2 * xen console driver interface to hvc_console.c
4 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
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.
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.
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
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>
31 #include <asm/xen/hypervisor.h>
34 #include <xen/interface/xen.h>
36 #include <xen/grant_table.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>
44 #include "hvc_console.h"
46 #define HVC_COOKIE 0x58656e /* "Xen" in hex */
49 struct list_head list;
50 struct xenbus_device *xbdev;
51 struct xencons_interface *intf;
53 XENCONS_RING_IDX out_cons;
54 unsigned int out_cons_same;
55 struct hvc_struct *hvc;
62 static LIST_HEAD(xenconsoles);
63 static DEFINE_SPINLOCK(xencons_lock);
65 /* ------------------------------------------------------------------ */
67 static struct xencons_info *vtermno_to_xencons(int vtermno)
69 struct xencons_info *entry, *ret = NULL;
72 spin_lock_irqsave(&xencons_lock, flags);
73 if (list_empty(&xenconsoles)) {
74 spin_unlock_irqrestore(&xencons_lock, flags);
78 list_for_each_entry(entry, &xenconsoles, list) {
79 if (entry->vtermno == vtermno) {
84 spin_unlock_irqrestore(&xencons_lock, flags);
89 static inline int xenbus_devid_to_vtermno(int devid)
91 return devid + HVC_COOKIE;
94 static inline void notify_daemon(struct xencons_info *cons)
96 /* Use evtchn: this is called early, before irq is set up. */
97 notify_remote_via_evtchn(cons->evtchn);
100 static int __write_console(struct xencons_info *xencons,
101 const char *data, int len)
103 XENCONS_RING_IDX cons, prod;
104 struct xencons_interface *intf = xencons->intf;
108 spin_lock_irqsave(&xencons->ring_lock, flags);
109 cons = intf->out_cons;
110 prod = intf->out_prod;
111 mb(); /* update queue values before going on */
113 if ((prod - cons) > sizeof(intf->out)) {
114 spin_unlock_irqrestore(&xencons->ring_lock, flags);
115 pr_err_once("xencons: Illegal ring page indices");
119 while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
120 intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
122 wmb(); /* write ring before updating pointer */
123 intf->out_prod = prod;
124 spin_unlock_irqrestore(&xencons->ring_lock, flags);
127 notify_daemon(xencons);
131 static int domU_write_console(uint32_t vtermno, const char *data, int len)
134 struct xencons_info *cons = vtermno_to_xencons(vtermno);
139 * Make sure the whole buffer is emitted, polling if
140 * necessary. We don't ever want to rely on the hvc daemon
141 * because the most interesting console output is when the
142 * kernel is crippled.
145 int sent = __write_console(cons, data, len);
154 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
160 static int domU_read_console(uint32_t vtermno, char *buf, int len)
162 struct xencons_interface *intf;
163 XENCONS_RING_IDX cons, prod;
165 struct xencons_info *xencons = vtermno_to_xencons(vtermno);
166 unsigned int eoiflag = 0;
171 intf = xencons->intf;
173 spin_lock_irqsave(&xencons->ring_lock, flags);
174 cons = intf->in_cons;
175 prod = intf->in_prod;
176 mb(); /* get pointers before reading ring */
178 if ((prod - cons) > sizeof(intf->in)) {
179 spin_unlock_irqrestore(&xencons->ring_lock, flags);
180 pr_err_once("xencons: Illegal ring page indices");
184 while (cons != prod && recv < len)
185 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
187 mb(); /* read ring before consuming */
188 intf->in_cons = cons;
191 * When to mark interrupt having been spurious:
192 * - there was no new data to be read, and
193 * - the backend did not consume some output bytes, and
194 * - the previous round with no read data didn't see consumed bytes
195 * (we might have a race with an interrupt being in flight while
196 * updating xencons->out_cons, so account for that by allowing one
197 * round without any visible reason)
199 if (intf->out_cons != xencons->out_cons) {
200 xencons->out_cons = intf->out_cons;
201 xencons->out_cons_same = 0;
203 if (!recv && xencons->out_cons_same++ > 1) {
204 eoiflag = XEN_EOI_FLAG_SPURIOUS;
206 spin_unlock_irqrestore(&xencons->ring_lock, flags);
209 notify_daemon(xencons);
212 xen_irq_lateeoi(xencons->irq, eoiflag);
217 static const struct hv_ops domU_hvc_ops = {
218 .get_chars = domU_read_console,
219 .put_chars = domU_write_console,
220 .notifier_add = notifier_add_irq,
221 .notifier_del = notifier_del_irq,
222 .notifier_hangup = notifier_hangup_irq,
225 static int dom0_read_console(uint32_t vtermno, char *buf, int len)
227 return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
231 * Either for a dom0 to write to the system console, or a domU with a
232 * debug version of Xen
234 static int dom0_write_console(uint32_t vtermno, const char *str, int len)
236 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
243 static const struct hv_ops dom0_hvc_ops = {
244 .get_chars = dom0_read_console,
245 .put_chars = dom0_write_console,
246 .notifier_add = notifier_add_irq,
247 .notifier_del = notifier_del_irq,
248 .notifier_hangup = notifier_hangup_irq,
251 static int xen_hvm_console_init(void)
255 unsigned long gfn, flags;
256 struct xencons_info *info;
258 if (!xen_hvm_domain())
261 info = vtermno_to_xencons(HVC_COOKIE);
263 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
266 spin_lock_init(&info->ring_lock);
267 } else if (info->intf != NULL) {
268 /* already configured */
272 * If the toolstack (or the hypervisor) hasn't set these values, the
273 * default value is 0. Even though gfn = 0 and evtchn = 0 are
274 * theoretically correct values, in practice they never are and they
275 * mean that a legacy toolstack hasn't initialized the pv console correctly.
277 r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
282 r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
286 info->intf = xen_remap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE);
287 if (info->intf == NULL)
289 info->vtermno = HVC_COOKIE;
291 spin_lock_irqsave(&xencons_lock, flags);
292 list_add_tail(&info->list, &xenconsoles);
293 spin_unlock_irqrestore(&xencons_lock, flags);
301 static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
303 spin_lock_init(&info->ring_lock);
304 info->evtchn = xen_start_info->console.domU.evtchn;
305 /* GFN == MFN for PV guest */
306 info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
307 info->vtermno = vtermno;
309 list_add_tail(&info->list, &xenconsoles);
314 static int xen_pv_console_init(void)
316 struct xencons_info *info;
319 if (!xen_pv_domain())
322 if (!xen_start_info->console.domU.evtchn)
325 info = vtermno_to_xencons(HVC_COOKIE);
327 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
330 } else if (info->intf != NULL) {
331 /* already configured */
334 spin_lock_irqsave(&xencons_lock, flags);
335 xencons_info_pv_init(info, HVC_COOKIE);
336 spin_unlock_irqrestore(&xencons_lock, flags);
341 static int xen_initial_domain_console_init(void)
343 struct xencons_info *info;
346 if (!xen_initial_domain())
349 info = vtermno_to_xencons(HVC_COOKIE);
351 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
354 spin_lock_init(&info->ring_lock);
357 info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
358 info->vtermno = HVC_COOKIE;
360 spin_lock_irqsave(&xencons_lock, flags);
361 list_add_tail(&info->list, &xenconsoles);
362 spin_unlock_irqrestore(&xencons_lock, flags);
367 static void xen_console_update_evtchn(struct xencons_info *info)
369 if (xen_hvm_domain()) {
373 err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
377 info->evtchn = xen_start_info->console.domU.evtchn;
380 void xen_console_resume(void)
382 struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
383 if (info != NULL && info->irq) {
384 if (!xen_initial_domain())
385 xen_console_update_evtchn(info);
386 rebind_evtchn_irq(info->evtchn, info->irq);
390 #ifdef CONFIG_HVC_XEN_FRONTEND
391 static void xencons_disconnect_backend(struct xencons_info *info)
394 unbind_from_irqhandler(info->irq, NULL);
396 if (info->evtchn > 0)
397 xenbus_free_evtchn(info->xbdev, info->evtchn);
399 if (info->gntref > 0)
400 gnttab_free_grant_references(info->gntref);
402 if (info->hvc != NULL)
403 hvc_remove(info->hvc);
407 static void xencons_free(struct xencons_info *info)
409 free_page((unsigned long)info->intf);
415 static int xen_console_remove(struct xencons_info *info)
419 xencons_disconnect_backend(info);
420 spin_lock_irqsave(&xencons_lock, flags);
421 list_del(&info->list);
422 spin_unlock_irqrestore(&xencons_lock, flags);
423 if (info->xbdev != NULL)
426 if (xen_hvm_domain())
433 static int xencons_remove(struct xenbus_device *dev)
435 return xen_console_remove(dev_get_drvdata(&dev->dev));
438 static int xencons_connect_backend(struct xenbus_device *dev,
439 struct xencons_info *info)
441 int ret, evtchn, devid, ref, irq;
442 struct xenbus_transaction xbt;
443 grant_ref_t gref_head;
445 ret = xenbus_alloc_evtchn(dev, &evtchn);
448 info->evtchn = evtchn;
449 irq = bind_interdomain_evtchn_to_irq_lateeoi(dev->otherend_id, evtchn);
453 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
454 info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
455 irq, &domU_hvc_ops, 256);
456 if (IS_ERR(info->hvc))
457 return PTR_ERR(info->hvc);
458 ret = gnttab_alloc_grant_references(1, &gref_head);
461 info->gntref = gref_head;
462 ref = gnttab_claim_grant_reference(&gref_head);
465 gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
466 virt_to_gfn(info->intf), 0);
469 ret = xenbus_transaction_start(&xbt);
471 xenbus_dev_fatal(dev, ret, "starting transaction");
474 ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
477 ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
481 ret = xenbus_transaction_end(xbt, 0);
485 xenbus_dev_fatal(dev, ret, "completing transaction");
489 xenbus_switch_state(dev, XenbusStateInitialised);
493 xenbus_transaction_end(xbt, 1);
494 xenbus_dev_fatal(dev, ret, "writing xenstore");
498 static int xencons_probe(struct xenbus_device *dev,
499 const struct xenbus_device_id *id)
502 struct xencons_info *info;
505 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
509 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
512 spin_lock_init(&info->ring_lock);
513 dev_set_drvdata(&dev->dev, info);
515 info->vtermno = xenbus_devid_to_vtermno(devid);
516 info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
520 ret = xencons_connect_backend(dev, info);
523 spin_lock_irqsave(&xencons_lock, flags);
524 list_add_tail(&info->list, &xenconsoles);
525 spin_unlock_irqrestore(&xencons_lock, flags);
531 xenbus_dev_fatal(dev, ret, "allocating device memory");
533 xencons_disconnect_backend(info);
538 static int xencons_resume(struct xenbus_device *dev)
540 struct xencons_info *info = dev_get_drvdata(&dev->dev);
542 xencons_disconnect_backend(info);
543 memset(info->intf, 0, XEN_PAGE_SIZE);
544 return xencons_connect_backend(dev, info);
547 static void xencons_backend_changed(struct xenbus_device *dev,
548 enum xenbus_state backend_state)
550 switch (backend_state) {
551 case XenbusStateReconfiguring:
552 case XenbusStateReconfigured:
553 case XenbusStateInitialising:
554 case XenbusStateInitialised:
555 case XenbusStateUnknown:
558 case XenbusStateInitWait:
561 case XenbusStateConnected:
562 xenbus_switch_state(dev, XenbusStateConnected);
565 case XenbusStateClosed:
566 if (dev->state == XenbusStateClosed)
568 /* Missed the backend's CLOSING state -- fallthrough */
569 case XenbusStateClosing:
570 xenbus_frontend_closed(dev);
575 static const struct xenbus_device_id xencons_ids[] = {
580 static struct xenbus_driver xencons_driver = {
581 .name = "xenconsole",
583 .probe = xencons_probe,
584 .remove = xencons_remove,
585 .resume = xencons_resume,
586 .otherend_changed = xencons_backend_changed,
588 #endif /* CONFIG_HVC_XEN_FRONTEND */
590 static int __init xen_hvc_init(void)
593 struct xencons_info *info;
594 const struct hv_ops *ops;
599 if (xen_initial_domain()) {
601 r = xen_initial_domain_console_init();
604 info = vtermno_to_xencons(HVC_COOKIE);
607 if (xen_hvm_domain())
608 r = xen_hvm_console_init();
610 r = xen_pv_console_init();
614 info = vtermno_to_xencons(HVC_COOKIE);
615 info->irq = bind_evtchn_to_irq_lateeoi(info->evtchn);
618 info->irq = 0; /* NO_IRQ */
620 irq_set_noprobe(info->irq);
622 info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
623 if (IS_ERR(info->hvc)) {
626 r = PTR_ERR(info->hvc);
627 spin_lock_irqsave(&xencons_lock, flags);
628 list_del(&info->list);
629 spin_unlock_irqrestore(&xencons_lock, flags);
631 unbind_from_irqhandler(info->irq, NULL);
637 #ifdef CONFIG_HVC_XEN_FRONTEND
638 r = xenbus_register_frontend(&xencons_driver);
642 device_initcall(xen_hvc_init);
644 static int xen_cons_init(void)
646 const struct hv_ops *ops;
651 if (xen_initial_domain())
657 if (xen_hvm_domain())
658 r = xen_hvm_console_init();
660 r = xen_pv_console_init();
665 hvc_instantiate(HVC_COOKIE, 0, ops);
668 console_initcall(xen_cons_init);
671 static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
673 if (xen_cpuid_base())
674 outsb(0xe9, str, len);
677 static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
680 #ifdef CONFIG_EARLY_PRINTK
681 static int __init xenboot_setup_console(struct console *console, char *string)
683 static struct xencons_info xenboot;
685 if (xen_initial_domain())
687 if (!xen_pv_domain())
690 return xencons_info_pv_init(&xenboot, 0);
693 static void xenboot_write_console(struct console *console, const char *string,
696 unsigned int linelen, off = 0;
699 if (!xen_pv_domain()) {
700 xen_hvm_early_write(0, string, len);
704 dom0_write_console(0, string, len);
706 if (xen_initial_domain())
709 domU_write_console(0, "(early) ", 8);
710 while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
711 linelen = pos-string+off;
712 if (off + linelen > len)
714 domU_write_console(0, string+off, linelen);
715 domU_write_console(0, "\r\n", 2);
719 domU_write_console(0, string+off, len-off);
722 struct console xenboot_console = {
724 .write = xenboot_write_console,
725 .setup = xenboot_setup_console,
726 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
729 #endif /* CONFIG_EARLY_PRINTK */
731 void xen_raw_console_write(const char *str)
733 ssize_t len = strlen(str);
737 rc = dom0_write_console(0, str, len);
738 if (rc != -ENOSYS || !xen_hvm_domain())
741 xen_hvm_early_write(0, str, len);
744 void xen_raw_printk(const char *fmt, ...)
746 static char buf[512];
750 vsnprintf(buf, sizeof(buf), fmt, ap);
753 xen_raw_console_write(buf);
756 static void xenboot_earlycon_write(struct console *console,
760 dom0_write_console(0, string, len);
763 static int __init xenboot_earlycon_setup(struct earlycon_device *device,
766 device->con->write = xenboot_earlycon_write;
769 EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);