hvc_xen.c revision cf8e019b523a8caa95b56ff0ce62a4856b14395f 
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
45struct 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
56static LIST_HEAD(xenconsoles);
57static DEFINE_SPINLOCK(xencons_lock);
58
59/* ------------------------------------------------------------------ */
60
61static 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
78static inline int xenbus_devid_to_vtermno(int devid)
79{
80	return devid + HVC_COOKIE;
81}
82
83static 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
89static 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
112static 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
138static 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
163static 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
171static 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 */
180static 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
189static 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
197static 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
244static 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
276static 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
300void 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
307static 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
323static 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
331static 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
348static struct xenbus_driver xencons_driver;
349
350static int xencons_remove(struct xenbus_device *dev)
351{
352	return xen_console_remove(dev_get_drvdata(&dev->dev));
353}
354
355static 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
423static 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
461static 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
470static 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
495static const struct xenbus_device_id xencons_ids[] = {
496	{ "console" },
497	{ "" }
498};
499
500
501static 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
509static 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
560static 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
572static 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
598module_init(xen_hvc_init);
599module_exit(xen_hvc_fini);
600console_initcall(xen_cons_init);
601
602#ifdef CONFIG_EARLY_PRINTK
603static 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
630struct 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
637void xen_raw_console_write(const char *str)
638{
639	dom0_write_console(0, str, strlen(str));
640}
641
642void 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