xref: /openbmc/qemu/hw/s390x/css.c (revision 88f62c2b)
1 /*
2  * Channel subsystem base support.
3  *
4  * Copyright 2012 IBM Corp.
5  * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
6  *
7  * This work is licensed under the terms of the GNU GPL, version 2 or (at
8  * your option) any later version. See the COPYING file in the top-level
9  * directory.
10  */
11 
12 #include <hw/qdev.h>
13 #include "qemu/bitops.h"
14 #include "cpu.h"
15 #include "ioinst.h"
16 #include "css.h"
17 #include "trace.h"
18 
19 typedef struct CrwContainer {
20     CRW crw;
21     QTAILQ_ENTRY(CrwContainer) sibling;
22 } CrwContainer;
23 
24 typedef struct ChpInfo {
25     uint8_t in_use;
26     uint8_t type;
27     uint8_t is_virtual;
28 } ChpInfo;
29 
30 typedef struct SubchSet {
31     SubchDev *sch[MAX_SCHID + 1];
32     unsigned long schids_used[BITS_TO_LONGS(MAX_SCHID + 1)];
33     unsigned long devnos_used[BITS_TO_LONGS(MAX_SCHID + 1)];
34 } SubchSet;
35 
36 typedef struct CssImage {
37     SubchSet *sch_set[MAX_SSID + 1];
38     ChpInfo chpids[MAX_CHPID + 1];
39 } CssImage;
40 
41 typedef struct ChannelSubSys {
42     QTAILQ_HEAD(, CrwContainer) pending_crws;
43     bool do_crw_mchk;
44     bool crws_lost;
45     uint8_t max_cssid;
46     uint8_t max_ssid;
47     bool chnmon_active;
48     uint64_t chnmon_area;
49     CssImage *css[MAX_CSSID + 1];
50     uint8_t default_cssid;
51 } ChannelSubSys;
52 
53 static ChannelSubSys *channel_subsys;
54 
55 int css_create_css_image(uint8_t cssid, bool default_image)
56 {
57     trace_css_new_image(cssid, default_image ? "(default)" : "");
58     if (cssid > MAX_CSSID) {
59         return -EINVAL;
60     }
61     if (channel_subsys->css[cssid]) {
62         return -EBUSY;
63     }
64     channel_subsys->css[cssid] = g_malloc0(sizeof(CssImage));
65     if (default_image) {
66         channel_subsys->default_cssid = cssid;
67     }
68     return 0;
69 }
70 
71 static uint16_t css_build_subchannel_id(SubchDev *sch)
72 {
73     if (channel_subsys->max_cssid > 0) {
74         return (sch->cssid << 8) | (1 << 3) | (sch->ssid << 1) | 1;
75     }
76     return (sch->ssid << 1) | 1;
77 }
78 
79 static void css_inject_io_interrupt(SubchDev *sch)
80 {
81     S390CPU *cpu = s390_cpu_addr2state(0);
82     uint8_t isc = (sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ISC) >> 11;
83 
84     trace_css_io_interrupt(sch->cssid, sch->ssid, sch->schid,
85                            sch->curr_status.pmcw.intparm, isc, "");
86     s390_io_interrupt(cpu,
87                       css_build_subchannel_id(sch),
88                       sch->schid,
89                       sch->curr_status.pmcw.intparm,
90                       isc << 27);
91 }
92 
93 void css_conditional_io_interrupt(SubchDev *sch)
94 {
95     /*
96      * If the subchannel is not currently status pending, make it pending
97      * with alert status.
98      */
99     if (!(sch->curr_status.scsw.ctrl & SCSW_STCTL_STATUS_PEND)) {
100         S390CPU *cpu = s390_cpu_addr2state(0);
101         uint8_t isc = (sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ISC) >> 11;
102 
103         trace_css_io_interrupt(sch->cssid, sch->ssid, sch->schid,
104                                sch->curr_status.pmcw.intparm, isc,
105                                "(unsolicited)");
106         sch->curr_status.scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
107         sch->curr_status.scsw.ctrl |=
108             SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
109         /* Inject an I/O interrupt. */
110         s390_io_interrupt(cpu,
111                           css_build_subchannel_id(sch),
112                           sch->schid,
113                           sch->curr_status.pmcw.intparm,
114                           isc << 27);
115     }
116 }
117 
118 static void sch_handle_clear_func(SubchDev *sch)
119 {
120     PMCW *p = &sch->curr_status.pmcw;
121     SCSW *s = &sch->curr_status.scsw;
122     int path;
123 
124     /* Path management: In our simple css, we always choose the only path. */
125     path = 0x80;
126 
127     /* Reset values prior to 'issueing the clear signal'. */
128     p->lpum = 0;
129     p->pom = 0xff;
130     s->flags &= ~SCSW_FLAGS_MASK_PNO;
131 
132     /* We always 'attempt to issue the clear signal', and we always succeed. */
133     sch->orb = NULL;
134     sch->channel_prog = 0x0;
135     sch->last_cmd_valid = false;
136     s->ctrl &= ~SCSW_ACTL_CLEAR_PEND;
137     s->ctrl |= SCSW_STCTL_STATUS_PEND;
138 
139     s->dstat = 0;
140     s->cstat = 0;
141     p->lpum = path;
142 
143 }
144 
145 static void sch_handle_halt_func(SubchDev *sch)
146 {
147 
148     PMCW *p = &sch->curr_status.pmcw;
149     SCSW *s = &sch->curr_status.scsw;
150     int path;
151 
152     /* Path management: In our simple css, we always choose the only path. */
153     path = 0x80;
154 
155     /* We always 'attempt to issue the halt signal', and we always succeed. */
156     sch->orb = NULL;
157     sch->channel_prog = 0x0;
158     sch->last_cmd_valid = false;
159     s->ctrl &= ~SCSW_ACTL_HALT_PEND;
160     s->ctrl |= SCSW_STCTL_STATUS_PEND;
161 
162     if ((s->ctrl & (SCSW_ACTL_SUBCH_ACTIVE | SCSW_ACTL_DEVICE_ACTIVE)) ||
163         !((s->ctrl & SCSW_ACTL_START_PEND) ||
164           (s->ctrl & SCSW_ACTL_SUSP))) {
165         s->dstat = SCSW_DSTAT_DEVICE_END;
166     }
167     s->cstat = 0;
168     p->lpum = path;
169 
170 }
171 
172 static void copy_sense_id_to_guest(SenseId *dest, SenseId *src)
173 {
174     int i;
175 
176     dest->reserved = src->reserved;
177     dest->cu_type = cpu_to_be16(src->cu_type);
178     dest->cu_model = src->cu_model;
179     dest->dev_type = cpu_to_be16(src->dev_type);
180     dest->dev_model = src->dev_model;
181     dest->unused = src->unused;
182     for (i = 0; i < ARRAY_SIZE(dest->ciw); i++) {
183         dest->ciw[i].type = src->ciw[i].type;
184         dest->ciw[i].command = src->ciw[i].command;
185         dest->ciw[i].count = cpu_to_be16(src->ciw[i].count);
186     }
187 }
188 
189 static CCW1 copy_ccw_from_guest(hwaddr addr)
190 {
191     CCW1 tmp;
192     CCW1 ret;
193 
194     cpu_physical_memory_read(addr, &tmp, sizeof(tmp));
195     ret.cmd_code = tmp.cmd_code;
196     ret.flags = tmp.flags;
197     ret.count = be16_to_cpu(tmp.count);
198     ret.cda = be32_to_cpu(tmp.cda);
199 
200     return ret;
201 }
202 
203 static int css_interpret_ccw(SubchDev *sch, hwaddr ccw_addr)
204 {
205     int ret;
206     bool check_len;
207     int len;
208     CCW1 ccw;
209 
210     if (!ccw_addr) {
211         return -EIO;
212     }
213 
214     ccw = copy_ccw_from_guest(ccw_addr);
215 
216     /* Check for invalid command codes. */
217     if ((ccw.cmd_code & 0x0f) == 0) {
218         return -EINVAL;
219     }
220     if (((ccw.cmd_code & 0x0f) == CCW_CMD_TIC) &&
221         ((ccw.cmd_code & 0xf0) != 0)) {
222         return -EINVAL;
223     }
224 
225     if (ccw.flags & CCW_FLAG_SUSPEND) {
226         return -EINPROGRESS;
227     }
228 
229     check_len = !((ccw.flags & CCW_FLAG_SLI) && !(ccw.flags & CCW_FLAG_DC));
230 
231     /* Look at the command. */
232     switch (ccw.cmd_code) {
233     case CCW_CMD_NOOP:
234         /* Nothing to do. */
235         ret = 0;
236         break;
237     case CCW_CMD_BASIC_SENSE:
238         if (check_len) {
239             if (ccw.count != sizeof(sch->sense_data)) {
240                 ret = -EINVAL;
241                 break;
242             }
243         }
244         len = MIN(ccw.count, sizeof(sch->sense_data));
245         cpu_physical_memory_write(ccw.cda, sch->sense_data, len);
246         sch->curr_status.scsw.count = ccw.count - len;
247         memset(sch->sense_data, 0, sizeof(sch->sense_data));
248         ret = 0;
249         break;
250     case CCW_CMD_SENSE_ID:
251     {
252         SenseId sense_id;
253 
254         copy_sense_id_to_guest(&sense_id, &sch->id);
255         /* Sense ID information is device specific. */
256         if (check_len) {
257             if (ccw.count != sizeof(sense_id)) {
258                 ret = -EINVAL;
259                 break;
260             }
261         }
262         len = MIN(ccw.count, sizeof(sense_id));
263         /*
264          * Only indicate 0xff in the first sense byte if we actually
265          * have enough place to store at least bytes 0-3.
266          */
267         if (len >= 4) {
268             sense_id.reserved = 0xff;
269         } else {
270             sense_id.reserved = 0;
271         }
272         cpu_physical_memory_write(ccw.cda, &sense_id, len);
273         sch->curr_status.scsw.count = ccw.count - len;
274         ret = 0;
275         break;
276     }
277     case CCW_CMD_TIC:
278         if (sch->last_cmd_valid && (sch->last_cmd.cmd_code == CCW_CMD_TIC)) {
279             ret = -EINVAL;
280             break;
281         }
282         if (ccw.flags & (CCW_FLAG_CC | CCW_FLAG_DC)) {
283             ret = -EINVAL;
284             break;
285         }
286         sch->channel_prog = ccw.cda;
287         ret = -EAGAIN;
288         break;
289     default:
290         if (sch->ccw_cb) {
291             /* Handle device specific commands. */
292             ret = sch->ccw_cb(sch, ccw);
293         } else {
294             ret = -ENOSYS;
295         }
296         break;
297     }
298     sch->last_cmd = ccw;
299     sch->last_cmd_valid = true;
300     if (ret == 0) {
301         if (ccw.flags & CCW_FLAG_CC) {
302             sch->channel_prog += 8;
303             ret = -EAGAIN;
304         }
305     }
306 
307     return ret;
308 }
309 
310 static void sch_handle_start_func(SubchDev *sch)
311 {
312 
313     PMCW *p = &sch->curr_status.pmcw;
314     SCSW *s = &sch->curr_status.scsw;
315     ORB *orb = sch->orb;
316     int path;
317     int ret;
318 
319     /* Path management: In our simple css, we always choose the only path. */
320     path = 0x80;
321 
322     if (!(s->ctrl & SCSW_ACTL_SUSP)) {
323         /* Look at the orb and try to execute the channel program. */
324         p->intparm = orb->intparm;
325         if (!(orb->lpm & path)) {
326             /* Generate a deferred cc 3 condition. */
327             s->flags |= SCSW_FLAGS_MASK_CC;
328             s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
329             s->ctrl |= (SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND);
330             return;
331         }
332     } else {
333         s->ctrl &= ~(SCSW_ACTL_SUSP | SCSW_ACTL_RESUME_PEND);
334     }
335     sch->last_cmd_valid = false;
336     do {
337         ret = css_interpret_ccw(sch, sch->channel_prog);
338         switch (ret) {
339         case -EAGAIN:
340             /* ccw chain, continue processing */
341             break;
342         case 0:
343             /* success */
344             s->ctrl &= ~SCSW_ACTL_START_PEND;
345             s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
346             s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
347                     SCSW_STCTL_STATUS_PEND;
348             s->dstat = SCSW_DSTAT_CHANNEL_END | SCSW_DSTAT_DEVICE_END;
349             break;
350         case -ENOSYS:
351             /* unsupported command, generate unit check (command reject) */
352             s->ctrl &= ~SCSW_ACTL_START_PEND;
353             s->dstat = SCSW_DSTAT_UNIT_CHECK;
354             /* Set sense bit 0 in ecw0. */
355             sch->sense_data[0] = 0x80;
356             s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
357             s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
358                     SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
359             break;
360         case -EFAULT:
361             /* memory problem, generate channel data check */
362             s->ctrl &= ~SCSW_ACTL_START_PEND;
363             s->cstat = SCSW_CSTAT_DATA_CHECK;
364             s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
365             s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
366                     SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
367             break;
368         case -EBUSY:
369             /* subchannel busy, generate deferred cc 1 */
370             s->flags &= ~SCSW_FLAGS_MASK_CC;
371             s->flags |= (1 << 8);
372             s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
373             s->ctrl |= SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
374             break;
375         case -EINPROGRESS:
376             /* channel program has been suspended */
377             s->ctrl &= ~SCSW_ACTL_START_PEND;
378             s->ctrl |= SCSW_ACTL_SUSP;
379             break;
380         default:
381             /* error, generate channel program check */
382             s->ctrl &= ~SCSW_ACTL_START_PEND;
383             s->cstat = SCSW_CSTAT_PROG_CHECK;
384             s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
385             s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
386                     SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
387             break;
388         }
389     } while (ret == -EAGAIN);
390 
391 }
392 
393 /*
394  * On real machines, this would run asynchronously to the main vcpus.
395  * We might want to make some parts of the ssch handling (interpreting
396  * read/writes) asynchronous later on if we start supporting more than
397  * our current very simple devices.
398  */
399 static void do_subchannel_work(SubchDev *sch)
400 {
401 
402     SCSW *s = &sch->curr_status.scsw;
403 
404     if (s->ctrl & SCSW_FCTL_CLEAR_FUNC) {
405         sch_handle_clear_func(sch);
406     } else if (s->ctrl & SCSW_FCTL_HALT_FUNC) {
407         sch_handle_halt_func(sch);
408     } else if (s->ctrl & SCSW_FCTL_START_FUNC) {
409         sch_handle_start_func(sch);
410     } else {
411         /* Cannot happen. */
412         return;
413     }
414     css_inject_io_interrupt(sch);
415 }
416 
417 static void copy_pmcw_to_guest(PMCW *dest, const PMCW *src)
418 {
419     int i;
420 
421     dest->intparm = cpu_to_be32(src->intparm);
422     dest->flags = cpu_to_be16(src->flags);
423     dest->devno = cpu_to_be16(src->devno);
424     dest->lpm = src->lpm;
425     dest->pnom = src->pnom;
426     dest->lpum = src->lpum;
427     dest->pim = src->pim;
428     dest->mbi = cpu_to_be16(src->mbi);
429     dest->pom = src->pom;
430     dest->pam = src->pam;
431     for (i = 0; i < ARRAY_SIZE(dest->chpid); i++) {
432         dest->chpid[i] = src->chpid[i];
433     }
434     dest->chars = cpu_to_be32(src->chars);
435 }
436 
437 static void copy_scsw_to_guest(SCSW *dest, const SCSW *src)
438 {
439     dest->flags = cpu_to_be16(src->flags);
440     dest->ctrl = cpu_to_be16(src->ctrl);
441     dest->cpa = cpu_to_be32(src->cpa);
442     dest->dstat = src->dstat;
443     dest->cstat = src->cstat;
444     dest->count = cpu_to_be16(src->count);
445 }
446 
447 static void copy_schib_to_guest(SCHIB *dest, const SCHIB *src)
448 {
449     int i;
450 
451     copy_pmcw_to_guest(&dest->pmcw, &src->pmcw);
452     copy_scsw_to_guest(&dest->scsw, &src->scsw);
453     dest->mba = cpu_to_be64(src->mba);
454     for (i = 0; i < ARRAY_SIZE(dest->mda); i++) {
455         dest->mda[i] = src->mda[i];
456     }
457 }
458 
459 int css_do_stsch(SubchDev *sch, SCHIB *schib)
460 {
461     /* Use current status. */
462     copy_schib_to_guest(schib, &sch->curr_status);
463     return 0;
464 }
465 
466 static void copy_pmcw_from_guest(PMCW *dest, const PMCW *src)
467 {
468     int i;
469 
470     dest->intparm = be32_to_cpu(src->intparm);
471     dest->flags = be16_to_cpu(src->flags);
472     dest->devno = be16_to_cpu(src->devno);
473     dest->lpm = src->lpm;
474     dest->pnom = src->pnom;
475     dest->lpum = src->lpum;
476     dest->pim = src->pim;
477     dest->mbi = be16_to_cpu(src->mbi);
478     dest->pom = src->pom;
479     dest->pam = src->pam;
480     for (i = 0; i < ARRAY_SIZE(dest->chpid); i++) {
481         dest->chpid[i] = src->chpid[i];
482     }
483     dest->chars = be32_to_cpu(src->chars);
484 }
485 
486 static void copy_scsw_from_guest(SCSW *dest, const SCSW *src)
487 {
488     dest->flags = be16_to_cpu(src->flags);
489     dest->ctrl = be16_to_cpu(src->ctrl);
490     dest->cpa = be32_to_cpu(src->cpa);
491     dest->dstat = src->dstat;
492     dest->cstat = src->cstat;
493     dest->count = be16_to_cpu(src->count);
494 }
495 
496 static void copy_schib_from_guest(SCHIB *dest, const SCHIB *src)
497 {
498     int i;
499 
500     copy_pmcw_from_guest(&dest->pmcw, &src->pmcw);
501     copy_scsw_from_guest(&dest->scsw, &src->scsw);
502     dest->mba = be64_to_cpu(src->mba);
503     for (i = 0; i < ARRAY_SIZE(dest->mda); i++) {
504         dest->mda[i] = src->mda[i];
505     }
506 }
507 
508 int css_do_msch(SubchDev *sch, SCHIB *orig_schib)
509 {
510     SCSW *s = &sch->curr_status.scsw;
511     PMCW *p = &sch->curr_status.pmcw;
512     int ret;
513     SCHIB schib;
514 
515     if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_DNV)) {
516         ret = 0;
517         goto out;
518     }
519 
520     if (s->ctrl & SCSW_STCTL_STATUS_PEND) {
521         ret = -EINPROGRESS;
522         goto out;
523     }
524 
525     if (s->ctrl &
526         (SCSW_FCTL_START_FUNC|SCSW_FCTL_HALT_FUNC|SCSW_FCTL_CLEAR_FUNC)) {
527         ret = -EBUSY;
528         goto out;
529     }
530 
531     copy_schib_from_guest(&schib, orig_schib);
532     /* Only update the program-modifiable fields. */
533     p->intparm = schib.pmcw.intparm;
534     p->flags &= ~(PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |
535                   PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |
536                   PMCW_FLAGS_MASK_MP);
537     p->flags |= schib.pmcw.flags &
538             (PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |
539              PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |
540              PMCW_FLAGS_MASK_MP);
541     p->lpm = schib.pmcw.lpm;
542     p->mbi = schib.pmcw.mbi;
543     p->pom = schib.pmcw.pom;
544     p->chars &= ~(PMCW_CHARS_MASK_MBFC | PMCW_CHARS_MASK_CSENSE);
545     p->chars |= schib.pmcw.chars &
546             (PMCW_CHARS_MASK_MBFC | PMCW_CHARS_MASK_CSENSE);
547     sch->curr_status.mba = schib.mba;
548 
549     ret = 0;
550 
551 out:
552     return ret;
553 }
554 
555 int css_do_xsch(SubchDev *sch)
556 {
557     SCSW *s = &sch->curr_status.scsw;
558     PMCW *p = &sch->curr_status.pmcw;
559     int ret;
560 
561     if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {
562         ret = -ENODEV;
563         goto out;
564     }
565 
566     if (!(s->ctrl & SCSW_CTRL_MASK_FCTL) ||
567         ((s->ctrl & SCSW_CTRL_MASK_FCTL) != SCSW_FCTL_START_FUNC) ||
568         (!(s->ctrl &
569            (SCSW_ACTL_RESUME_PEND | SCSW_ACTL_START_PEND | SCSW_ACTL_SUSP))) ||
570         (s->ctrl & SCSW_ACTL_SUBCH_ACTIVE)) {
571         ret = -EINPROGRESS;
572         goto out;
573     }
574 
575     if (s->ctrl & SCSW_CTRL_MASK_STCTL) {
576         ret = -EBUSY;
577         goto out;
578     }
579 
580     /* Cancel the current operation. */
581     s->ctrl &= ~(SCSW_FCTL_START_FUNC |
582                  SCSW_ACTL_RESUME_PEND |
583                  SCSW_ACTL_START_PEND |
584                  SCSW_ACTL_SUSP);
585     sch->channel_prog = 0x0;
586     sch->last_cmd_valid = false;
587     sch->orb = NULL;
588     s->dstat = 0;
589     s->cstat = 0;
590     ret = 0;
591 
592 out:
593     return ret;
594 }
595 
596 int css_do_csch(SubchDev *sch)
597 {
598     SCSW *s = &sch->curr_status.scsw;
599     PMCW *p = &sch->curr_status.pmcw;
600     int ret;
601 
602     if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {
603         ret = -ENODEV;
604         goto out;
605     }
606 
607     /* Trigger the clear function. */
608     s->ctrl &= ~(SCSW_CTRL_MASK_FCTL | SCSW_CTRL_MASK_ACTL);
609     s->ctrl |= SCSW_FCTL_CLEAR_FUNC | SCSW_FCTL_CLEAR_FUNC;
610 
611     do_subchannel_work(sch);
612     ret = 0;
613 
614 out:
615     return ret;
616 }
617 
618 int css_do_hsch(SubchDev *sch)
619 {
620     SCSW *s = &sch->curr_status.scsw;
621     PMCW *p = &sch->curr_status.pmcw;
622     int ret;
623 
624     if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {
625         ret = -ENODEV;
626         goto out;
627     }
628 
629     if (((s->ctrl & SCSW_CTRL_MASK_STCTL) == SCSW_STCTL_STATUS_PEND) ||
630         (s->ctrl & (SCSW_STCTL_PRIMARY |
631                     SCSW_STCTL_SECONDARY |
632                     SCSW_STCTL_ALERT))) {
633         ret = -EINPROGRESS;
634         goto out;
635     }
636 
637     if (s->ctrl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) {
638         ret = -EBUSY;
639         goto out;
640     }
641 
642     /* Trigger the halt function. */
643     s->ctrl |= SCSW_FCTL_HALT_FUNC;
644     s->ctrl &= ~SCSW_FCTL_START_FUNC;
645     if (((s->ctrl & SCSW_CTRL_MASK_ACTL) ==
646          (SCSW_ACTL_SUBCH_ACTIVE | SCSW_ACTL_DEVICE_ACTIVE)) &&
647         ((s->ctrl & SCSW_CTRL_MASK_STCTL) == SCSW_STCTL_INTERMEDIATE)) {
648         s->ctrl &= ~SCSW_STCTL_STATUS_PEND;
649     }
650     s->ctrl |= SCSW_ACTL_HALT_PEND;
651 
652     do_subchannel_work(sch);
653     ret = 0;
654 
655 out:
656     return ret;
657 }
658 
659 static void css_update_chnmon(SubchDev *sch)
660 {
661     if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_MME)) {
662         /* Not active. */
663         return;
664     }
665     /* The counter is conveniently located at the beginning of the struct. */
666     if (sch->curr_status.pmcw.chars & PMCW_CHARS_MASK_MBFC) {
667         /* Format 1, per-subchannel area. */
668         uint32_t count;
669 
670         count = ldl_phys(sch->curr_status.mba);
671         count++;
672         stl_phys(sch->curr_status.mba, count);
673     } else {
674         /* Format 0, global area. */
675         uint32_t offset;
676         uint16_t count;
677 
678         offset = sch->curr_status.pmcw.mbi << 5;
679         count = lduw_phys(channel_subsys->chnmon_area + offset);
680         count++;
681         stw_phys(channel_subsys->chnmon_area + offset, count);
682     }
683 }
684 
685 int css_do_ssch(SubchDev *sch, ORB *orb)
686 {
687     SCSW *s = &sch->curr_status.scsw;
688     PMCW *p = &sch->curr_status.pmcw;
689     int ret;
690 
691     if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {
692         ret = -ENODEV;
693         goto out;
694     }
695 
696     if (s->ctrl & SCSW_STCTL_STATUS_PEND) {
697         ret = -EINPROGRESS;
698         goto out;
699     }
700 
701     if (s->ctrl & (SCSW_FCTL_START_FUNC |
702                    SCSW_FCTL_HALT_FUNC |
703                    SCSW_FCTL_CLEAR_FUNC)) {
704         ret = -EBUSY;
705         goto out;
706     }
707 
708     /* If monitoring is active, update counter. */
709     if (channel_subsys->chnmon_active) {
710         css_update_chnmon(sch);
711     }
712     sch->orb = orb;
713     sch->channel_prog = orb->cpa;
714     /* Trigger the start function. */
715     s->ctrl |= (SCSW_FCTL_START_FUNC | SCSW_ACTL_START_PEND);
716     s->flags &= ~SCSW_FLAGS_MASK_PNO;
717 
718     do_subchannel_work(sch);
719     ret = 0;
720 
721 out:
722     return ret;
723 }
724 
725 static void copy_irb_to_guest(IRB *dest, const IRB *src)
726 {
727     int i;
728 
729     copy_scsw_to_guest(&dest->scsw, &src->scsw);
730 
731     for (i = 0; i < ARRAY_SIZE(dest->esw); i++) {
732         dest->esw[i] = cpu_to_be32(src->esw[i]);
733     }
734     for (i = 0; i < ARRAY_SIZE(dest->ecw); i++) {
735         dest->ecw[i] = cpu_to_be32(src->ecw[i]);
736     }
737     for (i = 0; i < ARRAY_SIZE(dest->emw); i++) {
738         dest->emw[i] = cpu_to_be32(src->emw[i]);
739     }
740 }
741 
742 int css_do_tsch(SubchDev *sch, IRB *target_irb)
743 {
744     SCSW *s = &sch->curr_status.scsw;
745     PMCW *p = &sch->curr_status.pmcw;
746     uint16_t stctl;
747     uint16_t fctl;
748     uint16_t actl;
749     IRB irb;
750     int ret;
751 
752     if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {
753         ret = 3;
754         goto out;
755     }
756 
757     stctl = s->ctrl & SCSW_CTRL_MASK_STCTL;
758     fctl = s->ctrl & SCSW_CTRL_MASK_FCTL;
759     actl = s->ctrl & SCSW_CTRL_MASK_ACTL;
760 
761     /* Prepare the irb for the guest. */
762     memset(&irb, 0, sizeof(IRB));
763 
764     /* Copy scsw from current status. */
765     memcpy(&irb.scsw, s, sizeof(SCSW));
766     if (stctl & SCSW_STCTL_STATUS_PEND) {
767         if (s->cstat & (SCSW_CSTAT_DATA_CHECK |
768                         SCSW_CSTAT_CHN_CTRL_CHK |
769                         SCSW_CSTAT_INTF_CTRL_CHK)) {
770             irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF;
771             irb.esw[0] = 0x04804000;
772         } else {
773             irb.esw[0] = 0x00800000;
774         }
775         /* If a unit check is pending, copy sense data. */
776         if ((s->dstat & SCSW_DSTAT_UNIT_CHECK) &&
777             (p->chars & PMCW_CHARS_MASK_CSENSE)) {
778             irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF | SCSW_FLAGS_MASK_ECTL;
779             memcpy(irb.ecw, sch->sense_data, sizeof(sch->sense_data));
780             irb.esw[1] = 0x01000000 | (sizeof(sch->sense_data) << 8);
781         }
782     }
783     /* Store the irb to the guest. */
784     copy_irb_to_guest(target_irb, &irb);
785 
786     /* Clear conditions on subchannel, if applicable. */
787     if (stctl & SCSW_STCTL_STATUS_PEND) {
788         s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
789         if ((stctl != (SCSW_STCTL_INTERMEDIATE | SCSW_STCTL_STATUS_PEND)) ||
790             ((fctl & SCSW_FCTL_HALT_FUNC) &&
791              (actl & SCSW_ACTL_SUSP))) {
792             s->ctrl &= ~SCSW_CTRL_MASK_FCTL;
793         }
794         if (stctl != (SCSW_STCTL_INTERMEDIATE | SCSW_STCTL_STATUS_PEND)) {
795             s->flags &= ~SCSW_FLAGS_MASK_PNO;
796             s->ctrl &= ~(SCSW_ACTL_RESUME_PEND |
797                          SCSW_ACTL_START_PEND |
798                          SCSW_ACTL_HALT_PEND |
799                          SCSW_ACTL_CLEAR_PEND |
800                          SCSW_ACTL_SUSP);
801         } else {
802             if ((actl & SCSW_ACTL_SUSP) &&
803                 (fctl & SCSW_FCTL_START_FUNC)) {
804                 s->flags &= ~SCSW_FLAGS_MASK_PNO;
805                 if (fctl & SCSW_FCTL_HALT_FUNC) {
806                     s->ctrl &= ~(SCSW_ACTL_RESUME_PEND |
807                                  SCSW_ACTL_START_PEND |
808                                  SCSW_ACTL_HALT_PEND |
809                                  SCSW_ACTL_CLEAR_PEND |
810                                  SCSW_ACTL_SUSP);
811                 } else {
812                     s->ctrl &= ~SCSW_ACTL_RESUME_PEND;
813                 }
814             }
815         }
816         /* Clear pending sense data. */
817         if (p->chars & PMCW_CHARS_MASK_CSENSE) {
818             memset(sch->sense_data, 0 , sizeof(sch->sense_data));
819         }
820     }
821 
822     ret = ((stctl & SCSW_STCTL_STATUS_PEND) == 0);
823 
824 out:
825     return ret;
826 }
827 
828 static void copy_crw_to_guest(CRW *dest, const CRW *src)
829 {
830     dest->flags = cpu_to_be16(src->flags);
831     dest->rsid = cpu_to_be16(src->rsid);
832 }
833 
834 int css_do_stcrw(CRW *crw)
835 {
836     CrwContainer *crw_cont;
837     int ret;
838 
839     crw_cont = QTAILQ_FIRST(&channel_subsys->pending_crws);
840     if (crw_cont) {
841         QTAILQ_REMOVE(&channel_subsys->pending_crws, crw_cont, sibling);
842         copy_crw_to_guest(crw, &crw_cont->crw);
843         g_free(crw_cont);
844         ret = 0;
845     } else {
846         /* List was empty, turn crw machine checks on again. */
847         memset(crw, 0, sizeof(*crw));
848         channel_subsys->do_crw_mchk = true;
849         ret = 1;
850     }
851 
852     return ret;
853 }
854 
855 int css_do_tpi(IOIntCode *int_code, int lowcore)
856 {
857     /* No pending interrupts for !KVM. */
858     return 0;
859  }
860 
861 int css_collect_chp_desc(int m, uint8_t cssid, uint8_t f_chpid, uint8_t l_chpid,
862                          int rfmt, void *buf)
863 {
864     int i, desc_size;
865     uint32_t words[8];
866     uint32_t chpid_type_word;
867     CssImage *css;
868 
869     if (!m && !cssid) {
870         css = channel_subsys->css[channel_subsys->default_cssid];
871     } else {
872         css = channel_subsys->css[cssid];
873     }
874     if (!css) {
875         return 0;
876     }
877     desc_size = 0;
878     for (i = f_chpid; i <= l_chpid; i++) {
879         if (css->chpids[i].in_use) {
880             chpid_type_word = 0x80000000 | (css->chpids[i].type << 8) | i;
881             if (rfmt == 0) {
882                 words[0] = cpu_to_be32(chpid_type_word);
883                 words[1] = 0;
884                 memcpy(buf + desc_size, words, 8);
885                 desc_size += 8;
886             } else if (rfmt == 1) {
887                 words[0] = cpu_to_be32(chpid_type_word);
888                 words[1] = 0;
889                 words[2] = 0;
890                 words[3] = 0;
891                 words[4] = 0;
892                 words[5] = 0;
893                 words[6] = 0;
894                 words[7] = 0;
895                 memcpy(buf + desc_size, words, 32);
896                 desc_size += 32;
897             }
898         }
899     }
900     return desc_size;
901 }
902 
903 void css_do_schm(uint8_t mbk, int update, int dct, uint64_t mbo)
904 {
905     /* dct is currently ignored (not really meaningful for our devices) */
906     /* TODO: Don't ignore mbk. */
907     if (update && !channel_subsys->chnmon_active) {
908         /* Enable measuring. */
909         channel_subsys->chnmon_area = mbo;
910         channel_subsys->chnmon_active = true;
911     }
912     if (!update && channel_subsys->chnmon_active) {
913         /* Disable measuring. */
914         channel_subsys->chnmon_area = 0;
915         channel_subsys->chnmon_active = false;
916     }
917 }
918 
919 int css_do_rsch(SubchDev *sch)
920 {
921     SCSW *s = &sch->curr_status.scsw;
922     PMCW *p = &sch->curr_status.pmcw;
923     int ret;
924 
925     if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {
926         ret = -ENODEV;
927         goto out;
928     }
929 
930     if (s->ctrl & SCSW_STCTL_STATUS_PEND) {
931         ret = -EINPROGRESS;
932         goto out;
933     }
934 
935     if (((s->ctrl & SCSW_CTRL_MASK_FCTL) != SCSW_FCTL_START_FUNC) ||
936         (s->ctrl & SCSW_ACTL_RESUME_PEND) ||
937         (!(s->ctrl & SCSW_ACTL_SUSP))) {
938         ret = -EINVAL;
939         goto out;
940     }
941 
942     /* If monitoring is active, update counter. */
943     if (channel_subsys->chnmon_active) {
944         css_update_chnmon(sch);
945     }
946 
947     s->ctrl |= SCSW_ACTL_RESUME_PEND;
948     do_subchannel_work(sch);
949     ret = 0;
950 
951 out:
952     return ret;
953 }
954 
955 int css_do_rchp(uint8_t cssid, uint8_t chpid)
956 {
957     uint8_t real_cssid;
958 
959     if (cssid > channel_subsys->max_cssid) {
960         return -EINVAL;
961     }
962     if (channel_subsys->max_cssid == 0) {
963         real_cssid = channel_subsys->default_cssid;
964     } else {
965         real_cssid = cssid;
966     }
967     if (!channel_subsys->css[real_cssid]) {
968         return -EINVAL;
969     }
970 
971     if (!channel_subsys->css[real_cssid]->chpids[chpid].in_use) {
972         return -ENODEV;
973     }
974 
975     if (!channel_subsys->css[real_cssid]->chpids[chpid].is_virtual) {
976         fprintf(stderr,
977                 "rchp unsupported for non-virtual chpid %x.%02x!\n",
978                 real_cssid, chpid);
979         return -ENODEV;
980     }
981 
982     /* We don't really use a channel path, so we're done here. */
983     css_queue_crw(CRW_RSC_CHP, CRW_ERC_INIT,
984                   channel_subsys->max_cssid > 0 ? 1 : 0, chpid);
985     if (channel_subsys->max_cssid > 0) {
986         css_queue_crw(CRW_RSC_CHP, CRW_ERC_INIT, 0, real_cssid << 8);
987     }
988     return 0;
989 }
990 
991 bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid)
992 {
993     SubchSet *set;
994     uint8_t real_cssid;
995 
996     real_cssid = (!m && (cssid == 0)) ? channel_subsys->default_cssid : cssid;
997     if (real_cssid > MAX_CSSID || ssid > MAX_SSID ||
998         !channel_subsys->css[real_cssid] ||
999         !channel_subsys->css[real_cssid]->sch_set[ssid]) {
1000         return true;
1001     }
1002     set = channel_subsys->css[real_cssid]->sch_set[ssid];
1003     return schid > find_last_bit(set->schids_used,
1004                                  (MAX_SCHID + 1) / sizeof(unsigned long));
1005 }
1006 
1007 static int css_add_virtual_chpid(uint8_t cssid, uint8_t chpid, uint8_t type)
1008 {
1009     CssImage *css;
1010 
1011     trace_css_chpid_add(cssid, chpid, type);
1012     if (cssid > MAX_CSSID) {
1013         return -EINVAL;
1014     }
1015     css = channel_subsys->css[cssid];
1016     if (!css) {
1017         return -EINVAL;
1018     }
1019     if (css->chpids[chpid].in_use) {
1020         return -EEXIST;
1021     }
1022     css->chpids[chpid].in_use = 1;
1023     css->chpids[chpid].type = type;
1024     css->chpids[chpid].is_virtual = 1;
1025 
1026     css_generate_chp_crws(cssid, chpid);
1027 
1028     return 0;
1029 }
1030 
1031 void css_sch_build_virtual_schib(SubchDev *sch, uint8_t chpid, uint8_t type)
1032 {
1033     PMCW *p = &sch->curr_status.pmcw;
1034     SCSW *s = &sch->curr_status.scsw;
1035     int i;
1036     CssImage *css = channel_subsys->css[sch->cssid];
1037 
1038     assert(css != NULL);
1039     memset(p, 0, sizeof(PMCW));
1040     p->flags |= PMCW_FLAGS_MASK_DNV;
1041     p->devno = sch->devno;
1042     /* single path */
1043     p->pim = 0x80;
1044     p->pom = 0xff;
1045     p->pam = 0x80;
1046     p->chpid[0] = chpid;
1047     if (!css->chpids[chpid].in_use) {
1048         css_add_virtual_chpid(sch->cssid, chpid, type);
1049     }
1050 
1051     memset(s, 0, sizeof(SCSW));
1052     sch->curr_status.mba = 0;
1053     for (i = 0; i < ARRAY_SIZE(sch->curr_status.mda); i++) {
1054         sch->curr_status.mda[i] = 0;
1055     }
1056 }
1057 
1058 SubchDev *css_find_subch(uint8_t m, uint8_t cssid, uint8_t ssid, uint16_t schid)
1059 {
1060     uint8_t real_cssid;
1061 
1062     real_cssid = (!m && (cssid == 0)) ? channel_subsys->default_cssid : cssid;
1063 
1064     if (!channel_subsys->css[real_cssid]) {
1065         return NULL;
1066     }
1067 
1068     if (!channel_subsys->css[real_cssid]->sch_set[ssid]) {
1069         return NULL;
1070     }
1071 
1072     return channel_subsys->css[real_cssid]->sch_set[ssid]->sch[schid];
1073 }
1074 
1075 bool css_subch_visible(SubchDev *sch)
1076 {
1077     if (sch->ssid > channel_subsys->max_ssid) {
1078         return false;
1079     }
1080 
1081     if (sch->cssid != channel_subsys->default_cssid) {
1082         return (channel_subsys->max_cssid > 0);
1083     }
1084 
1085     return true;
1086 }
1087 
1088 bool css_present(uint8_t cssid)
1089 {
1090     return (channel_subsys->css[cssid] != NULL);
1091 }
1092 
1093 bool css_devno_used(uint8_t cssid, uint8_t ssid, uint16_t devno)
1094 {
1095     if (!channel_subsys->css[cssid]) {
1096         return false;
1097     }
1098     if (!channel_subsys->css[cssid]->sch_set[ssid]) {
1099         return false;
1100     }
1101 
1102     return !!test_bit(devno,
1103                       channel_subsys->css[cssid]->sch_set[ssid]->devnos_used);
1104 }
1105 
1106 void css_subch_assign(uint8_t cssid, uint8_t ssid, uint16_t schid,
1107                       uint16_t devno, SubchDev *sch)
1108 {
1109     CssImage *css;
1110     SubchSet *s_set;
1111 
1112     trace_css_assign_subch(sch ? "assign" : "deassign", cssid, ssid, schid,
1113                            devno);
1114     if (!channel_subsys->css[cssid]) {
1115         fprintf(stderr,
1116                 "Suspicious call to %s (%x.%x.%04x) for non-existing css!\n",
1117                 __func__, cssid, ssid, schid);
1118         return;
1119     }
1120     css = channel_subsys->css[cssid];
1121 
1122     if (!css->sch_set[ssid]) {
1123         css->sch_set[ssid] = g_malloc0(sizeof(SubchSet));
1124     }
1125     s_set = css->sch_set[ssid];
1126 
1127     s_set->sch[schid] = sch;
1128     if (sch) {
1129         set_bit(schid, s_set->schids_used);
1130         set_bit(devno, s_set->devnos_used);
1131     } else {
1132         clear_bit(schid, s_set->schids_used);
1133         clear_bit(devno, s_set->devnos_used);
1134     }
1135 }
1136 
1137 void css_queue_crw(uint8_t rsc, uint8_t erc, int chain, uint16_t rsid)
1138 {
1139     CrwContainer *crw_cont;
1140 
1141     trace_css_crw(rsc, erc, rsid, chain ? "(chained)" : "");
1142     /* TODO: Maybe use a static crw pool? */
1143     crw_cont = g_try_malloc0(sizeof(CrwContainer));
1144     if (!crw_cont) {
1145         channel_subsys->crws_lost = true;
1146         return;
1147     }
1148     crw_cont->crw.flags = (rsc << 8) | erc;
1149     if (chain) {
1150         crw_cont->crw.flags |= CRW_FLAGS_MASK_C;
1151     }
1152     crw_cont->crw.rsid = rsid;
1153     if (channel_subsys->crws_lost) {
1154         crw_cont->crw.flags |= CRW_FLAGS_MASK_R;
1155         channel_subsys->crws_lost = false;
1156     }
1157 
1158     QTAILQ_INSERT_TAIL(&channel_subsys->pending_crws, crw_cont, sibling);
1159 
1160     if (channel_subsys->do_crw_mchk) {
1161         S390CPU *cpu = s390_cpu_addr2state(0);
1162 
1163         channel_subsys->do_crw_mchk = false;
1164         /* Inject crw pending machine check. */
1165         s390_crw_mchk(cpu);
1166     }
1167 }
1168 
1169 void css_generate_sch_crws(uint8_t cssid, uint8_t ssid, uint16_t schid,
1170                            int hotplugged, int add)
1171 {
1172     uint8_t guest_cssid;
1173     bool chain_crw;
1174 
1175     if (add && !hotplugged) {
1176         return;
1177     }
1178     if (channel_subsys->max_cssid == 0) {
1179         /* Default cssid shows up as 0. */
1180         guest_cssid = (cssid == channel_subsys->default_cssid) ? 0 : cssid;
1181     } else {
1182         /* Show real cssid to the guest. */
1183         guest_cssid = cssid;
1184     }
1185     /*
1186      * Only notify for higher subchannel sets/channel subsystems if the
1187      * guest has enabled it.
1188      */
1189     if ((ssid > channel_subsys->max_ssid) ||
1190         (guest_cssid > channel_subsys->max_cssid) ||
1191         ((channel_subsys->max_cssid == 0) &&
1192          (cssid != channel_subsys->default_cssid))) {
1193         return;
1194     }
1195     chain_crw = (channel_subsys->max_ssid > 0) ||
1196             (channel_subsys->max_cssid > 0);
1197     css_queue_crw(CRW_RSC_SUBCH, CRW_ERC_IPI, chain_crw ? 1 : 0, schid);
1198     if (chain_crw) {
1199         css_queue_crw(CRW_RSC_SUBCH, CRW_ERC_IPI, 0,
1200                       (guest_cssid << 8) | (ssid << 4));
1201     }
1202 }
1203 
1204 void css_generate_chp_crws(uint8_t cssid, uint8_t chpid)
1205 {
1206     /* TODO */
1207 }
1208 
1209 int css_enable_mcsse(void)
1210 {
1211     trace_css_enable_facility("mcsse");
1212     channel_subsys->max_cssid = MAX_CSSID;
1213     return 0;
1214 }
1215 
1216 int css_enable_mss(void)
1217 {
1218     trace_css_enable_facility("mss");
1219     channel_subsys->max_ssid = MAX_SSID;
1220     return 0;
1221 }
1222 
1223 static void css_init(void)
1224 {
1225     channel_subsys = g_malloc0(sizeof(*channel_subsys));
1226     QTAILQ_INIT(&channel_subsys->pending_crws);
1227     channel_subsys->do_crw_mchk = true;
1228     channel_subsys->crws_lost = false;
1229     channel_subsys->chnmon_active = false;
1230 }
1231 machine_init(css_init);
1232 
1233 void css_reset_sch(SubchDev *sch)
1234 {
1235     PMCW *p = &sch->curr_status.pmcw;
1236 
1237     p->intparm = 0;
1238     p->flags &= ~(PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |
1239                   PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |
1240                   PMCW_FLAGS_MASK_MP | PMCW_FLAGS_MASK_TF);
1241     p->flags |= PMCW_FLAGS_MASK_DNV;
1242     p->devno = sch->devno;
1243     p->pim = 0x80;
1244     p->lpm = p->pim;
1245     p->pnom = 0;
1246     p->lpum = 0;
1247     p->mbi = 0;
1248     p->pom = 0xff;
1249     p->pam = 0x80;
1250     p->chars &= ~(PMCW_CHARS_MASK_MBFC | PMCW_CHARS_MASK_XMWME |
1251                   PMCW_CHARS_MASK_CSENSE);
1252 
1253     memset(&sch->curr_status.scsw, 0, sizeof(sch->curr_status.scsw));
1254     sch->curr_status.mba = 0;
1255 
1256     sch->channel_prog = 0x0;
1257     sch->last_cmd_valid = false;
1258     sch->orb = NULL;
1259 }
1260 
1261 void css_reset(void)
1262 {
1263     CrwContainer *crw_cont;
1264 
1265     /* Clean up monitoring. */
1266     channel_subsys->chnmon_active = false;
1267     channel_subsys->chnmon_area = 0;
1268 
1269     /* Clear pending CRWs. */
1270     while ((crw_cont = QTAILQ_FIRST(&channel_subsys->pending_crws))) {
1271         QTAILQ_REMOVE(&channel_subsys->pending_crws, crw_cont, sibling);
1272         g_free(crw_cont);
1273     }
1274     channel_subsys->do_crw_mchk = true;
1275     channel_subsys->crws_lost = false;
1276 
1277     /* Reset maximum ids. */
1278     channel_subsys->max_cssid = 0;
1279     channel_subsys->max_ssid = 0;
1280 }
1281