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

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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: 18b3670d79 ("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>
This commit is contained in:
David Gibson 2020-06-19 13:30:40 +10:00 committed by Jarkko Sakkinen
parent 82efeb161c
commit 72d0556dca
1 changed files with 7 additions and 7 deletions
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14
drivers/char/tpm/tpm_ibmvtpm.c
View file

@ -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 {