2 * Implementation of the Xen vTPM device frontend
4 * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2,
8 * as published by the Free Software Foundation.
10 #include <linux/errno.h>
11 #include <linux/err.h>
12 #include <linux/interrupt.h>
13 #include <xen/events.h>
14 #include <xen/interface/io/tpmif.h>
15 #include <xen/grant_table.h>
16 #include <xen/xenbus.h>
21 struct tpm_chip *chip;
22 struct xenbus_device *dev;
24 struct vtpm_shared_page *shr;
32 VTPM_STATUS_RUNNING = 0x1,
33 VTPM_STATUS_IDLE = 0x2,
34 VTPM_STATUS_RESULT = 0x4,
35 VTPM_STATUS_CANCELED = 0x8,
38 static u8 vtpm_status(struct tpm_chip *chip)
40 struct tpm_private *priv = TPM_VPRIV(chip);
41 switch (priv->shr->state) {
43 return VTPM_STATUS_IDLE | VTPM_STATUS_CANCELED;
44 case VTPM_STATE_FINISH:
45 return VTPM_STATUS_IDLE | VTPM_STATUS_RESULT;
46 case VTPM_STATE_SUBMIT:
47 case VTPM_STATE_CANCEL: /* cancel requested, not yet canceled */
48 return VTPM_STATUS_RUNNING;
54 static bool vtpm_req_canceled(struct tpm_chip *chip, u8 status)
56 return status & VTPM_STATUS_CANCELED;
59 static void vtpm_cancel(struct tpm_chip *chip)
61 struct tpm_private *priv = TPM_VPRIV(chip);
62 priv->shr->state = VTPM_STATE_CANCEL;
64 notify_remote_via_evtchn(priv->evtchn);
67 static unsigned int shr_data_offset(struct vtpm_shared_page *shr)
69 return sizeof(*shr) + sizeof(u32) * shr->nr_extra_pages;
72 static int vtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
74 struct tpm_private *priv = TPM_VPRIV(chip);
75 struct vtpm_shared_page *shr = priv->shr;
76 unsigned int offset = shr_data_offset(shr);
79 unsigned long duration;
81 if (offset > PAGE_SIZE)
84 if (offset + count > PAGE_SIZE)
87 /* Wait for completion of any existing command or cancellation */
88 if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, chip->vendor.timeout_c,
89 &chip->vendor.read_queue, true) < 0) {
94 memcpy(offset + (u8 *)shr, buf, count);
97 shr->state = VTPM_STATE_SUBMIT;
99 notify_remote_via_evtchn(priv->evtchn);
101 ordinal = be32_to_cpu(((struct tpm_input_header*)buf)->ordinal);
102 duration = tpm_calc_ordinal_duration(chip, ordinal);
104 if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, duration,
105 &chip->vendor.read_queue, true) < 0) {
106 /* got a signal or timeout, try to cancel */
114 static int vtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
116 struct tpm_private *priv = TPM_VPRIV(chip);
117 struct vtpm_shared_page *shr = priv->shr;
118 unsigned int offset = shr_data_offset(shr);
119 size_t length = shr->length;
121 if (shr->state == VTPM_STATE_IDLE)
124 /* In theory the wait at the end of _send makes this one unnecessary */
125 if (wait_for_tpm_stat(chip, VTPM_STATUS_RESULT, chip->vendor.timeout_c,
126 &chip->vendor.read_queue, true) < 0) {
131 if (offset > PAGE_SIZE)
134 if (offset + length > PAGE_SIZE)
135 length = PAGE_SIZE - offset;
140 memcpy(buf, offset + (u8 *)shr, length);
145 static const struct file_operations vtpm_ops = {
146 .owner = THIS_MODULE,
151 .release = tpm_release,
154 static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
155 static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
156 static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
157 static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
158 static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
159 static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated,
161 static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps, NULL);
162 static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
163 static DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL);
164 static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);
166 static struct attribute *vtpm_attrs[] = {
167 &dev_attr_pubek.attr,
169 &dev_attr_enabled.attr,
170 &dev_attr_active.attr,
171 &dev_attr_owned.attr,
172 &dev_attr_temp_deactivated.attr,
174 &dev_attr_cancel.attr,
175 &dev_attr_durations.attr,
176 &dev_attr_timeouts.attr,
180 static struct attribute_group vtpm_attr_grp = {
184 static const struct tpm_vendor_specific tpm_vtpm = {
185 .status = vtpm_status,
188 .cancel = vtpm_cancel,
189 .req_complete_mask = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
190 .req_complete_val = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
191 .req_canceled = vtpm_req_canceled,
192 .attr_group = &vtpm_attr_grp,
198 static irqreturn_t tpmif_interrupt(int dummy, void *dev_id)
200 struct tpm_private *priv = dev_id;
202 switch (priv->shr->state) {
203 case VTPM_STATE_IDLE:
204 case VTPM_STATE_FINISH:
205 wake_up_interruptible(&priv->chip->vendor.read_queue);
207 case VTPM_STATE_SUBMIT:
208 case VTPM_STATE_CANCEL:
215 static int setup_chip(struct device *dev, struct tpm_private *priv)
217 struct tpm_chip *chip;
219 chip = tpm_register_hardware(dev, &tpm_vtpm);
223 init_waitqueue_head(&chip->vendor.read_queue);
226 TPM_VPRIV(chip) = priv;
231 /* caller must clean up in case of errors */
232 static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv)
234 struct xenbus_transaction xbt;
235 const char *message = NULL;
238 priv->shr = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
240 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
244 rv = xenbus_grant_ring(dev, virt_to_mfn(priv->shr));
250 rv = xenbus_alloc_evtchn(dev, &priv->evtchn);
254 rv = bind_evtchn_to_irqhandler(priv->evtchn, tpmif_interrupt, 0,
257 xenbus_dev_fatal(dev, rv, "allocating TPM irq");
260 priv->chip->vendor.irq = rv;
263 rv = xenbus_transaction_start(&xbt);
265 xenbus_dev_fatal(dev, rv, "starting transaction");
269 rv = xenbus_printf(xbt, dev->nodename,
270 "ring-ref", "%u", priv->ring_ref);
272 message = "writing ring-ref";
273 goto abort_transaction;
276 rv = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
279 message = "writing event-channel";
280 goto abort_transaction;
283 rv = xenbus_printf(xbt, dev->nodename, "feature-protocol-v2", "1");
285 message = "writing feature-protocol-v2";
286 goto abort_transaction;
289 rv = xenbus_transaction_end(xbt, 0);
293 xenbus_dev_fatal(dev, rv, "completing transaction");
297 xenbus_switch_state(dev, XenbusStateInitialised);
302 xenbus_transaction_end(xbt, 1);
304 xenbus_dev_error(dev, rv, "%s", message);
309 static void ring_free(struct tpm_private *priv)
315 gnttab_end_foreign_access(priv->ring_ref, 0,
316 (unsigned long)priv->shr);
318 free_page((unsigned long)priv->shr);
320 if (priv->chip && priv->chip->vendor.irq)
321 unbind_from_irqhandler(priv->chip->vendor.irq, priv);
326 static int tpmfront_probe(struct xenbus_device *dev,
327 const struct xenbus_device_id *id)
329 struct tpm_private *priv;
332 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
334 xenbus_dev_fatal(dev, -ENOMEM, "allocating priv structure");
338 rv = setup_chip(&dev->dev, priv);
344 rv = setup_ring(dev, priv);
346 tpm_remove_hardware(&dev->dev);
351 tpm_get_timeouts(priv->chip);
353 dev_set_drvdata(&dev->dev, priv->chip);
358 static int tpmfront_remove(struct xenbus_device *dev)
360 struct tpm_chip *chip = dev_get_drvdata(&dev->dev);
361 struct tpm_private *priv = TPM_VPRIV(chip);
362 tpm_remove_hardware(&dev->dev);
364 TPM_VPRIV(chip) = NULL;
368 static int tpmfront_resume(struct xenbus_device *dev)
370 /* A suspend/resume/migrate will interrupt a vTPM anyway */
371 tpmfront_remove(dev);
372 return tpmfront_probe(dev, NULL);
375 static void backend_changed(struct xenbus_device *dev,
376 enum xenbus_state backend_state)
380 switch (backend_state) {
381 case XenbusStateInitialised:
382 case XenbusStateConnected:
383 if (dev->state == XenbusStateConnected)
386 if (xenbus_scanf(XBT_NIL, dev->otherend,
387 "feature-protocol-v2", "%d", &val) < 0)
390 xenbus_dev_fatal(dev, -EINVAL,
391 "vTPM protocol 2 required");
394 xenbus_switch_state(dev, XenbusStateConnected);
397 case XenbusStateClosing:
398 case XenbusStateClosed:
399 device_unregister(&dev->dev);
400 xenbus_frontend_closed(dev);
407 static const struct xenbus_device_id tpmfront_ids[] = {
411 MODULE_ALIAS("xen:vtpm");
413 static DEFINE_XENBUS_DRIVER(tpmfront, ,
414 .probe = tpmfront_probe,
415 .remove = tpmfront_remove,
416 .resume = tpmfront_resume,
417 .otherend_changed = backend_changed,
420 static int __init xen_tpmfront_init(void)
425 return xenbus_register_frontend(&tpmfront_driver);
427 module_init(xen_tpmfront_init);
429 static void __exit xen_tpmfront_exit(void)
431 xenbus_unregister_driver(&tpmfront_driver);
433 module_exit(xen_tpmfront_exit);
435 MODULE_AUTHOR("Daniel De Graaf <dgdegra@tycho.nsa.gov>");
436 MODULE_DESCRIPTION("Xen vTPM Driver");
437 MODULE_LICENSE("GPL");