Date:   Wed, 18 Mar 2020 19:49:27 -0400
From:   George Wilson <gcwilson@...ux.ibm.com>
To:     linux-integrity@...r.kernel.org
Cc:     Alexey Kardashevskiy <aik@...abs.ru>,
        Stefan Berger <stefanb@...ux.ibm.com>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Nayna Jain <nayna@...ux.vnet.ibm.com>,
        Jason Gunthorpe <jgg@...pe.ca>, linux-kernel@...r.kernel.org,
        George Wilson <gcwilson@...ux.ibm.com>,
        Linh Pham <phaml@...ibm.com>
Subject: [PATCH v3] tpm: ibmvtpm: retry on H_CLOSED in tpm_ibmvtpm_send()

tpm_ibmvtpm_send() can fail during PowerVM Live Partition Mobility 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@...ibm.com>
Reviewed-by: Stefan Berger <stefanb@...ux.ibm.com>
Signed-off-by: George Wilson <gcwilson@...ux.ibm.com>
Tested-by: Linh Pham <phaml@...ibm.com>
Fixes: 132f76294744 ("Add new device driver to support IBM vTPM")
---
 drivers/char/tpm/tpm_ibmvtpm.c | 136 ++++++++++++++++++---------------
 1 file changed, 73 insertions(+), 63 deletions(-)

diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index 78cc52690177..d097d47e0efa 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@...il.com>
  *
@@ -133,6 +133,64 @@ static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 	return len;
 }
 
+/**
+ * ibmvtpm_crq_send_init - Send a CRQ initialize message
+ * @ibmvtpm:	vtpm device struct
+ *
+ * Return:
+ *	0 on success.
+ *	Non-zero on failure.
+ */
+static int ibmvtpm_crq_send_init(struct ibmvtpm_dev *ibmvtpm)
+{
+	int rc;
+
+	rc = ibmvtpm_send_crq_word(ibmvtpm->vdev, INIT_CRQ_CMD);
+	if (rc != H_SUCCESS)
+		dev_err(ibmvtpm->dev,
+			"ibmvtpm_crq_send_init failed rc=%d\n", rc);
+
+	return rc;
+}
+
+/**
+ * tpm_ibmvtpm_resume - Resume from suspend
+ *
+ * @dev:	device struct
+ *
+ * Return: Always 0.
+ */
+static int tpm_ibmvtpm_resume(struct device *dev)
+{
+	struct tpm_chip *chip = dev_get_drvdata(dev);
+	struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
+	int rc = 0;
+
+	do {
+		if (rc)
+			msleep(100);
+		rc = plpar_hcall_norets(H_ENABLE_CRQ,
+					ibmvtpm->vdev->unit_address);
+	} while (rc == H_IN_PROGRESS || rc == H_BUSY || H_IS_LONG_BUSY(rc));
+
+	if (rc) {
+		dev_err(dev, "Error enabling ibmvtpm rc=%d\n", rc);
+		return rc;
+	}
+
+	rc = vio_enable_interrupts(ibmvtpm->vdev);
+	if (rc) {
+		dev_err(dev, "Error vio_enable_interrupts rc=%d\n", rc);
+		return rc;
+	}
+
+	rc = ibmvtpm_crq_send_init(ibmvtpm);
+	if (rc)
+		dev_err(dev, "Error send_init rc=%d\n", rc);
+
+	return rc;
+}
+
 /**
  * tpm_ibmvtpm_send() - Send a TPM command
  * @chip:	tpm chip struct
@@ -146,6 +204,7 @@ static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
 {
 	struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
+	bool retry = true;
 	int rc, sig;
 
 	if (!ibmvtpm->rtce_buf) {
@@ -179,18 +238,27 @@ 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)
@@ -268,26 +336,6 @@ static int ibmvtpm_crq_send_init_complete(struct ibmvtpm_dev *ibmvtpm)
 	return rc;
 }
 
-/**
- * ibmvtpm_crq_send_init - Send a CRQ initialize message
- * @ibmvtpm:	vtpm device struct
- *
- * Return:
- *	0 on success.
- *	Non-zero on failure.
- */
-static int ibmvtpm_crq_send_init(struct ibmvtpm_dev *ibmvtpm)
-{
-	int rc;
-
-	rc = ibmvtpm_send_crq_word(ibmvtpm->vdev, INIT_CRQ_CMD);
-	if (rc != H_SUCCESS)
-		dev_err(ibmvtpm->dev,
-			"ibmvtpm_crq_send_init failed rc=%d\n", rc);
-
-	return rc;
-}
-
 /**
  * tpm_ibmvtpm_remove - ibm vtpm remove entry point
  * @vdev:	vio device struct
@@ -400,44 +448,6 @@ static int ibmvtpm_reset_crq(struct ibmvtpm_dev *ibmvtpm)
 				  ibmvtpm->crq_dma_handle, CRQ_RES_BUF_SIZE);
 }
 
-/**
- * tpm_ibmvtpm_resume - Resume from suspend
- *
- * @dev:	device struct
- *
- * Return: Always 0.
- */
-static int tpm_ibmvtpm_resume(struct device *dev)
-{
-	struct tpm_chip *chip = dev_get_drvdata(dev);
-	struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
-	int rc = 0;
-
-	do {
-		if (rc)
-			msleep(100);
-		rc = plpar_hcall_norets(H_ENABLE_CRQ,
-					ibmvtpm->vdev->unit_address);
-	} while (rc == H_IN_PROGRESS || rc == H_BUSY || H_IS_LONG_BUSY(rc));
-
-	if (rc) {
-		dev_err(dev, "Error enabling ibmvtpm rc=%d\n", rc);
-		return rc;
-	}
-
-	rc = vio_enable_interrupts(ibmvtpm->vdev);
-	if (rc) {
-		dev_err(dev, "Error vio_enable_interrupts rc=%d\n", rc);
-		return rc;
-	}
-
-	rc = ibmvtpm_crq_send_init(ibmvtpm);
-	if (rc)
-		dev_err(dev, "Error send_init rc=%d\n", rc);
-
-	return rc;
-}
-
 static bool tpm_ibmvtpm_req_canceled(struct tpm_chip *chip, u8 status)
 {
 	return (status == 0);
-- 
2.24.1

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