1 /* 2 * xen console driver interface to hvc_console.c 3 * 4 * (c) 2007 Gerd Hoffmann <kraxel@suse.de> 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 as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 */ 20 21 #include <linux/console.h> 22 #include <linux/delay.h> 23 #include <linux/err.h> 24 #include <linux/init.h> 25 #include <linux/types.h> 26 #include <linux/list.h> 27 28 #include <asm/io.h> 29 #include <asm/xen/hypervisor.h> 30 31 #include <xen/xen.h> 32 #include <xen/interface/xen.h> 33 #include <xen/hvm.h> 34 #include <xen/grant_table.h> 35 #include <xen/page.h> 36 #include <xen/events.h> 37 #include <xen/interface/io/console.h> 38 #include <xen/hvc-console.h> 39 #include <xen/xenbus.h> 40 41 #include "hvc_console.h" 42 43 #define HVC_COOKIE 0x58656e /* "Xen" in hex */ 44 45 struct xencons_info { 46 struct list_head list; 47 struct xenbus_device *xbdev; 48 struct xencons_interface *intf; 49 unsigned int evtchn; 50 struct hvc_struct *hvc; 51 int irq; 52 int vtermno; 53 grant_ref_t gntref; 54 }; 55 56 static LIST_HEAD(xenconsoles); 57 static DEFINE_SPINLOCK(xencons_lock); 58 59 /* ------------------------------------------------------------------ */ 60 61 static struct xencons_info *vtermno_to_xencons(int vtermno) 62 { 63 struct xencons_info *entry, *n, *ret = NULL; 64 65 if (list_empty(&xenconsoles)) 66 return NULL; 67 68 list_for_each_entry_safe(entry, n, &xenconsoles, list) { 69 if (entry->vtermno == vtermno) { 70 ret = entry; 71 break; 72 } 73 } 74 75 return ret; 76 } 77 78 static inline int xenbus_devid_to_vtermno(int devid) 79 { 80 return devid + HVC_COOKIE; 81 } 82 83 static inline void notify_daemon(struct xencons_info *cons) 84 { 85 /* Use evtchn: this is called early, before irq is set up. */ 86 notify_remote_via_evtchn(cons->evtchn); 87 } 88 89 static int __write_console(struct xencons_info *xencons, 90 const char *data, int len) 91 { 92 XENCONS_RING_IDX cons, prod; 93 struct xencons_interface *intf = xencons->intf; 94 int sent = 0; 95 96 cons = intf->out_cons; 97 prod = intf->out_prod; 98 mb(); /* update queue values before going on */ 99 BUG_ON((prod - cons) > sizeof(intf->out)); 100 101 while ((sent < len) && ((prod - cons) < sizeof(intf->out))) 102 intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++]; 103 104 wmb(); /* write ring before updating pointer */ 105 intf->out_prod = prod; 106 107 if (sent) 108 notify_daemon(xencons); 109 return sent; 110 } 111 112 static int domU_write_console(uint32_t vtermno, const char *data, int len) 113 { 114 int ret = len; 115 struct xencons_info *cons = vtermno_to_xencons(vtermno); 116 if (cons == NULL) 117 return -EINVAL; 118 119 /* 120 * Make sure the whole buffer is emitted, polling if 121 * necessary. We don't ever want to rely on the hvc daemon 122 * because the most interesting console output is when the 123 * kernel is crippled. 124 */ 125 while (len) { 126 int sent = __write_console(cons, data, len); 127 128 data += sent; 129 len -= sent; 130 131 if (unlikely(len)) 132 HYPERVISOR_sched_op(SCHEDOP_yield, NULL); 133 } 134 135 return ret; 136 } 137 138 static int domU_read_console(uint32_t vtermno, char *buf, int len) 139 { 140 struct xencons_interface *intf; 141 XENCONS_RING_IDX cons, prod; 142 int recv = 0; 143 struct xencons_info *xencons = vtermno_to_xencons(vtermno); 144 if (xencons == NULL) 145 return -EINVAL; 146 intf = xencons->intf; 147 148 cons = intf->in_cons; 149 prod = intf->in_prod; 150 mb(); /* get pointers before reading ring */ 151 BUG_ON((prod - cons) > sizeof(intf->in)); 152 153 while (cons != prod && recv < len) 154 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)]; 155 156 mb(); /* read ring before consuming */ 157 intf->in_cons = cons; 158 159 notify_daemon(xencons); 160 return recv; 161 } 162 163 static struct hv_ops domU_hvc_ops = { 164 .get_chars = domU_read_console, 165 .put_chars = domU_write_console, 166 .notifier_add = notifier_add_irq, 167 .notifier_del = notifier_del_irq, 168 .notifier_hangup = notifier_hangup_irq, 169 }; 170 171 static int dom0_read_console(uint32_t vtermno, char *buf, int len) 172 { 173 return HYPERVISOR_console_io(CONSOLEIO_read, len, buf); 174 } 175 176 /* 177 * Either for a dom0 to write to the system console, or a domU with a 178 * debug version of Xen 179 */ 180 static int dom0_write_console(uint32_t vtermno, const char *str, int len) 181 { 182 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str); 183 if (rc < 0) 184 return 0; 185 186 return len; 187 } 188 189 static struct hv_ops dom0_hvc_ops = { 190 .get_chars = dom0_read_console, 191 .put_chars = dom0_write_console, 192 .notifier_add = notifier_add_irq, 193 .notifier_del = notifier_del_irq, 194 .notifier_hangup = notifier_hangup_irq, 195 }; 196 197 static int xen_hvm_console_init(void) 198 { 199 int r; 200 uint64_t v = 0; 201 unsigned long mfn; 202 struct xencons_info *info; 203 204 if (!xen_hvm_domain()) 205 return -ENODEV; 206 207 info = vtermno_to_xencons(HVC_COOKIE); 208 if (!info) { 209 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO); 210 if (!info) 211 return -ENOMEM; 212 } 213 214 /* already configured */ 215 if (info->intf != NULL) 216 return 0; 217 218 r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v); 219 if (r < 0) { 220 kfree(info); 221 return -ENODEV; 222 } 223 info->evtchn = v; 224 hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v); 225 if (r < 0) { 226 kfree(info); 227 return -ENODEV; 228 } 229 mfn = v; 230 info->intf = ioremap(mfn << PAGE_SHIFT, PAGE_SIZE); 231 if (info->intf == NULL) { 232 kfree(info); 233 return -ENODEV; 234 } 235 info->vtermno = HVC_COOKIE; 236 237 spin_lock(&xencons_lock); 238 list_add_tail(&info->list, &xenconsoles); 239 spin_unlock(&xencons_lock); 240 241 return 0; 242 } 243 244 static int xen_pv_console_init(void) 245 { 246 struct xencons_info *info; 247 248 if (!xen_pv_domain()) 249 return -ENODEV; 250 251 if (!xen_start_info->console.domU.evtchn) 252 return -ENODEV; 253 254 info = vtermno_to_xencons(HVC_COOKIE); 255 if (!info) { 256 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO); 257 if (!info) 258 return -ENOMEM; 259 } 260 261 /* already configured */ 262 if (info->intf != NULL) 263 return 0; 264 265 info->evtchn = xen_start_info->console.domU.evtchn; 266 info->intf = mfn_to_virt(xen_start_info->console.domU.mfn); 267 info->vtermno = HVC_COOKIE; 268 269 spin_lock(&xencons_lock); 270 list_add_tail(&info->list, &xenconsoles); 271 spin_unlock(&xencons_lock); 272 273 return 0; 274 } 275 276 static int xen_initial_domain_console_init(void) 277 { 278 struct xencons_info *info; 279 280 if (!xen_initial_domain()) 281 return -ENODEV; 282 283 info = vtermno_to_xencons(HVC_COOKIE); 284 if (!info) { 285 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO); 286 if (!info) 287 return -ENOMEM; 288 } 289 290 info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0); 291 info->vtermno = HVC_COOKIE; 292 293 spin_lock(&xencons_lock); 294 list_add_tail(&info->list, &xenconsoles); 295 spin_unlock(&xencons_lock); 296 297 return 0; 298 } 299 300 void xen_console_resume(void) 301 { 302 struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE); 303 if (info != NULL && info->irq) 304 rebind_evtchn_irq(info->evtchn, info->irq); 305 } 306 307 static void xencons_disconnect_backend(struct xencons_info *info) 308 { 309 if (info->irq > 0) 310 unbind_from_irqhandler(info->irq, NULL); 311 info->irq = 0; 312 if (info->evtchn > 0) 313 xenbus_free_evtchn(info->xbdev, info->evtchn); 314 info->evtchn = 0; 315 if (info->gntref > 0) 316 gnttab_free_grant_references(info->gntref); 317 info->gntref = 0; 318 if (info->hvc != NULL) 319 hvc_remove(info->hvc); 320 info->hvc = NULL; 321 } 322 323 static void xencons_free(struct xencons_info *info) 324 { 325 free_page((unsigned long)info->intf); 326 info->intf = NULL; 327 info->vtermno = 0; 328 kfree(info); 329 } 330 331 static int xen_console_remove(struct xencons_info *info) 332 { 333 xencons_disconnect_backend(info); 334 spin_lock(&xencons_lock); 335 list_del(&info->list); 336 spin_unlock(&xencons_lock); 337 if (info->xbdev != NULL) 338 xencons_free(info); 339 else { 340 if (xen_hvm_domain()) 341 iounmap(info->intf); 342 kfree(info); 343 } 344 return 0; 345 } 346 347 #ifdef CONFIG_HVC_XEN_FRONTEND 348 static struct xenbus_driver xencons_driver; 349 350 static int xencons_remove(struct xenbus_device *dev) 351 { 352 return xen_console_remove(dev_get_drvdata(&dev->dev)); 353 } 354 355 static int xencons_connect_backend(struct xenbus_device *dev, 356 struct xencons_info *info) 357 { 358 int ret, evtchn, devid, ref, irq; 359 struct xenbus_transaction xbt; 360 grant_ref_t gref_head; 361 unsigned long mfn; 362 363 ret = xenbus_alloc_evtchn(dev, &evtchn); 364 if (ret) 365 return ret; 366 info->evtchn = evtchn; 367 irq = bind_evtchn_to_irq(evtchn); 368 if (irq < 0) 369 return irq; 370 info->irq = irq; 371 devid = dev->nodename[strlen(dev->nodename) - 1] - '0'; 372 info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid), 373 irq, &domU_hvc_ops, 256); 374 if (IS_ERR(info->hvc)) 375 return PTR_ERR(info->hvc); 376 if (xen_pv_domain()) 377 mfn = virt_to_mfn(info->intf); 378 else 379 mfn = __pa(info->intf) >> PAGE_SHIFT; 380 ret = gnttab_alloc_grant_references(1, &gref_head); 381 if (ret < 0) 382 return ret; 383 info->gntref = gref_head; 384 ref = gnttab_claim_grant_reference(&gref_head); 385 if (ref < 0) 386 return ref; 387 gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id, 388 mfn, 0); 389 390 again: 391 ret = xenbus_transaction_start(&xbt); 392 if (ret) { 393 xenbus_dev_fatal(dev, ret, "starting transaction"); 394 return ret; 395 } 396 ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref); 397 if (ret) 398 goto error_xenbus; 399 ret = xenbus_printf(xbt, dev->nodename, "port", "%u", 400 evtchn); 401 if (ret) 402 goto error_xenbus; 403 ret = xenbus_printf(xbt, dev->nodename, "type", "ioemu"); 404 if (ret) 405 goto error_xenbus; 406 ret = xenbus_transaction_end(xbt, 0); 407 if (ret) { 408 if (ret == -EAGAIN) 409 goto again; 410 xenbus_dev_fatal(dev, ret, "completing transaction"); 411 return ret; 412 } 413 414 xenbus_switch_state(dev, XenbusStateInitialised); 415 return 0; 416 417 error_xenbus: 418 xenbus_transaction_end(xbt, 1); 419 xenbus_dev_fatal(dev, ret, "writing xenstore"); 420 return ret; 421 } 422 423 static int __devinit xencons_probe(struct xenbus_device *dev, 424 const struct xenbus_device_id *id) 425 { 426 int ret, devid; 427 struct xencons_info *info; 428 429 devid = dev->nodename[strlen(dev->nodename) - 1] - '0'; 430 if (devid == 0) 431 return -ENODEV; 432 433 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO); 434 if (!info) 435 goto error_nomem; 436 dev_set_drvdata(&dev->dev, info); 437 info->xbdev = dev; 438 info->vtermno = xenbus_devid_to_vtermno(devid); 439 info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO); 440 if (!info->intf) 441 goto error_nomem; 442 443 ret = xencons_connect_backend(dev, info); 444 if (ret < 0) 445 goto error; 446 spin_lock(&xencons_lock); 447 list_add_tail(&info->list, &xenconsoles); 448 spin_unlock(&xencons_lock); 449 450 return 0; 451 452 error_nomem: 453 ret = -ENOMEM; 454 xenbus_dev_fatal(dev, ret, "allocating device memory"); 455 error: 456 xencons_disconnect_backend(info); 457 xencons_free(info); 458 return ret; 459 } 460 461 static int xencons_resume(struct xenbus_device *dev) 462 { 463 struct xencons_info *info = dev_get_drvdata(&dev->dev); 464 465 xencons_disconnect_backend(info); 466 memset(info->intf, 0, PAGE_SIZE); 467 return xencons_connect_backend(dev, info); 468 } 469 470 static void xencons_backend_changed(struct xenbus_device *dev, 471 enum xenbus_state backend_state) 472 { 473 switch (backend_state) { 474 case XenbusStateReconfiguring: 475 case XenbusStateReconfigured: 476 case XenbusStateInitialising: 477 case XenbusStateInitialised: 478 case XenbusStateUnknown: 479 case XenbusStateClosed: 480 break; 481 482 case XenbusStateInitWait: 483 break; 484 485 case XenbusStateConnected: 486 xenbus_switch_state(dev, XenbusStateConnected); 487 break; 488 489 case XenbusStateClosing: 490 xenbus_frontend_closed(dev); 491 break; 492 } 493 } 494 495 static const struct xenbus_device_id xencons_ids[] = { 496 { "console" }, 497 { "" } 498 }; 499 500 501 static DEFINE_XENBUS_DRIVER(xencons, "xenconsole", 502 .probe = xencons_probe, 503 .remove = xencons_remove, 504 .resume = xencons_resume, 505 .otherend_changed = xencons_backend_changed, 506 ); 507 #endif /* CONFIG_HVC_XEN_FRONTEND */ 508 509 static int __init xen_hvc_init(void) 510 { 511 int r; 512 struct xencons_info *info; 513 const struct hv_ops *ops; 514 515 if (!xen_domain()) 516 return -ENODEV; 517 518 if (xen_initial_domain()) { 519 ops = &dom0_hvc_ops; 520 r = xen_initial_domain_console_init(); 521 if (r < 0) 522 return r; 523 info = vtermno_to_xencons(HVC_COOKIE); 524 } else { 525 ops = &domU_hvc_ops; 526 if (xen_hvm_domain()) 527 r = xen_hvm_console_init(); 528 else 529 r = xen_pv_console_init(); 530 if (r < 0) 531 return r; 532 533 info = vtermno_to_xencons(HVC_COOKIE); 534 info->irq = bind_evtchn_to_irq(info->evtchn); 535 } 536 if (info->irq < 0) 537 info->irq = 0; /* NO_IRQ */ 538 else 539 irq_set_noprobe(info->irq); 540 541 info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256); 542 if (IS_ERR(info->hvc)) { 543 r = PTR_ERR(info->hvc); 544 spin_lock(&xencons_lock); 545 list_del(&info->list); 546 spin_unlock(&xencons_lock); 547 if (info->irq) 548 unbind_from_irqhandler(info->irq, NULL); 549 kfree(info); 550 return r; 551 } 552 553 r = 0; 554 #ifdef CONFIG_HVC_XEN_FRONTEND 555 r = xenbus_register_frontend(&xencons_driver); 556 #endif 557 return r; 558 } 559 560 static void __exit xen_hvc_fini(void) 561 { 562 struct xencons_info *entry, *next; 563 564 if (list_empty(&xenconsoles)) 565 return; 566 567 list_for_each_entry_safe(entry, next, &xenconsoles, list) { 568 xen_console_remove(entry); 569 } 570 } 571 572 static int xen_cons_init(void) 573 { 574 const struct hv_ops *ops; 575 576 if (!xen_domain()) 577 return 0; 578 579 if (xen_initial_domain()) 580 ops = &dom0_hvc_ops; 581 else { 582 int r; 583 ops = &domU_hvc_ops; 584 585 if (xen_hvm_domain()) 586 r = xen_hvm_console_init(); 587 else 588 r = xen_pv_console_init(); 589 if (r < 0) 590 return r; 591 } 592 593 hvc_instantiate(HVC_COOKIE, 0, ops); 594 return 0; 595 } 596 597 598 module_init(xen_hvc_init); 599 module_exit(xen_hvc_fini); 600 console_initcall(xen_cons_init); 601 602 #ifdef CONFIG_EARLY_PRINTK 603 static void xenboot_write_console(struct console *console, const char *string, 604 unsigned len) 605 { 606 unsigned int linelen, off = 0; 607 const char *pos; 608 609 if (!xen_pv_domain()) 610 return; 611 612 dom0_write_console(0, string, len); 613 614 if (xen_initial_domain()) 615 return; 616 617 domU_write_console(0, "(early) ", 8); 618 while (off < len && NULL != (pos = strchr(string+off, '\n'))) { 619 linelen = pos-string+off; 620 if (off + linelen > len) 621 break; 622 domU_write_console(0, string+off, linelen); 623 domU_write_console(0, "\r\n", 2); 624 off += linelen + 1; 625 } 626 if (off < len) 627 domU_write_console(0, string+off, len-off); 628 } 629 630 struct console xenboot_console = { 631 .name = "xenboot", 632 .write = xenboot_write_console, 633 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME, 634 }; 635 #endif /* CONFIG_EARLY_PRINTK */ 636 637 void xen_raw_console_write(const char *str) 638 { 639 dom0_write_console(0, str, strlen(str)); 640 } 641 642 void xen_raw_printk(const char *fmt, ...) 643 { 644 static char buf[512]; 645 va_list ap; 646 647 va_start(ap, fmt); 648 vsnprintf(buf, sizeof(buf), fmt, ap); 649 va_end(ap); 650 651 xen_raw_console_write(buf); 652 } 653