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Commit 6674ff14 authored by Stefan Berger's avatar Stefan Berger Committed by Jarkko Sakkinen
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tpm_ibmvtpm: properly handle interrupted packet receptions 



When the TPM response reception is interrupted in the wait_event_interruptable
call, the TPM is still busy processing the command and will only deliver the
response later. So we have to wait for an outstanding response before sending
a new request to avoid trying to put a 2nd request into the CRQ. Also reset
the res_len before sending a command so we will end up in that
wait_event_interruptable() waiting for the response rather than reading the
command packet as a response.

The easiest way to trigger the problem is to run the following

cd /sys/device/vio/71000004

while :; cat pcrs >/dev/null; done

And press Ctrl-C. This will then display an error

tpm_ibmvtpm 71000004: tpm_transmit: tpm_recv: error -4

followed by several other errors once interaction with the TPM resumes.

tpm_ibmvtpm 71000004: A TPM error (101) occurred attempting to determine the number of PCRS.

Signed-off-by: default avatarStefan Berger <stefanb@linux.vnet.ibm.com>
Tested-by: default avatarHon Ching(Vicky) Lo <honclo@linux.vnet.ibm.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: default avatarAshley Lai <ashley@ashleylai.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: default avatarPeter Huewe <peterhuewe@gmx.de>
parent b8ba1e74

drivers/char/tpm/tpm_ibmvtpm.c

+20 −2
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count) 
		return 0;

	}



	sig = wait_event_interruptible(ibmvtpm->wq, ibmvtpm->res_len != 0);

	sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd);

	if (sig)

		return -EINTR;
@@ -125,7 +125,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) 
	struct ibmvtpm_dev *ibmvtpm;

	struct ibmvtpm_crq crq;

	__be64 *word = (__be64 *)&crq;

	int rc;

	int rc, sig;



	ibmvtpm = (struct ibmvtpm_dev *)TPM_VPRIV(chip);
@@ -141,18 +141,35 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) 
		return -EIO;

	}



	if (ibmvtpm->tpm_processing_cmd) {

		dev_info(ibmvtpm->dev,

		         "Need to wait for TPM to finish\n");

		/* wait for previous command to finish */

		sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd);

		if (sig)

			return -EINTR;

	}



	spin_lock(&ibmvtpm->rtce_lock);

	ibmvtpm->res_len = 0;

	memcpy((void *)ibmvtpm->rtce_buf, (void *)buf, count);

	crq.valid = (u8)IBMVTPM_VALID_CMD;

	crq.msg = (u8)VTPM_TPM_COMMAND;

	crq.len = cpu_to_be16(count);

	crq.data = cpu_to_be32(ibmvtpm->rtce_dma_handle);



	/*

	 * set the processing flag before the Hcall, since we may get the

	 * result (interrupt) before even being able to check rc.

	 */

	ibmvtpm->tpm_processing_cmd = true;



	rc = ibmvtpm_send_crq(ibmvtpm->vdev, be64_to_cpu(word[0]),

			      be64_to_cpu(word[1]));

	if (rc != H_SUCCESS) {

		dev_err(ibmvtpm->dev, "tpm_ibmvtpm_send failed rc=%d\n", rc);

		rc = 0;

		ibmvtpm->tpm_processing_cmd = false;

	} else

		rc = count;
@@ -515,6 +532,7 @@ static void ibmvtpm_crq_process(struct ibmvtpm_crq *crq, 
		case VTPM_TPM_COMMAND_RES:

			/* len of the data in rtce buffer */

			ibmvtpm->res_len = be16_to_cpu(crq->len);

			ibmvtpm->tpm_processing_cmd = false;

			wake_up_interruptible(&ibmvtpm->wq);

			return;

		default:

drivers/char/tpm/tpm_ibmvtpm.h

+1 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ struct ibmvtpm_dev { 
	wait_queue_head_t wq;

	u16 res_len;

	u32 vtpm_version;

	bool tpm_processing_cmd;

};



#define CRQ_RES_BUF_SIZE	PAGE_SIZE