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: Stefan Berger <stefanb@linux.vnet.ibm.com>
Tested-by: Hon Ching(Vicky) Lo <honclo@linux.vnet.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Ashley Lai <ashley@ashleylai.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm_ibmvtpm.h b/drivers/char/tpm/tpm_ibmvtpm.h
index 6af92890518f..91dfe766d080 100644
--- a/drivers/char/tpm/tpm_ibmvtpm.h
+++ b/drivers/char/tpm/tpm_ibmvtpm.h
@@ -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