xref: /qemu/hw/s390x/event-facility.c (revision 6b3913e0) 
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 struct SCLPEventFacility {
30     SysBusDevice parent_obj;
31     SCLPEventsBus sbus;
32     /* guest's receive mask */
33     sccb_mask_t receive_mask;
34     /*
35      * when false, we keep the same broken, backwards compatible behaviour as
36      * before, allowing only masks of size exactly 4; when true, we implement
37      * the architecture correctly, allowing all valid mask sizes. Needed for
38      * migration toward older versions.
39      */
40     bool allow_all_mask_sizes;
41     /* length of the receive mask */
42     uint16_t mask_length;
43 };
44 
45 /* return true if any child has event pending set */
46 static bool event_pending(SCLPEventFacility *ef)
47 {
48     BusChild *kid;
49     SCLPEvent *event;
50     SCLPEventClass *event_class;
51 
52     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
53         DeviceState *qdev = kid->child;
54         event = DO_UPCAST(SCLPEvent, qdev, qdev);
55         event_class = SCLP_EVENT_GET_CLASS(event);
56         if (event->event_pending &&
57             event_class->get_send_mask() & ef->receive_mask) {
58             return true;
59         }
60     }
61     return false;
62 }
63 
64 static sccb_mask_t get_host_send_mask(SCLPEventFacility *ef)
65 {
66     sccb_mask_t mask;
67     BusChild *kid;
68     SCLPEventClass *child;
69 
70     mask = 0;
71 
72     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
73         DeviceState *qdev = kid->child;
74         child = SCLP_EVENT_GET_CLASS((SCLPEvent *) qdev);
75         mask |= child->get_send_mask();
76     }
77     return mask;
78 }
79 
80 static sccb_mask_t get_host_receive_mask(SCLPEventFacility *ef)
81 {
82     sccb_mask_t mask;
83     BusChild *kid;
84     SCLPEventClass *child;
85 
86     mask = 0;
87 
88     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
89         DeviceState *qdev = kid->child;
90         child = SCLP_EVENT_GET_CLASS((SCLPEvent *) qdev);
91         mask |= child->get_receive_mask();
92     }
93     return mask;
94 }
95 
96 static uint16_t write_event_length_check(SCCB *sccb)
97 {
98     int slen;
99     unsigned elen = 0;
100     EventBufferHeader *event;
101     WriteEventData *wed = (WriteEventData *) sccb;
102 
103     event = (EventBufferHeader *) &wed->ebh;
104     for (slen = sccb_data_len(sccb); slen > 0; slen -= elen) {
105         elen = be16_to_cpu(event->length);
106         if (elen < sizeof(*event) || elen > slen) {
107             return SCLP_RC_EVENT_BUFFER_SYNTAX_ERROR;
108         }
109         event = (void *) event + elen;
110     }
111     if (slen) {
112         return SCLP_RC_INCONSISTENT_LENGTHS;
113     }
114     return SCLP_RC_NORMAL_COMPLETION;
115 }
116 
117 static uint16_t handle_write_event_buf(SCLPEventFacility *ef,
118                                        EventBufferHeader *event_buf, SCCB *sccb)
119 {
120     uint16_t rc;
121     BusChild *kid;
122     SCLPEvent *event;
123     SCLPEventClass *ec;
124 
125     rc = SCLP_RC_INVALID_FUNCTION;
126 
127     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
128         DeviceState *qdev = kid->child;
129         event = (SCLPEvent *) qdev;
130         ec = SCLP_EVENT_GET_CLASS(event);
131 
132         if (ec->write_event_data &&
133             ec->can_handle_event(event_buf->type)) {
134             rc = ec->write_event_data(event, event_buf);
135             break;
136         }
137     }
138     return rc;
139 }
140 
141 static uint16_t handle_sccb_write_events(SCLPEventFacility *ef, SCCB *sccb)
142 {
143     uint16_t rc;
144     int slen;
145     unsigned elen = 0;
146     EventBufferHeader *event_buf;
147     WriteEventData *wed = (WriteEventData *) sccb;
148 
149     event_buf = &wed->ebh;
150     rc = SCLP_RC_NORMAL_COMPLETION;
151 
152     /* loop over all contained event buffers */
153     for (slen = sccb_data_len(sccb); slen > 0; slen -= elen) {
154         elen = be16_to_cpu(event_buf->length);
155 
156         /* in case of a previous error mark all trailing buffers
157          * as not accepted */
158         if (rc != SCLP_RC_NORMAL_COMPLETION) {
159             event_buf->flags &= ~(SCLP_EVENT_BUFFER_ACCEPTED);
160         } else {
161             rc = handle_write_event_buf(ef, event_buf, sccb);
162         }
163         event_buf = (void *) event_buf + elen;
164     }
165     return rc;
166 }
167 
168 static void write_event_data(SCLPEventFacility *ef, SCCB *sccb)
169 {
170     if (sccb->h.function_code != SCLP_FC_NORMAL_WRITE) {
171         sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_FUNCTION);
172         goto out;
173     }
174     if (be16_to_cpu(sccb->h.length) < 8) {
175         sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH);
176         goto out;
177     }
178     /* first do a sanity check of the write events */
179     sccb->h.response_code = cpu_to_be16(write_event_length_check(sccb));
180 
181     /* if no early error, then execute */
182     if (sccb->h.response_code == be16_to_cpu(SCLP_RC_NORMAL_COMPLETION)) {
183         sccb->h.response_code =
184                 cpu_to_be16(handle_sccb_write_events(ef, sccb));
185     }
186 
187 out:
188     return;
189 }
190 
191 static uint16_t handle_sccb_read_events(SCLPEventFacility *ef, SCCB *sccb,
192                                         sccb_mask_t mask)
193 {
194     uint16_t rc;
195     int slen;
196     unsigned elen;
197     BusChild *kid;
198     SCLPEvent *event;
199     SCLPEventClass *ec;
200     EventBufferHeader *event_buf;
201     ReadEventData *red = (ReadEventData *) sccb;
202 
203     event_buf = &red->ebh;
204     event_buf->length = 0;
205     slen = sizeof(sccb->data);
206 
207     rc = SCLP_RC_NO_EVENT_BUFFERS_STORED;
208 
209     QTAILQ_FOREACH(kid, &ef->sbus.qbus.children, sibling) {
210         DeviceState *qdev = kid->child;
211         event = (SCLPEvent *) qdev;
212         ec = SCLP_EVENT_GET_CLASS(event);
213 
214         if (mask & ec->get_send_mask()) {
215             if (ec->read_event_data(event, event_buf, &slen)) {
216                 elen = be16_to_cpu(event_buf->length);
217                 event_buf = (EventBufferHeader *) ((char *)event_buf + elen);
218                 rc = SCLP_RC_NORMAL_COMPLETION;
219             }
220         }
221     }
222 
223     if (sccb->h.control_mask[2] & SCLP_VARIABLE_LENGTH_RESPONSE) {
224         /* architecture suggests to reset variable-length-response bit */
225         sccb->h.control_mask[2] &= ~SCLP_VARIABLE_LENGTH_RESPONSE;
226         /* with a new length value */
227         sccb->h.length = cpu_to_be16(SCCB_SIZE - slen);
228     }
229     return rc;
230 }
231 
232 /* copy up to src_len bytes and fill the rest of dst with zeroes */
233 static void copy_mask(uint8_t *dst, uint8_t *src, uint16_t dst_len,
234                       uint16_t src_len)
235 {
236     int i;
237 
238     for (i = 0; i < dst_len; i++) {
239         dst[i] = i < src_len ? src[i] : 0;
240     }
241 }
242 
243 static void read_event_data(SCLPEventFacility *ef, SCCB *sccb)
244 {
245     sccb_mask_t sclp_active_selection_mask;
246     sccb_mask_t sclp_cp_receive_mask;
247 
248     ReadEventData *red = (ReadEventData *) sccb;
249 
250     if (be16_to_cpu(sccb->h.length) != SCCB_SIZE) {
251         sccb->h.response_code = cpu_to_be16(SCLP_RC_INSUFFICIENT_SCCB_LENGTH);
252         goto out;
253     }
254 
255     sclp_cp_receive_mask = ef->receive_mask;
256 
257     /* get active selection mask */
258     switch (sccb->h.function_code) {
259     case SCLP_UNCONDITIONAL_READ:
260         sclp_active_selection_mask = sclp_cp_receive_mask;
261         break;
262     case SCLP_SELECTIVE_READ:
263         copy_mask((uint8_t *)&sclp_active_selection_mask, (uint8_t *)&red->mask,
264                   sizeof(sclp_active_selection_mask), ef->mask_length);
265         sclp_active_selection_mask = be32_to_cpu(sclp_active_selection_mask);
266         if (!sclp_cp_receive_mask ||
267             (sclp_active_selection_mask & ~sclp_cp_receive_mask)) {
268             sccb->h.response_code =
269                     cpu_to_be16(SCLP_RC_INVALID_SELECTION_MASK);
270             goto out;
271         }
272         break;
273     default:
274         sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_FUNCTION);
275         goto out;
276     }
277     sccb->h.response_code = cpu_to_be16(
278             handle_sccb_read_events(ef, sccb, sclp_active_selection_mask));
279 
280 out:
281     return;
282 }
283 
284 static void write_event_mask(SCLPEventFacility *ef, SCCB *sccb)
285 {
286     WriteEventMask *we_mask = (WriteEventMask *) sccb;
287     uint16_t mask_length = be16_to_cpu(we_mask->mask_length);
288     sccb_mask_t tmp_mask;
289 
290     if (!mask_length || (mask_length > SCLP_EVENT_MASK_LEN_MAX) ||
291         ((mask_length != 4) && !ef->allow_all_mask_sizes)) {
292         sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_MASK_LENGTH);
293         goto out;
294     }
295 
296     /*
297      * Note: We currently only support masks up to 4 byte length;
298      *       the remainder is filled up with zeroes. Linux uses
299      *       a 4 byte mask length.
300      */
301 
302     /* keep track of the guest's capability masks */
303     copy_mask((uint8_t *)&tmp_mask, WEM_CP_RECEIVE_MASK(we_mask, mask_length),
304               sizeof(tmp_mask), mask_length);
305     ef->receive_mask = be32_to_cpu(tmp_mask);
306 
307     /* return the SCLP's capability masks to the guest */
308     tmp_mask = cpu_to_be32(get_host_receive_mask(ef));
309     copy_mask(WEM_RECEIVE_MASK(we_mask, mask_length), (uint8_t *)&tmp_mask,
310               mask_length, sizeof(tmp_mask));
311     tmp_mask = cpu_to_be32(get_host_send_mask(ef));
312     copy_mask(WEM_SEND_MASK(we_mask, mask_length), (uint8_t *)&tmp_mask,
313               mask_length, sizeof(tmp_mask));
314 
315     sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_COMPLETION);
316     ef->mask_length = mask_length;
317 
318 out:
319     return;
320 }
321 
322 /* qemu object creation and initialization functions */
323 
324 #define TYPE_SCLP_EVENTS_BUS "s390-sclp-events-bus"
325 
326 static void sclp_events_bus_realize(BusState *bus, Error **errp)
327 {
328     BusChild *kid;
329 
330     /* TODO: recursive realization has to be done in common code */
331     QTAILQ_FOREACH(kid, &bus->children, sibling) {
332         DeviceState *dev = kid->child;
333 
334         object_property_set_bool(OBJECT(dev), true, "realized", errp);
335         if (*errp) {
336             return;
337         }
338     }
339 }
340 
341 static void sclp_events_bus_class_init(ObjectClass *klass, void *data)
342 {
343     BusClass *bc = BUS_CLASS(klass);
344 
345     bc->realize = sclp_events_bus_realize;
346 }
347 
348 static const TypeInfo sclp_events_bus_info = {
349     .name = TYPE_SCLP_EVENTS_BUS,
350     .parent = TYPE_BUS,
351     .class_init = sclp_events_bus_class_init,
352 };
353 
354 static void command_handler(SCLPEventFacility *ef, SCCB *sccb, uint64_t code)
355 {
356     switch (code & SCLP_CMD_CODE_MASK) {
357     case SCLP_CMD_READ_EVENT_DATA:
358         read_event_data(ef, sccb);
359         break;
360     case SCLP_CMD_WRITE_EVENT_DATA:
361         write_event_data(ef, sccb);
362         break;
363     case SCLP_CMD_WRITE_EVENT_MASK:
364         write_event_mask(ef, sccb);
365         break;
366     default:
367         sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
368         break;
369     }
370 }
371 
372 static bool vmstate_event_facility_mask_length_needed(void *opaque)
373 {
374     SCLPEventFacility *ef = opaque;
375 
376     return ef->allow_all_mask_sizes;
377 }
378 
379 static const VMStateDescription vmstate_event_facility_mask_length = {
380     .name = "vmstate-event-facility/mask_length",
381     .version_id = 0,
382     .minimum_version_id = 0,
383     .needed = vmstate_event_facility_mask_length_needed,
384     .fields = (VMStateField[]) {
385         VMSTATE_UINT16(mask_length, SCLPEventFacility),
386         VMSTATE_END_OF_LIST()
387      }
388 };
389 
390 static const VMStateDescription vmstate_event_facility = {
391     .name = "vmstate-event-facility",
392     .version_id = 0,
393     .minimum_version_id = 0,
394     .fields = (VMStateField[]) {
395         VMSTATE_UINT32(receive_mask, SCLPEventFacility),
396         VMSTATE_END_OF_LIST()
397      },
398     .subsections = (const VMStateDescription * []) {
399         &vmstate_event_facility_mask_length,
400         NULL
401      }
402 };
403 
404 static void sclp_event_set_allow_all_mask_sizes(Object *obj, bool value,
405                                                        Error **errp)
406 {
407     SCLPEventFacility *ef = (SCLPEventFacility *)obj;
408 
409     ef->allow_all_mask_sizes = value;
410 }
411 
412 static bool sclp_event_get_allow_all_mask_sizes(Object *obj, Error **e)
413 {
414     SCLPEventFacility *ef = (SCLPEventFacility *)obj;
415 
416     return ef->allow_all_mask_sizes;
417 }
418 
419 static void init_event_facility(Object *obj)
420 {
421     SCLPEventFacility *event_facility = EVENT_FACILITY(obj);
422     DeviceState *sdev = DEVICE(obj);
423     Object *new;
424 
425     event_facility->mask_length = 4;
426     event_facility->allow_all_mask_sizes = true;
427     object_property_add_bool(obj, "allow_all_mask_sizes",
428                              sclp_event_get_allow_all_mask_sizes,
429                              sclp_event_set_allow_all_mask_sizes, NULL);
430     /* Spawn a new bus for SCLP events */
431     qbus_create_inplace(&event_facility->sbus, sizeof(event_facility->sbus),
432                         TYPE_SCLP_EVENTS_BUS, sdev, NULL);
433 
434     new = object_new(TYPE_SCLP_QUIESCE);
435     object_property_add_child(obj, TYPE_SCLP_QUIESCE, new, NULL);
436     object_unref(new);
437     qdev_set_parent_bus(DEVICE(new), &event_facility->sbus.qbus);
438 
439     new = object_new(TYPE_SCLP_CPU_HOTPLUG);
440     object_property_add_child(obj, TYPE_SCLP_CPU_HOTPLUG, new, NULL);
441     object_unref(new);
442     qdev_set_parent_bus(DEVICE(new), &event_facility->sbus.qbus);
443     /* the facility will automatically realize the devices via the bus */
444 }
445 
446 static void reset_event_facility(DeviceState *dev)
447 {
448     SCLPEventFacility *sdev = EVENT_FACILITY(dev);
449 
450     sdev->receive_mask = 0;
451 }
452 
453 static void init_event_facility_class(ObjectClass *klass, void *data)
454 {
455     SysBusDeviceClass *sbdc = SYS_BUS_DEVICE_CLASS(klass);
456     DeviceClass *dc = DEVICE_CLASS(sbdc);
457     SCLPEventFacilityClass *k = EVENT_FACILITY_CLASS(dc);
458 
459     dc->reset = reset_event_facility;
460     dc->vmsd = &vmstate_event_facility;
461     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
462     k->command_handler = command_handler;
463     k->event_pending = event_pending;
464 }
465 
466 static const TypeInfo sclp_event_facility_info = {
467     .name          = TYPE_SCLP_EVENT_FACILITY,
468     .parent        = TYPE_SYS_BUS_DEVICE,
469     .instance_init = init_event_facility,
470     .instance_size = sizeof(SCLPEventFacility),
471     .class_init    = init_event_facility_class,
472     .class_size    = sizeof(SCLPEventFacilityClass),
473 };
474 
475 static void event_realize(DeviceState *qdev, Error **errp)
476 {
477     SCLPEvent *event = SCLP_EVENT(qdev);
478     SCLPEventClass *child = SCLP_EVENT_GET_CLASS(event);
479 
480     if (child->init) {
481         int rc = child->init(event);
482         if (rc < 0) {
483             error_setg(errp, "SCLP event initialization failed.");
484             return;
485         }
486     }
487 }
488 
489 static void event_class_init(ObjectClass *klass, void *data)
490 {
491     DeviceClass *dc = DEVICE_CLASS(klass);
492 
493     dc->bus_type = TYPE_SCLP_EVENTS_BUS;
494     dc->realize = event_realize;
495 }
496 
497 static const TypeInfo sclp_event_type_info = {
498     .name = TYPE_SCLP_EVENT,
499     .parent = TYPE_DEVICE,
500     .instance_size = sizeof(SCLPEvent),
501     .class_init = event_class_init,
502     .class_size = sizeof(SCLPEventClass),
503     .abstract = true,
504 };
505 
506 static void register_types(void)
507 {
508     type_register_static(&sclp_events_bus_info);
509     type_register_static(&sclp_event_facility_info);
510     type_register_static(&sclp_event_type_info);
511 }
512 
513 type_init(register_types)
514