1 /*
2 * Copyright (C) International Business Machines Corp., 2005
3 * Author(s): Anthony Liguori <aliguori@us.ibm.com>
4 *
5 * Copyright (C) Red Hat 2007
6 *
7 * Xen Console
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; under version 2 of the License.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, see <http://www.gnu.org/licenses/>.
20 */
21
22 #include "qemu/osdep.h"
23 #include "qemu/cutils.h"
24 #include <sys/select.h>
25 #include <termios.h>
26
27 #include "qapi/error.h"
28 #include "sysemu/sysemu.h"
29 #include "chardev/char-fe.h"
30 #include "hw/xen/xen-backend.h"
31 #include "hw/xen/xen-bus-helper.h"
32 #include "hw/qdev-properties.h"
33 #include "hw/qdev-properties-system.h"
34 #include "hw/xen/interface/io/console.h"
35 #include "hw/xen/interface/io/xs_wire.h"
36 #include "hw/xen/interface/grant_table.h"
37 #include "hw/i386/kvm/xen_primary_console.h"
38 #include "trace.h"
39
40 struct buffer {
41 uint8_t *data;
42 size_t consumed;
43 size_t size;
44 size_t capacity;
45 size_t max_capacity;
46 };
47
48 struct XenConsole {
49 struct XenDevice xendev; /* must be first */
50 XenEventChannel *event_channel;
51 int dev;
52 struct buffer buffer;
53 char *fe_path;
54 unsigned int ring_ref;
55 void *sring;
56 CharBackend chr;
57 int backlog;
58 };
59 typedef struct XenConsole XenConsole;
60
61 #define TYPE_XEN_CONSOLE_DEVICE "xen-console"
OBJECT_DECLARE_SIMPLE_TYPE(XenConsole,XEN_CONSOLE_DEVICE)62 OBJECT_DECLARE_SIMPLE_TYPE(XenConsole, XEN_CONSOLE_DEVICE)
63
64 static bool buffer_append(XenConsole *con)
65 {
66 struct buffer *buffer = &con->buffer;
67 XENCONS_RING_IDX cons, prod, size;
68 struct xencons_interface *intf = con->sring;
69
70 cons = intf->out_cons;
71 prod = intf->out_prod;
72 xen_mb();
73
74 size = prod - cons;
75 if ((size == 0) || (size > sizeof(intf->out)))
76 return false;
77
78 if ((buffer->capacity - buffer->size) < size) {
79 buffer->capacity += (size + 1024);
80 buffer->data = g_realloc(buffer->data, buffer->capacity);
81 }
82
83 while (cons != prod)
84 buffer->data[buffer->size++] = intf->out[
85 MASK_XENCONS_IDX(cons++, intf->out)];
86
87 xen_mb();
88 intf->out_cons = cons;
89 xen_device_notify_event_channel(XEN_DEVICE(con), con->event_channel, NULL);
90
91 if (buffer->max_capacity &&
92 buffer->size > buffer->max_capacity) {
93 /* Discard the middle of the data. */
94
95 size_t over = buffer->size - buffer->max_capacity;
96 uint8_t *maxpos = buffer->data + buffer->max_capacity;
97
98 memmove(maxpos - over, maxpos, over);
99 buffer->data = g_realloc(buffer->data, buffer->max_capacity);
100 buffer->size = buffer->capacity = buffer->max_capacity;
101
102 if (buffer->consumed > buffer->max_capacity - over)
103 buffer->consumed = buffer->max_capacity - over;
104 }
105 return true;
106 }
107
buffer_advance(struct buffer * buffer,size_t len)108 static void buffer_advance(struct buffer *buffer, size_t len)
109 {
110 buffer->consumed += len;
111 if (buffer->consumed == buffer->size) {
112 buffer->consumed = 0;
113 buffer->size = 0;
114 }
115 }
116
ring_free_bytes(XenConsole * con)117 static int ring_free_bytes(XenConsole *con)
118 {
119 struct xencons_interface *intf = con->sring;
120 XENCONS_RING_IDX cons, prod, space;
121
122 cons = intf->in_cons;
123 prod = intf->in_prod;
124 xen_mb();
125
126 space = prod - cons;
127 if (space > sizeof(intf->in))
128 return 0; /* ring is screwed: ignore it */
129
130 return (sizeof(intf->in) - space);
131 }
132
xencons_can_receive(void * opaque)133 static int xencons_can_receive(void *opaque)
134 {
135 XenConsole *con = opaque;
136 return ring_free_bytes(con);
137 }
138
xencons_receive(void * opaque,const uint8_t * buf,int len)139 static void xencons_receive(void *opaque, const uint8_t *buf, int len)
140 {
141 XenConsole *con = opaque;
142 struct xencons_interface *intf = con->sring;
143 XENCONS_RING_IDX prod;
144 int i, max;
145
146 max = ring_free_bytes(con);
147 /* The can_receive() func limits this, but check again anyway */
148 if (max < len)
149 len = max;
150
151 prod = intf->in_prod;
152 for (i = 0; i < len; i++) {
153 intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
154 buf[i];
155 }
156 xen_wmb();
157 intf->in_prod = prod;
158 xen_device_notify_event_channel(XEN_DEVICE(con), con->event_channel, NULL);
159 }
160
xencons_send(XenConsole * con)161 static bool xencons_send(XenConsole *con)
162 {
163 ssize_t len, size;
164
165 size = con->buffer.size - con->buffer.consumed;
166 if (qemu_chr_fe_backend_connected(&con->chr)) {
167 len = qemu_chr_fe_write(&con->chr,
168 con->buffer.data + con->buffer.consumed,
169 size);
170 } else {
171 len = size;
172 }
173 if (len < 1) {
174 if (!con->backlog) {
175 con->backlog = 1;
176 }
177 } else {
178 buffer_advance(&con->buffer, len);
179 if (con->backlog && len == size) {
180 con->backlog = 0;
181 }
182 }
183 return len > 0;
184 }
185
186 /* -------------------------------------------------------------------- */
187
con_event(void * _xendev)188 static bool con_event(void *_xendev)
189 {
190 XenConsole *con = XEN_CONSOLE_DEVICE(_xendev);
191 bool done_something;
192
193 if (xen_device_backend_get_state(&con->xendev) != XenbusStateConnected) {
194 return false;
195 }
196
197 done_something = buffer_append(con);
198
199 if (con->buffer.size - con->buffer.consumed) {
200 done_something |= xencons_send(con);
201 }
202 return done_something;
203 }
204
205 /* -------------------------------------------------------------------- */
206
xen_console_connect(XenDevice * xendev,Error ** errp)207 static bool xen_console_connect(XenDevice *xendev, Error **errp)
208 {
209 XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
210 unsigned int port, limit;
211
212 if (xen_device_frontend_scanf(xendev, "ring-ref", "%u",
213 &con->ring_ref) != 1) {
214 error_setg(errp, "failed to read ring-ref");
215 return false;
216 }
217
218 if (xen_device_frontend_scanf(xendev, "port", "%u", &port) != 1) {
219 error_setg(errp, "failed to read remote port");
220 return false;
221 }
222
223 if (xen_device_frontend_scanf(xendev, "limit", "%u", &limit) == 1) {
224 con->buffer.max_capacity = limit;
225 }
226
227 con->event_channel = xen_device_bind_event_channel(xendev, port,
228 con_event,
229 con,
230 errp);
231 if (!con->event_channel) {
232 return false;
233 }
234
235 switch (con->dev) {
236 case 0:
237 /*
238 * The primary console is special. For real Xen the ring-ref is
239 * actually a GFN which needs to be mapped as foreignmem.
240 */
241 if (xen_mode != XEN_EMULATE) {
242 xen_pfn_t mfn = (xen_pfn_t)con->ring_ref;
243 con->sring = qemu_xen_foreignmem_map(xendev->frontend_id, NULL,
244 PROT_READ | PROT_WRITE,
245 1, &mfn, NULL);
246 if (!con->sring) {
247 error_setg(errp, "failed to map console page");
248 return false;
249 }
250 break;
251 }
252
253 /*
254 * For Xen emulation, we still follow the convention of ring-ref
255 * holding the GFN, but we map the fixed GNTTAB_RESERVED_CONSOLE
256 * grant ref because there is no implementation of foreignmem
257 * operations for emulated mode. The emulation code which handles
258 * the guest-side page and event channel also needs to be informed
259 * of the backend event channel port, in order to reconnect to it
260 * after a soft reset.
261 */
262 xen_primary_console_set_be_port(
263 xen_event_channel_get_local_port(con->event_channel));
264 con->ring_ref = GNTTAB_RESERVED_CONSOLE;
265 /* fallthrough */
266 default:
267 con->sring = xen_device_map_grant_refs(xendev,
268 &con->ring_ref, 1,
269 PROT_READ | PROT_WRITE,
270 errp);
271 if (!con->sring) {
272 error_prepend(errp, "failed to map console grant ref: ");
273 return false;
274 }
275 break;
276 }
277
278 trace_xen_console_connect(con->dev, con->ring_ref, port,
279 con->buffer.max_capacity);
280
281 qemu_chr_fe_set_handlers(&con->chr, xencons_can_receive,
282 xencons_receive, NULL, NULL, con, NULL,
283 true);
284 return true;
285 }
286
xen_console_disconnect(XenDevice * xendev,Error ** errp)287 static void xen_console_disconnect(XenDevice *xendev, Error **errp)
288 {
289 XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
290
291 trace_xen_console_disconnect(con->dev);
292
293 qemu_chr_fe_set_handlers(&con->chr, NULL, NULL, NULL, NULL,
294 con, NULL, true);
295
296 if (con->event_channel) {
297 xen_device_unbind_event_channel(xendev, con->event_channel,
298 errp);
299 con->event_channel = NULL;
300
301 if (xen_mode == XEN_EMULATE && !con->dev) {
302 xen_primary_console_set_be_port(0);
303 }
304 }
305
306 if (con->sring) {
307 if (!con->dev && xen_mode != XEN_EMULATE) {
308 qemu_xen_foreignmem_unmap(con->sring, 1);
309 } else {
310 xen_device_unmap_grant_refs(xendev, con->sring,
311 &con->ring_ref, 1, errp);
312 }
313 con->sring = NULL;
314 }
315 }
316
xen_console_frontend_changed(XenDevice * xendev,enum xenbus_state frontend_state,Error ** errp)317 static void xen_console_frontend_changed(XenDevice *xendev,
318 enum xenbus_state frontend_state,
319 Error **errp)
320 {
321 ERRP_GUARD();
322 enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
323
324 switch (frontend_state) {
325 case XenbusStateInitialised:
326 case XenbusStateConnected:
327 if (backend_state == XenbusStateConnected) {
328 break;
329 }
330
331 xen_console_disconnect(xendev, errp);
332 if (*errp) {
333 break;
334 }
335
336 if (!xen_console_connect(xendev, errp)) {
337 xen_device_backend_set_state(xendev, XenbusStateClosing);
338 break;
339 }
340
341 xen_device_backend_set_state(xendev, XenbusStateConnected);
342 break;
343
344 case XenbusStateClosing:
345 xen_device_backend_set_state(xendev, XenbusStateClosing);
346 break;
347
348 case XenbusStateClosed:
349 case XenbusStateUnknown:
350 xen_console_disconnect(xendev, errp);
351 if (*errp) {
352 break;
353 }
354
355 xen_device_backend_set_state(xendev, XenbusStateClosed);
356 break;
357
358 default:
359 break;
360 }
361 }
362
xen_console_get_name(XenDevice * xendev,Error ** errp)363 static char *xen_console_get_name(XenDevice *xendev, Error **errp)
364 {
365 XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
366
367 if (con->dev == -1) {
368 XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
369 char fe_path[XENSTORE_ABS_PATH_MAX + 1];
370 int idx = (xen_mode == XEN_EMULATE) ? 0 : 1;
371 char *value;
372
373 /* Theoretically we could go up to INT_MAX here but that's overkill */
374 while (idx < 100) {
375 if (!idx) {
376 snprintf(fe_path, sizeof(fe_path),
377 "/local/domain/%u/console", xendev->frontend_id);
378 } else {
379 snprintf(fe_path, sizeof(fe_path),
380 "/local/domain/%u/device/console/%u",
381 xendev->frontend_id, idx);
382 }
383 value = qemu_xen_xs_read(xenbus->xsh, XBT_NULL, fe_path, NULL);
384 if (!value) {
385 if (errno == ENOENT) {
386 con->dev = idx;
387 goto found;
388 }
389 error_setg(errp, "cannot read %s: %s", fe_path,
390 strerror(errno));
391 return NULL;
392 }
393 free(value);
394 idx++;
395 }
396 error_setg(errp, "cannot find device index for console device");
397 return NULL;
398 }
399 found:
400 return g_strdup_printf("%u", con->dev);
401 }
402
xen_console_unrealize(XenDevice * xendev)403 static void xen_console_unrealize(XenDevice *xendev)
404 {
405 XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
406
407 trace_xen_console_unrealize(con->dev);
408
409 /* Disconnect from the frontend in case this has not already happened */
410 xen_console_disconnect(xendev, NULL);
411
412 qemu_chr_fe_deinit(&con->chr, false);
413 }
414
xen_console_realize(XenDevice * xendev,Error ** errp)415 static void xen_console_realize(XenDevice *xendev, Error **errp)
416 {
417 ERRP_GUARD();
418 XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
419 Chardev *cs = qemu_chr_fe_get_driver(&con->chr);
420 unsigned int u;
421
422 if (!cs) {
423 error_setg(errp, "no backing character device");
424 return;
425 }
426
427 if (con->dev == -1) {
428 error_setg(errp, "no device index provided");
429 return;
430 }
431
432 /*
433 * The Xen primary console is special. The ring-ref is actually a GFN to
434 * be mapped directly as foreignmem (not a grant ref), and the guest port
435 * was allocated *for* the guest by the toolstack. The guest gets these
436 * through HVMOP_get_param and can use the console long before it's got
437 * XenStore up and running. We cannot create those for a true Xen guest,
438 * but we can for Xen emulation.
439 */
440 if (!con->dev) {
441 if (xen_mode == XEN_EMULATE) {
442 xen_primary_console_create();
443 } else if (xen_device_frontend_scanf(xendev, "ring-ref", "%u", &u)
444 != 1 ||
445 xen_device_frontend_scanf(xendev, "port", "%u", &u) != 1) {
446 error_setg(errp, "cannot create primary Xen console");
447 return;
448 }
449 }
450
451 trace_xen_console_realize(con->dev, object_get_typename(OBJECT(cs)));
452
453 if (CHARDEV_IS_PTY(cs)) {
454 /* Strip the leading 'pty:' */
455 xen_device_frontend_printf(xendev, "tty", "%s", cs->filename + 4);
456 }
457
458 /* No normal PV driver initialization for the primary console under Xen */
459 if (!con->dev && xen_mode != XEN_EMULATE) {
460 xen_console_connect(xendev, errp);
461 }
462 }
463
console_frontend_path(struct qemu_xs_handle * xenstore,unsigned int dom_id,unsigned int dev)464 static char *console_frontend_path(struct qemu_xs_handle *xenstore,
465 unsigned int dom_id, unsigned int dev)
466 {
467 if (!dev) {
468 return g_strdup_printf("/local/domain/%u/console", dom_id);
469 } else {
470 return g_strdup_printf("/local/domain/%u/device/console/%u", dom_id,
471 dev);
472 }
473 }
474
xen_console_get_frontend_path(XenDevice * xendev,Error ** errp)475 static char *xen_console_get_frontend_path(XenDevice *xendev, Error **errp)
476 {
477 XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
478 XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
479 char *ret = console_frontend_path(xenbus->xsh, xendev->frontend_id,
480 con->dev);
481
482 if (!ret) {
483 error_setg(errp, "failed to create frontend path");
484 }
485 return ret;
486 }
487
488
489 static Property xen_console_properties[] = {
490 DEFINE_PROP_CHR("chardev", XenConsole, chr),
491 DEFINE_PROP_INT32("idx", XenConsole, dev, -1),
492 DEFINE_PROP_END_OF_LIST(),
493 };
494
xen_console_class_init(ObjectClass * class,void * data)495 static void xen_console_class_init(ObjectClass *class, void *data)
496 {
497 DeviceClass *dev_class = DEVICE_CLASS(class);
498 XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
499
500 xendev_class->backend = "console";
501 xendev_class->device = "console";
502 xendev_class->get_name = xen_console_get_name;
503 xendev_class->realize = xen_console_realize;
504 xendev_class->frontend_changed = xen_console_frontend_changed;
505 xendev_class->unrealize = xen_console_unrealize;
506 xendev_class->get_frontend_path = xen_console_get_frontend_path;
507
508 device_class_set_props(dev_class, xen_console_properties);
509 }
510
511 static const TypeInfo xen_console_type_info = {
512 .name = TYPE_XEN_CONSOLE_DEVICE,
513 .parent = TYPE_XEN_DEVICE,
514 .instance_size = sizeof(XenConsole),
515 .class_init = xen_console_class_init,
516 };
517
xen_console_register_types(void)518 static void xen_console_register_types(void)
519 {
520 type_register_static(&xen_console_type_info);
521 }
522
type_init(xen_console_register_types)523 type_init(xen_console_register_types)
524
525 /* Called to instantiate a XenConsole when the backend is detected. */
526 static void xen_console_device_create(XenBackendInstance *backend,
527 QDict *opts, Error **errp)
528 {
529 ERRP_GUARD();
530 XenBus *xenbus = xen_backend_get_bus(backend);
531 const char *name = xen_backend_get_name(backend);
532 unsigned long number;
533 char *fe = NULL, *type = NULL, *output = NULL;
534 char label[32];
535 XenDevice *xendev = NULL;
536 XenConsole *con;
537 Chardev *cd = NULL;
538 struct qemu_xs_handle *xsh = xenbus->xsh;
539
540 if (qemu_strtoul(name, NULL, 10, &number) || number > INT_MAX) {
541 error_setg(errp, "failed to parse name '%s'", name);
542 goto fail;
543 }
544
545 trace_xen_console_device_create(number);
546
547 fe = console_frontend_path(xsh, xen_domid, number);
548 if (fe == NULL) {
549 error_setg(errp, "failed to generate frontend path");
550 goto fail;
551 }
552
553 if (xs_node_scanf(xsh, XBT_NULL, fe, "type", errp, "%ms", &type) != 1) {
554 error_prepend(errp, "failed to read console device type: ");
555 goto fail;
556 }
557
558 if (strcmp(type, "ioemu")) {
559 error_setg(errp, "declining to handle console type '%s'",
560 type);
561 goto fail;
562 }
563
564 xendev = XEN_DEVICE(qdev_new(TYPE_XEN_CONSOLE_DEVICE));
565 con = XEN_CONSOLE_DEVICE(xendev);
566
567 con->dev = number;
568
569 snprintf(label, sizeof(label), "xencons%ld", number);
570
571 if (xs_node_scanf(xsh, XBT_NULL, fe, "output", NULL, "%ms", &output) == 1) {
572 /*
573 * FIXME: sure we want to support implicit
574 * muxed monitors here?
575 */
576 cd = qemu_chr_new_mux_mon(label, output, NULL);
577 if (!cd) {
578 error_setg(errp, "console: No valid chardev found at '%s': ",
579 output);
580 goto fail;
581 }
582 } else if (number) {
583 cd = serial_hd(number);
584 if (!cd) {
585 error_prepend(errp, "console: No serial device #%ld found: ",
586 number);
587 goto fail;
588 }
589 } else {
590 /* No 'output' node on primary console: use null. */
591 cd = qemu_chr_new(label, "null", NULL);
592 if (!cd) {
593 error_setg(errp, "console: failed to create null device");
594 goto fail;
595 }
596 }
597
598 if (!qemu_chr_fe_init(&con->chr, cd, errp)) {
599 error_prepend(errp, "console: failed to initialize backing chardev: ");
600 goto fail;
601 }
602
603 if (qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), errp)) {
604 xen_backend_set_device(backend, xendev);
605 goto done;
606 }
607
608 error_prepend(errp, "realization of console device %lu failed: ",
609 number);
610
611 fail:
612 if (xendev) {
613 object_unparent(OBJECT(xendev));
614 }
615 done:
616 g_free(fe);
617 free(type);
618 free(output);
619 }
620
xen_console_device_destroy(XenBackendInstance * backend,Error ** errp)621 static void xen_console_device_destroy(XenBackendInstance *backend,
622 Error **errp)
623 {
624 ERRP_GUARD();
625 XenDevice *xendev = xen_backend_get_device(backend);
626 XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
627
628 trace_xen_console_device_destroy(con->dev);
629
630 object_unparent(OBJECT(xendev));
631 }
632
633 static const XenBackendInfo xen_console_backend_info = {
634 .type = "console",
635 .create = xen_console_device_create,
636 .destroy = xen_console_device_destroy,
637 };
638
xen_console_register_backend(void)639 static void xen_console_register_backend(void)
640 {
641 xen_backend_register(&xen_console_backend_info);
642 }
643
644 xen_backend_init(xen_console_register_backend);
645