Messages in this thread | | | Date | Thu, 18 Jun 2020 20:42:40 -0700 | From | Jerry Snitselaar <> | Subject | Re: [PATCHv2] tpm: ibmvtpm: Wait for ready buffer before probing for TPM2 attributes |
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On Fri Jun 19 20, 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. > >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: 18b3670d79ae9 ("tpm: ibmvtpm: Add support for TPM2") >Signed-off-by: David Gibson <david@gibson.dropbear.id.au> >---
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
> >Changes from v1: > * Fixed a formatting error in the commit message > * Added some more detail to the commit message > >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 09fe45246b8cc..994385bf37c0c 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 >
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