From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: stefanb@linux.ibm.com, 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
Subject: Re: [PATCHv2] tpm: ibmvtpm: Wait for ready buffer before probing for TPM2 attributes
Date: Tue, 23 Jun 2020 03:48:13 +0300 [thread overview]
Message-ID: <20200623004813.GB28795@linux.intel.com> (raw)
In-Reply-To: <20200619033040.121412-1-david@gibson.dropbear.id.au>
On Fri, Jun 19, 2020 at 01:30:40PM +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.
>
> 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: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
/Jarkko
prev parent reply other threads:[~2020-06-23 0:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-19 3:30 [PATCHv2] tpm: ibmvtpm: Wait for ready buffer before probing for TPM2 attributes David Gibson
2020-06-19 3:42 ` Jerry Snitselaar
2020-06-23 0:48 ` Jarkko Sakkinen [this message]
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