Retry count is suggested in the spec.
PtpCrbWaitRegisterBits() already has delay.
Thanks!
Qi Zhang
-----Original Message-----
From: Kinney, Michael D <michael.d.kin...@intel.com>
Sent: Thursday, July 28, 2022 12:38 AM
To: devel@edk2.groups.io; Yao, Jiewen <jiewen....@intel.com>; Zhang, Qi1
<qi1.zh...@intel.com>; Kinney, Michael D <michael.d.kin...@intel.com>
Cc: Wang, Jian J <jian.j.w...@intel.com>
Subject: RE: [edk2-devel] [PATCH] SecurityPkg: Add retry mechanism for tpm
command
Why is 3 the correct retry count?
Do we need this to be configurable?
Is a delay required between retries?
What specific state is a DTPM getting into that requires this retry mechanism?
Can that state be detected?
Thanks,
Mike
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Yao,
> Jiewen
> Sent: Wednesday, July 27, 2022 5:07 AM
> To: Zhang, Qi1 <qi1.zh...@intel.com>; devel@edk2.groups.io
> Cc: Wang, Jian J <jian.j.w...@intel.com>
> Subject: Re: [edk2-devel] [PATCH] SecurityPkg: Add retry mechanism for
> tpm command
>
> Thanks. Please add Bugzilla ID and add tested-by tag by the people who
> performed the test.
>
> For the code, reviewed-by: Jiewen Yao <jiewen....@intel.com>
>
> > -----Original Message-----
> > From: Zhang, Qi1 <qi1.zh...@intel.com>
> > Sent: Wednesday, July 27, 2022 7:36 PM
> > To: devel@edk2.groups.io
> > Cc: Zhang, Qi1 <qi1.zh...@intel.com>; Yao, Jiewen
> > <jiewen....@intel.com>; Wang, Jian J <jian.j.w...@intel.com>
> > Subject: [PATCH] SecurityPkg: Add retry mechanism for tpm command
> >
> > Signed-off-by: Qi Zhang <qi1.zh...@intel.com>
> > Cc: Jiewen Yao <jiewen....@intel.com>
> > Cc: Jian J Wang <jian.j.w...@intel.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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