On Fri, Jun 05, 2020 at 04:37:19PM +1000, David Gibson wrote:
> 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.
>
> Fixes: 18b3670d79ae9 "tpm: ibmvtpm: Add support for TPM2"
Should be Fixes: 18b3670d79ae ("tpm: ibmvtpm: Add support for TPM2")
Also briefly state what the commit does, not just the problem
description. The code change looks legit.
Please send v2 with these changes.
> Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/char/tpm/tpm_ibmvtpm.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
> index 09fe45246b8c..994385bf37c0 100644
> --- a/drivers/char/tpm/tpm_ibmvtpm.c
> +++ b/drivers/char/tpm/tpm_ibmvtpm.c
> @@ -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 {
> --
> 2.26.2
>
/Jarkko
