hvc_xen.c revision 85fc3e3eba89272acb005f320ccafa0588a48f49 
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		goto err;
221	info->evtchn = v;
222	v = 0;
223	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
224	if (r < 0)
225		goto err;
226	mfn = v;
227	info->intf = ioremap(mfn << PAGE_SHIFT, PAGE_SIZE);
228	if (info->intf == NULL)
229		goto err;
230	info->vtermno = HVC_COOKIE;
231
232	spin_lock(&xencons_lock);
233	list_add_tail(&info->list, &xenconsoles);
234	spin_unlock(&xencons_lock);
235
236	return 0;
237err:
238	kfree(info);
239	return -ENODEV;
240}
241
242static int xen_pv_console_init(void)
243{
244	struct xencons_info *info;
245
246	if (!xen_pv_domain())
247		return -ENODEV;
248
249	if (!xen_start_info->console.domU.evtchn)
250		return -ENODEV;
251
252	info = vtermno_to_xencons(HVC_COOKIE);
253	if (!info) {
254		info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO);
255		if (!info)
256			return -ENOMEM;
257	}
258
259	/* already configured */
260	if (info->intf != NULL)
261		return 0;
262
263	info->evtchn = xen_start_info->console.domU.evtchn;
264	info->intf = mfn_to_virt(xen_start_info->console.domU.mfn);
265	info->vtermno = HVC_COOKIE;
266
267	spin_lock(&xencons_lock);
268	list_add_tail(&info->list, &xenconsoles);
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 | __GFP_ZERO);
284		if (!info)
285			return -ENOMEM;
286	}
287
288	info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
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
298void xen_console_resume(void)
299{
300	struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
301	if (info != NULL && info->irq)
302		rebind_evtchn_irq(info->evtchn, info->irq);
303}
304
305static void xencons_disconnect_backend(struct xencons_info *info)
306{
307	if (info->irq > 0)
308		unbind_from_irqhandler(info->irq, NULL);
309	info->irq = 0;
310	if (info->evtchn > 0)
311		xenbus_free_evtchn(info->xbdev, info->evtchn);
312	info->evtchn = 0;
313	if (info->gntref > 0)
314		gnttab_free_grant_references(info->gntref);
315	info->gntref = 0;
316	if (info->hvc != NULL)
317		hvc_remove(info->hvc);
318	info->hvc = NULL;
319}
320
321static void xencons_free(struct xencons_info *info)
322{
323	free_page((unsigned long)info->intf);
324	info->intf = NULL;
325	info->vtermno = 0;
326	kfree(info);
327}
328
329static int xen_console_remove(struct xencons_info *info)
330{
331	xencons_disconnect_backend(info);
332	spin_lock(&xencons_lock);
333	list_del(&info->list);
334	spin_unlock(&xencons_lock);
335	if (info->xbdev != NULL)
336		xencons_free(info);
337	else {
338		if (xen_hvm_domain())
339			iounmap(info->intf);
340		kfree(info);
341	}
342	return 0;
343}
344
345#ifdef CONFIG_HVC_XEN_FRONTEND
346static struct xenbus_driver xencons_driver;
347
348static int xencons_remove(struct xenbus_device *dev)
349{
350	return xen_console_remove(dev_get_drvdata(&dev->dev));
351}
352
353static int xencons_connect_backend(struct xenbus_device *dev,
354				  struct xencons_info *info)
355{
356	int ret, evtchn, devid, ref, irq;
357	struct xenbus_transaction xbt;
358	grant_ref_t gref_head;
359	unsigned long mfn;
360
361	ret = xenbus_alloc_evtchn(dev, &evtchn);
362	if (ret)
363		return ret;
364	info->evtchn = evtchn;
365	irq = bind_evtchn_to_irq(evtchn);
366	if (irq < 0)
367		return irq;
368	info->irq = irq;
369	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
370	info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
371			irq, &domU_hvc_ops, 256);
372	if (IS_ERR(info->hvc))
373		return PTR_ERR(info->hvc);
374	if (xen_pv_domain())
375		mfn = virt_to_mfn(info->intf);
376	else
377		mfn = __pa(info->intf) >> PAGE_SHIFT;
378	ret = gnttab_alloc_grant_references(1, &gref_head);
379	if (ret < 0)
380		return ret;
381	info->gntref = gref_head;
382	ref = gnttab_claim_grant_reference(&gref_head);
383	if (ref < 0)
384		return ref;
385	gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
386			mfn, 0);
387
388 again:
389	ret = xenbus_transaction_start(&xbt);
390	if (ret) {
391		xenbus_dev_fatal(dev, ret, "starting transaction");
392		return ret;
393	}
394	ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
395	if (ret)
396		goto error_xenbus;
397	ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
398			    evtchn);
399	if (ret)
400		goto error_xenbus;
401	ret = xenbus_printf(xbt, dev->nodename, "type", "ioemu");
402	if (ret)
403		goto error_xenbus;
404	ret = xenbus_transaction_end(xbt, 0);
405	if (ret) {
406		if (ret == -EAGAIN)
407			goto again;
408		xenbus_dev_fatal(dev, ret, "completing transaction");
409		return ret;
410	}
411
412	xenbus_switch_state(dev, XenbusStateInitialised);
413	return 0;
414
415 error_xenbus:
416	xenbus_transaction_end(xbt, 1);
417	xenbus_dev_fatal(dev, ret, "writing xenstore");
418	return ret;
419}
420
421static int __devinit xencons_probe(struct xenbus_device *dev,
422				  const struct xenbus_device_id *id)
423{
424	int ret, devid;
425	struct xencons_info *info;
426
427	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
428	if (devid == 0)
429		return -ENODEV;
430
431	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
432	if (!info)
433		return -ENOMEM;
434	dev_set_drvdata(&dev->dev, info);
435	info->xbdev = dev;
436	info->vtermno = xenbus_devid_to_vtermno(devid);
437	info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
438	if (!info->intf)
439		goto error_nomem;
440
441	ret = xencons_connect_backend(dev, info);
442	if (ret < 0)
443		goto error;
444	spin_lock(&xencons_lock);
445	list_add_tail(&info->list, &xenconsoles);
446	spin_unlock(&xencons_lock);
447
448	return 0;
449
450 error_nomem:
451	ret = -ENOMEM;
452	xenbus_dev_fatal(dev, ret, "allocating device memory");
453 error:
454	xencons_disconnect_backend(info);
455	xencons_free(info);
456	return ret;
457}
458
459static int xencons_resume(struct xenbus_device *dev)
460{
461	struct xencons_info *info = dev_get_drvdata(&dev->dev);
462
463	xencons_disconnect_backend(info);
464	memset(info->intf, 0, PAGE_SIZE);
465	return xencons_connect_backend(dev, info);
466}
467
468static void xencons_backend_changed(struct xenbus_device *dev,
469				   enum xenbus_state backend_state)
470{
471	switch (backend_state) {
472	case XenbusStateReconfiguring:
473	case XenbusStateReconfigured:
474	case XenbusStateInitialising:
475	case XenbusStateInitialised:
476	case XenbusStateUnknown:
477	case XenbusStateClosed:
478		break;
479
480	case XenbusStateInitWait:
481		break;
482
483	case XenbusStateConnected:
484		xenbus_switch_state(dev, XenbusStateConnected);
485		break;
486
487	case XenbusStateClosing:
488		xenbus_frontend_closed(dev);
489		break;
490	}
491}
492
493static const struct xenbus_device_id xencons_ids[] = {
494	{ "console" },
495	{ "" }
496};
497
498
499static DEFINE_XENBUS_DRIVER(xencons, "xenconsole",
500	.probe = xencons_probe,
501	.remove = xencons_remove,
502	.resume = xencons_resume,
503	.otherend_changed = xencons_backend_changed,
504);
505#endif /* CONFIG_HVC_XEN_FRONTEND */
506
507static int __init xen_hvc_init(void)
508{
509	int r;
510	struct xencons_info *info;
511	const struct hv_ops *ops;
512
513	if (!xen_domain())
514		return -ENODEV;
515
516	if (xen_initial_domain()) {
517		ops = &dom0_hvc_ops;
518		r = xen_initial_domain_console_init();
519		if (r < 0)
520			return r;
521		info = vtermno_to_xencons(HVC_COOKIE);
522	} else {
523		ops = &domU_hvc_ops;
524		if (xen_hvm_domain())
525			r = xen_hvm_console_init();
526		else
527			r = xen_pv_console_init();
528		if (r < 0)
529			return r;
530
531		info = vtermno_to_xencons(HVC_COOKIE);
532		info->irq = bind_evtchn_to_irq(info->evtchn);
533	}
534	if (info->irq < 0)
535		info->irq = 0; /* NO_IRQ */
536	else
537		irq_set_noprobe(info->irq);
538
539	info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
540	if (IS_ERR(info->hvc)) {
541		r = PTR_ERR(info->hvc);
542		spin_lock(&xencons_lock);
543		list_del(&info->list);
544		spin_unlock(&xencons_lock);
545		if (info->irq)
546			unbind_from_irqhandler(info->irq, NULL);
547		kfree(info);
548		return r;
549	}
550
551	r = 0;
552#ifdef CONFIG_HVC_XEN_FRONTEND
553	r = xenbus_register_frontend(&xencons_driver);
554#endif
555	return r;
556}
557
558static void __exit xen_hvc_fini(void)
559{
560	struct xencons_info *entry, *next;
561
562	if (list_empty(&xenconsoles))
563			return;
564
565	list_for_each_entry_safe(entry, next, &xenconsoles, list) {
566		xen_console_remove(entry);
567	}
568}
569
570static int xen_cons_init(void)
571{
572	const struct hv_ops *ops;
573
574	if (!xen_domain())
575		return 0;
576
577	if (xen_initial_domain())
578		ops = &dom0_hvc_ops;
579	else {
580		int r;
581		ops = &domU_hvc_ops;
582
583		if (xen_hvm_domain())
584			r = xen_hvm_console_init();
585		else
586			r = xen_pv_console_init();
587		if (r < 0)
588			return r;
589	}
590
591	hvc_instantiate(HVC_COOKIE, 0, ops);
592	return 0;
593}
594
595
596module_init(xen_hvc_init);
597module_exit(xen_hvc_fini);
598console_initcall(xen_cons_init);
599
600#ifdef CONFIG_EARLY_PRINTK
601static void xenboot_write_console(struct console *console, const char *string,
602				  unsigned len)
603{
604	unsigned int linelen, off = 0;
605	const char *pos;
606
607	if (!xen_pv_domain())
608		return;
609
610	dom0_write_console(0, string, len);
611
612	if (xen_initial_domain())
613		return;
614
615	domU_write_console(0, "(early) ", 8);
616	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
617		linelen = pos-string+off;
618		if (off + linelen > len)
619			break;
620		domU_write_console(0, string+off, linelen);
621		domU_write_console(0, "\r\n", 2);
622		off += linelen + 1;
623	}
624	if (off < len)
625		domU_write_console(0, string+off, len-off);
626}
627
628struct console xenboot_console = {
629	.name		= "xenboot",
630	.write		= xenboot_write_console,
631	.flags		= CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
632};
633#endif	/* CONFIG_EARLY_PRINTK */
634
635void xen_raw_console_write(const char *str)
636{
637	dom0_write_console(0, str, strlen(str));
638}
639
640void xen_raw_printk(const char *fmt, ...)
641{
642	static char buf[512];
643	va_list ap;
644
645	va_start(ap, fmt);
646	vsnprintf(buf, sizeof(buf), fmt, ap);
647	va_end(ap);
648
649	xen_raw_console_write(buf);
650}
651