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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// 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 XENCONS_RING_IDX out_cons;
41 unsigned int out_cons_same;
42 struct hvc_struct *hvc;
43 int irq;
44 int vtermno;
45 grant_ref_t gntref;
46};
47
48static LIST_HEAD(xenconsoles);
49static DEFINE_SPINLOCK(xencons_lock);
50
51/* ------------------------------------------------------------------ */
52
53static struct xencons_info *vtermno_to_xencons(int vtermno)
54{
55 struct xencons_info *entry, *ret = NULL;
56 unsigned long flags;
57
58 spin_lock_irqsave(&xencons_lock, flags);
59 if (list_empty(&xenconsoles)) {
60 spin_unlock_irqrestore(&xencons_lock, flags);
61 return NULL;
62 }
63
64 list_for_each_entry(entry, &xenconsoles, list) {
65 if (entry->vtermno == vtermno) {
66 ret = entry;
67 break;
68 }
69 }
70 spin_unlock_irqrestore(&xencons_lock, flags);
71
72 return ret;
73}
74
75static inline int xenbus_devid_to_vtermno(int devid)
76{
77 return devid + HVC_COOKIE;
78}
79
80static inline void notify_daemon(struct xencons_info *cons)
81{
82 /* Use evtchn: this is called early, before irq is set up. */
83 notify_remote_via_evtchn(cons->evtchn);
84}
85
86static int __write_console(struct xencons_info *xencons,
87 const char *data, int len)
88{
89 XENCONS_RING_IDX cons, prod;
90 struct xencons_interface *intf = xencons->intf;
91 int sent = 0;
92
93 cons = intf->out_cons;
94 prod = intf->out_prod;
95 mb(); /* update queue values before going on */
96
97 if ((prod - cons) > sizeof(intf->out)) {
98 pr_err_once("xencons: Illegal ring page indices");
99 return -EINVAL;
100 }
101
102 while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
103 intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
104
105 wmb(); /* write ring before updating pointer */
106 intf->out_prod = prod;
107
108 if (sent)
109 notify_daemon(xencons);
110 return sent;
111}
112
113static int domU_write_console(uint32_t vtermno, const char *data, int len)
114{
115 int ret = len;
116 struct xencons_info *cons = vtermno_to_xencons(vtermno);
117 if (cons == NULL)
118 return -EINVAL;
119
120 /*
121 * Make sure the whole buffer is emitted, polling if
122 * necessary. We don't ever want to rely on the hvc daemon
123 * because the most interesting console output is when the
124 * kernel is crippled.
125 */
126 while (len) {
127 int sent = __write_console(cons, data, len);
128
129 if (sent < 0)
130 return sent;
131
132 data += sent;
133 len -= sent;
134
135 if (unlikely(len))
136 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
137 }
138
139 return ret;
140}
141
142static int domU_read_console(uint32_t vtermno, char *buf, int len)
143{
144 struct xencons_interface *intf;
145 XENCONS_RING_IDX cons, prod;
146 int recv = 0;
147 struct xencons_info *xencons = vtermno_to_xencons(vtermno);
148 unsigned int eoiflag = 0;
149
150 if (xencons == NULL)
151 return -EINVAL;
152 intf = xencons->intf;
153
154 cons = intf->in_cons;
155 prod = intf->in_prod;
156 mb(); /* get pointers before reading ring */
157
158 if ((prod - cons) > sizeof(intf->in)) {
159 pr_err_once("xencons: Illegal ring page indices");
160 return -EINVAL;
161 }
162
163 while (cons != prod && recv < len)
164 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
165
166 mb(); /* read ring before consuming */
167 intf->in_cons = cons;
168
169 /*
170 * When to mark interrupt having been spurious:
171 * - there was no new data to be read, and
172 * - the backend did not consume some output bytes, and
173 * - the previous round with no read data didn't see consumed bytes
174 * (we might have a race with an interrupt being in flight while
175 * updating xencons->out_cons, so account for that by allowing one
176 * round without any visible reason)
177 */
178 if (intf->out_cons != xencons->out_cons) {
179 xencons->out_cons = intf->out_cons;
180 xencons->out_cons_same = 0;
181 }
182 if (recv) {
183 notify_daemon(xencons);
184 } else if (xencons->out_cons_same++ > 1) {
185 eoiflag = XEN_EOI_FLAG_SPURIOUS;
186 }
187
188 xen_irq_lateeoi(xencons->irq, eoiflag);
189
190 return recv;
191}
192
193static const struct hv_ops domU_hvc_ops = {
194 .get_chars = domU_read_console,
195 .put_chars = domU_write_console,
196 .notifier_add = notifier_add_irq,
197 .notifier_del = notifier_del_irq,
198 .notifier_hangup = notifier_hangup_irq,
199};
200
201static int dom0_read_console(uint32_t vtermno, char *buf, int len)
202{
203 return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
204}
205
206/*
207 * Either for a dom0 to write to the system console, or a domU with a
208 * debug version of Xen
209 */
210static int dom0_write_console(uint32_t vtermno, const char *str, int len)
211{
212 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
213 if (rc < 0)
214 return rc;
215
216 return len;
217}
218
219static const struct hv_ops dom0_hvc_ops = {
220 .get_chars = dom0_read_console,
221 .put_chars = dom0_write_console,
222 .notifier_add = notifier_add_irq,
223 .notifier_del = notifier_del_irq,
224 .notifier_hangup = notifier_hangup_irq,
225};
226
227static int xen_hvm_console_init(void)
228{
229 int r;
230 uint64_t v = 0;
231 unsigned long gfn, flags;
232 struct xencons_info *info;
233
234 if (!xen_hvm_domain())
235 return -ENODEV;
236
237 info = vtermno_to_xencons(HVC_COOKIE);
238 if (!info) {
239 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
240 if (!info)
241 return -ENOMEM;
242 } else if (info->intf != NULL) {
243 /* already configured */
244 return 0;
245 }
246 /*
247 * If the toolstack (or the hypervisor) hasn't set these values, the
248 * default value is 0. Even though gfn = 0 and evtchn = 0 are
249 * theoretically correct values, in practice they never are and they
250 * mean that a legacy toolstack hasn't initialized the pv console correctly.
251 */
252 r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
253 if (r < 0 || v == 0)
254 goto err;
255 info->evtchn = v;
256 v = 0;
257 r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
258 if (r < 0 || v == 0)
259 goto err;
260 gfn = v;
261 info->intf = memremap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE, MEMREMAP_WB);
262 if (info->intf == NULL)
263 goto err;
264 info->vtermno = HVC_COOKIE;
265
266 spin_lock_irqsave(&xencons_lock, flags);
267 list_add_tail(&info->list, &xenconsoles);
268 spin_unlock_irqrestore(&xencons_lock, flags);
269
270 return 0;
271err:
272 kfree(info);
273 return -ENODEV;
274}
275
276static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
277{
278 info->evtchn = xen_start_info->console.domU.evtchn;
279 /* GFN == MFN for PV guest */
280 info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
281 info->vtermno = vtermno;
282
283 list_add_tail(&info->list, &xenconsoles);
284
285 return 0;
286}
287
288static int xen_pv_console_init(void)
289{
290 struct xencons_info *info;
291 unsigned long flags;
292
293 if (!xen_pv_domain())
294 return -ENODEV;
295
296 if (!xen_start_info->console.domU.evtchn)
297 return -ENODEV;
298
299 info = vtermno_to_xencons(HVC_COOKIE);
300 if (!info) {
301 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
302 if (!info)
303 return -ENOMEM;
304 } else if (info->intf != NULL) {
305 /* already configured */
306 return 0;
307 }
308 spin_lock_irqsave(&xencons_lock, flags);
309 xencons_info_pv_init(info, HVC_COOKIE);
310 spin_unlock_irqrestore(&xencons_lock, flags);
311
312 return 0;
313}
314
315static int xen_initial_domain_console_init(void)
316{
317 struct xencons_info *info;
318 unsigned long flags;
319
320 if (!xen_initial_domain())
321 return -ENODEV;
322
323 info = vtermno_to_xencons(HVC_COOKIE);
324 if (!info) {
325 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
326 if (!info)
327 return -ENOMEM;
328 }
329
330 info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
331 info->vtermno = HVC_COOKIE;
332
333 spin_lock_irqsave(&xencons_lock, flags);
334 list_add_tail(&info->list, &xenconsoles);
335 spin_unlock_irqrestore(&xencons_lock, flags);
336
337 return 0;
338}
339
340static void xen_console_update_evtchn(struct xencons_info *info)
341{
342 if (xen_hvm_domain()) {
343 uint64_t v = 0;
344 int err;
345
346 err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
347 if (!err && v)
348 info->evtchn = v;
349 } else
350 info->evtchn = xen_start_info->console.domU.evtchn;
351}
352
353void xen_console_resume(void)
354{
355 struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
356 if (info != NULL && info->irq) {
357 if (!xen_initial_domain())
358 xen_console_update_evtchn(info);
359 rebind_evtchn_irq(info->evtchn, info->irq);
360 }
361}
362
363#ifdef CONFIG_HVC_XEN_FRONTEND
364static void xencons_disconnect_backend(struct xencons_info *info)
365{
366 if (info->irq > 0)
367 unbind_from_irqhandler(info->irq, NULL);
368 info->irq = 0;
369 if (info->evtchn > 0)
370 xenbus_free_evtchn(info->xbdev, info->evtchn);
371 info->evtchn = 0;
372 if (info->gntref > 0)
373 gnttab_free_grant_references(info->gntref);
374 info->gntref = 0;
375 if (info->hvc != NULL)
376 hvc_remove(info->hvc);
377 info->hvc = NULL;
378}
379
380static void xencons_free(struct xencons_info *info)
381{
382 free_page((unsigned long)info->intf);
383 info->intf = NULL;
384 info->vtermno = 0;
385 kfree(info);
386}
387
388static int xen_console_remove(struct xencons_info *info)
389{
390 unsigned long flags;
391
392 xencons_disconnect_backend(info);
393 spin_lock_irqsave(&xencons_lock, flags);
394 list_del(&info->list);
395 spin_unlock_irqrestore(&xencons_lock, flags);
396 if (info->xbdev != NULL)
397 xencons_free(info);
398 else {
399 if (xen_hvm_domain())
400 iounmap(info->intf);
401 kfree(info);
402 }
403 return 0;
404}
405
406static void xencons_remove(struct xenbus_device *dev)
407{
408 xen_console_remove(dev_get_drvdata(&dev->dev));
409}
410
411static int xencons_connect_backend(struct xenbus_device *dev,
412 struct xencons_info *info)
413{
414 int ret, evtchn, devid, ref, irq;
415 struct xenbus_transaction xbt;
416 grant_ref_t gref_head;
417
418 ret = xenbus_alloc_evtchn(dev, &evtchn);
419 if (ret)
420 return ret;
421 info->evtchn = evtchn;
422 irq = bind_interdomain_evtchn_to_irq_lateeoi(dev, evtchn);
423 if (irq < 0)
424 return irq;
425 info->irq = irq;
426 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
427 info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
428 irq, &domU_hvc_ops, 256);
429 if (IS_ERR(info->hvc))
430 return PTR_ERR(info->hvc);
431 ret = gnttab_alloc_grant_references(1, &gref_head);
432 if (ret < 0)
433 return ret;
434 info->gntref = gref_head;
435 ref = gnttab_claim_grant_reference(&gref_head);
436 if (ref < 0)
437 return ref;
438 gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
439 virt_to_gfn(info->intf), 0);
440
441 again:
442 ret = xenbus_transaction_start(&xbt);
443 if (ret) {
444 xenbus_dev_fatal(dev, ret, "starting transaction");
445 return ret;
446 }
447 ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
448 if (ret)
449 goto error_xenbus;
450 ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
451 evtchn);
452 if (ret)
453 goto error_xenbus;
454 ret = xenbus_transaction_end(xbt, 0);
455 if (ret) {
456 if (ret == -EAGAIN)
457 goto again;
458 xenbus_dev_fatal(dev, ret, "completing transaction");
459 return ret;
460 }
461
462 xenbus_switch_state(dev, XenbusStateInitialised);
463 return 0;
464
465 error_xenbus:
466 xenbus_transaction_end(xbt, 1);
467 xenbus_dev_fatal(dev, ret, "writing xenstore");
468 return ret;
469}
470
471static int xencons_probe(struct xenbus_device *dev,
472 const struct xenbus_device_id *id)
473{
474 int ret, devid;
475 struct xencons_info *info;
476 unsigned long flags;
477
478 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
479 if (devid == 0)
480 return -ENODEV;
481
482 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
483 if (!info)
484 return -ENOMEM;
485 dev_set_drvdata(&dev->dev, info);
486 info->xbdev = dev;
487 info->vtermno = xenbus_devid_to_vtermno(devid);
488 info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
489 if (!info->intf)
490 goto error_nomem;
491
492 ret = xencons_connect_backend(dev, info);
493 if (ret < 0)
494 goto error;
495 spin_lock_irqsave(&xencons_lock, flags);
496 list_add_tail(&info->list, &xenconsoles);
497 spin_unlock_irqrestore(&xencons_lock, flags);
498
499 return 0;
500
501 error_nomem:
502 ret = -ENOMEM;
503 xenbus_dev_fatal(dev, ret, "allocating device memory");
504 error:
505 xencons_disconnect_backend(info);
506 xencons_free(info);
507 return ret;
508}
509
510static int xencons_resume(struct xenbus_device *dev)
511{
512 struct xencons_info *info = dev_get_drvdata(&dev->dev);
513
514 xencons_disconnect_backend(info);
515 memset(info->intf, 0, XEN_PAGE_SIZE);
516 return xencons_connect_backend(dev, info);
517}
518
519static void xencons_backend_changed(struct xenbus_device *dev,
520 enum xenbus_state backend_state)
521{
522 switch (backend_state) {
523 case XenbusStateReconfiguring:
524 case XenbusStateReconfigured:
525 case XenbusStateInitialising:
526 case XenbusStateInitialised:
527 case XenbusStateUnknown:
528 break;
529
530 case XenbusStateInitWait:
531 break;
532
533 case XenbusStateConnected:
534 xenbus_switch_state(dev, XenbusStateConnected);
535 break;
536
537 case XenbusStateClosed:
538 if (dev->state == XenbusStateClosed)
539 break;
540 fallthrough; /* Missed the backend's CLOSING state */
541 case XenbusStateClosing:
542 xenbus_frontend_closed(dev);
543 break;
544 }
545}
546
547static const struct xenbus_device_id xencons_ids[] = {
548 { "console" },
549 { "" }
550};
551
552static struct xenbus_driver xencons_driver = {
553 .name = "xenconsole",
554 .ids = xencons_ids,
555 .probe = xencons_probe,
556 .remove = xencons_remove,
557 .resume = xencons_resume,
558 .otherend_changed = xencons_backend_changed,
559 .not_essential = true,
560};
561#endif /* CONFIG_HVC_XEN_FRONTEND */
562
563static int __init xen_hvc_init(void)
564{
565 int r;
566 struct xencons_info *info;
567 const struct hv_ops *ops;
568
569 if (!xen_domain())
570 return -ENODEV;
571
572 if (xen_initial_domain()) {
573 ops = &dom0_hvc_ops;
574 r = xen_initial_domain_console_init();
575 if (r < 0)
576 return r;
577 info = vtermno_to_xencons(HVC_COOKIE);
578 } else {
579 ops = &domU_hvc_ops;
580 if (xen_hvm_domain())
581 r = xen_hvm_console_init();
582 else
583 r = xen_pv_console_init();
584 if (r < 0)
585 return r;
586
587 info = vtermno_to_xencons(HVC_COOKIE);
588 info->irq = bind_evtchn_to_irq_lateeoi(info->evtchn);
589 }
590 if (info->irq < 0)
591 info->irq = 0; /* NO_IRQ */
592 else
593 irq_set_noprobe(info->irq);
594
595 info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
596 if (IS_ERR(info->hvc)) {
597 unsigned long flags;
598
599 r = PTR_ERR(info->hvc);
600 spin_lock_irqsave(&xencons_lock, flags);
601 list_del(&info->list);
602 spin_unlock_irqrestore(&xencons_lock, flags);
603 if (info->irq)
604 unbind_from_irqhandler(info->irq, NULL);
605 kfree(info);
606 return r;
607 }
608
609 r = 0;
610#ifdef CONFIG_HVC_XEN_FRONTEND
611 r = xenbus_register_frontend(&xencons_driver);
612#endif
613 return r;
614}
615device_initcall(xen_hvc_init);
616
617static int xen_cons_init(void)
618{
619 const struct hv_ops *ops;
620
621 if (!xen_domain())
622 return 0;
623
624 if (xen_initial_domain())
625 ops = &dom0_hvc_ops;
626 else {
627 int r;
628 ops = &domU_hvc_ops;
629
630 if (xen_hvm_domain())
631 r = xen_hvm_console_init();
632 else
633 r = xen_pv_console_init();
634 if (r < 0)
635 return r;
636 }
637
638 hvc_instantiate(HVC_COOKIE, 0, ops);
639 return 0;
640}
641console_initcall(xen_cons_init);
642
643#ifdef CONFIG_X86
644static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
645{
646 if (xen_cpuid_base())
647 outsb(0xe9, str, len);
648}
649#else
650static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
651#endif
652
653#ifdef CONFIG_EARLY_PRINTK
654static int __init xenboot_console_setup(struct console *console, char *string)
655{
656 static struct xencons_info xenboot;
657
658 if (xen_initial_domain() || !xen_pv_domain())
659 return 0;
660
661 return xencons_info_pv_init(&xenboot, 0);
662}
663
664static void xenboot_write_console(struct console *console, const char *string,
665 unsigned len)
666{
667 unsigned int linelen, off = 0;
668 const char *pos;
669
670 if (dom0_write_console(0, string, len) >= 0)
671 return;
672
673 if (!xen_pv_domain()) {
674 xen_hvm_early_write(0, string, len);
675 return;
676 }
677
678 if (domU_write_console(0, "(early) ", 8) < 0)
679 return;
680 while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
681 linelen = pos-string+off;
682 if (off + linelen > len)
683 break;
684 domU_write_console(0, string+off, linelen);
685 domU_write_console(0, "\r\n", 2);
686 off += linelen + 1;
687 }
688 if (off < len)
689 domU_write_console(0, string+off, len-off);
690}
691
692struct console xenboot_console = {
693 .name = "xenboot",
694 .write = xenboot_write_console,
695 .setup = xenboot_console_setup,
696 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
697 .index = -1,
698};
699#endif /* CONFIG_EARLY_PRINTK */
700
701void xen_raw_console_write(const char *str)
702{
703 ssize_t len = strlen(str);
704 int rc = 0;
705
706 if (xen_domain()) {
707 rc = dom0_write_console(0, str, len);
708 if (rc != -ENOSYS || !xen_hvm_domain())
709 return;
710 }
711 xen_hvm_early_write(0, str, len);
712}
713
714void xen_raw_printk(const char *fmt, ...)
715{
716 static char buf[512];
717 va_list ap;
718
719 va_start(ap, fmt);
720 vsnprintf(buf, sizeof(buf), fmt, ap);
721 va_end(ap);
722
723 xen_raw_console_write(buf);
724}
725
726static void xenboot_earlycon_write(struct console *console,
727 const char *string,
728 unsigned len)
729{
730 dom0_write_console(0, string, len);
731}
732
733static int __init xenboot_earlycon_setup(struct earlycon_device *device,
734 const char *opt)
735{
736 device->con->write = xenboot_earlycon_write;
737 return 0;
738}
739EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);