+  The width of the RmmRealmMeasurement type is 512 bits.
+*/
+#define MAX_MEASUREMENT_DATA_SIZE_BYTES  64
+
+/* Minimum and Maximum indices for REMs
+  See Section A2.1.3 Realm attributes, RMM Specification, version A-bet0
+  IFMPYL - Attributes of a Realm include an array of measurement values. The
+  first entry in this array is a RIM. The remaining entries in this array are
+  REMs.
+*/
+#define MIN_REM_INDEX  1
+#define MAX_REM_INDEX  4
+
 /** An enum describing the RSI RIPAS.
    See Section A5.2.2 Realm IPA state, RMM Specification, version A-bet0
 */
@@ -127,6 +144,42 @@ RsiSetIpaState (
   IN  RIPAS   State
   );
 
+/**
+  Extends a measurement to a REM.
+
+  @param [in] MeasurementIndex     Index of the REM.
+  @param [in] Measurement          Pointer to the measurement buffer.
+  @param [in] MeasurementSize      Size of the measurement data.
+
+  @retval RETURN_SUCCESS            Success.
+  @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+**/
+RETURN_STATUS
+EFIAPI
+RsiExtendMeasurement (
+  IN        UINTN          MeasurementIndex,
+  IN  CONST UINT8  *CONST  Measurement,
+  IN        UINTN          MeasurementSize
+  );
+
+/**
+  Read the measurement value from a REM.
+
+  @param [in]   MeasurementIndex     Index of the REM.
+  @param [out]  MeasurementBuffer     Pointer to store the measurement data.
+  @param [in]   MeasurementBufferSize Size of the measurement buffer.
+
+  @retval RETURN_SUCCESS            Success.
+  @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+**/
+RETURN_STATUS
+EFIAPI
+RsiReadMeasurement (
+  IN    UINTN          MeasurementIndex,
+  OUT   UINT8  *CONST  MeasurementBuffer,
+  IN    UINTN          MeasurementBufferSize
+  );
+
 /**
   Read the Realm Configuration.
 
diff --git a/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsi.h b/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsi.h
index 325234d06695befc840dcf37e951130dfe0550c3..6f0ee3061ade5a4a99b717a52d5a241e0e446270 100644
--- a/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsi.h
+++ b/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsi.h
@@ -22,6 +22,8 @@
 #define FID_RSI_ATTESTATION_TOKEN_INIT      0xC4000194
 #define FID_RSI_IPA_STATE_GET               0xC4000198
 #define FID_RSI_IPA_STATE_SET               0xC4000197
+#define FID_RSI_MEASUREMENT_EXTEND          0xC4000193
+#define FID_RSI_MEASUREMENT_READ            0xC4000192
 #define FID_RSI_REALM_CONFIG                0xC4000196
 #define FID_RSI_VERSION                     0xC4000190
 
diff --git a/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c b/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c
index 01ecee3a6798c0e5cefd9fb4f48788d3063c94cd..fd29fc61caf880bcaf96d982f3a4d973e7ebb70f 100644
--- a/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c
+++ b/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c
@@ -8,6 +8,7 @@
     - Rsi or RSI   - Realm Service Interface
     - IPA          - Intermediate Physical Address
     - RIPAS        - Realm IPA state
+    - REM          - Realm Extensible Measurement
 
   @par Reference(s):
    - Realm Management Monitor (RMM) Specification, version A-bet0
@@ -366,6 +367,96 @@ RsiSetIpaState (
   return Status;
 }
 
+/**
+  Extends a measurement to a REM.
+
+  @param [in] MeasurementIndex     Index of the REM.
+  @param [in] Measurement          Pointer to the measurement buffer.
+  @param [in] MeasurementSize      Size of the measurement data.
+
+  @retval RETURN_SUCCESS            Success.
+  @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+**/
+RETURN_STATUS
+EFIAPI
+RsiExtendMeasurement (
+  IN        UINTN          MeasurementIndex,
+  IN  CONST UINT8  *CONST  Measurement,
+  IN        UINTN          MeasurementSize
+  )
+{
+  ARM_SMC_ARGS  SmcCmd;
+  UINT64        *Data64;
+
+  if ((MeasurementIndex < MIN_REM_INDEX)  ||
+      (MeasurementIndex > MAX_REM_INDEX)  ||
+      (Measurement == NULL)               ||
+      (MeasurementSize == 0)              ||
+      (MeasurementSize > MAX_MEASUREMENT_DATA_SIZE_BYTES))
+  {
+    return RETURN_INVALID_PARAMETER;
+  }
+
+  ZeroMem (&SmcCmd, sizeof (SmcCmd));
+
+  SmcCmd.Arg0 = FID_RSI_MEASUREMENT_EXTEND;
+  SmcCmd.Arg1 = MeasurementIndex;
+  SmcCmd.Arg2 = MeasurementSize;
+
+  Data64 = &SmcCmd.Arg3;
+  CopyMem (Data64, Measurement, MeasurementSize);
+
+  ArmCallSmc (&SmcCmd);
+  return RsiCmdStatusToEfiStatus (SmcCmd.Arg0);
+}
+
+/**
+  Read the measurement value from a REM.
+
+  @param [in]   MeasurementIndex     Index of the REM.
+  @param [out]  MeasurementBuffer     Pointer to store the measurement data.
+  @param [in]   MeasurementBufferSize Size of the measurement buffer.
+
+  @retval RETURN_SUCCESS            Success.
+  @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+**/
+RETURN_STATUS
+EFIAPI
+RsiReadMeasurement (
+  IN    UINTN          MeasurementIndex,
+  OUT   UINT8  *CONST  MeasurementBuffer,
+  IN    UINTN          MeasurementBufferSize
+  )
+{
+  RETURN_STATUS  Status;
+  ARM_SMC_ARGS   SmcCmd;
+  UINT64         *Data64;
+
+  if ((MeasurementIndex < MIN_REM_INDEX)  ||
+      (MeasurementIndex > MAX_REM_INDEX)  ||
+      (MeasurementBuffer == NULL))
+  {
+    return RETURN_INVALID_PARAMETER;
+  }
+
+  if (MeasurementBufferSize < MAX_MEASUREMENT_DATA_SIZE_BYTES) {
+    return RETURN_BUFFER_TOO_SMALL;
+  }
+
+  ZeroMem (&SmcCmd, sizeof (SmcCmd));
+  SmcCmd.Arg0 = FID_RSI_MEASUREMENT_READ;
+  SmcCmd.Arg1 = MeasurementIndex;
+
+  ArmCallSmc (&SmcCmd);
+  Status = RsiCmdStatusToEfiStatus (SmcCmd.Arg0);
+  if (!RETURN_ERROR (Status)) {
+    Data64 = &SmcCmd.Arg1;
+    CopyMem (MeasurementBuffer, Data64, MAX_MEASUREMENT_DATA_SIZE_BYTES);
+  }
+
+  return Status;
+}
+
 /**
   Read the Realm Configuration.
 
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'