From: David Gibson <david@gibson.dropbear.id.au>
To: jarkko.sakkinen@linux.intel.com, stefanb@linux.ibm.com
Cc: mpe@ellerman.id.au, peterhuewe@gmx.de, jgg@ziepe.ca,
nayna@linux.ibm.com, paulus@samba.org,
linuxppc-dev@lists.ozlabs.org, linux-integrity@vger.kernel.org,
linux-kernel@vger.kernel.org,
David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCHv2] tpm: ibmvtpm: Wait for ready buffer before probing for TPM2 attributes
Date: Fri, 19 Jun 2020 13:30:40 +1000 [thread overview]
Message-ID: <20200619033040.121412-1-david@gibson.dropbear.id.au> (raw)
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>
---
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
next reply other threads:[~2020-06-19 3:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-19 3:30 David Gibson [this message]
2020-06-19 3:42 ` [PATCHv2] tpm: ibmvtpm: Wait for ready buffer before probing for TPM2 attributes Jerry Snitselaar
2020-06-23 0:48 ` Jarkko Sakkinen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200619033040.121412-1-david@gibson.dropbear.id.au \
--to=david@gibson.dropbear.id.au \
--cc=jarkko.sakkinen@linux.intel.com \
--cc=jgg@ziepe.ca \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=nayna@linux.ibm.com \
--cc=paulus@samba.org \
--cc=peterhuewe@gmx.de \
--cc=stefanb@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).