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* [PATCH v3] SecurityPkg: Add retry mechanism for tpm command
@ 2022-07-28  8:51 Qi Zhang
  2022-07-28 12:50 ` Yao, Jiewen
  0 siblings, 1 reply; 2+ messages in thread
From: Qi Zhang @ 2022-07-28  8:51 UTC (permalink / raw)
  To: devel; +Cc: Qi Zhang, Jiewen Yao, Jian J Wang, Swapnil Patil

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3980

As per TCG PC Client Device Driver Design Principle document,
if tpm commands fails due to timeout condition, then it should
have retry mechanism (3 retry attempts).
Existing implementation of PtpCrbTpmCommand does not have retry
mechanism if it fails with EFI_TIMEOUT.

See TCG PC Client Device Driver Design Principles for TPM 2.0
https://trustedcomputinggroup.org/wp-content/uploads/TCG_PCClient_Device_Driver_Design_Principles_TPM2p0_v1p1_r4_211104_final.pdf
Vision 1.1, Revision 0.04
Section 7.2.1

Signed-off-by: Qi Zhang <qi1.zhang@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Tested-by: Swapnil Patil <S.Keshavrao.Patil@dell.com>
---
 .../Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c       | 107 +++++++++++-------
 1 file changed, 68 insertions(+), 39 deletions(-)

diff --git a/SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c b/SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c
index 1d99beaa10..6b5994fde2 100644
--- a/SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c
+++ b/SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2Ptp.c
@@ -33,6 +33,11 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 //
 #define TPMCMDBUFLENGTH  0x500
 
+//
+// Max retry count
+//
+#define RETRY_CNT_MAX  3
+
 /**
   Check whether TPM PTP register exist.
 
@@ -153,6 +158,7 @@ PtpCrbTpmCommand (
   UINT32      TpmOutSize;
   UINT16      Data16;
   UINT32      Data32;
+  UINT8       RetryCnt;
 
   DEBUG_CODE_BEGIN ();
   UINTN  DebugSize;
@@ -179,53 +185,76 @@ PtpCrbTpmCommand (
   DEBUG_CODE_END ();
   TpmOutSize = 0;
 
-  //
-  // STEP 0:
-  // if CapCRbIdelByPass == 0, enforce Idle state before sending command
-  //
-  if ((GetCachedIdleByPass () == 0) && ((MmioRead32 ((UINTN)&CrbReg->CrbControlStatus) & PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE) == 0)) {
+  RetryCnt = 0;
+  while (TRUE) {
+    //
+    // STEP 0:
+    // if CapCRbIdelByPass == 0, enforce Idle state before sending command
+    //
+    if ((GetCachedIdleByPass () == 0) && ((MmioRead32 ((UINTN)&CrbReg->CrbControlStatus) & PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE) == 0)) {
+      Status = PtpCrbWaitRegisterBits (
+                 &CrbReg->CrbControlStatus,
+                 PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE,
+                 0,
+                 PTP_TIMEOUT_C
+                 );
+      if (EFI_ERROR (Status)) {
+        RetryCnt++;
+        if (RetryCnt < RETRY_CNT_MAX) {
+          MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_GO_IDLE);
+          continue;
+        } else {
+          //
+          // Try to goIdle to recover TPM
+          //
+          Status = EFI_DEVICE_ERROR;
+          goto GoIdle_Exit;
+        }
+      }
+    }
+
+    //
+    // STEP 1:
+    // Ready is any time the TPM is ready to receive a command, following a write
+    // of 1 by software to Request.cmdReady, as indicated by the Status field
+    // being cleared to 0.
+    //
+    MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_COMMAND_READY);
     Status = PtpCrbWaitRegisterBits (
-               &CrbReg->CrbControlStatus,
-               PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE,
+               &CrbReg->CrbControlRequest,
                0,
+               PTP_CRB_CONTROL_AREA_REQUEST_COMMAND_READY,
                PTP_TIMEOUT_C
                );
     if (EFI_ERROR (Status)) {
-      //
-      // Try to goIdle to recover TPM
-      //
-      Status = EFI_DEVICE_ERROR;
-      goto GoIdle_Exit;
+      RetryCnt++;
+      if (RetryCnt < RETRY_CNT_MAX) {
+        MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_GO_IDLE);
+        continue;
+      } else {
+        Status = EFI_DEVICE_ERROR;
+        goto GoIdle_Exit;
+      }
     }
-  }
 
-  //
-  // STEP 1:
-  // Ready is any time the TPM is ready to receive a command, following a write
-  // of 1 by software to Request.cmdReady, as indicated by the Status field
-  // being cleared to 0.
-  //
-  MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_COMMAND_READY);
-  Status = PtpCrbWaitRegisterBits (
-             &CrbReg->CrbControlRequest,
-             0,
-             PTP_CRB_CONTROL_AREA_REQUEST_COMMAND_READY,
-             PTP_TIMEOUT_C
-             );
-  if (EFI_ERROR (Status)) {
-    Status = EFI_DEVICE_ERROR;
-    goto GoIdle_Exit;
-  }
+    Status = PtpCrbWaitRegisterBits (
+               &CrbReg->CrbControlStatus,
+               0,
+               PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE,
+               PTP_TIMEOUT_C
+               );
+    if (EFI_ERROR (Status)) {
+      RetryCnt++;
+      if (RetryCnt < RETRY_CNT_MAX) {
+        MmioWrite32 ((UINTN)&CrbReg->CrbControlRequest, PTP_CRB_CONTROL_AREA_REQUEST_GO_IDLE);
+        continue;
+      } else {
+        Status = EFI_DEVICE_ERROR;
+        goto GoIdle_Exit;
+      }
+    }
 
-  Status = PtpCrbWaitRegisterBits (
-             &CrbReg->CrbControlStatus,
-             0,
-             PTP_CRB_CONTROL_AREA_STATUS_TPM_IDLE,
-             PTP_TIMEOUT_C
-             );
-  if (EFI_ERROR (Status)) {
-    Status = EFI_DEVICE_ERROR;
-    goto GoIdle_Exit;
+    break;
   }
 
   //
-- 
2.26.2.windows.1


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2022-07-28  8:51 [PATCH v3] SecurityPkg: Add retry mechanism for tpm command Qi Zhang
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