Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Implementation of the Xen vTPM device frontend |
| 3 | * |
| 4 | * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov> |
| 5 | * |
| 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. |
| 9 | */ |
| 10 | #include <linux/errno.h> |
| 11 | #include <linux/err.h> |
| 12 | #include <linux/interrupt.h> |
Rob Herring | 8702c67 | 2013-10-10 14:38:27 +0000 | [diff] [blame] | 13 | #include <xen/xen.h> |
Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 14 | #include <xen/events.h> |
| 15 | #include <xen/interface/io/tpmif.h> |
| 16 | #include <xen/grant_table.h> |
| 17 | #include <xen/xenbus.h> |
| 18 | #include <xen/page.h> |
| 19 | #include "tpm.h" |
Konrad Rzeszutek Wilk | 51c71a3 | 2013-11-26 15:05:40 -0500 | [diff] [blame^] | 20 | #include <xen/platform_pci.h> |
Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 21 | |
| 22 | struct tpm_private { |
| 23 | struct tpm_chip *chip; |
| 24 | struct xenbus_device *dev; |
| 25 | |
| 26 | struct vtpm_shared_page *shr; |
| 27 | |
| 28 | unsigned int evtchn; |
| 29 | int ring_ref; |
| 30 | domid_t backend_id; |
| 31 | }; |
| 32 | |
| 33 | enum status_bits { |
| 34 | VTPM_STATUS_RUNNING = 0x1, |
| 35 | VTPM_STATUS_IDLE = 0x2, |
| 36 | VTPM_STATUS_RESULT = 0x4, |
| 37 | VTPM_STATUS_CANCELED = 0x8, |
| 38 | }; |
| 39 | |
| 40 | static u8 vtpm_status(struct tpm_chip *chip) |
| 41 | { |
| 42 | struct tpm_private *priv = TPM_VPRIV(chip); |
| 43 | switch (priv->shr->state) { |
| 44 | case VTPM_STATE_IDLE: |
| 45 | return VTPM_STATUS_IDLE | VTPM_STATUS_CANCELED; |
| 46 | case VTPM_STATE_FINISH: |
| 47 | return VTPM_STATUS_IDLE | VTPM_STATUS_RESULT; |
| 48 | case VTPM_STATE_SUBMIT: |
| 49 | case VTPM_STATE_CANCEL: /* cancel requested, not yet canceled */ |
| 50 | return VTPM_STATUS_RUNNING; |
| 51 | default: |
| 52 | return 0; |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | static bool vtpm_req_canceled(struct tpm_chip *chip, u8 status) |
| 57 | { |
| 58 | return status & VTPM_STATUS_CANCELED; |
| 59 | } |
| 60 | |
| 61 | static void vtpm_cancel(struct tpm_chip *chip) |
| 62 | { |
| 63 | struct tpm_private *priv = TPM_VPRIV(chip); |
| 64 | priv->shr->state = VTPM_STATE_CANCEL; |
| 65 | wmb(); |
| 66 | notify_remote_via_evtchn(priv->evtchn); |
| 67 | } |
| 68 | |
| 69 | static unsigned int shr_data_offset(struct vtpm_shared_page *shr) |
| 70 | { |
| 71 | return sizeof(*shr) + sizeof(u32) * shr->nr_extra_pages; |
| 72 | } |
| 73 | |
| 74 | static int vtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) |
| 75 | { |
| 76 | struct tpm_private *priv = TPM_VPRIV(chip); |
| 77 | struct vtpm_shared_page *shr = priv->shr; |
| 78 | unsigned int offset = shr_data_offset(shr); |
| 79 | |
| 80 | u32 ordinal; |
| 81 | unsigned long duration; |
| 82 | |
| 83 | if (offset > PAGE_SIZE) |
| 84 | return -EINVAL; |
| 85 | |
| 86 | if (offset + count > PAGE_SIZE) |
| 87 | return -EINVAL; |
| 88 | |
| 89 | /* Wait for completion of any existing command or cancellation */ |
| 90 | if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, chip->vendor.timeout_c, |
| 91 | &chip->vendor.read_queue, true) < 0) { |
| 92 | vtpm_cancel(chip); |
| 93 | return -ETIME; |
| 94 | } |
| 95 | |
| 96 | memcpy(offset + (u8 *)shr, buf, count); |
| 97 | shr->length = count; |
| 98 | barrier(); |
| 99 | shr->state = VTPM_STATE_SUBMIT; |
| 100 | wmb(); |
| 101 | notify_remote_via_evtchn(priv->evtchn); |
| 102 | |
| 103 | ordinal = be32_to_cpu(((struct tpm_input_header*)buf)->ordinal); |
| 104 | duration = tpm_calc_ordinal_duration(chip, ordinal); |
| 105 | |
| 106 | if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, duration, |
| 107 | &chip->vendor.read_queue, true) < 0) { |
| 108 | /* got a signal or timeout, try to cancel */ |
| 109 | vtpm_cancel(chip); |
| 110 | return -ETIME; |
| 111 | } |
| 112 | |
| 113 | return count; |
| 114 | } |
| 115 | |
| 116 | static int vtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count) |
| 117 | { |
| 118 | struct tpm_private *priv = TPM_VPRIV(chip); |
| 119 | struct vtpm_shared_page *shr = priv->shr; |
| 120 | unsigned int offset = shr_data_offset(shr); |
| 121 | size_t length = shr->length; |
| 122 | |
| 123 | if (shr->state == VTPM_STATE_IDLE) |
| 124 | return -ECANCELED; |
| 125 | |
| 126 | /* In theory the wait at the end of _send makes this one unnecessary */ |
| 127 | if (wait_for_tpm_stat(chip, VTPM_STATUS_RESULT, chip->vendor.timeout_c, |
| 128 | &chip->vendor.read_queue, true) < 0) { |
| 129 | vtpm_cancel(chip); |
| 130 | return -ETIME; |
| 131 | } |
| 132 | |
| 133 | if (offset > PAGE_SIZE) |
| 134 | return -EIO; |
| 135 | |
| 136 | if (offset + length > PAGE_SIZE) |
| 137 | length = PAGE_SIZE - offset; |
| 138 | |
| 139 | if (length > count) |
| 140 | length = count; |
| 141 | |
| 142 | memcpy(buf, offset + (u8 *)shr, length); |
| 143 | |
| 144 | return length; |
| 145 | } |
| 146 | |
Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 147 | static const struct file_operations vtpm_ops = { |
| 148 | .owner = THIS_MODULE, |
| 149 | .llseek = no_llseek, |
| 150 | .open = tpm_open, |
| 151 | .read = tpm_read, |
| 152 | .write = tpm_write, |
| 153 | .release = tpm_release, |
| 154 | }; |
| 155 | |
| 156 | static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL); |
| 157 | static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL); |
| 158 | static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL); |
| 159 | static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL); |
| 160 | static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL); |
| 161 | static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated, |
| 162 | NULL); |
| 163 | static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps, NULL); |
| 164 | static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel); |
| 165 | static DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL); |
| 166 | static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL); |
Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 167 | |
| 168 | static struct attribute *vtpm_attrs[] = { |
| 169 | &dev_attr_pubek.attr, |
| 170 | &dev_attr_pcrs.attr, |
| 171 | &dev_attr_enabled.attr, |
| 172 | &dev_attr_active.attr, |
| 173 | &dev_attr_owned.attr, |
| 174 | &dev_attr_temp_deactivated.attr, |
| 175 | &dev_attr_caps.attr, |
| 176 | &dev_attr_cancel.attr, |
| 177 | &dev_attr_durations.attr, |
| 178 | &dev_attr_timeouts.attr, |
Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 179 | NULL, |
| 180 | }; |
| 181 | |
| 182 | static struct attribute_group vtpm_attr_grp = { |
| 183 | .attrs = vtpm_attrs, |
| 184 | }; |
| 185 | |
Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 186 | static const struct tpm_vendor_specific tpm_vtpm = { |
| 187 | .status = vtpm_status, |
| 188 | .recv = vtpm_recv, |
| 189 | .send = vtpm_send, |
| 190 | .cancel = vtpm_cancel, |
| 191 | .req_complete_mask = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT, |
| 192 | .req_complete_val = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT, |
| 193 | .req_canceled = vtpm_req_canceled, |
| 194 | .attr_group = &vtpm_attr_grp, |
| 195 | .miscdev = { |
| 196 | .fops = &vtpm_ops, |
| 197 | }, |
Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 198 | }; |
| 199 | |
| 200 | static irqreturn_t tpmif_interrupt(int dummy, void *dev_id) |
| 201 | { |
| 202 | struct tpm_private *priv = dev_id; |
| 203 | |
| 204 | switch (priv->shr->state) { |
| 205 | case VTPM_STATE_IDLE: |
| 206 | case VTPM_STATE_FINISH: |
| 207 | wake_up_interruptible(&priv->chip->vendor.read_queue); |
| 208 | break; |
| 209 | case VTPM_STATE_SUBMIT: |
| 210 | case VTPM_STATE_CANCEL: |
| 211 | default: |
| 212 | break; |
| 213 | } |
| 214 | return IRQ_HANDLED; |
| 215 | } |
| 216 | |
| 217 | static int setup_chip(struct device *dev, struct tpm_private *priv) |
| 218 | { |
| 219 | struct tpm_chip *chip; |
| 220 | |
| 221 | chip = tpm_register_hardware(dev, &tpm_vtpm); |
| 222 | if (!chip) |
| 223 | return -ENODEV; |
| 224 | |
| 225 | init_waitqueue_head(&chip->vendor.read_queue); |
| 226 | |
| 227 | priv->chip = chip; |
| 228 | TPM_VPRIV(chip) = priv; |
| 229 | |
| 230 | return 0; |
| 231 | } |
| 232 | |
| 233 | /* caller must clean up in case of errors */ |
| 234 | static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv) |
| 235 | { |
| 236 | struct xenbus_transaction xbt; |
| 237 | const char *message = NULL; |
| 238 | int rv; |
| 239 | |
| 240 | priv->shr = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO); |
| 241 | if (!priv->shr) { |
| 242 | xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); |
| 243 | return -ENOMEM; |
| 244 | } |
| 245 | |
| 246 | rv = xenbus_grant_ring(dev, virt_to_mfn(priv->shr)); |
| 247 | if (rv < 0) |
| 248 | return rv; |
| 249 | |
| 250 | priv->ring_ref = rv; |
| 251 | |
| 252 | rv = xenbus_alloc_evtchn(dev, &priv->evtchn); |
| 253 | if (rv) |
| 254 | return rv; |
| 255 | |
| 256 | rv = bind_evtchn_to_irqhandler(priv->evtchn, tpmif_interrupt, 0, |
| 257 | "tpmif", priv); |
| 258 | if (rv <= 0) { |
| 259 | xenbus_dev_fatal(dev, rv, "allocating TPM irq"); |
| 260 | return rv; |
| 261 | } |
| 262 | priv->chip->vendor.irq = rv; |
| 263 | |
| 264 | again: |
| 265 | rv = xenbus_transaction_start(&xbt); |
| 266 | if (rv) { |
| 267 | xenbus_dev_fatal(dev, rv, "starting transaction"); |
| 268 | return rv; |
| 269 | } |
| 270 | |
| 271 | rv = xenbus_printf(xbt, dev->nodename, |
| 272 | "ring-ref", "%u", priv->ring_ref); |
| 273 | if (rv) { |
| 274 | message = "writing ring-ref"; |
| 275 | goto abort_transaction; |
| 276 | } |
| 277 | |
| 278 | rv = xenbus_printf(xbt, dev->nodename, "event-channel", "%u", |
| 279 | priv->evtchn); |
| 280 | if (rv) { |
| 281 | message = "writing event-channel"; |
| 282 | goto abort_transaction; |
| 283 | } |
| 284 | |
| 285 | rv = xenbus_printf(xbt, dev->nodename, "feature-protocol-v2", "1"); |
| 286 | if (rv) { |
| 287 | message = "writing feature-protocol-v2"; |
| 288 | goto abort_transaction; |
| 289 | } |
| 290 | |
| 291 | rv = xenbus_transaction_end(xbt, 0); |
| 292 | if (rv == -EAGAIN) |
| 293 | goto again; |
| 294 | if (rv) { |
| 295 | xenbus_dev_fatal(dev, rv, "completing transaction"); |
| 296 | return rv; |
| 297 | } |
| 298 | |
| 299 | xenbus_switch_state(dev, XenbusStateInitialised); |
| 300 | |
| 301 | return 0; |
| 302 | |
| 303 | abort_transaction: |
| 304 | xenbus_transaction_end(xbt, 1); |
| 305 | if (message) |
| 306 | xenbus_dev_error(dev, rv, "%s", message); |
| 307 | |
| 308 | return rv; |
| 309 | } |
| 310 | |
| 311 | static void ring_free(struct tpm_private *priv) |
| 312 | { |
| 313 | if (!priv) |
| 314 | return; |
| 315 | |
| 316 | if (priv->ring_ref) |
| 317 | gnttab_end_foreign_access(priv->ring_ref, 0, |
| 318 | (unsigned long)priv->shr); |
| 319 | else |
| 320 | free_page((unsigned long)priv->shr); |
| 321 | |
| 322 | if (priv->chip && priv->chip->vendor.irq) |
| 323 | unbind_from_irqhandler(priv->chip->vendor.irq, priv); |
| 324 | |
| 325 | kfree(priv); |
| 326 | } |
| 327 | |
| 328 | static int tpmfront_probe(struct xenbus_device *dev, |
| 329 | const struct xenbus_device_id *id) |
| 330 | { |
| 331 | struct tpm_private *priv; |
| 332 | int rv; |
| 333 | |
| 334 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
| 335 | if (!priv) { |
| 336 | xenbus_dev_fatal(dev, -ENOMEM, "allocating priv structure"); |
| 337 | return -ENOMEM; |
| 338 | } |
| 339 | |
| 340 | rv = setup_chip(&dev->dev, priv); |
| 341 | if (rv) { |
| 342 | kfree(priv); |
| 343 | return rv; |
| 344 | } |
| 345 | |
| 346 | rv = setup_ring(dev, priv); |
| 347 | if (rv) { |
| 348 | tpm_remove_hardware(&dev->dev); |
| 349 | ring_free(priv); |
| 350 | return rv; |
| 351 | } |
| 352 | |
| 353 | tpm_get_timeouts(priv->chip); |
| 354 | |
Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 355 | return rv; |
| 356 | } |
| 357 | |
| 358 | static int tpmfront_remove(struct xenbus_device *dev) |
| 359 | { |
| 360 | struct tpm_chip *chip = dev_get_drvdata(&dev->dev); |
| 361 | struct tpm_private *priv = TPM_VPRIV(chip); |
| 362 | tpm_remove_hardware(&dev->dev); |
| 363 | ring_free(priv); |
| 364 | TPM_VPRIV(chip) = NULL; |
| 365 | return 0; |
| 366 | } |
| 367 | |
| 368 | static int tpmfront_resume(struct xenbus_device *dev) |
| 369 | { |
| 370 | /* A suspend/resume/migrate will interrupt a vTPM anyway */ |
| 371 | tpmfront_remove(dev); |
| 372 | return tpmfront_probe(dev, NULL); |
| 373 | } |
| 374 | |
| 375 | static void backend_changed(struct xenbus_device *dev, |
| 376 | enum xenbus_state backend_state) |
| 377 | { |
| 378 | int val; |
| 379 | |
| 380 | switch (backend_state) { |
| 381 | case XenbusStateInitialised: |
| 382 | case XenbusStateConnected: |
| 383 | if (dev->state == XenbusStateConnected) |
| 384 | break; |
| 385 | |
| 386 | if (xenbus_scanf(XBT_NIL, dev->otherend, |
| 387 | "feature-protocol-v2", "%d", &val) < 0) |
| 388 | val = 0; |
| 389 | if (!val) { |
| 390 | xenbus_dev_fatal(dev, -EINVAL, |
| 391 | "vTPM protocol 2 required"); |
| 392 | return; |
| 393 | } |
| 394 | xenbus_switch_state(dev, XenbusStateConnected); |
| 395 | break; |
| 396 | |
| 397 | case XenbusStateClosing: |
| 398 | case XenbusStateClosed: |
| 399 | device_unregister(&dev->dev); |
| 400 | xenbus_frontend_closed(dev); |
| 401 | break; |
| 402 | default: |
| 403 | break; |
| 404 | } |
| 405 | } |
| 406 | |
| 407 | static const struct xenbus_device_id tpmfront_ids[] = { |
| 408 | { "vtpm" }, |
| 409 | { "" } |
| 410 | }; |
| 411 | MODULE_ALIAS("xen:vtpm"); |
| 412 | |
| 413 | static DEFINE_XENBUS_DRIVER(tpmfront, , |
| 414 | .probe = tpmfront_probe, |
| 415 | .remove = tpmfront_remove, |
| 416 | .resume = tpmfront_resume, |
| 417 | .otherend_changed = backend_changed, |
| 418 | ); |
| 419 | |
| 420 | static int __init xen_tpmfront_init(void) |
| 421 | { |
| 422 | if (!xen_domain()) |
| 423 | return -ENODEV; |
| 424 | |
Konrad Rzeszutek Wilk | 51c71a3 | 2013-11-26 15:05:40 -0500 | [diff] [blame^] | 425 | if (!xen_has_pv_devices()) |
| 426 | return -ENODEV; |
| 427 | |
Daniel De Graaf | e268395 | 2013-07-30 13:29:47 -0400 | [diff] [blame] | 428 | return xenbus_register_frontend(&tpmfront_driver); |
| 429 | } |
| 430 | module_init(xen_tpmfront_init); |
| 431 | |
| 432 | static void __exit xen_tpmfront_exit(void) |
| 433 | { |
| 434 | xenbus_unregister_driver(&tpmfront_driver); |
| 435 | } |
| 436 | module_exit(xen_tpmfront_exit); |
| 437 | |
| 438 | MODULE_AUTHOR("Daniel De Graaf <dgdegra@tycho.nsa.gov>"); |
| 439 | MODULE_DESCRIPTION("Xen vTPM Driver"); |
| 440 | MODULE_LICENSE("GPL"); |