xref: /openbmc/qemu/hw/s390x/event-facility.c (revision 438c78da)
1 /*
2  * SCLP
3  *    Event Facility
4  *       handles SCLP event types
5  *          - Signal Quiesce - system power down
6  *          - ASCII Console Data - VT220 read and write
7  *
8  * Copyright IBM, Corp. 2012
9  *
10  * Authors:
11  *  Heinz Graalfs <graalfs@de.ibm.com>
12  *
13  * This work is licensed under the terms of the GNU GPL, version 2 or (at your
14  * option) any later version.  See the COPYING file in the top-level directory.
15  *
16  */
17 
18 #include "qemu/osdep.h"
19 #include "qapi/error.h"
20 #include "sysemu/sysemu.h"
21 
22 #include "hw/s390x/sclp.h"
23 #include "hw/s390x/event-facility.h"
24 
25 typedef struct SCLPEventsBus {
26     BusState qbus;
27 } SCLPEventsBus;
28 
29 /* we need to save 32 bit chunks for compatibility */
30 #ifdef HOST_WORDS_BIGENDIAN
31 #define RECV_MASK_LOWER 1
32 #define RECV_MASK_UPPER 0
33 #else /* little endian host */
34 #define RECV_MASK_LOWER 0
35 #define RECV_MASK_UPPER 1
36 #endif
37 
38 struct SCLPEventFacility {
39     SysBusDevice parent_obj;
40     SCLPEventsBus sbus;
41     /* guest's receive mask */
42     union {
43         uint32_t receive_mask_pieces[2];
44         sccb_mask_t receive_mask;
45     };
46     /*
47      * when false, we keep the same broken, backwards compatible behaviour as
48      * before, allowing only masks of size exactly 4; when true, we implement
49      * the architecture correctly, allowing all valid mask sizes. Needed for
50      * migration toward older versions.
51      */
52     bool allow_all_mask_sizes;
53     /* length of the receive mask */
54     uint16_t mask_length;
55 };
56 
57 /* return true if any child has event pending set */
58 static bool event_pending(SCLPEventFacility *ef)
59 {
60     BusChild *kid;
61     SCLPEvent *event;
62     SCLPEventClass *event_class;
63 
64     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
65         DeviceState *qdev = kid->child;
66         event = DO_UPCAST(SCLPEvent, qdev, qdev);
67         event_class = SCLP_EVENT_GET_CLASS(event);
68         if (event->event_pending &&
69             event_class->get_send_mask() & ef->receive_mask) {
70             return true;
71         }
72     }
73     return false;
74 }
75 
76 static sccb_mask_t get_host_send_mask(SCLPEventFacility *ef)
77 {
78     sccb_mask_t mask;
79     BusChild *kid;
80     SCLPEventClass *child;
81 
82     mask = 0;
83 
84     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
85         DeviceState *qdev = kid->child;
86         child = SCLP_EVENT_GET_CLASS((SCLPEvent *) qdev);
87         mask |= child->get_send_mask();
88     }
89     return mask;
90 }
91 
92 static sccb_mask_t get_host_receive_mask(SCLPEventFacility *ef)
93 {
94     sccb_mask_t mask;
95     BusChild *kid;
96     SCLPEventClass *child;
97 
98     mask = 0;
99 
100     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
101         DeviceState *qdev = kid->child;
102         child = SCLP_EVENT_GET_CLASS((SCLPEvent *) qdev);
103         mask |= child->get_receive_mask();
104     }
105     return mask;
106 }
107 
108 static uint16_t write_event_length_check(SCCB *sccb)
109 {
110     int slen;
111     unsigned elen = 0;
112     EventBufferHeader *event;
113     WriteEventData *wed = (WriteEventData *) sccb;
114 
115     event = (EventBufferHeader *) &wed->ebh;
116     for (slen = sccb_data_len(sccb); slen > 0; slen -= elen) {
117         elen = be16_to_cpu(event->length);
118         if (elen < sizeof(*event) || elen > slen) {
119             return SCLP_RC_EVENT_BUFFER_SYNTAX_ERROR;
120         }
121         event = (void *) event + elen;
122     }
123     if (slen) {
124         return SCLP_RC_INCONSISTENT_LENGTHS;
125     }
126     return SCLP_RC_NORMAL_COMPLETION;
127 }
128 
129 static uint16_t handle_write_event_buf(SCLPEventFacility *ef,
130                                        EventBufferHeader *event_buf, SCCB *sccb)
131 {
132     uint16_t rc;
133     BusChild *kid;
134     SCLPEvent *event;
135     SCLPEventClass *ec;
136 
137     rc = SCLP_RC_INVALID_FUNCTION;
138 
139     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
140         DeviceState *qdev = kid->child;
141         event = (SCLPEvent *) qdev;
142         ec = SCLP_EVENT_GET_CLASS(event);
143 
144         if (ec->write_event_data &&
145             ec->can_handle_event(event_buf->type)) {
146             rc = ec->write_event_data(event, event_buf);
147             break;
148         }
149     }
150     return rc;
151 }
152 
153 static uint16_t handle_sccb_write_events(SCLPEventFacility *ef, SCCB *sccb)
154 {
155     uint16_t rc;
156     int slen;
157     unsigned elen = 0;
158     EventBufferHeader *event_buf;
159     WriteEventData *wed = (WriteEventData *) sccb;
160 
161     event_buf = &wed->ebh;
162     rc = SCLP_RC_NORMAL_COMPLETION;
163 
164     /* loop over all contained event buffers */
165     for (slen = sccb_data_len(sccb); slen > 0; slen -= elen) {
166         elen = be16_to_cpu(event_buf->length);
167 
168         /* in case of a previous error mark all trailing buffers
169          * as not accepted */
170         if (rc != SCLP_RC_NORMAL_COMPLETION) {
171             event_buf->flags &= ~(SCLP_EVENT_BUFFER_ACCEPTED);
172         } else {
173             rc = handle_write_event_buf(ef, event_buf, sccb);
174         }
175         event_buf = (void *) event_buf + elen;
176     }
177     return rc;
178 }
179 
180 static void write_event_data(SCLPEventFacility *ef, SCCB *sccb)
181 {
182     if (sccb->h.function_code != SCLP_FC_NORMAL_WRITE) {
183         sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_FUNCTION);
184         goto out;
185     }
186     if (be16_to_cpu(sccb->h.length) < 8) {
187         sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH);
188         goto out;
189     }
190     /* first do a sanity check of the write events */
191     sccb->h.response_code = cpu_to_be16(write_event_length_check(sccb));
192 
193     /* if no early error, then execute */
194     if (sccb->h.response_code == be16_to_cpu(SCLP_RC_NORMAL_COMPLETION)) {
195         sccb->h.response_code =
196                 cpu_to_be16(handle_sccb_write_events(ef, sccb));
197     }
198 
199 out:
200     return;
201 }
202 
203 static uint16_t handle_sccb_read_events(SCLPEventFacility *ef, SCCB *sccb,
204                                         sccb_mask_t mask)
205 {
206     uint16_t rc;
207     int slen;
208     unsigned elen;
209     BusChild *kid;
210     SCLPEvent *event;
211     SCLPEventClass *ec;
212     EventBufferHeader *event_buf;
213     ReadEventData *red = (ReadEventData *) sccb;
214 
215     event_buf = &red->ebh;
216     event_buf->length = 0;
217     slen = sizeof(sccb->data);
218 
219     rc = SCLP_RC_NO_EVENT_BUFFERS_STORED;
220 
221     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
222         DeviceState *qdev = kid->child;
223         event = (SCLPEvent *) qdev;
224         ec = SCLP_EVENT_GET_CLASS(event);
225 
226         if (mask & ec->get_send_mask()) {
227             if (ec->read_event_data(event, event_buf, &slen)) {
228                 elen = be16_to_cpu(event_buf->length);
229                 event_buf = (EventBufferHeader *) ((char *)event_buf + elen);
230                 rc = SCLP_RC_NORMAL_COMPLETION;
231             }
232         }
233     }
234 
235     if (sccb->h.control_mask[2] & SCLP_VARIABLE_LENGTH_RESPONSE) {
236         /* architecture suggests to reset variable-length-response bit */
237         sccb->h.control_mask[2] &= ~SCLP_VARIABLE_LENGTH_RESPONSE;
238         /* with a new length value */
239         sccb->h.length = cpu_to_be16(SCCB_SIZE - slen);
240     }
241     return rc;
242 }
243 
244 /* copy up to src_len bytes and fill the rest of dst with zeroes */
245 static void copy_mask(uint8_t *dst, uint8_t *src, uint16_t dst_len,
246                       uint16_t src_len)
247 {
248     int i;
249 
250     for (i = 0; i < dst_len; i++) {
251         dst[i] = i < src_len ? src[i] : 0;
252     }
253 }
254 
255 static void read_event_data(SCLPEventFacility *ef, SCCB *sccb)
256 {
257     sccb_mask_t sclp_active_selection_mask;
258     sccb_mask_t sclp_cp_receive_mask;
259 
260     ReadEventData *red = (ReadEventData *) sccb;
261 
262     if (be16_to_cpu(sccb->h.length) != SCCB_SIZE) {
263         sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH);
264         goto out;
265     }
266 
267     sclp_cp_receive_mask = ef->receive_mask;
268 
269     /* get active selection mask */
270     switch (sccb->h.function_code) {
271     case SCLP_UNCONDITIONAL_READ:
272         sclp_active_selection_mask = sclp_cp_receive_mask;
273         break;
274     case SCLP_SELECTIVE_READ:
275         copy_mask((uint8_t *)&sclp_active_selection_mask, (uint8_t *)&red->mask,
276                   sizeof(sclp_active_selection_mask), ef->mask_length);
277         sclp_active_selection_mask = be64_to_cpu(sclp_active_selection_mask);
278         if (!sclp_cp_receive_mask ||
279             (sclp_active_selection_mask & ~sclp_cp_receive_mask)) {
280             sccb->h.response_code =
281                     cpu_to_be16(SCLP_RC_INVALID_SELECTION_MASK);
282             goto out;
283         }
284         break;
285     default:
286         sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_FUNCTION);
287         goto out;
288     }
289     sccb->h.response_code = cpu_to_be16(
290             handle_sccb_read_events(ef, sccb, sclp_active_selection_mask));
291 
292 out:
293     return;
294 }
295 
296 static void write_event_mask(SCLPEventFacility *ef, SCCB *sccb)
297 {
298     WriteEventMask *we_mask = (WriteEventMask *) sccb;
299     uint16_t mask_length = be16_to_cpu(we_mask->mask_length);
300     sccb_mask_t tmp_mask;
301 
302     if (!mask_length || (mask_length > SCLP_EVENT_MASK_LEN_MAX) ||
303         ((mask_length != 4) && !ef->allow_all_mask_sizes)) {
304         sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_MASK_LENGTH);
305         goto out;
306     }
307 
308     /*
309      * Note: We currently only support masks up to 8 byte length;
310      *       the remainder is filled up with zeroes. Older Linux
311      *       kernels use a 4 byte mask length, newer ones can use both
312      *       8 or 4 depending on what is available on the host.
313      */
314 
315     /* keep track of the guest's capability masks */
316     copy_mask((uint8_t *)&tmp_mask, WEM_CP_RECEIVE_MASK(we_mask, mask_length),
317               sizeof(tmp_mask), mask_length);
318     ef->receive_mask = be64_to_cpu(tmp_mask);
319 
320     /* return the SCLP's capability masks to the guest */
321     tmp_mask = cpu_to_be64(get_host_receive_mask(ef));
322     copy_mask(WEM_RECEIVE_MASK(we_mask, mask_length), (uint8_t *)&tmp_mask,
323               mask_length, sizeof(tmp_mask));
324     tmp_mask = cpu_to_be64(get_host_send_mask(ef));
325     copy_mask(WEM_SEND_MASK(we_mask, mask_length), (uint8_t *)&tmp_mask,
326               mask_length, sizeof(tmp_mask));
327 
328     sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_COMPLETION);
329     ef->mask_length = mask_length;
330 
331 out:
332     return;
333 }
334 
335 /* qemu object creation and initialization functions */
336 
337 #define TYPE_SCLP_EVENTS_BUS "s390-sclp-events-bus"
338 
339 static void sclp_events_bus_realize(BusState *bus, Error **errp)
340 {
341     BusChild *kid;
342 
343     /* TODO: recursive realization has to be done in common code */
344     QTAILQ_FOREACH(kid, &bus->children, sibling) {
345         DeviceState *dev = kid->child;
346 
347         object_property_set_bool(OBJECT(dev), true, "realized", errp);
348         if (*errp) {
349             return;
350         }
351     }
352 }
353 
354 static void sclp_events_bus_class_init(ObjectClass *klass, void *data)
355 {
356     BusClass *bc = BUS_CLASS(klass);
357 
358     bc->realize = sclp_events_bus_realize;
359 }
360 
361 static const TypeInfo sclp_events_bus_info = {
362     .name = TYPE_SCLP_EVENTS_BUS,
363     .parent = TYPE_BUS,
364     .class_init = sclp_events_bus_class_init,
365 };
366 
367 static void command_handler(SCLPEventFacility *ef, SCCB *sccb, uint64_t code)
368 {
369     switch (code & SCLP_CMD_CODE_MASK) {
370     case SCLP_CMD_READ_EVENT_DATA:
371         read_event_data(ef, sccb);
372         break;
373     case SCLP_CMD_WRITE_EVENT_DATA:
374         write_event_data(ef, sccb);
375         break;
376     case SCLP_CMD_WRITE_EVENT_MASK:
377         write_event_mask(ef, sccb);
378         break;
379     default:
380         sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
381         break;
382     }
383 }
384 
385 static bool vmstate_event_facility_mask64_needed(void *opaque)
386 {
387     SCLPEventFacility *ef = opaque;
388 
389     return (ef->receive_mask & 0xFFFFFFFF) != 0;
390 }
391 
392 static bool vmstate_event_facility_mask_length_needed(void *opaque)
393 {
394     SCLPEventFacility *ef = opaque;
395 
396     return ef->allow_all_mask_sizes;
397 }
398 
399 static const VMStateDescription vmstate_event_facility_mask64 = {
400     .name = "vmstate-event-facility/mask64",
401     .version_id = 0,
402     .minimum_version_id = 0,
403     .needed = vmstate_event_facility_mask64_needed,
404     .fields = (VMStateField[]) {
405         VMSTATE_UINT32(receive_mask_pieces[RECV_MASK_LOWER], SCLPEventFacility),
406         VMSTATE_END_OF_LIST()
407      }
408 };
409 
410 static const VMStateDescription vmstate_event_facility_mask_length = {
411     .name = "vmstate-event-facility/mask_length",
412     .version_id = 0,
413     .minimum_version_id = 0,
414     .needed = vmstate_event_facility_mask_length_needed,
415     .fields = (VMStateField[]) {
416         VMSTATE_UINT16(mask_length, SCLPEventFacility),
417         VMSTATE_END_OF_LIST()
418      }
419 };
420 
421 static const VMStateDescription vmstate_event_facility = {
422     .name = "vmstate-event-facility",
423     .version_id = 0,
424     .minimum_version_id = 0,
425     .fields = (VMStateField[]) {
426         VMSTATE_UINT32(receive_mask_pieces[RECV_MASK_UPPER], SCLPEventFacility),
427         VMSTATE_END_OF_LIST()
428      },
429     .subsections = (const VMStateDescription * []) {
430         &vmstate_event_facility_mask64,
431         &vmstate_event_facility_mask_length,
432         NULL
433      }
434 };
435 
436 static void sclp_event_set_allow_all_mask_sizes(Object *obj, bool value,
437                                                        Error **errp)
438 {
439     SCLPEventFacility *ef = (SCLPEventFacility *)obj;
440 
441     ef->allow_all_mask_sizes = value;
442 }
443 
444 static bool sclp_event_get_allow_all_mask_sizes(Object *obj, Error **e)
445 {
446     SCLPEventFacility *ef = (SCLPEventFacility *)obj;
447 
448     return ef->allow_all_mask_sizes;
449 }
450 
451 static void init_event_facility(Object *obj)
452 {
453     SCLPEventFacility *event_facility = EVENT_FACILITY(obj);
454     DeviceState *sdev = DEVICE(obj);
455     Object *new;
456 
457     event_facility->mask_length = 4;
458     event_facility->allow_all_mask_sizes = true;
459     object_property_add_bool(obj, "allow_all_mask_sizes",
460                              sclp_event_get_allow_all_mask_sizes,
461                              sclp_event_set_allow_all_mask_sizes, NULL);
462     /* Spawn a new bus for SCLP events */
463     qbus_create_inplace(&event_facility->sbus, sizeof(event_facility->sbus),
464                         TYPE_SCLP_EVENTS_BUS, sdev, NULL);
465 
466     new = object_new(TYPE_SCLP_QUIESCE);
467     object_property_add_child(obj, TYPE_SCLP_QUIESCE, new, NULL);
468     object_unref(new);
469     qdev_set_parent_bus(DEVICE(new), &event_facility->sbus.qbus);
470 
471     new = object_new(TYPE_SCLP_CPU_HOTPLUG);
472     object_property_add_child(obj, TYPE_SCLP_CPU_HOTPLUG, new, NULL);
473     object_unref(new);
474     qdev_set_parent_bus(DEVICE(new), &event_facility->sbus.qbus);
475     /* the facility will automatically realize the devices via the bus */
476 }
477 
478 static void reset_event_facility(DeviceState *dev)
479 {
480     SCLPEventFacility *sdev = EVENT_FACILITY(dev);
481 
482     sdev->receive_mask = 0;
483 }
484 
485 static void init_event_facility_class(ObjectClass *klass, void *data)
486 {
487     SysBusDeviceClass *sbdc = SYS_BUS_DEVICE_CLASS(klass);
488     DeviceClass *dc = DEVICE_CLASS(sbdc);
489     SCLPEventFacilityClass *k = EVENT_FACILITY_CLASS(dc);
490 
491     dc->reset = reset_event_facility;
492     dc->vmsd = &vmstate_event_facility;
493     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
494     k->command_handler = command_handler;
495     k->event_pending = event_pending;
496 }
497 
498 static const TypeInfo sclp_event_facility_info = {
499     .name          = TYPE_SCLP_EVENT_FACILITY,
500     .parent        = TYPE_SYS_BUS_DEVICE,
501     .instance_init = init_event_facility,
502     .instance_size = sizeof(SCLPEventFacility),
503     .class_init    = init_event_facility_class,
504     .class_size    = sizeof(SCLPEventFacilityClass),
505 };
506 
507 static void event_realize(DeviceState *qdev, Error **errp)
508 {
509     SCLPEvent *event = SCLP_EVENT(qdev);
510     SCLPEventClass *child = SCLP_EVENT_GET_CLASS(event);
511 
512     if (child->init) {
513         int rc = child->init(event);
514         if (rc < 0) {
515             error_setg(errp, "SCLP event initialization failed.");
516             return;
517         }
518     }
519 }
520 
521 static void event_class_init(ObjectClass *klass, void *data)
522 {
523     DeviceClass *dc = DEVICE_CLASS(klass);
524 
525     dc->bus_type = TYPE_SCLP_EVENTS_BUS;
526     dc->realize = event_realize;
527 }
528 
529 static const TypeInfo sclp_event_type_info = {
530     .name = TYPE_SCLP_EVENT,
531     .parent = TYPE_DEVICE,
532     .instance_size = sizeof(SCLPEvent),
533     .class_init = event_class_init,
534     .class_size = sizeof(SCLPEventClass),
535     .abstract = true,
536 };
537 
538 static void register_types(void)
539 {
540     type_register_static(&sclp_events_bus_info);
541     type_register_static(&sclp_event_facility_info);
542     type_register_static(&sclp_event_type_info);
543 }
544 
545 type_init(register_types)
546 
547 BusState *sclp_get_event_facility_bus(void)
548 {
549     Object *busobj;
550     SCLPEventsBus *sbus;
551 
552     busobj = object_resolve_path_type("", TYPE_SCLP_EVENTS_BUS, NULL);
553     sbus = OBJECT_CHECK(SCLPEventsBus, busobj, TYPE_SCLP_EVENTS_BUS);
554     if (!sbus) {
555         return NULL;
556     }
557 
558     return &sbus->qbus;
559 }
560