Re: [PATCH v4 1/2] fTPM: firmware TPM running in TEE

On Wed, 5 Jun 2019 at 16:39, Sumit Garg [off-list ref] wrote:

On Wed, 5 Jun 2019 at 01:39, Sasha Levin [off-list ref] wrote:

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On Tue, Jun 04, 2019 at 11:45:52AM +0530, Sumit Garg wrote:

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On Thu, 30 May 2019 at 20:58, Sasha Levin [off-list ref] wrote:

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+       /* Open context with TEE driver */
+       pvt_data->ctx = tee_client_open_context(NULL, ftpm_tee_match, NULL,
+                                               NULL);
+       if (IS_ERR(pvt_data->ctx)) {
+               dev_err(dev, "%s:tee_client_open_context failed\n", __func__);

Is this well tested? I see this misleading error multiple times as
follows although TEE driver works pretty well.

Yes, this was all functionally tested.

Can you share your build instructions and testing approach?

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Why is this error message misleading? I'd be happy to fix it.

But still this message should be updated to represent correct status.
Maybe something like:

dev_warn(dev, "waiting for OP-TEE to be alive\n");

IIUC, here you are trying to resolve dependency with OP-TEE driver
using "-EPROBE_DEFER". So user shouldn't be prompted with error
messages until OP-TEE driver comes up.

BTW, for me this OP-TEE driver dependency seems not to work, boot is
simply stuck waiting for device. Probably the reason being this fTPM
driver is a platform driver and OP-TEE NOT a platform driver.

Apologies for the noise here. It works as expected.

-Sumit

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Module built with "CONFIG_TCG_FTPM_TEE=y"

[    1.436878] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.509471] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.517268] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.525596] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed

Does the TEE have the fTPM implementation and such? Could you provide
details about your testing environment (hardware, fTPM verions, etc)?

I just did a sanity check on my arm64 machine (Developerbox), just
adding following DT node and enabled CONFIG_TCG_FTPM_TEE=y:

+    tpm@0 {
+        compatible = "microsoft,ftpm";
+    };

Basically with no fTPM TA, I expected the driver to fail during
"tee_client_open_session()" call with TA not found error and boot
should continue. But it fails during "tee_client_open_context()" which
opens a context with OP-TEE driver and has nothing to do with fTPM TA.

-Sumit

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--
Thanks,
Sasha