[edk2-devel] [PATCH v2 40/45] ArmVirtPkg: RMM 1.0-eac3 - Handle RsiSetIpaState() response

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

The RMM 1.0-eac3 specification extends the RSI_IPA_STATE_SET
command to return a new RsiResponse value to indicate if the
Host accepts or rejects the IPA state change request to RAM.

Therefore, define the RsiResponse enum and return an error
RETURN_ACCESS_DENIED if the Host rejects the RIPAS change
request to RAM.

Such a failure is fatal and not recoverable and the caller
is then expected to tear down the Realm.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
---
 ArmVirtPkg/Include/Library/ArmCcaRsiLib.h      | 26 +++++++++++++++++++-
 ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c |  8 +++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/ArmVirtPkg/Include/Library/ArmCcaRsiLib.h b/ArmVirtPkg/Include/Library/ArmCcaRsiLib.h
index 5c2f996d3b4376e831a901f2919780acffec3313..88351f53336c42c032fcff6ea97ea7728b917b76 100644
--- a/ArmVirtPkg/Include/Library/ArmCcaRsiLib.h
+++ b/ArmVirtPkg/Include/Library/ArmCcaRsiLib.h
@@ -11,7 +11,7 @@
     - REM          - Realm Extensible Measurement
 
   @par Reference(s):
-   - Realm Management Monitor (RMM) Specification, version 1.0-eac2
+   - Realm Management Monitor (RMM) Specification, version 1.0-eac3
      (https://developer.arm.com/documentation/den0137/)
 **/
 
@@ -91,6 +91,29 @@
 */
 #define RIPAS_CHANGE_FLAGS_RSI_CHANGE_DESTROYED  1
 
+/* The RsiResponse type is a value returned by the
+   RSI_IPA_STATE_SET command and represents whether
+   the Host accepted or rejected a Realm request.
+   See section B4.4.6 RsiResponse type in the
+   RMM Specification, version 1.0-eac3.
+   The width of the RsiResponse enumeration is 1 bit
+   and the following macros prefixed RIPAS_CHANGE_RESPONSE_xxx
+   define the values of the RsiResponse type.
+*/
+
+/* The RIPAS change request to RAM was accepted
+   by the host.
+*/
+#define RIPAS_CHANGE_RESPONSE_ACCEPT  0
+
+/* The RIPAS change request to RAM was rejected
+   by the host.
+*/
+#define RIPAS_CHANGE_RESPONSE_REJECT  1
+
+/* A mask for the RSI Response bit */
+#define RSI_RESPONSE_MASK  BIT0
+
 /** An enum describing the RSI RIPAS.
    See Section A5.2.2 Realm IPA state, RMM Specification, version 1.0-eac2
 */
@@ -209,6 +232,7 @@ RsiGetIpaState (
 
   @retval RETURN_SUCCESS            Success.
   @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+  @retval RETURN_ACCESS_DENIED      RIPAS change request was rejected.
 **/
 RETURN_STATUS
 EFIAPI
diff --git a/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c b/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c
index 0535254a3991bfe7a19b904e83b9482f801da20c..12636c484824426b2ea81ca007d962f5f7c58f8c 100644
--- a/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c
+++ b/ArmVirtPkg/Library/ArmCcaRsiLib/ArmCcaRsiLib.c
@@ -11,7 +11,7 @@
     - REM          - Realm Extensible Measurement
 
   @par Reference(s):
-   - Realm Management Monitor (RMM) Specification, version 1.0-eac2
+   - Realm Management Monitor (RMM) Specification, version 1.0-eac3
      (https://developer.arm.com/documentation/den0137/)
 
 **/
@@ -322,6 +322,7 @@ RsiGetIpaState (
 
   @retval RETURN_SUCCESS            Success.
   @retval RETURN_INVALID_PARAMETER  A parameter is invalid.
+  @retval RETURN_ACCESS_DENIED      RIPAS change request was rejected.
 **/
 RETURN_STATUS
 EFIAPI
@@ -365,6 +366,11 @@ RsiSetIpaState (
 
     BaseAddress = (UINT64 *)SmcCmd.Arg1;
     Size        = EndAddress - BaseAddress;
+
+    if ((SmcCmd.Arg2 & RSI_RESPONSE_MASK) == RIPAS_CHANGE_RESPONSE_REJECT) {
+      Status = RETURN_ACCESS_DENIED;
+      break;
+    }
   }   // while
 
   return Status;
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'



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