Enable vTPM 2.0 for the IBM vTPM driver

From: Stefan Berger <[email protected]>

Synchronize with the results from the CRQs before continuing with the initialization. This avoids trying to send TPM commands while the rtce buffer has not been allocated, yet.

This patch fixes an existing race condition that may occurr if the hypervisor does not quickly respond to the VTPM_GET_RTCE_BUFFER_SIZE request sent during initialization and therefore the ibmvtpm->rtce_buf has not been allocated at the time the first TPM command is sent.

Signed-off-by Stefan Berger <[email protected]>

Fixes 132f76294744 ("Add new device driver to support IBM vTPM")

---
 drivers/char/tpm/tpm_ibmvtpm.c | 9 +++++++++
 drivers/char/tpm/tpm_ibmvtpm.h | 1 +
 2 files changed, 10 insertions(+)

drivers/char/tpm/tpm_ibmvtpm.c +9 -0

index 78cc52690177..eee566eddb35 100644
@@ -571,6 +571,7 @@ static irqreturn_t ibmvtpm_interrupt(int irq, void *vtpm_instance)
 	 */
 	while ((crq = ibmvtpm_crq_get_next(ibmvtpm)) != NULL) {
 		ibmvtpm_crq_process(crq, ibmvtpm);
+		wake_up_interruptible(&ibmvtpm->crq_queue.wq);
 		crq->valid = 0;
 		smp_wmb();
 	}

@@ -618,6 +619,7 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev,
 	}
 
 	crq_q->num_entry = CRQ_RES_BUF_SIZE / sizeof(*crq_q->crq_addr);
+	init_waitqueue_head(&crq_q->wq);
 	ibmvtpm->crq_dma_handle = dma_map_single(dev, crq_q->crq_addr,
 						 CRQ_RES_BUF_SIZE,
 						 DMA_BIDIRECTIONAL);

@@ -670,6 +672,13 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev,
 	if (rc)
 		goto init_irq_cleanup;
 
+	if (!wait_event_timeout(ibmvtpm->crq_queue.wq,
+				ibmvtpm->rtce_buf != NULL,
+				HZ)) {
+		dev_err(dev, "Initialization failed\n");
+		goto init_irq_cleanup;
+	}
+
 	return tpm_chip_register(chip);
 init_irq_cleanup:
 	do {

drivers/char/tpm/tpm_ibmvtpm.h +1 -0

index 7983f1a33267..b92aa7d3e93e 100644
@@ -26,6 +26,7 @@ struct ibmvtpm_crq_queue {
 	struct ibmvtpm_crq *crq_addr;
 	u32 index;
 	u32 num_entry;
+	wait_queue_head_t wq;
 };
 
 struct ibmvtpm_dev {

Signature · 1 line

2.23.0

From: Stefan Berger <[email protected]>

The IBM vTPM device driver will not use TPM_OPS_AUTO_STARTUP since we assume the firmware has initialized the TPM 2 and TPM2_Startup() need not be sent. Therefore, tpm2_auto_startup() will not be called. To cover the tpm_chip's initialization of timeouts, command durations, and command attributes we implement tpm2_init_commands() function that will be called instead of tpm2_auto_startup().

Signed-off-by Stefan Berger <[email protected]>

---
 drivers/char/tpm/tpm-interface.c |  5 ++++-
 drivers/char/tpm/tpm.h           |  1 +
 drivers/char/tpm/tpm2-cmd.c      | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

drivers/char/tpm/tpm-interface.c +4 -1

index a438b1206fcb..30d80b94db33 100644
@@ -371,8 +371,11 @@ int tpm_auto_startup(struct tpm_chip *chip)
 {
 	int rc;
 
-	if (!(chip->ops->flags & TPM_OPS_AUTO_STARTUP))
+	if (!(chip->ops->flags & TPM_OPS_AUTO_STARTUP)) {
+		if (chip->flags & TPM_CHIP_FLAG_TPM2)
+			return tpm2_init_commands(chip);
 		return 0;
+	}
 
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		rc = tpm2_auto_startup(chip);

drivers/char/tpm/tpm.h +1 -0

index 5620747da0cf..30da942d714a 100644
@@ -222,6 +222,7 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,
 			u32 *value, const char *desc);
 
 ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip);
+int tpm2_init_commands(struct tpm_chip *chip);
 int tpm2_auto_startup(struct tpm_chip *chip);
 void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type);
 unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);

drivers/char/tpm/tpm2-cmd.c +2 -0

index 13696deceae8..2d0c5a3b65c0 100644
@@ -709,6 +709,20 @@ static int tpm2_startup(struct tpm_chip *chip)
 	return rc;
 }
 
+/**
+ * tpm2_init_commands - Get timeouts, durations and command code attributes

From: Stefan Berger <[email protected]>

Support TPM 2 in the IBM vTPM driver. The hypervisor tells us what version of TPM is connected through the vio_device_id.

In case a TPM 2 is found, we set the TPM_CHIP_FLAG_TPM2 flag.

Signed-off-by Stefan Berger <[email protected]>