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Subject[PATCH] tpm: ibmvtpm: retry on H_CLOSED in tpm_ibmvtpm_send()
Date
tpm_ibmvtpm_send() can fail during LPM resume with an H_CLOSED return
from ibmvtpm_send_crq(). The PAPR says, 'The “partner partition
suspended” transport event disables the associated CRQ such that any
H_SEND_CRQ hcall() to the associated CRQ returns H_Closed until the CRQ
has been explicitly enabled using the H_ENABLE_CRQ hcall.' This patch
adds a check in tpm_ibmvtpm_send() for an H_CLOSED return from
ibmvtpm_send_crq() and in that case calls tpm_ibmvtpm_resume() and
retries the ibmvtpm_send_crq() once.

Reported-by: Linh Pham <phaml@us.ibm.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: George Wilson <gcwilson@linux.ibm.com>
---
drivers/char/tpm/tpm_ibmvtpm.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index 78cc52690177..ba3bd503e080 100644
--- a/drivers/char/tpm/tpm_ibmvtpm.c
+++ b/drivers/char/tpm/tpm_ibmvtpm.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * Copyright (C) 2012 IBM Corporation
+ * Copyright (C) 2012-2020 IBM Corporation
*
* Author: Ashley Lai <ashleydlai@gmail.com>
*
@@ -25,6 +25,8 @@
#include "tpm.h"
#include "tpm_ibmvtpm.h"

+static int tpm_ibmvtpm_resume(struct device *dev);
+
static const char tpm_ibmvtpm_driver_name[] = "tpm_ibmvtpm";

static const struct vio_device_id tpm_ibmvtpm_device_table[] = {
@@ -147,6 +149,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
{
struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
int rc, sig;
+ bool retry = true;

if (!ibmvtpm->rtce_buf) {
dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n");
@@ -179,18 +182,28 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
*/
ibmvtpm->tpm_processing_cmd = true;

+again:
rc = ibmvtpm_send_crq(ibmvtpm->vdev,
IBMVTPM_VALID_CMD, VTPM_TPM_COMMAND,
count, ibmvtpm->rtce_dma_handle);
+
if (rc != H_SUCCESS) {
+ /*
+ * H_CLOSED can be returned after LPM resume. Call
+ * tpm_ibmvtpm_resume() to re-enable the CRQ then retry
+ * ibmvtpm_send_crq() once before failing.
+ */
+ if (rc == H_CLOSED && retry) {
+ tpm_ibmvtpm_resume(ibmvtpm->dev);
+ retry = false;
+ goto again;
+ }
dev_err(ibmvtpm->dev, "tpm_ibmvtpm_send failed rc=%d\n", rc);
- rc = 0;
ibmvtpm->tpm_processing_cmd = false;
- } else
- rc = 0;
+ }

spin_unlock(&ibmvtpm->rtce_lock);
- return rc;
+ return 0;
}

static void tpm_ibmvtpm_cancel(struct tpm_chip *chip)
--
2.23.0
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