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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * xen console driver interface to hvc_console.c
4 *
5 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
6 */
7
8#include <linux/console.h>
9#include <linux/delay.h>
10#include <linux/err.h>
11#include <linux/irq.h>
12#include <linux/init.h>
13#include <linux/types.h>
14#include <linux/list.h>
15#include <linux/serial_core.h>
16
17#include <asm/io.h>
18#include <asm/xen/hypervisor.h>
19
20#include <xen/xen.h>
21#include <xen/interface/xen.h>
22#include <xen/hvm.h>
23#include <xen/grant_table.h>
24#include <xen/page.h>
25#include <xen/events.h>
26#include <xen/interface/io/console.h>
27#include <xen/interface/sched.h>
28#include <xen/hvc-console.h>
29#include <xen/xenbus.h>
30
31#include "hvc_console.h"
32
33#define HVC_COOKIE 0x58656e /* "Xen" in hex */
34
35struct xencons_info {
36 struct list_head list;
37 struct xenbus_device *xbdev;
38 struct xencons_interface *intf;
39 unsigned int evtchn;
40 struct hvc_struct *hvc;
41 int irq;
42 int vtermno;
43 grant_ref_t gntref;
44};
45
46static LIST_HEAD(xenconsoles);
47static DEFINE_SPINLOCK(xencons_lock);
48
49/* ------------------------------------------------------------------ */
50
51static struct xencons_info *vtermno_to_xencons(int vtermno)
52{
53 struct xencons_info *entry, *n, *ret = NULL;
54
55 if (list_empty(&xenconsoles))
56 return NULL;
57
58 list_for_each_entry_safe(entry, n, &xenconsoles, list) {
59 if (entry->vtermno == vtermno) {
60 ret = entry;
61 break;
62 }
63 }
64
65 return ret;
66}
67
68static inline int xenbus_devid_to_vtermno(int devid)
69{
70 return devid + HVC_COOKIE;
71}
72
73static inline void notify_daemon(struct xencons_info *cons)
74{
75 /* Use evtchn: this is called early, before irq is set up. */
76 notify_remote_via_evtchn(cons->evtchn);
77}
78
79static int __write_console(struct xencons_info *xencons,
80 const char *data, int len)
81{
82 XENCONS_RING_IDX cons, prod;
83 struct xencons_interface *intf = xencons->intf;
84 int sent = 0;
85
86 cons = intf->out_cons;
87 prod = intf->out_prod;
88 mb(); /* update queue values before going on */
89 BUG_ON((prod - cons) > sizeof(intf->out));
90
91 while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
92 intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
93
94 wmb(); /* write ring before updating pointer */
95 intf->out_prod = prod;
96
97 if (sent)
98 notify_daemon(xencons);
99 return sent;
100}
101
102static int domU_write_console(uint32_t vtermno, const char *data, int len)
103{
104 int ret = len;
105 struct xencons_info *cons = vtermno_to_xencons(vtermno);
106 if (cons == NULL)
107 return -EINVAL;
108
109 /*
110 * Make sure the whole buffer is emitted, polling if
111 * necessary. We don't ever want to rely on the hvc daemon
112 * because the most interesting console output is when the
113 * kernel is crippled.
114 */
115 while (len) {
116 int sent = __write_console(cons, data, len);
117
118 data += sent;
119 len -= sent;
120
121 if (unlikely(len))
122 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
123 }
124
125 return ret;
126}
127
128static int domU_read_console(uint32_t vtermno, char *buf, int len)
129{
130 struct xencons_interface *intf;
131 XENCONS_RING_IDX cons, prod;
132 int recv = 0;
133 struct xencons_info *xencons = vtermno_to_xencons(vtermno);
134 if (xencons == NULL)
135 return -EINVAL;
136 intf = xencons->intf;
137
138 cons = intf->in_cons;
139 prod = intf->in_prod;
140 mb(); /* get pointers before reading ring */
141 BUG_ON((prod - cons) > sizeof(intf->in));
142
143 while (cons != prod && recv < len)
144 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
145
146 mb(); /* read ring before consuming */
147 intf->in_cons = cons;
148
149 notify_daemon(xencons);
150 return recv;
151}
152
153static const struct hv_ops domU_hvc_ops = {
154 .get_chars = domU_read_console,
155 .put_chars = domU_write_console,
156 .notifier_add = notifier_add_irq,
157 .notifier_del = notifier_del_irq,
158 .notifier_hangup = notifier_hangup_irq,
159};
160
161static int dom0_read_console(uint32_t vtermno, char *buf, int len)
162{
163 return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
164}
165
166/*
167 * Either for a dom0 to write to the system console, or a domU with a
168 * debug version of Xen
169 */
170static int dom0_write_console(uint32_t vtermno, const char *str, int len)
171{
172 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
173 if (rc < 0)
174 return rc;
175
176 return len;
177}
178
179static const struct hv_ops dom0_hvc_ops = {
180 .get_chars = dom0_read_console,
181 .put_chars = dom0_write_console,
182 .notifier_add = notifier_add_irq,
183 .notifier_del = notifier_del_irq,
184 .notifier_hangup = notifier_hangup_irq,
185};
186
187static int xen_hvm_console_init(void)
188{
189 int r;
190 uint64_t v = 0;
191 unsigned long gfn;
192 struct xencons_info *info;
193
194 if (!xen_hvm_domain())
195 return -ENODEV;
196
197 info = vtermno_to_xencons(HVC_COOKIE);
198 if (!info) {
199 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
200 if (!info)
201 return -ENOMEM;
202 } else if (info->intf != NULL) {
203 /* already configured */
204 return 0;
205 }
206 /*
207 * If the toolstack (or the hypervisor) hasn't set these values, the
208 * default value is 0. Even though gfn = 0 and evtchn = 0 are
209 * theoretically correct values, in practice they never are and they
210 * mean that a legacy toolstack hasn't initialized the pv console correctly.
211 */
212 r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
213 if (r < 0 || v == 0)
214 goto err;
215 info->evtchn = v;
216 v = 0;
217 r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
218 if (r < 0 || v == 0)
219 goto err;
220 gfn = v;
221 info->intf = xen_remap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE);
222 if (info->intf == NULL)
223 goto err;
224 info->vtermno = HVC_COOKIE;
225
226 spin_lock(&xencons_lock);
227 list_add_tail(&info->list, &xenconsoles);
228 spin_unlock(&xencons_lock);
229
230 return 0;
231err:
232 kfree(info);
233 return -ENODEV;
234}
235
236static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
237{
238 info->evtchn = xen_start_info->console.domU.evtchn;
239 /* GFN == MFN for PV guest */
240 info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
241 info->vtermno = vtermno;
242
243 list_add_tail(&info->list, &xenconsoles);
244
245 return 0;
246}
247
248static int xen_pv_console_init(void)
249{
250 struct xencons_info *info;
251
252 if (!xen_pv_domain())
253 return -ENODEV;
254
255 if (!xen_start_info->console.domU.evtchn)
256 return -ENODEV;
257
258 info = vtermno_to_xencons(HVC_COOKIE);
259 if (!info) {
260 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
261 if (!info)
262 return -ENOMEM;
263 } else if (info->intf != NULL) {
264 /* already configured */
265 return 0;
266 }
267 spin_lock(&xencons_lock);
268 xencons_info_pv_init(info, HVC_COOKIE);
269 spin_unlock(&xencons_lock);
270
271 return 0;
272}
273
274static int xen_initial_domain_console_init(void)
275{
276 struct xencons_info *info;
277
278 if (!xen_initial_domain())
279 return -ENODEV;
280
281 info = vtermno_to_xencons(HVC_COOKIE);
282 if (!info) {
283 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
284 if (!info)
285 return -ENOMEM;
286 }
287
288 info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
289 info->vtermno = HVC_COOKIE;
290
291 spin_lock(&xencons_lock);
292 list_add_tail(&info->list, &xenconsoles);
293 spin_unlock(&xencons_lock);
294
295 return 0;
296}
297
298static void xen_console_update_evtchn(struct xencons_info *info)
299{
300 if (xen_hvm_domain()) {
301 uint64_t v = 0;
302 int err;
303
304 err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
305 if (!err && v)
306 info->evtchn = v;
307 } else
308 info->evtchn = xen_start_info->console.domU.evtchn;
309}
310
311void xen_console_resume(void)
312{
313 struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
314 if (info != NULL && info->irq) {
315 if (!xen_initial_domain())
316 xen_console_update_evtchn(info);
317 rebind_evtchn_irq(info->evtchn, info->irq);
318 }
319}
320
321#ifdef CONFIG_HVC_XEN_FRONTEND
322static void xencons_disconnect_backend(struct xencons_info *info)
323{
324 if (info->irq > 0)
325 unbind_from_irqhandler(info->irq, NULL);
326 info->irq = 0;
327 if (info->evtchn > 0)
328 xenbus_free_evtchn(info->xbdev, info->evtchn);
329 info->evtchn = 0;
330 if (info->gntref > 0)
331 gnttab_free_grant_references(info->gntref);
332 info->gntref = 0;
333 if (info->hvc != NULL)
334 hvc_remove(info->hvc);
335 info->hvc = NULL;
336}
337
338static void xencons_free(struct xencons_info *info)
339{
340 free_page((unsigned long)info->intf);
341 info->intf = NULL;
342 info->vtermno = 0;
343 kfree(info);
344}
345
346static int xen_console_remove(struct xencons_info *info)
347{
348 xencons_disconnect_backend(info);
349 spin_lock(&xencons_lock);
350 list_del(&info->list);
351 spin_unlock(&xencons_lock);
352 if (info->xbdev != NULL)
353 xencons_free(info);
354 else {
355 if (xen_hvm_domain())
356 iounmap(info->intf);
357 kfree(info);
358 }
359 return 0;
360}
361
362static int xencons_remove(struct xenbus_device *dev)
363{
364 return xen_console_remove(dev_get_drvdata(&dev->dev));
365}
366
367static int xencons_connect_backend(struct xenbus_device *dev,
368 struct xencons_info *info)
369{
370 int ret, evtchn, devid, ref, irq;
371 struct xenbus_transaction xbt;
372 grant_ref_t gref_head;
373
374 ret = xenbus_alloc_evtchn(dev, &evtchn);
375 if (ret)
376 return ret;
377 info->evtchn = evtchn;
378 irq = bind_evtchn_to_irq(evtchn);
379 if (irq < 0)
380 return irq;
381 info->irq = irq;
382 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
383 info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
384 irq, &domU_hvc_ops, 256);
385 if (IS_ERR(info->hvc))
386 return PTR_ERR(info->hvc);
387 ret = gnttab_alloc_grant_references(1, &gref_head);
388 if (ret < 0)
389 return ret;
390 info->gntref = gref_head;
391 ref = gnttab_claim_grant_reference(&gref_head);
392 if (ref < 0)
393 return ref;
394 gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
395 virt_to_gfn(info->intf), 0);
396
397 again:
398 ret = xenbus_transaction_start(&xbt);
399 if (ret) {
400 xenbus_dev_fatal(dev, ret, "starting transaction");
401 return ret;
402 }
403 ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
404 if (ret)
405 goto error_xenbus;
406 ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
407 evtchn);
408 if (ret)
409 goto error_xenbus;
410 ret = xenbus_transaction_end(xbt, 0);
411 if (ret) {
412 if (ret == -EAGAIN)
413 goto again;
414 xenbus_dev_fatal(dev, ret, "completing transaction");
415 return ret;
416 }
417
418 xenbus_switch_state(dev, XenbusStateInitialised);
419 return 0;
420
421 error_xenbus:
422 xenbus_transaction_end(xbt, 1);
423 xenbus_dev_fatal(dev, ret, "writing xenstore");
424 return ret;
425}
426
427static int xencons_probe(struct xenbus_device *dev,
428 const struct xenbus_device_id *id)
429{
430 int ret, devid;
431 struct xencons_info *info;
432
433 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
434 if (devid == 0)
435 return -ENODEV;
436
437 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
438 if (!info)
439 return -ENOMEM;
440 dev_set_drvdata(&dev->dev, info);
441 info->xbdev = dev;
442 info->vtermno = xenbus_devid_to_vtermno(devid);
443 info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
444 if (!info->intf)
445 goto error_nomem;
446
447 ret = xencons_connect_backend(dev, info);
448 if (ret < 0)
449 goto error;
450 spin_lock(&xencons_lock);
451 list_add_tail(&info->list, &xenconsoles);
452 spin_unlock(&xencons_lock);
453
454 return 0;
455
456 error_nomem:
457 ret = -ENOMEM;
458 xenbus_dev_fatal(dev, ret, "allocating device memory");
459 error:
460 xencons_disconnect_backend(info);
461 xencons_free(info);
462 return ret;
463}
464
465static int xencons_resume(struct xenbus_device *dev)
466{
467 struct xencons_info *info = dev_get_drvdata(&dev->dev);
468
469 xencons_disconnect_backend(info);
470 memset(info->intf, 0, XEN_PAGE_SIZE);
471 return xencons_connect_backend(dev, info);
472}
473
474static void xencons_backend_changed(struct xenbus_device *dev,
475 enum xenbus_state backend_state)
476{
477 switch (backend_state) {
478 case XenbusStateReconfiguring:
479 case XenbusStateReconfigured:
480 case XenbusStateInitialising:
481 case XenbusStateInitialised:
482 case XenbusStateUnknown:
483 break;
484
485 case XenbusStateInitWait:
486 break;
487
488 case XenbusStateConnected:
489 xenbus_switch_state(dev, XenbusStateConnected);
490 break;
491
492 case XenbusStateClosed:
493 if (dev->state == XenbusStateClosed)
494 break;
495 /* fall through - Missed the backend's CLOSING state. */
496 case XenbusStateClosing:
497 xenbus_frontend_closed(dev);
498 break;
499 }
500}
501
502static const struct xenbus_device_id xencons_ids[] = {
503 { "console" },
504 { "" }
505};
506
507static struct xenbus_driver xencons_driver = {
508 .name = "xenconsole",
509 .ids = xencons_ids,
510 .probe = xencons_probe,
511 .remove = xencons_remove,
512 .resume = xencons_resume,
513 .otherend_changed = xencons_backend_changed,
514};
515#endif /* CONFIG_HVC_XEN_FRONTEND */
516
517static int __init xen_hvc_init(void)
518{
519 int r;
520 struct xencons_info *info;
521 const struct hv_ops *ops;
522
523 if (!xen_domain())
524 return -ENODEV;
525
526 if (xen_initial_domain()) {
527 ops = &dom0_hvc_ops;
528 r = xen_initial_domain_console_init();
529 if (r < 0)
530 return r;
531 info = vtermno_to_xencons(HVC_COOKIE);
532 } else {
533 ops = &domU_hvc_ops;
534 if (xen_hvm_domain())
535 r = xen_hvm_console_init();
536 else
537 r = xen_pv_console_init();
538 if (r < 0)
539 return r;
540
541 info = vtermno_to_xencons(HVC_COOKIE);
542 info->irq = bind_evtchn_to_irq(info->evtchn);
543 }
544 if (info->irq < 0)
545 info->irq = 0; /* NO_IRQ */
546 else
547 irq_set_noprobe(info->irq);
548
549 info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
550 if (IS_ERR(info->hvc)) {
551 r = PTR_ERR(info->hvc);
552 spin_lock(&xencons_lock);
553 list_del(&info->list);
554 spin_unlock(&xencons_lock);
555 if (info->irq)
556 unbind_from_irqhandler(info->irq, NULL);
557 kfree(info);
558 return r;
559 }
560
561 r = 0;
562#ifdef CONFIG_HVC_XEN_FRONTEND
563 r = xenbus_register_frontend(&xencons_driver);
564#endif
565 return r;
566}
567device_initcall(xen_hvc_init);
568
569static int xen_cons_init(void)
570{
571 const struct hv_ops *ops;
572
573 if (!xen_domain())
574 return 0;
575
576 if (xen_initial_domain())
577 ops = &dom0_hvc_ops;
578 else {
579 int r;
580 ops = &domU_hvc_ops;
581
582 if (xen_hvm_domain())
583 r = xen_hvm_console_init();
584 else
585 r = xen_pv_console_init();
586 if (r < 0)
587 return r;
588 }
589
590 hvc_instantiate(HVC_COOKIE, 0, ops);
591 return 0;
592}
593console_initcall(xen_cons_init);
594
595#ifdef CONFIG_X86
596static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
597{
598 if (xen_cpuid_base())
599 outsb(0xe9, str, len);
600}
601#else
602static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
603#endif
604
605#ifdef CONFIG_EARLY_PRINTK
606static int __init xenboot_setup_console(struct console *console, char *string)
607{
608 static struct xencons_info xenboot;
609
610 if (xen_initial_domain())
611 return 0;
612 if (!xen_pv_domain())
613 return -ENODEV;
614
615 return xencons_info_pv_init(&xenboot, 0);
616}
617
618static void xenboot_write_console(struct console *console, const char *string,
619 unsigned len)
620{
621 unsigned int linelen, off = 0;
622 const char *pos;
623
624 if (!xen_pv_domain()) {
625 xen_hvm_early_write(0, string, len);
626 return;
627 }
628
629 dom0_write_console(0, string, len);
630
631 if (xen_initial_domain())
632 return;
633
634 domU_write_console(0, "(early) ", 8);
635 while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
636 linelen = pos-string+off;
637 if (off + linelen > len)
638 break;
639 domU_write_console(0, string+off, linelen);
640 domU_write_console(0, "\r\n", 2);
641 off += linelen + 1;
642 }
643 if (off < len)
644 domU_write_console(0, string+off, len-off);
645}
646
647struct console xenboot_console = {
648 .name = "xenboot",
649 .write = xenboot_write_console,
650 .setup = xenboot_setup_console,
651 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
652 .index = -1,
653};
654#endif /* CONFIG_EARLY_PRINTK */
655
656void xen_raw_console_write(const char *str)
657{
658 ssize_t len = strlen(str);
659 int rc = 0;
660
661 if (xen_domain()) {
662 rc = dom0_write_console(0, str, len);
663 if (rc != -ENOSYS || !xen_hvm_domain())
664 return;
665 }
666 xen_hvm_early_write(0, str, len);
667}
668
669void xen_raw_printk(const char *fmt, ...)
670{
671 static char buf[512];
672 va_list ap;
673
674 va_start(ap, fmt);
675 vsnprintf(buf, sizeof(buf), fmt, ap);
676 va_end(ap);
677
678 xen_raw_console_write(buf);
679}
680
681static void xenboot_earlycon_write(struct console *console,
682 const char *string,
683 unsigned len)
684{
685 dom0_write_console(0, string, len);
686}
687
688static int __init xenboot_earlycon_setup(struct earlycon_device *device,
689 const char *opt)
690{
691 device->con->write = xenboot_earlycon_write;
692 return 0;
693}
694EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);
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/irq.h>
25#include <linux/init.h>
26#include <linux/types.h>
27#include <linux/list.h>
28#include <linux/serial_core.h>
29
30#include <asm/io.h>
31#include <asm/xen/hypervisor.h>
32
33#include <xen/xen.h>
34#include <xen/interface/xen.h>
35#include <xen/hvm.h>
36#include <xen/grant_table.h>
37#include <xen/page.h>
38#include <xen/events.h>
39#include <xen/interface/io/console.h>
40#include <xen/interface/sched.h>
41#include <xen/hvc-console.h>
42#include <xen/xenbus.h>
43
44#include "hvc_console.h"
45
46#define HVC_COOKIE 0x58656e /* "Xen" in hex */
47
48struct xencons_info {
49 struct list_head list;
50 struct xenbus_device *xbdev;
51 struct xencons_interface *intf;
52 unsigned int evtchn;
53 struct hvc_struct *hvc;
54 int irq;
55 int vtermno;
56 grant_ref_t gntref;
57};
58
59static LIST_HEAD(xenconsoles);
60static DEFINE_SPINLOCK(xencons_lock);
61
62/* ------------------------------------------------------------------ */
63
64static struct xencons_info *vtermno_to_xencons(int vtermno)
65{
66 struct xencons_info *entry, *n, *ret = NULL;
67
68 if (list_empty(&xenconsoles))
69 return NULL;
70
71 list_for_each_entry_safe(entry, n, &xenconsoles, list) {
72 if (entry->vtermno == vtermno) {
73 ret = entry;
74 break;
75 }
76 }
77
78 return ret;
79}
80
81static inline int xenbus_devid_to_vtermno(int devid)
82{
83 return devid + HVC_COOKIE;
84}
85
86static inline void notify_daemon(struct xencons_info *cons)
87{
88 /* Use evtchn: this is called early, before irq is set up. */
89 notify_remote_via_evtchn(cons->evtchn);
90}
91
92static int __write_console(struct xencons_info *xencons,
93 const char *data, int len)
94{
95 XENCONS_RING_IDX cons, prod;
96 struct xencons_interface *intf = xencons->intf;
97 int sent = 0;
98
99 cons = intf->out_cons;
100 prod = intf->out_prod;
101 mb(); /* update queue values before going on */
102 BUG_ON((prod - cons) > sizeof(intf->out));
103
104 while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
105 intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
106
107 wmb(); /* write ring before updating pointer */
108 intf->out_prod = prod;
109
110 if (sent)
111 notify_daemon(xencons);
112 return sent;
113}
114
115static int domU_write_console(uint32_t vtermno, const char *data, int len)
116{
117 int ret = len;
118 struct xencons_info *cons = vtermno_to_xencons(vtermno);
119 if (cons == NULL)
120 return -EINVAL;
121
122 /*
123 * Make sure the whole buffer is emitted, polling if
124 * necessary. We don't ever want to rely on the hvc daemon
125 * because the most interesting console output is when the
126 * kernel is crippled.
127 */
128 while (len) {
129 int sent = __write_console(cons, data, len);
130
131 data += sent;
132 len -= sent;
133
134 if (unlikely(len))
135 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
136 }
137
138 return ret;
139}
140
141static int domU_read_console(uint32_t vtermno, char *buf, int len)
142{
143 struct xencons_interface *intf;
144 XENCONS_RING_IDX cons, prod;
145 int recv = 0;
146 struct xencons_info *xencons = vtermno_to_xencons(vtermno);
147 if (xencons == NULL)
148 return -EINVAL;
149 intf = xencons->intf;
150
151 cons = intf->in_cons;
152 prod = intf->in_prod;
153 mb(); /* get pointers before reading ring */
154 BUG_ON((prod - cons) > sizeof(intf->in));
155
156 while (cons != prod && recv < len)
157 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
158
159 mb(); /* read ring before consuming */
160 intf->in_cons = cons;
161
162 notify_daemon(xencons);
163 return recv;
164}
165
166static const struct hv_ops domU_hvc_ops = {
167 .get_chars = domU_read_console,
168 .put_chars = domU_write_console,
169 .notifier_add = notifier_add_irq,
170 .notifier_del = notifier_del_irq,
171 .notifier_hangup = notifier_hangup_irq,
172};
173
174static int dom0_read_console(uint32_t vtermno, char *buf, int len)
175{
176 return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
177}
178
179/*
180 * Either for a dom0 to write to the system console, or a domU with a
181 * debug version of Xen
182 */
183static int dom0_write_console(uint32_t vtermno, const char *str, int len)
184{
185 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
186 if (rc < 0)
187 return rc;
188
189 return len;
190}
191
192static const struct hv_ops dom0_hvc_ops = {
193 .get_chars = dom0_read_console,
194 .put_chars = dom0_write_console,
195 .notifier_add = notifier_add_irq,
196 .notifier_del = notifier_del_irq,
197 .notifier_hangup = notifier_hangup_irq,
198};
199
200static int xen_hvm_console_init(void)
201{
202 int r;
203 uint64_t v = 0;
204 unsigned long gfn;
205 struct xencons_info *info;
206
207 if (!xen_hvm_domain())
208 return -ENODEV;
209
210 info = vtermno_to_xencons(HVC_COOKIE);
211 if (!info) {
212 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
213 if (!info)
214 return -ENOMEM;
215 } else if (info->intf != NULL) {
216 /* already configured */
217 return 0;
218 }
219 /*
220 * If the toolstack (or the hypervisor) hasn't set these values, the
221 * default value is 0. Even though gfn = 0 and evtchn = 0 are
222 * theoretically correct values, in practice they never are and they
223 * mean that a legacy toolstack hasn't initialized the pv console correctly.
224 */
225 r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
226 if (r < 0 || v == 0)
227 goto err;
228 info->evtchn = v;
229 v = 0;
230 r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
231 if (r < 0 || v == 0)
232 goto err;
233 gfn = v;
234 info->intf = xen_remap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE);
235 if (info->intf == NULL)
236 goto err;
237 info->vtermno = HVC_COOKIE;
238
239 spin_lock(&xencons_lock);
240 list_add_tail(&info->list, &xenconsoles);
241 spin_unlock(&xencons_lock);
242
243 return 0;
244err:
245 kfree(info);
246 return -ENODEV;
247}
248
249static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
250{
251 info->evtchn = xen_start_info->console.domU.evtchn;
252 /* GFN == MFN for PV guest */
253 info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
254 info->vtermno = vtermno;
255
256 list_add_tail(&info->list, &xenconsoles);
257
258 return 0;
259}
260
261static int xen_pv_console_init(void)
262{
263 struct xencons_info *info;
264
265 if (!xen_pv_domain())
266 return -ENODEV;
267
268 if (!xen_start_info->console.domU.evtchn)
269 return -ENODEV;
270
271 info = vtermno_to_xencons(HVC_COOKIE);
272 if (!info) {
273 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
274 if (!info)
275 return -ENOMEM;
276 } else if (info->intf != NULL) {
277 /* already configured */
278 return 0;
279 }
280 spin_lock(&xencons_lock);
281 xencons_info_pv_init(info, HVC_COOKIE);
282 spin_unlock(&xencons_lock);
283
284 return 0;
285}
286
287static int xen_initial_domain_console_init(void)
288{
289 struct xencons_info *info;
290
291 if (!xen_initial_domain())
292 return -ENODEV;
293
294 info = vtermno_to_xencons(HVC_COOKIE);
295 if (!info) {
296 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
297 if (!info)
298 return -ENOMEM;
299 }
300
301 info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
302 info->vtermno = HVC_COOKIE;
303
304 spin_lock(&xencons_lock);
305 list_add_tail(&info->list, &xenconsoles);
306 spin_unlock(&xencons_lock);
307
308 return 0;
309}
310
311static void xen_console_update_evtchn(struct xencons_info *info)
312{
313 if (xen_hvm_domain()) {
314 uint64_t v = 0;
315 int err;
316
317 err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
318 if (!err && v)
319 info->evtchn = v;
320 } else
321 info->evtchn = xen_start_info->console.domU.evtchn;
322}
323
324void xen_console_resume(void)
325{
326 struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
327 if (info != NULL && info->irq) {
328 if (!xen_initial_domain())
329 xen_console_update_evtchn(info);
330 rebind_evtchn_irq(info->evtchn, info->irq);
331 }
332}
333
334#ifdef CONFIG_HVC_XEN_FRONTEND
335static void xencons_disconnect_backend(struct xencons_info *info)
336{
337 if (info->irq > 0)
338 unbind_from_irqhandler(info->irq, NULL);
339 info->irq = 0;
340 if (info->evtchn > 0)
341 xenbus_free_evtchn(info->xbdev, info->evtchn);
342 info->evtchn = 0;
343 if (info->gntref > 0)
344 gnttab_free_grant_references(info->gntref);
345 info->gntref = 0;
346 if (info->hvc != NULL)
347 hvc_remove(info->hvc);
348 info->hvc = NULL;
349}
350
351static void xencons_free(struct xencons_info *info)
352{
353 free_page((unsigned long)info->intf);
354 info->intf = NULL;
355 info->vtermno = 0;
356 kfree(info);
357}
358
359static int xen_console_remove(struct xencons_info *info)
360{
361 xencons_disconnect_backend(info);
362 spin_lock(&xencons_lock);
363 list_del(&info->list);
364 spin_unlock(&xencons_lock);
365 if (info->xbdev != NULL)
366 xencons_free(info);
367 else {
368 if (xen_hvm_domain())
369 iounmap(info->intf);
370 kfree(info);
371 }
372 return 0;
373}
374
375static int xencons_remove(struct xenbus_device *dev)
376{
377 return xen_console_remove(dev_get_drvdata(&dev->dev));
378}
379
380static int xencons_connect_backend(struct xenbus_device *dev,
381 struct xencons_info *info)
382{
383 int ret, evtchn, devid, ref, irq;
384 struct xenbus_transaction xbt;
385 grant_ref_t gref_head;
386
387 ret = xenbus_alloc_evtchn(dev, &evtchn);
388 if (ret)
389 return ret;
390 info->evtchn = evtchn;
391 irq = bind_evtchn_to_irq(evtchn);
392 if (irq < 0)
393 return irq;
394 info->irq = irq;
395 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
396 info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
397 irq, &domU_hvc_ops, 256);
398 if (IS_ERR(info->hvc))
399 return PTR_ERR(info->hvc);
400 ret = gnttab_alloc_grant_references(1, &gref_head);
401 if (ret < 0)
402 return ret;
403 info->gntref = gref_head;
404 ref = gnttab_claim_grant_reference(&gref_head);
405 if (ref < 0)
406 return ref;
407 gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
408 virt_to_gfn(info->intf), 0);
409
410 again:
411 ret = xenbus_transaction_start(&xbt);
412 if (ret) {
413 xenbus_dev_fatal(dev, ret, "starting transaction");
414 return ret;
415 }
416 ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
417 if (ret)
418 goto error_xenbus;
419 ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
420 evtchn);
421 if (ret)
422 goto error_xenbus;
423 ret = xenbus_transaction_end(xbt, 0);
424 if (ret) {
425 if (ret == -EAGAIN)
426 goto again;
427 xenbus_dev_fatal(dev, ret, "completing transaction");
428 return ret;
429 }
430
431 xenbus_switch_state(dev, XenbusStateInitialised);
432 return 0;
433
434 error_xenbus:
435 xenbus_transaction_end(xbt, 1);
436 xenbus_dev_fatal(dev, ret, "writing xenstore");
437 return ret;
438}
439
440static int xencons_probe(struct xenbus_device *dev,
441 const struct xenbus_device_id *id)
442{
443 int ret, devid;
444 struct xencons_info *info;
445
446 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
447 if (devid == 0)
448 return -ENODEV;
449
450 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
451 if (!info)
452 return -ENOMEM;
453 dev_set_drvdata(&dev->dev, info);
454 info->xbdev = dev;
455 info->vtermno = xenbus_devid_to_vtermno(devid);
456 info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
457 if (!info->intf)
458 goto error_nomem;
459
460 ret = xencons_connect_backend(dev, info);
461 if (ret < 0)
462 goto error;
463 spin_lock(&xencons_lock);
464 list_add_tail(&info->list, &xenconsoles);
465 spin_unlock(&xencons_lock);
466
467 return 0;
468
469 error_nomem:
470 ret = -ENOMEM;
471 xenbus_dev_fatal(dev, ret, "allocating device memory");
472 error:
473 xencons_disconnect_backend(info);
474 xencons_free(info);
475 return ret;
476}
477
478static int xencons_resume(struct xenbus_device *dev)
479{
480 struct xencons_info *info = dev_get_drvdata(&dev->dev);
481
482 xencons_disconnect_backend(info);
483 memset(info->intf, 0, XEN_PAGE_SIZE);
484 return xencons_connect_backend(dev, info);
485}
486
487static void xencons_backend_changed(struct xenbus_device *dev,
488 enum xenbus_state backend_state)
489{
490 switch (backend_state) {
491 case XenbusStateReconfiguring:
492 case XenbusStateReconfigured:
493 case XenbusStateInitialising:
494 case XenbusStateInitialised:
495 case XenbusStateUnknown:
496 break;
497
498 case XenbusStateInitWait:
499 break;
500
501 case XenbusStateConnected:
502 xenbus_switch_state(dev, XenbusStateConnected);
503 break;
504
505 case XenbusStateClosed:
506 if (dev->state == XenbusStateClosed)
507 break;
508 /* Missed the backend's CLOSING state -- fallthrough */
509 case XenbusStateClosing:
510 xenbus_frontend_closed(dev);
511 break;
512 }
513}
514
515static const struct xenbus_device_id xencons_ids[] = {
516 { "console" },
517 { "" }
518};
519
520static struct xenbus_driver xencons_driver = {
521 .name = "xenconsole",
522 .ids = xencons_ids,
523 .probe = xencons_probe,
524 .remove = xencons_remove,
525 .resume = xencons_resume,
526 .otherend_changed = xencons_backend_changed,
527};
528#endif /* CONFIG_HVC_XEN_FRONTEND */
529
530static int __init xen_hvc_init(void)
531{
532 int r;
533 struct xencons_info *info;
534 const struct hv_ops *ops;
535
536 if (!xen_domain())
537 return -ENODEV;
538
539 if (xen_initial_domain()) {
540 ops = &dom0_hvc_ops;
541 r = xen_initial_domain_console_init();
542 if (r < 0)
543 return r;
544 info = vtermno_to_xencons(HVC_COOKIE);
545 } else {
546 ops = &domU_hvc_ops;
547 if (xen_hvm_domain())
548 r = xen_hvm_console_init();
549 else
550 r = xen_pv_console_init();
551 if (r < 0)
552 return r;
553
554 info = vtermno_to_xencons(HVC_COOKIE);
555 info->irq = bind_evtchn_to_irq(info->evtchn);
556 }
557 if (info->irq < 0)
558 info->irq = 0; /* NO_IRQ */
559 else
560 irq_set_noprobe(info->irq);
561
562 info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
563 if (IS_ERR(info->hvc)) {
564 r = PTR_ERR(info->hvc);
565 spin_lock(&xencons_lock);
566 list_del(&info->list);
567 spin_unlock(&xencons_lock);
568 if (info->irq)
569 unbind_from_irqhandler(info->irq, NULL);
570 kfree(info);
571 return r;
572 }
573
574 r = 0;
575#ifdef CONFIG_HVC_XEN_FRONTEND
576 r = xenbus_register_frontend(&xencons_driver);
577#endif
578 return r;
579}
580device_initcall(xen_hvc_init);
581
582static int xen_cons_init(void)
583{
584 const struct hv_ops *ops;
585
586 if (!xen_domain())
587 return 0;
588
589 if (xen_initial_domain())
590 ops = &dom0_hvc_ops;
591 else {
592 int r;
593 ops = &domU_hvc_ops;
594
595 if (xen_hvm_domain())
596 r = xen_hvm_console_init();
597 else
598 r = xen_pv_console_init();
599 if (r < 0)
600 return r;
601 }
602
603 hvc_instantiate(HVC_COOKIE, 0, ops);
604 return 0;
605}
606console_initcall(xen_cons_init);
607
608#ifdef CONFIG_X86
609static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
610{
611 if (xen_cpuid_base())
612 outsb(0xe9, str, len);
613}
614#else
615static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
616#endif
617
618#ifdef CONFIG_EARLY_PRINTK
619static int __init xenboot_setup_console(struct console *console, char *string)
620{
621 static struct xencons_info xenboot;
622
623 if (xen_initial_domain())
624 return 0;
625 if (!xen_pv_domain())
626 return -ENODEV;
627
628 return xencons_info_pv_init(&xenboot, 0);
629}
630
631static void xenboot_write_console(struct console *console, const char *string,
632 unsigned len)
633{
634 unsigned int linelen, off = 0;
635 const char *pos;
636
637 if (!xen_pv_domain()) {
638 xen_hvm_early_write(0, string, len);
639 return;
640 }
641
642 dom0_write_console(0, string, len);
643
644 if (xen_initial_domain())
645 return;
646
647 domU_write_console(0, "(early) ", 8);
648 while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
649 linelen = pos-string+off;
650 if (off + linelen > len)
651 break;
652 domU_write_console(0, string+off, linelen);
653 domU_write_console(0, "\r\n", 2);
654 off += linelen + 1;
655 }
656 if (off < len)
657 domU_write_console(0, string+off, len-off);
658}
659
660struct console xenboot_console = {
661 .name = "xenboot",
662 .write = xenboot_write_console,
663 .setup = xenboot_setup_console,
664 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
665 .index = -1,
666};
667#endif /* CONFIG_EARLY_PRINTK */
668
669void xen_raw_console_write(const char *str)
670{
671 ssize_t len = strlen(str);
672 int rc = 0;
673
674 if (xen_domain()) {
675 rc = dom0_write_console(0, str, len);
676 if (rc != -ENOSYS || !xen_hvm_domain())
677 return;
678 }
679 xen_hvm_early_write(0, str, len);
680}
681
682void xen_raw_printk(const char *fmt, ...)
683{
684 static char buf[512];
685 va_list ap;
686
687 va_start(ap, fmt);
688 vsnprintf(buf, sizeof(buf), fmt, ap);
689 va_end(ap);
690
691 xen_raw_console_write(buf);
692}
693
694static void xenboot_earlycon_write(struct console *console,
695 const char *string,
696 unsigned len)
697{
698 dom0_write_console(0, string, len);
699}
700
701static int __init xenboot_earlycon_setup(struct earlycon_device *device,
702 const char *opt)
703{
704 device->con->write = xenboot_earlycon_write;
705 return 0;
706}
707EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);