On 03/31/2016 04:24 AM, Jarkko Sakkinen wrote:
> On Tue, Mar 29, 2016 at 02:19:13PM -0400, Stefan Berger wrote:
>> Add the retrieval of TPM 1.2 durations and timeouts. Since this requires
>> the startup of the TPM, do this for TPM 1.2 and TPM 2.
>> @@ -343,6 +362,55 @@ static const struct tpm_class_ops vtpm_proxy_tpm_ops = {
>> };
>>
>> /*
>> + * Code related to the startup of the TPM 2 and startup of TPM 1.2 +
>> + * retrieval of timeouts and durations.
>> + */
>> +
>> +static void vtpm_proxy_work(struct work_struct *work)
>> +{
>> + struct proxy_dev *proxy_dev = container_of(work, struct proxy_dev,
>> + work);
>> + int rc;
>> +
>> + if (proxy_dev->flags & VTPM_PROXY_FLAG_TPM2)
>> + rc = tpm2_startup(proxy_dev->chip, TPM2_SU_CLEAR);
>> + else
>> + rc = tpm_get_timeouts(proxy_dev->chip);
>> +
>> + if (rc)
>> + goto err;
>> +
>> + rc = tpm_chip_register(proxy_dev->chip);
>> + if (rc)
>> + goto err;
>> +
>> + return;
>> +
>> +err:
>> + vtpm_proxy_fops_undo_open(proxy_dev);
>> +}
>> +
>> +/*
>> + * vtpm_proxy_work_stop: make sure the work has finished
>> + *
>> + * This function is useful when user space closed the fd
>> + * while the driver still determines timeouts.
>> + */
>> +static void vtpm_proxy_work_stop(struct proxy_dev *proxy_dev)
>> +{
>> + vtpm_proxy_fops_undo_open(proxy_dev);
>> + flush_work(&proxy_dev->work);
> The main proxy driver patch should implement cancel() callback and then
> these could be swapped. This whole use of OPENED callback looks like a
> hack that is done because cancel is not implemented.
What OPENED callback are you referring to? We have a OPENED flag but not
a callback.
The above handles the case where the vTPM process for example dies
[during TPM_Startup()] and the file descriptor is closed.
vtpm_proxy_fops_undo_open() ensures that the vtpm thread is not stuck
waiting for the response to the TPM_Startup(). The subsequent
flush_work() ensures that the thread has finished before we continue
shutting down the instance. This cannot be swapped.
> A new flag CANCELED could be added and functions would return -ECANCEL
> if it is set. This should be part of original vTPM proxy driver
> functionally.
The above has nothing to do with cancellation from what I can see. We
have an OPENED flag now which is set when the driver is fully
operational and cleared when it is not. We could instead use a SHUTDOWN
or CLOSED flag that works with the reverse meaning, clearing it where
OPENED is set now and setting it where OPENED is cleared. Would this help?
>
> The current solution is unclean and hard to follow. It looks like "it
> could work" but the OPENED flag has too many hats that it wears IMHO.
It has only one meaning which can be replaced with a flag as indicated
above.
That it is tested in vtpm_tpm_req_canceled is due to it indicating that
the driver is not operational for the current command anymore, which
gets it out of the loop in tpm_transmit. It would probably be worse to
return a status flag from the status() callback and return a flag in the
req_complete_mask that would then end up calling the recv() callback
when there is nothing to receive. So the way it is now it triggers
-ECANCELED in the tpm_transmit loop, which seems appropriate.
Stefan
>
> /Jarkko
>
>> +}
>> +
>> +/*
>> + * vtpm_proxy_work_start: Schedule the work for TPM 1.2 & 2 initialization
>> + */
>> +static inline void vtpm_proxy_work_start(struct proxy_dev *proxy_dev)
>> +{
>> + queue_work(workqueue, &proxy_dev->work);
>> +}
>> +
>> +/*
>> * Code related to creation and deletion of device pairs
>> */
>> static struct proxy_dev *vtpm_proxy_create_proxy_dev(void)
>> @@ -357,6 +425,7 @@ static struct proxy_dev
>> *vtpm_proxy_create_proxy_dev(void)
>>
>> init_waitqueue_head(&proxy_dev->wq);
>> mutex_init(&proxy_dev->buf_lock);
>> + INIT_WORK(&proxy_dev->work, vtpm_proxy_work);
>>
>> chip = tpm_chip_alloc(NULL, &vtpm_proxy_tpm_ops);
>> if (IS_ERR(chip)) {
>> @@ -427,9 +496,7 @@ static struct file *vtpm_proxy_create_device(
>> if (proxy_dev->flags & VTPM_PROXY_FLAG_TPM2)
>> proxy_dev->chip->flags |= TPM_CHIP_FLAG_TPM2;
>>
>> - rc = tpm_chip_register(proxy_dev->chip);
>> - if (rc)
>> - goto err_vtpm_fput;
>> + vtpm_proxy_work_start(proxy_dev);
>>
>> vtpm_new_dev->fd = fd;
>> vtpm_new_dev->major = MAJOR(proxy_dev->chip->dev.devt);
>> @@ -438,12 +505,6 @@ static struct file *vtpm_proxy_create_device(
>>
>> return file;
>>
>> -err_vtpm_fput:
>> - put_unused_fd(fd);
>> - fput(file);
>> -
>> - return ERR_PTR(rc);
>> -
>> err_put_unused_fd:
>> put_unused_fd(fd);
>>
>> @@ -458,6 +519,8 @@ err_delete_proxy_dev:
>> */
>> static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev)
>> {
>> + vtpm_proxy_work_stop(proxy_dev);
>> +
>> /*
>> * A client may hold the 'ops' lock, so let it know that the server
>> * side shuts down before we try to grab the 'ops' lock when
>> @@ -557,11 +620,24 @@ static int __init vtpm_module_init(void)
>> return rc;
>> }
>>
>> + workqueue = create_workqueue("tpm-vtpm");
>> + if (!workqueue) {
>> + pr_err("couldn't create workqueue\n");
>> + rc = -ENOMEM;
>> + goto err_vtpmx_cleanup;
>> + }
>> +
>> return 0;
>> +
>> +err_vtpmx_cleanup:
>> + vtpmx_cleanup();
>> +
>> + return rc;
>> }
>>
>> static void __exit vtpm_module_exit(void)
>> {
>> + destroy_workqueue(workqueue);
>> vtpmx_cleanup();
>> }
>>
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