Commit 72d0556d authored Jun 19, 2020 by David Gibson Committed by Jarkko Sakkinen Jul 02, 2020

tpm: ibmvtpm: Wait for ready buffer before probing for TPM2 attributes



The tpm2_get_cc_attrs_tbl() call will result in TPM commands being issued,
which will need the use of the internal command/response buffer.  But,
we're issuing this *before* we've waited to make sure that buffer is
allocated.

This can result in intermittent failures to probe if the hypervisor / TPM
implementation doesn't respond quickly enough.  I find it fails almost
every time with an 8 vcpu guest under KVM with software emulated TPM.

To fix it, just move the tpm2_get_cc_attrs_tlb() call after the
existing code to wait for initialization, which will ensure the buffer
is allocated.

Fixes: 18b3670d ("tpm: ibmvtpm: Add support for TPM2")
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

parent 82efeb16

drivers/char/tpm/tpm_ibmvtpm.c

+7 −7

Original line number	Diff line number	Diff line
		@@ -683,13 +683,6 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev,
		if (rc)
		goto init_irq_cleanup;

		if (!strcmp(id->compat, "IBM,vtpm20")) {
		chip->flags \|= TPM_CHIP_FLAG_TPM2;
		rc = tpm2_get_cc_attrs_tbl(chip);
		if (rc)
		goto init_irq_cleanup;
		}

		if (!wait_event_timeout(ibmvtpm->crq_queue.wq,
		ibmvtpm->rtce_buf != NULL,
		HZ)) {
		@@ -697,6 +690,13 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev,
		goto init_irq_cleanup;
		}

		if (!strcmp(id->compat, "IBM,vtpm20")) {
		chip->flags \|= TPM_CHIP_FLAG_TPM2;
		rc = tpm2_get_cc_attrs_tbl(chip);
		if (rc)
		goto init_irq_cleanup;
		}

		return tpm_chip_register(chip);
		init_irq_cleanup:
		do {

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