xref: /openbmc/qemu/hw/s390x/css.c (revision 354908ce)
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 "qemu/osdep.h"
13 #include "qapi/error.h"
14 #include "qapi/visitor.h"
15 #include "qemu/bitops.h"
16 #include "qemu/error-report.h"
17 #include "exec/address-spaces.h"
18 #include "cpu.h"
19 #include "hw/s390x/ioinst.h"
20 #include "hw/qdev-properties.h"
21 #include "hw/s390x/css.h"
22 #include "trace.h"
23 #include "hw/s390x/s390_flic.h"
24 #include "hw/s390x/s390-virtio-ccw.h"
25 #include "hw/s390x/s390-ccw.h"
26 
27 typedef struct CrwContainer {
28     CRW crw;
29     QTAILQ_ENTRY(CrwContainer) sibling;
30 } CrwContainer;
31 
32 static const VMStateDescription vmstate_crw = {
33     .name = "s390_crw",
34     .version_id = 1,
35     .minimum_version_id = 1,
36     .fields = (VMStateField[]) {
37         VMSTATE_UINT16(flags, CRW),
38         VMSTATE_UINT16(rsid, CRW),
39         VMSTATE_END_OF_LIST()
40     },
41 };
42 
43 static const VMStateDescription vmstate_crw_container = {
44     .name = "s390_crw_container",
45     .version_id = 1,
46     .minimum_version_id = 1,
47     .fields = (VMStateField[]) {
48         VMSTATE_STRUCT(crw, CrwContainer, 0, vmstate_crw, CRW),
49         VMSTATE_END_OF_LIST()
50     },
51 };
52 
53 typedef struct ChpInfo {
54     uint8_t in_use;
55     uint8_t type;
56     uint8_t is_virtual;
57 } ChpInfo;
58 
59 static const VMStateDescription vmstate_chp_info = {
60     .name = "s390_chp_info",
61     .version_id = 1,
62     .minimum_version_id = 1,
63     .fields = (VMStateField[]) {
64         VMSTATE_UINT8(in_use, ChpInfo),
65         VMSTATE_UINT8(type, ChpInfo),
66         VMSTATE_UINT8(is_virtual, ChpInfo),
67         VMSTATE_END_OF_LIST()
68     }
69 };
70 
71 typedef struct SubchSet {
72     SubchDev *sch[MAX_SCHID + 1];
73     unsigned long schids_used[BITS_TO_LONGS(MAX_SCHID + 1)];
74     unsigned long devnos_used[BITS_TO_LONGS(MAX_SCHID + 1)];
75 } SubchSet;
76 
77 static const VMStateDescription vmstate_scsw = {
78     .name = "s390_scsw",
79     .version_id = 1,
80     .minimum_version_id = 1,
81     .fields = (VMStateField[]) {
82         VMSTATE_UINT16(flags, SCSW),
83         VMSTATE_UINT16(ctrl, SCSW),
84         VMSTATE_UINT32(cpa, SCSW),
85         VMSTATE_UINT8(dstat, SCSW),
86         VMSTATE_UINT8(cstat, SCSW),
87         VMSTATE_UINT16(count, SCSW),
88         VMSTATE_END_OF_LIST()
89     }
90 };
91 
92 static const VMStateDescription vmstate_pmcw = {
93     .name = "s390_pmcw",
94     .version_id = 1,
95     .minimum_version_id = 1,
96     .fields = (VMStateField[]) {
97         VMSTATE_UINT32(intparm, PMCW),
98         VMSTATE_UINT16(flags, PMCW),
99         VMSTATE_UINT16(devno, PMCW),
100         VMSTATE_UINT8(lpm, PMCW),
101         VMSTATE_UINT8(pnom, PMCW),
102         VMSTATE_UINT8(lpum, PMCW),
103         VMSTATE_UINT8(pim, PMCW),
104         VMSTATE_UINT16(mbi, PMCW),
105         VMSTATE_UINT8(pom, PMCW),
106         VMSTATE_UINT8(pam, PMCW),
107         VMSTATE_UINT8_ARRAY(chpid, PMCW, 8),
108         VMSTATE_UINT32(chars, PMCW),
109         VMSTATE_END_OF_LIST()
110     }
111 };
112 
113 static const VMStateDescription vmstate_schib = {
114     .name = "s390_schib",
115     .version_id = 1,
116     .minimum_version_id = 1,
117     .fields = (VMStateField[]) {
118         VMSTATE_STRUCT(pmcw, SCHIB, 0, vmstate_pmcw, PMCW),
119         VMSTATE_STRUCT(scsw, SCHIB, 0, vmstate_scsw, SCSW),
120         VMSTATE_UINT64(mba, SCHIB),
121         VMSTATE_UINT8_ARRAY(mda, SCHIB, 4),
122         VMSTATE_END_OF_LIST()
123     }
124 };
125 
126 
127 static const VMStateDescription vmstate_ccw1 = {
128     .name = "s390_ccw1",
129     .version_id = 1,
130     .minimum_version_id = 1,
131     .fields = (VMStateField[]) {
132         VMSTATE_UINT8(cmd_code, CCW1),
133         VMSTATE_UINT8(flags, CCW1),
134         VMSTATE_UINT16(count, CCW1),
135         VMSTATE_UINT32(cda, CCW1),
136         VMSTATE_END_OF_LIST()
137     }
138 };
139 
140 static const VMStateDescription vmstate_ciw = {
141     .name = "s390_ciw",
142     .version_id = 1,
143     .minimum_version_id = 1,
144     .fields = (VMStateField[]) {
145         VMSTATE_UINT8(type, CIW),
146         VMSTATE_UINT8(command, CIW),
147         VMSTATE_UINT16(count, CIW),
148         VMSTATE_END_OF_LIST()
149     }
150 };
151 
152 static const VMStateDescription vmstate_sense_id = {
153     .name = "s390_sense_id",
154     .version_id = 1,
155     .minimum_version_id = 1,
156     .fields = (VMStateField[]) {
157         VMSTATE_UINT8(reserved, SenseId),
158         VMSTATE_UINT16(cu_type, SenseId),
159         VMSTATE_UINT8(cu_model, SenseId),
160         VMSTATE_UINT16(dev_type, SenseId),
161         VMSTATE_UINT8(dev_model, SenseId),
162         VMSTATE_UINT8(unused, SenseId),
163         VMSTATE_STRUCT_ARRAY(ciw, SenseId, MAX_CIWS, 0, vmstate_ciw, CIW),
164         VMSTATE_END_OF_LIST()
165     }
166 };
167 
168 static const VMStateDescription vmstate_orb = {
169     .name = "s390_orb",
170     .version_id = 1,
171     .minimum_version_id = 1,
172     .fields = (VMStateField[]) {
173         VMSTATE_UINT32(intparm, ORB),
174         VMSTATE_UINT16(ctrl0, ORB),
175         VMSTATE_UINT8(lpm, ORB),
176         VMSTATE_UINT8(ctrl1, ORB),
177         VMSTATE_UINT32(cpa, ORB),
178         VMSTATE_END_OF_LIST()
179     }
180 };
181 
182 static bool vmstate_schdev_orb_needed(void *opaque)
183 {
184     return css_migration_enabled();
185 }
186 
187 static const VMStateDescription vmstate_schdev_orb = {
188     .name = "s390_subch_dev/orb",
189     .version_id = 1,
190     .minimum_version_id = 1,
191     .needed = vmstate_schdev_orb_needed,
192     .fields = (VMStateField[]) {
193         VMSTATE_STRUCT(orb, SubchDev, 1, vmstate_orb, ORB),
194         VMSTATE_END_OF_LIST()
195     }
196 };
197 
198 static int subch_dev_post_load(void *opaque, int version_id);
199 static int subch_dev_pre_save(void *opaque);
200 
201 const char err_hint_devno[] = "Devno mismatch, tried to load wrong section!"
202     " Likely reason: some sequences of plug and unplug  can break"
203     " migration for machine versions prior to  2.7 (known design flaw).";
204 
205 const VMStateDescription vmstate_subch_dev = {
206     .name = "s390_subch_dev",
207     .version_id = 1,
208     .minimum_version_id = 1,
209     .post_load = subch_dev_post_load,
210     .pre_save = subch_dev_pre_save,
211     .fields = (VMStateField[]) {
212         VMSTATE_UINT8_EQUAL(cssid, SubchDev, "Bug!"),
213         VMSTATE_UINT8_EQUAL(ssid, SubchDev, "Bug!"),
214         VMSTATE_UINT16(migrated_schid, SubchDev),
215         VMSTATE_UINT16_EQUAL(devno, SubchDev, err_hint_devno),
216         VMSTATE_BOOL(thinint_active, SubchDev),
217         VMSTATE_STRUCT(curr_status, SubchDev, 0, vmstate_schib, SCHIB),
218         VMSTATE_UINT8_ARRAY(sense_data, SubchDev, 32),
219         VMSTATE_UINT64(channel_prog, SubchDev),
220         VMSTATE_STRUCT(last_cmd, SubchDev, 0, vmstate_ccw1, CCW1),
221         VMSTATE_BOOL(last_cmd_valid, SubchDev),
222         VMSTATE_STRUCT(id, SubchDev, 0, vmstate_sense_id, SenseId),
223         VMSTATE_BOOL(ccw_fmt_1, SubchDev),
224         VMSTATE_UINT8(ccw_no_data_cnt, SubchDev),
225         VMSTATE_END_OF_LIST()
226     },
227     .subsections = (const VMStateDescription * []) {
228         &vmstate_schdev_orb,
229         NULL
230     }
231 };
232 
233 typedef struct IndAddrPtrTmp {
234     IndAddr **parent;
235     uint64_t addr;
236     int32_t len;
237 } IndAddrPtrTmp;
238 
239 static int post_load_ind_addr(void *opaque, int version_id)
240 {
241     IndAddrPtrTmp *ptmp = opaque;
242     IndAddr **ind_addr = ptmp->parent;
243 
244     if (ptmp->len != 0) {
245         *ind_addr = get_indicator(ptmp->addr, ptmp->len);
246     } else {
247         *ind_addr = NULL;
248     }
249     return 0;
250 }
251 
252 static int pre_save_ind_addr(void *opaque)
253 {
254     IndAddrPtrTmp *ptmp = opaque;
255     IndAddr *ind_addr = *(ptmp->parent);
256 
257     if (ind_addr != NULL) {
258         ptmp->len = ind_addr->len;
259         ptmp->addr = ind_addr->addr;
260     } else {
261         ptmp->len = 0;
262         ptmp->addr = 0L;
263     }
264 
265     return 0;
266 }
267 
268 const VMStateDescription vmstate_ind_addr_tmp = {
269     .name = "s390_ind_addr_tmp",
270     .pre_save = pre_save_ind_addr,
271     .post_load = post_load_ind_addr,
272 
273     .fields = (VMStateField[]) {
274         VMSTATE_INT32(len, IndAddrPtrTmp),
275         VMSTATE_UINT64(addr, IndAddrPtrTmp),
276         VMSTATE_END_OF_LIST()
277     }
278 };
279 
280 const VMStateDescription vmstate_ind_addr = {
281     .name = "s390_ind_addr_tmp",
282     .fields = (VMStateField[]) {
283         VMSTATE_WITH_TMP(IndAddr*, IndAddrPtrTmp, vmstate_ind_addr_tmp),
284         VMSTATE_END_OF_LIST()
285     }
286 };
287 
288 typedef struct CssImage {
289     SubchSet *sch_set[MAX_SSID + 1];
290     ChpInfo chpids[MAX_CHPID + 1];
291 } CssImage;
292 
293 static const VMStateDescription vmstate_css_img = {
294     .name = "s390_css_img",
295     .version_id = 1,
296     .minimum_version_id = 1,
297     .fields = (VMStateField[]) {
298         /* Subchannel sets have no relevant state. */
299         VMSTATE_STRUCT_ARRAY(chpids, CssImage, MAX_CHPID + 1, 0,
300                              vmstate_chp_info, ChpInfo),
301         VMSTATE_END_OF_LIST()
302     }
303 
304 };
305 
306 typedef struct IoAdapter {
307     uint32_t id;
308     uint8_t type;
309     uint8_t isc;
310     uint8_t flags;
311 } IoAdapter;
312 
313 typedef struct ChannelSubSys {
314     QTAILQ_HEAD(, CrwContainer) pending_crws;
315     bool sei_pending;
316     bool do_crw_mchk;
317     bool crws_lost;
318     uint8_t max_cssid;
319     uint8_t max_ssid;
320     bool chnmon_active;
321     uint64_t chnmon_area;
322     CssImage *css[MAX_CSSID + 1];
323     uint8_t default_cssid;
324     /* don't migrate, see css_register_io_adapters */
325     IoAdapter *io_adapters[CSS_IO_ADAPTER_TYPE_NUMS][MAX_ISC + 1];
326     /* don't migrate, see get_indicator and IndAddrPtrTmp */
327     QTAILQ_HEAD(, IndAddr) indicator_addresses;
328 } ChannelSubSys;
329 
330 static const VMStateDescription vmstate_css = {
331     .name = "s390_css",
332     .version_id = 1,
333     .minimum_version_id = 1,
334     .fields = (VMStateField[]) {
335         VMSTATE_QTAILQ_V(pending_crws, ChannelSubSys, 1, vmstate_crw_container,
336                          CrwContainer, sibling),
337         VMSTATE_BOOL(sei_pending, ChannelSubSys),
338         VMSTATE_BOOL(do_crw_mchk, ChannelSubSys),
339         VMSTATE_BOOL(crws_lost, ChannelSubSys),
340         /* These were kind of migrated by virtio */
341         VMSTATE_UINT8(max_cssid, ChannelSubSys),
342         VMSTATE_UINT8(max_ssid, ChannelSubSys),
343         VMSTATE_BOOL(chnmon_active, ChannelSubSys),
344         VMSTATE_UINT64(chnmon_area, ChannelSubSys),
345         VMSTATE_ARRAY_OF_POINTER_TO_STRUCT(css, ChannelSubSys, MAX_CSSID + 1,
346                 0, vmstate_css_img, CssImage),
347         VMSTATE_UINT8(default_cssid, ChannelSubSys),
348         VMSTATE_END_OF_LIST()
349     }
350 };
351 
352 static ChannelSubSys channel_subsys = {
353     .pending_crws = QTAILQ_HEAD_INITIALIZER(channel_subsys.pending_crws),
354     .do_crw_mchk = true,
355     .sei_pending = false,
356     .do_crw_mchk = true,
357     .crws_lost = false,
358     .chnmon_active = false,
359     .indicator_addresses =
360         QTAILQ_HEAD_INITIALIZER(channel_subsys.indicator_addresses),
361 };
362 
363 static int subch_dev_pre_save(void *opaque)
364 {
365     SubchDev *s = opaque;
366 
367     /* Prepare remote_schid for save */
368     s->migrated_schid = s->schid;
369 
370     return 0;
371 }
372 
373 static int subch_dev_post_load(void *opaque, int version_id)
374 {
375 
376     SubchDev *s = opaque;
377 
378     /* Re-assign the subchannel to remote_schid if necessary */
379     if (s->migrated_schid != s->schid) {
380         if (css_find_subch(true, s->cssid, s->ssid, s->schid) == s) {
381             /*
382              * Cleanup the slot before moving to s->migrated_schid provided
383              * it still belongs to us, i.e. it was not changed by previous
384              * invocation of this function.
385              */
386             css_subch_assign(s->cssid, s->ssid, s->schid, s->devno, NULL);
387         }
388         /* It's OK to re-assign without a prior de-assign. */
389         s->schid = s->migrated_schid;
390         css_subch_assign(s->cssid, s->ssid, s->schid, s->devno, s);
391     }
392 
393     if (css_migration_enabled()) {
394         /* No compat voodoo to do ;) */
395         return 0;
396     }
397     /*
398      * Hack alert. If we don't migrate the channel subsystem status
399      * we still need to find out if the guest enabled mss/mcss-e.
400      * If the subchannel is enabled, it certainly was able to access it,
401      * so adjust the max_ssid/max_cssid values for relevant ssid/cssid
402      * values. This is not watertight, but better than nothing.
403      */
404     if (s->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ENA) {
405         if (s->ssid) {
406             channel_subsys.max_ssid = MAX_SSID;
407         }
408         if (s->cssid != channel_subsys.default_cssid) {
409             channel_subsys.max_cssid = MAX_CSSID;
410         }
411     }
412     return 0;
413 }
414 
415 void css_register_vmstate(void)
416 {
417     vmstate_register(NULL, 0, &vmstate_css, &channel_subsys);
418 }
419 
420 IndAddr *get_indicator(hwaddr ind_addr, int len)
421 {
422     IndAddr *indicator;
423 
424     QTAILQ_FOREACH(indicator, &channel_subsys.indicator_addresses, sibling) {
425         if (indicator->addr == ind_addr) {
426             indicator->refcnt++;
427             return indicator;
428         }
429     }
430     indicator = g_new0(IndAddr, 1);
431     indicator->addr = ind_addr;
432     indicator->len = len;
433     indicator->refcnt = 1;
434     QTAILQ_INSERT_TAIL(&channel_subsys.indicator_addresses,
435                        indicator, sibling);
436     return indicator;
437 }
438 
439 static int s390_io_adapter_map(AdapterInfo *adapter, uint64_t map_addr,
440                                bool do_map)
441 {
442     S390FLICState *fs = s390_get_flic();
443     S390FLICStateClass *fsc = s390_get_flic_class(fs);
444 
445     return fsc->io_adapter_map(fs, adapter->adapter_id, map_addr, do_map);
446 }
447 
448 void release_indicator(AdapterInfo *adapter, IndAddr *indicator)
449 {
450     assert(indicator->refcnt > 0);
451     indicator->refcnt--;
452     if (indicator->refcnt > 0) {
453         return;
454     }
455     QTAILQ_REMOVE(&channel_subsys.indicator_addresses, indicator, sibling);
456     if (indicator->map) {
457         s390_io_adapter_map(adapter, indicator->map, false);
458     }
459     g_free(indicator);
460 }
461 
462 int map_indicator(AdapterInfo *adapter, IndAddr *indicator)
463 {
464     int ret;
465 
466     if (indicator->map) {
467         return 0; /* already mapped is not an error */
468     }
469     indicator->map = indicator->addr;
470     ret = s390_io_adapter_map(adapter, indicator->map, true);
471     if ((ret != 0) && (ret != -ENOSYS)) {
472         goto out_err;
473     }
474     return 0;
475 
476 out_err:
477     indicator->map = 0;
478     return ret;
479 }
480 
481 int css_create_css_image(uint8_t cssid, bool default_image)
482 {
483     trace_css_new_image(cssid, default_image ? "(default)" : "");
484     /* 255 is reserved */
485     if (cssid == 255) {
486         return -EINVAL;
487     }
488     if (channel_subsys.css[cssid]) {
489         return -EBUSY;
490     }
491     channel_subsys.css[cssid] = g_new0(CssImage, 1);
492     if (default_image) {
493         channel_subsys.default_cssid = cssid;
494     }
495     return 0;
496 }
497 
498 uint32_t css_get_adapter_id(CssIoAdapterType type, uint8_t isc)
499 {
500     if (type >= CSS_IO_ADAPTER_TYPE_NUMS || isc > MAX_ISC ||
501         !channel_subsys.io_adapters[type][isc]) {
502         return -1;
503     }
504 
505     return channel_subsys.io_adapters[type][isc]->id;
506 }
507 
508 /**
509  * css_register_io_adapters: Register I/O adapters per ISC during init
510  *
511  * @swap: an indication if byte swap is needed.
512  * @maskable: an indication if the adapter is subject to the mask operation.
513  * @flags: further characteristics of the adapter.
514  *         e.g. suppressible, an indication if the adapter is subject to AIS.
515  * @errp: location to store error information.
516  */
517 void css_register_io_adapters(CssIoAdapterType type, bool swap, bool maskable,
518                               uint8_t flags, Error **errp)
519 {
520     uint32_t id;
521     int ret, isc;
522     IoAdapter *adapter;
523     S390FLICState *fs = s390_get_flic();
524     S390FLICStateClass *fsc = s390_get_flic_class(fs);
525 
526     /*
527      * Disallow multiple registrations for the same device type.
528      * Report an error if registering for an already registered type.
529      */
530     if (channel_subsys.io_adapters[type][0]) {
531         error_setg(errp, "Adapters for type %d already registered", type);
532     }
533 
534     for (isc = 0; isc <= MAX_ISC; isc++) {
535         id = (type << 3) | isc;
536         ret = fsc->register_io_adapter(fs, id, isc, swap, maskable, flags);
537         if (ret == 0) {
538             adapter = g_new0(IoAdapter, 1);
539             adapter->id = id;
540             adapter->isc = isc;
541             adapter->type = type;
542             adapter->flags = flags;
543             channel_subsys.io_adapters[type][isc] = adapter;
544         } else {
545             error_setg_errno(errp, -ret, "Unexpected error %d when "
546                              "registering adapter %d", ret, id);
547             break;
548         }
549     }
550 
551     /*
552      * No need to free registered adapters in kvm: kvm will clean up
553      * when the machine goes away.
554      */
555     if (ret) {
556         for (isc--; isc >= 0; isc--) {
557             g_free(channel_subsys.io_adapters[type][isc]);
558             channel_subsys.io_adapters[type][isc] = NULL;
559         }
560     }
561 
562 }
563 
564 static void css_clear_io_interrupt(uint16_t subchannel_id,
565                                    uint16_t subchannel_nr)
566 {
567     Error *err = NULL;
568     static bool no_clear_irq;
569     S390FLICState *fs = s390_get_flic();
570     S390FLICStateClass *fsc = s390_get_flic_class(fs);
571     int r;
572 
573     if (unlikely(no_clear_irq)) {
574         return;
575     }
576     r = fsc->clear_io_irq(fs, subchannel_id, subchannel_nr);
577     switch (r) {
578     case 0:
579         break;
580     case -ENOSYS:
581         no_clear_irq = true;
582         /*
583         * Ignore unavailability, as the user can't do anything
584         * about it anyway.
585         */
586         break;
587     default:
588         error_setg_errno(&err, -r, "unexpected error condition");
589         error_propagate(&error_abort, err);
590     }
591 }
592 
593 static inline uint16_t css_do_build_subchannel_id(uint8_t cssid, uint8_t ssid)
594 {
595     if (channel_subsys.max_cssid > 0) {
596         return (cssid << 8) | (1 << 3) | (ssid << 1) | 1;
597     }
598     return (ssid << 1) | 1;
599 }
600 
601 uint16_t css_build_subchannel_id(SubchDev *sch)
602 {
603     return css_do_build_subchannel_id(sch->cssid, sch->ssid);
604 }
605 
606 void css_inject_io_interrupt(SubchDev *sch)
607 {
608     uint8_t isc = (sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ISC) >> 11;
609 
610     trace_css_io_interrupt(sch->cssid, sch->ssid, sch->schid,
611                            sch->curr_status.pmcw.intparm, isc, "");
612     s390_io_interrupt(css_build_subchannel_id(sch),
613                       sch->schid,
614                       sch->curr_status.pmcw.intparm,
615                       isc << 27);
616 }
617 
618 void css_conditional_io_interrupt(SubchDev *sch)
619 {
620     /*
621      * If the subchannel is not enabled, it is not made status pending
622      * (see PoP p. 16-17, "Status Control").
623      */
624     if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ENA)) {
625         return;
626     }
627 
628     /*
629      * If the subchannel is not currently status pending, make it pending
630      * with alert status.
631      */
632     if (!(sch->curr_status.scsw.ctrl & SCSW_STCTL_STATUS_PEND)) {
633         uint8_t isc = (sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ISC) >> 11;
634 
635         trace_css_io_interrupt(sch->cssid, sch->ssid, sch->schid,
636                                sch->curr_status.pmcw.intparm, isc,
637                                "(unsolicited)");
638         sch->curr_status.scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
639         sch->curr_status.scsw.ctrl |=
640             SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
641         /* Inject an I/O interrupt. */
642         s390_io_interrupt(css_build_subchannel_id(sch),
643                           sch->schid,
644                           sch->curr_status.pmcw.intparm,
645                           isc << 27);
646     }
647 }
648 
649 int css_do_sic(CPUS390XState *env, uint8_t isc, uint16_t mode)
650 {
651     S390FLICState *fs = s390_get_flic();
652     S390FLICStateClass *fsc = s390_get_flic_class(fs);
653     int r;
654 
655     if (env->psw.mask & PSW_MASK_PSTATE) {
656         r = -PGM_PRIVILEGED;
657         goto out;
658     }
659 
660     trace_css_do_sic(mode, isc);
661     switch (mode) {
662     case SIC_IRQ_MODE_ALL:
663     case SIC_IRQ_MODE_SINGLE:
664         break;
665     default:
666         r = -PGM_OPERAND;
667         goto out;
668     }
669 
670     r = fsc->modify_ais_mode(fs, isc, mode) ? -PGM_OPERATION : 0;
671 out:
672     return r;
673 }
674 
675 void css_adapter_interrupt(CssIoAdapterType type, uint8_t isc)
676 {
677     S390FLICState *fs = s390_get_flic();
678     S390FLICStateClass *fsc = s390_get_flic_class(fs);
679     uint32_t io_int_word = (isc << 27) | IO_INT_WORD_AI;
680     IoAdapter *adapter = channel_subsys.io_adapters[type][isc];
681 
682     if (!adapter) {
683         return;
684     }
685 
686     trace_css_adapter_interrupt(isc);
687     if (fs->ais_supported) {
688         if (fsc->inject_airq(fs, type, isc, adapter->flags)) {
689             error_report("Failed to inject airq with AIS supported");
690             exit(1);
691         }
692     } else {
693         s390_io_interrupt(0, 0, 0, io_int_word);
694     }
695 }
696 
697 static void sch_handle_clear_func(SubchDev *sch)
698 {
699     SCHIB *schib = &sch->curr_status;
700     int path;
701 
702     /* Path management: In our simple css, we always choose the only path. */
703     path = 0x80;
704 
705     /* Reset values prior to 'issuing the clear signal'. */
706     schib->pmcw.lpum = 0;
707     schib->pmcw.pom = 0xff;
708     schib->scsw.flags &= ~SCSW_FLAGS_MASK_PNO;
709 
710     /* We always 'attempt to issue the clear signal', and we always succeed. */
711     sch->channel_prog = 0x0;
712     sch->last_cmd_valid = false;
713     schib->scsw.ctrl &= ~SCSW_ACTL_CLEAR_PEND;
714     schib->scsw.ctrl |= SCSW_STCTL_STATUS_PEND;
715 
716     schib->scsw.dstat = 0;
717     schib->scsw.cstat = 0;
718     schib->pmcw.lpum = path;
719 
720 }
721 
722 static void sch_handle_halt_func(SubchDev *sch)
723 {
724     SCHIB *schib = &sch->curr_status;
725     hwaddr curr_ccw = sch->channel_prog;
726     int path;
727 
728     /* Path management: In our simple css, we always choose the only path. */
729     path = 0x80;
730 
731     /* We always 'attempt to issue the halt signal', and we always succeed. */
732     sch->channel_prog = 0x0;
733     sch->last_cmd_valid = false;
734     schib->scsw.ctrl &= ~SCSW_ACTL_HALT_PEND;
735     schib->scsw.ctrl |= SCSW_STCTL_STATUS_PEND;
736 
737     if ((schib->scsw.ctrl & (SCSW_ACTL_SUBCH_ACTIVE |
738                              SCSW_ACTL_DEVICE_ACTIVE)) ||
739         !((schib->scsw.ctrl & SCSW_ACTL_START_PEND) ||
740           (schib->scsw.ctrl & SCSW_ACTL_SUSP))) {
741         schib->scsw.dstat = SCSW_DSTAT_DEVICE_END;
742     }
743     if ((schib->scsw.ctrl & (SCSW_ACTL_SUBCH_ACTIVE |
744                              SCSW_ACTL_DEVICE_ACTIVE)) ||
745         (schib->scsw.ctrl & SCSW_ACTL_SUSP)) {
746         schib->scsw.cpa = curr_ccw + 8;
747     }
748     schib->scsw.cstat = 0;
749     schib->pmcw.lpum = path;
750 
751 }
752 
753 /*
754  * As the SenseId struct cannot be packed (would cause unaligned accesses), we
755  * have to copy the individual fields to an unstructured area using the correct
756  * layout (see SA22-7204-01 "Common I/O-Device Commands").
757  */
758 static void copy_sense_id_to_guest(uint8_t *dest, SenseId *src)
759 {
760     int i;
761 
762     dest[0] = src->reserved;
763     stw_be_p(dest + 1, src->cu_type);
764     dest[3] = src->cu_model;
765     stw_be_p(dest + 4, src->dev_type);
766     dest[6] = src->dev_model;
767     dest[7] = src->unused;
768     for (i = 0; i < ARRAY_SIZE(src->ciw); i++) {
769         dest[8 + i * 4] = src->ciw[i].type;
770         dest[9 + i * 4] = src->ciw[i].command;
771         stw_be_p(dest + 10 + i * 4, src->ciw[i].count);
772     }
773 }
774 
775 static CCW1 copy_ccw_from_guest(hwaddr addr, bool fmt1)
776 {
777     CCW0 tmp0;
778     CCW1 tmp1;
779     CCW1 ret;
780 
781     if (fmt1) {
782         cpu_physical_memory_read(addr, &tmp1, sizeof(tmp1));
783         ret.cmd_code = tmp1.cmd_code;
784         ret.flags = tmp1.flags;
785         ret.count = be16_to_cpu(tmp1.count);
786         ret.cda = be32_to_cpu(tmp1.cda);
787     } else {
788         cpu_physical_memory_read(addr, &tmp0, sizeof(tmp0));
789         if ((tmp0.cmd_code & 0x0f) == CCW_CMD_TIC) {
790             ret.cmd_code = CCW_CMD_TIC;
791             ret.flags = 0;
792             ret.count = 0;
793         } else {
794             ret.cmd_code = tmp0.cmd_code;
795             ret.flags = tmp0.flags;
796             ret.count = be16_to_cpu(tmp0.count);
797         }
798         ret.cda = be16_to_cpu(tmp0.cda1) | (tmp0.cda0 << 16);
799     }
800     return ret;
801 }
802 /**
803  * If out of bounds marks the stream broken. If broken returns -EINVAL,
804  * otherwise the requested length (may be zero)
805  */
806 static inline int cds_check_len(CcwDataStream *cds, int len)
807 {
808     if (cds->at_byte + len > cds->count) {
809         cds->flags |= CDS_F_STREAM_BROKEN;
810     }
811     return cds->flags & CDS_F_STREAM_BROKEN ? -EINVAL : len;
812 }
813 
814 static inline bool cds_ccw_addrs_ok(hwaddr addr, int len, bool ccw_fmt1)
815 {
816     return (addr + len) < (ccw_fmt1 ? (1UL << 31) : (1UL << 24));
817 }
818 
819 static int ccw_dstream_rw_noflags(CcwDataStream *cds, void *buff, int len,
820                                   CcwDataStreamOp op)
821 {
822     int ret;
823 
824     ret = cds_check_len(cds, len);
825     if (ret <= 0) {
826         return ret;
827     }
828     if (!cds_ccw_addrs_ok(cds->cda, len, cds->flags & CDS_F_FMT)) {
829         return -EINVAL; /* channel program check */
830     }
831     if (op == CDS_OP_A) {
832         goto incr;
833     }
834     if (!cds->do_skip) {
835         ret = address_space_rw(&address_space_memory, cds->cda,
836                                MEMTXATTRS_UNSPECIFIED, buff, len, op);
837     } else {
838         ret = MEMTX_OK;
839     }
840     if (ret != MEMTX_OK) {
841         cds->flags |= CDS_F_STREAM_BROKEN;
842         return -EINVAL;
843     }
844 incr:
845     cds->at_byte += len;
846     cds->cda += len;
847     return 0;
848 }
849 
850 /* returns values between 1 and bsz, where bsz is a power of 2 */
851 static inline uint16_t ida_continuous_left(hwaddr cda, uint64_t bsz)
852 {
853     return bsz - (cda & (bsz - 1));
854 }
855 
856 static inline uint64_t ccw_ida_block_size(uint8_t flags)
857 {
858     if ((flags & CDS_F_C64) && !(flags & CDS_F_I2K)) {
859         return 1ULL << 12;
860     }
861     return 1ULL << 11;
862 }
863 
864 static inline int ida_read_next_idaw(CcwDataStream *cds)
865 {
866     union {uint64_t fmt2; uint32_t fmt1; } idaw;
867     int ret;
868     hwaddr idaw_addr;
869     bool idaw_fmt2 = cds->flags & CDS_F_C64;
870     bool ccw_fmt1 = cds->flags & CDS_F_FMT;
871 
872     if (idaw_fmt2) {
873         idaw_addr = cds->cda_orig + sizeof(idaw.fmt2) * cds->at_idaw;
874         if (idaw_addr & 0x07 || !cds_ccw_addrs_ok(idaw_addr, 0, ccw_fmt1)) {
875             return -EINVAL; /* channel program check */
876         }
877         ret = address_space_read(&address_space_memory, idaw_addr,
878                                  MEMTXATTRS_UNSPECIFIED, &idaw.fmt2,
879                                  sizeof(idaw.fmt2));
880         cds->cda = be64_to_cpu(idaw.fmt2);
881     } else {
882         idaw_addr = cds->cda_orig + sizeof(idaw.fmt1) * cds->at_idaw;
883         if (idaw_addr & 0x03 || !cds_ccw_addrs_ok(idaw_addr, 0, ccw_fmt1)) {
884             return -EINVAL; /* channel program check */
885         }
886         ret = address_space_read(&address_space_memory, idaw_addr,
887                                  MEMTXATTRS_UNSPECIFIED, &idaw.fmt1,
888                                  sizeof(idaw.fmt1));
889         cds->cda = be64_to_cpu(idaw.fmt1);
890         if (cds->cda & 0x80000000) {
891             return -EINVAL; /* channel program check */
892         }
893     }
894     ++(cds->at_idaw);
895     if (ret != MEMTX_OK) {
896         /* assume inaccessible address */
897         return -EINVAL; /* channel program check */
898     }
899     return 0;
900 }
901 
902 static int ccw_dstream_rw_ida(CcwDataStream *cds, void *buff, int len,
903                               CcwDataStreamOp op)
904 {
905     uint64_t bsz = ccw_ida_block_size(cds->flags);
906     int ret = 0;
907     uint16_t cont_left, iter_len;
908 
909     ret = cds_check_len(cds, len);
910     if (ret <= 0) {
911         return ret;
912     }
913     if (!cds->at_idaw) {
914         /* read first idaw */
915         ret = ida_read_next_idaw(cds);
916         if (ret) {
917             goto err;
918         }
919         cont_left = ida_continuous_left(cds->cda, bsz);
920     } else {
921         cont_left = ida_continuous_left(cds->cda, bsz);
922         if (cont_left == bsz) {
923             ret = ida_read_next_idaw(cds);
924             if (ret) {
925                 goto err;
926             }
927             if (cds->cda & (bsz - 1)) {
928                 ret = -EINVAL; /* channel program check */
929                 goto err;
930             }
931         }
932     }
933     do {
934         iter_len = MIN(len, cont_left);
935         if (op != CDS_OP_A) {
936             if (!cds->do_skip) {
937                 ret = address_space_rw(&address_space_memory, cds->cda,
938                                        MEMTXATTRS_UNSPECIFIED, buff, iter_len,
939                                        op);
940             } else {
941                 ret = MEMTX_OK;
942             }
943             if (ret != MEMTX_OK) {
944                 /* assume inaccessible address */
945                 ret = -EINVAL; /* channel program check */
946                 goto err;
947             }
948         }
949         cds->at_byte += iter_len;
950         cds->cda += iter_len;
951         len -= iter_len;
952         if (!len) {
953             break;
954         }
955         ret = ida_read_next_idaw(cds);
956         if (ret) {
957             goto err;
958         }
959         cont_left = bsz;
960     } while (true);
961     return ret;
962 err:
963     cds->flags |= CDS_F_STREAM_BROKEN;
964     return ret;
965 }
966 
967 void ccw_dstream_init(CcwDataStream *cds, CCW1 const *ccw, ORB const *orb)
968 {
969     /*
970      * We don't support MIDA (an optional facility) yet and we
971      * catch this earlier. Just for expressing the precondition.
972      */
973     g_assert(!(orb->ctrl1 & ORB_CTRL1_MASK_MIDAW));
974     cds->flags = (orb->ctrl0 & ORB_CTRL0_MASK_I2K ? CDS_F_I2K : 0) |
975                  (orb->ctrl0 & ORB_CTRL0_MASK_C64 ? CDS_F_C64 : 0) |
976                  (orb->ctrl0 & ORB_CTRL0_MASK_FMT ? CDS_F_FMT : 0) |
977                  (ccw->flags & CCW_FLAG_IDA ? CDS_F_IDA : 0);
978 
979     cds->count = ccw->count;
980     cds->cda_orig = ccw->cda;
981     /* skip is only effective for read, read backwards, or sense commands */
982     cds->do_skip = (ccw->flags & CCW_FLAG_SKIP) &&
983         ((ccw->cmd_code & 0x0f) == CCW_CMD_BASIC_SENSE ||
984          (ccw->cmd_code & 0x03) == 0x02 /* read */ ||
985          (ccw->cmd_code & 0x0f) == 0x0c /* read backwards */);
986     ccw_dstream_rewind(cds);
987     if (!(cds->flags & CDS_F_IDA)) {
988         cds->op_handler = ccw_dstream_rw_noflags;
989     } else {
990         cds->op_handler = ccw_dstream_rw_ida;
991     }
992 }
993 
994 static int css_interpret_ccw(SubchDev *sch, hwaddr ccw_addr,
995                              bool suspend_allowed)
996 {
997     int ret;
998     bool check_len;
999     int len;
1000     CCW1 ccw;
1001 
1002     if (!ccw_addr) {
1003         return -EINVAL; /* channel-program check */
1004     }
1005     /* Check doubleword aligned and 31 or 24 (fmt 0) bit addressable. */
1006     if (ccw_addr & (sch->ccw_fmt_1 ? 0x80000007 : 0xff000007)) {
1007         return -EINVAL;
1008     }
1009 
1010     /* Translate everything to format-1 ccws - the information is the same. */
1011     ccw = copy_ccw_from_guest(ccw_addr, sch->ccw_fmt_1);
1012 
1013     /* Check for invalid command codes. */
1014     if ((ccw.cmd_code & 0x0f) == 0) {
1015         return -EINVAL;
1016     }
1017     if (((ccw.cmd_code & 0x0f) == CCW_CMD_TIC) &&
1018         ((ccw.cmd_code & 0xf0) != 0)) {
1019         return -EINVAL;
1020     }
1021     if (!sch->ccw_fmt_1 && (ccw.count == 0) &&
1022         (ccw.cmd_code != CCW_CMD_TIC)) {
1023         return -EINVAL;
1024     }
1025 
1026     /* We don't support MIDA. */
1027     if (ccw.flags & CCW_FLAG_MIDA) {
1028         return -EINVAL;
1029     }
1030 
1031     if (ccw.flags & CCW_FLAG_SUSPEND) {
1032         return suspend_allowed ? -EINPROGRESS : -EINVAL;
1033     }
1034 
1035     check_len = !((ccw.flags & CCW_FLAG_SLI) && !(ccw.flags & CCW_FLAG_DC));
1036 
1037     if (!ccw.cda) {
1038         if (sch->ccw_no_data_cnt == 255) {
1039             return -EINVAL;
1040         }
1041         sch->ccw_no_data_cnt++;
1042     }
1043 
1044     /* Look at the command. */
1045     ccw_dstream_init(&sch->cds, &ccw, &(sch->orb));
1046     switch (ccw.cmd_code) {
1047     case CCW_CMD_NOOP:
1048         /* Nothing to do. */
1049         ret = 0;
1050         break;
1051     case CCW_CMD_BASIC_SENSE:
1052         if (check_len) {
1053             if (ccw.count != sizeof(sch->sense_data)) {
1054                 ret = -EINVAL;
1055                 break;
1056             }
1057         }
1058         len = MIN(ccw.count, sizeof(sch->sense_data));
1059         ccw_dstream_write_buf(&sch->cds, sch->sense_data, len);
1060         sch->curr_status.scsw.count = ccw_dstream_residual_count(&sch->cds);
1061         memset(sch->sense_data, 0, sizeof(sch->sense_data));
1062         ret = 0;
1063         break;
1064     case CCW_CMD_SENSE_ID:
1065     {
1066         /* According to SA22-7204-01, Sense-ID can store up to 256 bytes */
1067         uint8_t sense_id[256];
1068 
1069         copy_sense_id_to_guest(sense_id, &sch->id);
1070         /* Sense ID information is device specific. */
1071         if (check_len) {
1072             if (ccw.count != sizeof(sense_id)) {
1073                 ret = -EINVAL;
1074                 break;
1075             }
1076         }
1077         len = MIN(ccw.count, sizeof(sense_id));
1078         /*
1079          * Only indicate 0xff in the first sense byte if we actually
1080          * have enough place to store at least bytes 0-3.
1081          */
1082         if (len >= 4) {
1083             sense_id[0] = 0xff;
1084         } else {
1085             sense_id[0] = 0;
1086         }
1087         ccw_dstream_write_buf(&sch->cds, sense_id, len);
1088         sch->curr_status.scsw.count = ccw_dstream_residual_count(&sch->cds);
1089         ret = 0;
1090         break;
1091     }
1092     case CCW_CMD_TIC:
1093         if (sch->last_cmd_valid && (sch->last_cmd.cmd_code == CCW_CMD_TIC)) {
1094             ret = -EINVAL;
1095             break;
1096         }
1097         if (ccw.flags || ccw.count) {
1098             /* We have already sanitized these if converted from fmt 0. */
1099             ret = -EINVAL;
1100             break;
1101         }
1102         sch->channel_prog = ccw.cda;
1103         ret = -EAGAIN;
1104         break;
1105     default:
1106         if (sch->ccw_cb) {
1107             /* Handle device specific commands. */
1108             ret = sch->ccw_cb(sch, ccw);
1109         } else {
1110             ret = -ENOSYS;
1111         }
1112         break;
1113     }
1114     sch->last_cmd = ccw;
1115     sch->last_cmd_valid = true;
1116     if (ret == 0) {
1117         if (ccw.flags & CCW_FLAG_CC) {
1118             sch->channel_prog += 8;
1119             ret = -EAGAIN;
1120         }
1121     }
1122 
1123     return ret;
1124 }
1125 
1126 static void sch_handle_start_func_virtual(SubchDev *sch)
1127 {
1128     SCHIB *schib = &sch->curr_status;
1129     int path;
1130     int ret;
1131     bool suspend_allowed;
1132 
1133     /* Path management: In our simple css, we always choose the only path. */
1134     path = 0x80;
1135 
1136     if (!(schib->scsw.ctrl & SCSW_ACTL_SUSP)) {
1137         /* Start Function triggered via ssch, i.e. we have an ORB */
1138         ORB *orb = &sch->orb;
1139         schib->scsw.cstat = 0;
1140         schib->scsw.dstat = 0;
1141         /* Look at the orb and try to execute the channel program. */
1142         schib->pmcw.intparm = orb->intparm;
1143         if (!(orb->lpm & path)) {
1144             /* Generate a deferred cc 3 condition. */
1145             schib->scsw.flags |= SCSW_FLAGS_MASK_CC;
1146             schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
1147             schib->scsw.ctrl |= (SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND);
1148             return;
1149         }
1150         sch->ccw_fmt_1 = !!(orb->ctrl0 & ORB_CTRL0_MASK_FMT);
1151         schib->scsw.flags |= (sch->ccw_fmt_1) ? SCSW_FLAGS_MASK_FMT : 0;
1152         sch->ccw_no_data_cnt = 0;
1153         suspend_allowed = !!(orb->ctrl0 & ORB_CTRL0_MASK_SPND);
1154     } else {
1155         /* Start Function resumed via rsch */
1156         schib->scsw.ctrl &= ~(SCSW_ACTL_SUSP | SCSW_ACTL_RESUME_PEND);
1157         /* The channel program had been suspended before. */
1158         suspend_allowed = true;
1159     }
1160     sch->last_cmd_valid = false;
1161     do {
1162         ret = css_interpret_ccw(sch, sch->channel_prog, suspend_allowed);
1163         switch (ret) {
1164         case -EAGAIN:
1165             /* ccw chain, continue processing */
1166             break;
1167         case 0:
1168             /* success */
1169             schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
1170             schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
1171             schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
1172                     SCSW_STCTL_STATUS_PEND;
1173             schib->scsw.dstat = SCSW_DSTAT_CHANNEL_END | SCSW_DSTAT_DEVICE_END;
1174             schib->scsw.cpa = sch->channel_prog + 8;
1175             break;
1176         case -EIO:
1177             /* I/O errors, status depends on specific devices */
1178             break;
1179         case -ENOSYS:
1180             /* unsupported command, generate unit check (command reject) */
1181             schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
1182             schib->scsw.dstat = SCSW_DSTAT_UNIT_CHECK;
1183             /* Set sense bit 0 in ecw0. */
1184             sch->sense_data[0] = 0x80;
1185             schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
1186             schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
1187                     SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
1188             schib->scsw.cpa = sch->channel_prog + 8;
1189             break;
1190         case -EINPROGRESS:
1191             /* channel program has been suspended */
1192             schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
1193             schib->scsw.ctrl |= SCSW_ACTL_SUSP;
1194             break;
1195         default:
1196             /* error, generate channel program check */
1197             schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
1198             schib->scsw.cstat = SCSW_CSTAT_PROG_CHECK;
1199             schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
1200             schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
1201                     SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
1202             schib->scsw.cpa = sch->channel_prog + 8;
1203             break;
1204         }
1205     } while (ret == -EAGAIN);
1206 
1207 }
1208 
1209 static void sch_handle_halt_func_passthrough(SubchDev *sch)
1210 {
1211     int ret;
1212 
1213     ret = s390_ccw_halt(sch);
1214     if (ret == -ENOSYS) {
1215         sch_handle_halt_func(sch);
1216     }
1217 }
1218 
1219 static void sch_handle_clear_func_passthrough(SubchDev *sch)
1220 {
1221     int ret;
1222 
1223     ret = s390_ccw_clear(sch);
1224     if (ret == -ENOSYS) {
1225         sch_handle_clear_func(sch);
1226     }
1227 }
1228 
1229 static IOInstEnding sch_handle_start_func_passthrough(SubchDev *sch)
1230 {
1231     SCHIB *schib = &sch->curr_status;
1232     ORB *orb = &sch->orb;
1233     if (!(schib->scsw.ctrl & SCSW_ACTL_SUSP)) {
1234         assert(orb != NULL);
1235         schib->pmcw.intparm = orb->intparm;
1236     }
1237     return s390_ccw_cmd_request(sch);
1238 }
1239 
1240 /*
1241  * On real machines, this would run asynchronously to the main vcpus.
1242  * We might want to make some parts of the ssch handling (interpreting
1243  * read/writes) asynchronous later on if we start supporting more than
1244  * our current very simple devices.
1245  */
1246 IOInstEnding do_subchannel_work_virtual(SubchDev *sch)
1247 {
1248     SCHIB *schib = &sch->curr_status;
1249 
1250     if (schib->scsw.ctrl & SCSW_FCTL_CLEAR_FUNC) {
1251         sch_handle_clear_func(sch);
1252     } else if (schib->scsw.ctrl & SCSW_FCTL_HALT_FUNC) {
1253         sch_handle_halt_func(sch);
1254     } else if (schib->scsw.ctrl & SCSW_FCTL_START_FUNC) {
1255         /* Triggered by both ssch and rsch. */
1256         sch_handle_start_func_virtual(sch);
1257     }
1258     css_inject_io_interrupt(sch);
1259     /* inst must succeed if this func is called */
1260     return IOINST_CC_EXPECTED;
1261 }
1262 
1263 IOInstEnding do_subchannel_work_passthrough(SubchDev *sch)
1264 {
1265     SCHIB *schib = &sch->curr_status;
1266 
1267     if (schib->scsw.ctrl & SCSW_FCTL_CLEAR_FUNC) {
1268         sch_handle_clear_func_passthrough(sch);
1269     } else if (schib->scsw.ctrl & SCSW_FCTL_HALT_FUNC) {
1270         sch_handle_halt_func_passthrough(sch);
1271     } else if (schib->scsw.ctrl & SCSW_FCTL_START_FUNC) {
1272         return sch_handle_start_func_passthrough(sch);
1273     }
1274     return IOINST_CC_EXPECTED;
1275 }
1276 
1277 static IOInstEnding do_subchannel_work(SubchDev *sch)
1278 {
1279     if (!sch->do_subchannel_work) {
1280         return IOINST_CC_STATUS_PRESENT;
1281     }
1282     g_assert(sch->curr_status.scsw.ctrl & SCSW_CTRL_MASK_FCTL);
1283     return sch->do_subchannel_work(sch);
1284 }
1285 
1286 static void copy_pmcw_to_guest(PMCW *dest, const PMCW *src)
1287 {
1288     int i;
1289 
1290     dest->intparm = cpu_to_be32(src->intparm);
1291     dest->flags = cpu_to_be16(src->flags);
1292     dest->devno = cpu_to_be16(src->devno);
1293     dest->lpm = src->lpm;
1294     dest->pnom = src->pnom;
1295     dest->lpum = src->lpum;
1296     dest->pim = src->pim;
1297     dest->mbi = cpu_to_be16(src->mbi);
1298     dest->pom = src->pom;
1299     dest->pam = src->pam;
1300     for (i = 0; i < ARRAY_SIZE(dest->chpid); i++) {
1301         dest->chpid[i] = src->chpid[i];
1302     }
1303     dest->chars = cpu_to_be32(src->chars);
1304 }
1305 
1306 void copy_scsw_to_guest(SCSW *dest, const SCSW *src)
1307 {
1308     dest->flags = cpu_to_be16(src->flags);
1309     dest->ctrl = cpu_to_be16(src->ctrl);
1310     dest->cpa = cpu_to_be32(src->cpa);
1311     dest->dstat = src->dstat;
1312     dest->cstat = src->cstat;
1313     dest->count = cpu_to_be16(src->count);
1314 }
1315 
1316 static void copy_schib_to_guest(SCHIB *dest, const SCHIB *src)
1317 {
1318     int i;
1319     /*
1320      * We copy the PMCW and SCSW in and out of local variables to
1321      * avoid taking the address of members of a packed struct.
1322      */
1323     PMCW src_pmcw, dest_pmcw;
1324     SCSW src_scsw, dest_scsw;
1325 
1326     src_pmcw = src->pmcw;
1327     copy_pmcw_to_guest(&dest_pmcw, &src_pmcw);
1328     dest->pmcw = dest_pmcw;
1329     src_scsw = src->scsw;
1330     copy_scsw_to_guest(&dest_scsw, &src_scsw);
1331     dest->scsw = dest_scsw;
1332     dest->mba = cpu_to_be64(src->mba);
1333     for (i = 0; i < ARRAY_SIZE(dest->mda); i++) {
1334         dest->mda[i] = src->mda[i];
1335     }
1336 }
1337 
1338 IOInstEnding css_do_stsch(SubchDev *sch, SCHIB *schib)
1339 {
1340     int ret;
1341 
1342     /*
1343      * For some subchannels, we may want to update parts of
1344      * the schib (e.g., update path masks from the host device
1345      * for passthrough subchannels).
1346      */
1347     ret = s390_ccw_store(sch);
1348 
1349     /* Use current status. */
1350     copy_schib_to_guest(schib, &sch->curr_status);
1351     return ret;
1352 }
1353 
1354 static void copy_pmcw_from_guest(PMCW *dest, const PMCW *src)
1355 {
1356     int i;
1357 
1358     dest->intparm = be32_to_cpu(src->intparm);
1359     dest->flags = be16_to_cpu(src->flags);
1360     dest->devno = be16_to_cpu(src->devno);
1361     dest->lpm = src->lpm;
1362     dest->pnom = src->pnom;
1363     dest->lpum = src->lpum;
1364     dest->pim = src->pim;
1365     dest->mbi = be16_to_cpu(src->mbi);
1366     dest->pom = src->pom;
1367     dest->pam = src->pam;
1368     for (i = 0; i < ARRAY_SIZE(dest->chpid); i++) {
1369         dest->chpid[i] = src->chpid[i];
1370     }
1371     dest->chars = be32_to_cpu(src->chars);
1372 }
1373 
1374 static void copy_scsw_from_guest(SCSW *dest, const SCSW *src)
1375 {
1376     dest->flags = be16_to_cpu(src->flags);
1377     dest->ctrl = be16_to_cpu(src->ctrl);
1378     dest->cpa = be32_to_cpu(src->cpa);
1379     dest->dstat = src->dstat;
1380     dest->cstat = src->cstat;
1381     dest->count = be16_to_cpu(src->count);
1382 }
1383 
1384 static void copy_schib_from_guest(SCHIB *dest, const SCHIB *src)
1385 {
1386     int i;
1387     /*
1388      * We copy the PMCW and SCSW in and out of local variables to
1389      * avoid taking the address of members of a packed struct.
1390      */
1391     PMCW src_pmcw, dest_pmcw;
1392     SCSW src_scsw, dest_scsw;
1393 
1394     src_pmcw = src->pmcw;
1395     copy_pmcw_from_guest(&dest_pmcw, &src_pmcw);
1396     dest->pmcw = dest_pmcw;
1397     src_scsw = src->scsw;
1398     copy_scsw_from_guest(&dest_scsw, &src_scsw);
1399     dest->scsw = dest_scsw;
1400     dest->mba = be64_to_cpu(src->mba);
1401     for (i = 0; i < ARRAY_SIZE(dest->mda); i++) {
1402         dest->mda[i] = src->mda[i];
1403     }
1404 }
1405 
1406 IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
1407 {
1408     SCHIB *schib = &sch->curr_status;
1409     uint16_t oldflags;
1410     SCHIB schib_copy;
1411 
1412     if (!(schib->pmcw.flags & PMCW_FLAGS_MASK_DNV)) {
1413         return IOINST_CC_EXPECTED;
1414     }
1415 
1416     if (schib->scsw.ctrl & SCSW_STCTL_STATUS_PEND) {
1417         return IOINST_CC_STATUS_PRESENT;
1418     }
1419 
1420     if (schib->scsw.ctrl &
1421         (SCSW_FCTL_START_FUNC|SCSW_FCTL_HALT_FUNC|SCSW_FCTL_CLEAR_FUNC)) {
1422         return IOINST_CC_BUSY;
1423     }
1424 
1425     copy_schib_from_guest(&schib_copy, orig_schib);
1426     /* Only update the program-modifiable fields. */
1427     schib->pmcw.intparm = schib_copy.pmcw.intparm;
1428     oldflags = schib->pmcw.flags;
1429     schib->pmcw.flags &= ~(PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |
1430                   PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |
1431                   PMCW_FLAGS_MASK_MP);
1432     schib->pmcw.flags |= schib_copy.pmcw.flags &
1433             (PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |
1434              PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |
1435              PMCW_FLAGS_MASK_MP);
1436     schib->pmcw.lpm = schib_copy.pmcw.lpm;
1437     schib->pmcw.mbi = schib_copy.pmcw.mbi;
1438     schib->pmcw.pom = schib_copy.pmcw.pom;
1439     schib->pmcw.chars &= ~(PMCW_CHARS_MASK_MBFC | PMCW_CHARS_MASK_CSENSE);
1440     schib->pmcw.chars |= schib_copy.pmcw.chars &
1441             (PMCW_CHARS_MASK_MBFC | PMCW_CHARS_MASK_CSENSE);
1442     schib->mba = schib_copy.mba;
1443 
1444     /* Has the channel been disabled? */
1445     if (sch->disable_cb && (oldflags & PMCW_FLAGS_MASK_ENA) != 0
1446         && (schib->pmcw.flags & PMCW_FLAGS_MASK_ENA) == 0) {
1447         sch->disable_cb(sch);
1448     }
1449     return IOINST_CC_EXPECTED;
1450 }
1451 
1452 IOInstEnding css_do_xsch(SubchDev *sch)
1453 {
1454     SCHIB *schib = &sch->curr_status;
1455 
1456     if (~(schib->pmcw.flags) & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA)) {
1457         return IOINST_CC_NOT_OPERATIONAL;
1458     }
1459 
1460     if (schib->scsw.ctrl & SCSW_CTRL_MASK_STCTL) {
1461         return IOINST_CC_STATUS_PRESENT;
1462     }
1463 
1464     if (!(schib->scsw.ctrl & SCSW_CTRL_MASK_FCTL) ||
1465         ((schib->scsw.ctrl & SCSW_CTRL_MASK_FCTL) != SCSW_FCTL_START_FUNC) ||
1466         (!(schib->scsw.ctrl &
1467            (SCSW_ACTL_RESUME_PEND | SCSW_ACTL_START_PEND | SCSW_ACTL_SUSP))) ||
1468         (schib->scsw.ctrl & SCSW_ACTL_SUBCH_ACTIVE)) {
1469         return IOINST_CC_BUSY;
1470     }
1471 
1472     /* Cancel the current operation. */
1473     schib->scsw.ctrl &= ~(SCSW_FCTL_START_FUNC |
1474                  SCSW_ACTL_RESUME_PEND |
1475                  SCSW_ACTL_START_PEND |
1476                  SCSW_ACTL_SUSP);
1477     sch->channel_prog = 0x0;
1478     sch->last_cmd_valid = false;
1479     schib->scsw.dstat = 0;
1480     schib->scsw.cstat = 0;
1481     return IOINST_CC_EXPECTED;
1482 }
1483 
1484 IOInstEnding css_do_csch(SubchDev *sch)
1485 {
1486     SCHIB *schib = &sch->curr_status;
1487 
1488     if (~(schib->pmcw.flags) & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA)) {
1489         return IOINST_CC_NOT_OPERATIONAL;
1490     }
1491 
1492     /* Trigger the clear function. */
1493     schib->scsw.ctrl &= ~(SCSW_CTRL_MASK_FCTL | SCSW_CTRL_MASK_ACTL);
1494     schib->scsw.ctrl |= SCSW_FCTL_CLEAR_FUNC | SCSW_ACTL_CLEAR_PEND;
1495 
1496     return do_subchannel_work(sch);
1497 }
1498 
1499 IOInstEnding css_do_hsch(SubchDev *sch)
1500 {
1501     SCHIB *schib = &sch->curr_status;
1502 
1503     if (~(schib->pmcw.flags) & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA)) {
1504         return IOINST_CC_NOT_OPERATIONAL;
1505     }
1506 
1507     if (((schib->scsw.ctrl & SCSW_CTRL_MASK_STCTL) == SCSW_STCTL_STATUS_PEND) ||
1508         (schib->scsw.ctrl & (SCSW_STCTL_PRIMARY |
1509                     SCSW_STCTL_SECONDARY |
1510                     SCSW_STCTL_ALERT))) {
1511         return IOINST_CC_STATUS_PRESENT;
1512     }
1513 
1514     if (schib->scsw.ctrl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) {
1515         return IOINST_CC_BUSY;
1516     }
1517 
1518     /* Trigger the halt function. */
1519     schib->scsw.ctrl |= SCSW_FCTL_HALT_FUNC;
1520     schib->scsw.ctrl &= ~SCSW_FCTL_START_FUNC;
1521     if (((schib->scsw.ctrl & SCSW_CTRL_MASK_ACTL) ==
1522          (SCSW_ACTL_SUBCH_ACTIVE | SCSW_ACTL_DEVICE_ACTIVE)) &&
1523         ((schib->scsw.ctrl & SCSW_CTRL_MASK_STCTL) ==
1524          SCSW_STCTL_INTERMEDIATE)) {
1525         schib->scsw.ctrl &= ~SCSW_STCTL_STATUS_PEND;
1526     }
1527     schib->scsw.ctrl |= SCSW_ACTL_HALT_PEND;
1528 
1529     return do_subchannel_work(sch);
1530 }
1531 
1532 static void css_update_chnmon(SubchDev *sch)
1533 {
1534     if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_MME)) {
1535         /* Not active. */
1536         return;
1537     }
1538     /* The counter is conveniently located at the beginning of the struct. */
1539     if (sch->curr_status.pmcw.chars & PMCW_CHARS_MASK_MBFC) {
1540         /* Format 1, per-subchannel area. */
1541         uint32_t count;
1542 
1543         count = address_space_ldl(&address_space_memory,
1544                                   sch->curr_status.mba,
1545                                   MEMTXATTRS_UNSPECIFIED,
1546                                   NULL);
1547         count++;
1548         address_space_stl(&address_space_memory, sch->curr_status.mba, count,
1549                           MEMTXATTRS_UNSPECIFIED, NULL);
1550     } else {
1551         /* Format 0, global area. */
1552         uint32_t offset;
1553         uint16_t count;
1554 
1555         offset = sch->curr_status.pmcw.mbi << 5;
1556         count = address_space_lduw(&address_space_memory,
1557                                    channel_subsys.chnmon_area + offset,
1558                                    MEMTXATTRS_UNSPECIFIED,
1559                                    NULL);
1560         count++;
1561         address_space_stw(&address_space_memory,
1562                           channel_subsys.chnmon_area + offset, count,
1563                           MEMTXATTRS_UNSPECIFIED, NULL);
1564     }
1565 }
1566 
1567 IOInstEnding css_do_ssch(SubchDev *sch, ORB *orb)
1568 {
1569     SCHIB *schib = &sch->curr_status;
1570 
1571     if (~(schib->pmcw.flags) & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA)) {
1572         return IOINST_CC_NOT_OPERATIONAL;
1573     }
1574 
1575     if (schib->scsw.ctrl & SCSW_STCTL_STATUS_PEND) {
1576         return IOINST_CC_STATUS_PRESENT;
1577     }
1578 
1579     if (schib->scsw.ctrl & (SCSW_FCTL_START_FUNC |
1580                    SCSW_FCTL_HALT_FUNC |
1581                    SCSW_FCTL_CLEAR_FUNC)) {
1582         return IOINST_CC_BUSY;
1583     }
1584 
1585     /* If monitoring is active, update counter. */
1586     if (channel_subsys.chnmon_active) {
1587         css_update_chnmon(sch);
1588     }
1589     sch->orb = *orb;
1590     sch->channel_prog = orb->cpa;
1591     /* Trigger the start function. */
1592     schib->scsw.ctrl |= (SCSW_FCTL_START_FUNC | SCSW_ACTL_START_PEND);
1593     schib->scsw.flags &= ~SCSW_FLAGS_MASK_PNO;
1594 
1595     return do_subchannel_work(sch);
1596 }
1597 
1598 static void copy_irb_to_guest(IRB *dest, const IRB *src, const PMCW *pmcw,
1599                               int *irb_len)
1600 {
1601     int i;
1602     uint16_t stctl = src->scsw.ctrl & SCSW_CTRL_MASK_STCTL;
1603     uint16_t actl = src->scsw.ctrl & SCSW_CTRL_MASK_ACTL;
1604 
1605     copy_scsw_to_guest(&dest->scsw, &src->scsw);
1606 
1607     for (i = 0; i < ARRAY_SIZE(dest->esw); i++) {
1608         dest->esw[i] = cpu_to_be32(src->esw[i]);
1609     }
1610     for (i = 0; i < ARRAY_SIZE(dest->ecw); i++) {
1611         dest->ecw[i] = cpu_to_be32(src->ecw[i]);
1612     }
1613     *irb_len = sizeof(*dest) - sizeof(dest->emw);
1614 
1615     /* extended measurements enabled? */
1616     if ((src->scsw.flags & SCSW_FLAGS_MASK_ESWF) ||
1617         !(pmcw->flags & PMCW_FLAGS_MASK_TF) ||
1618         !(pmcw->chars & PMCW_CHARS_MASK_XMWME)) {
1619         return;
1620     }
1621     /* extended measurements pending? */
1622     if (!(stctl & SCSW_STCTL_STATUS_PEND)) {
1623         return;
1624     }
1625     if ((stctl & SCSW_STCTL_PRIMARY) ||
1626         (stctl == SCSW_STCTL_SECONDARY) ||
1627         ((stctl & SCSW_STCTL_INTERMEDIATE) && (actl & SCSW_ACTL_SUSP))) {
1628         for (i = 0; i < ARRAY_SIZE(dest->emw); i++) {
1629             dest->emw[i] = cpu_to_be32(src->emw[i]);
1630         }
1631     }
1632     *irb_len = sizeof(*dest);
1633 }
1634 
1635 int css_do_tsch_get_irb(SubchDev *sch, IRB *target_irb, int *irb_len)
1636 {
1637     SCHIB *schib = &sch->curr_status;
1638     PMCW p;
1639     uint16_t stctl;
1640     IRB irb;
1641 
1642     if (~(schib->pmcw.flags) & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA)) {
1643         return 3;
1644     }
1645 
1646     stctl = schib->scsw.ctrl & SCSW_CTRL_MASK_STCTL;
1647 
1648     /* Prepare the irb for the guest. */
1649     memset(&irb, 0, sizeof(IRB));
1650 
1651     /* Copy scsw from current status. */
1652     irb.scsw = schib->scsw;
1653     if (stctl & SCSW_STCTL_STATUS_PEND) {
1654         if (schib->scsw.cstat & (SCSW_CSTAT_DATA_CHECK |
1655                         SCSW_CSTAT_CHN_CTRL_CHK |
1656                         SCSW_CSTAT_INTF_CTRL_CHK)) {
1657             irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF;
1658             irb.esw[0] = 0x04804000;
1659         } else {
1660             irb.esw[0] = 0x00800000;
1661         }
1662         /* If a unit check is pending, copy sense data. */
1663         if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) &&
1664             (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) {
1665             int i;
1666 
1667             irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF | SCSW_FLAGS_MASK_ECTL;
1668             /* Attention: sense_data is already BE! */
1669             memcpy(irb.ecw, sch->sense_data, sizeof(sch->sense_data));
1670             for (i = 0; i < ARRAY_SIZE(irb.ecw); i++) {
1671                 irb.ecw[i] = be32_to_cpu(irb.ecw[i]);
1672             }
1673             irb.esw[1] = 0x01000000 | (sizeof(sch->sense_data) << 8);
1674         }
1675     }
1676     /* Store the irb to the guest. */
1677     p = schib->pmcw;
1678     copy_irb_to_guest(target_irb, &irb, &p, irb_len);
1679 
1680     return ((stctl & SCSW_STCTL_STATUS_PEND) == 0);
1681 }
1682 
1683 void css_do_tsch_update_subch(SubchDev *sch)
1684 {
1685     SCHIB *schib = &sch->curr_status;
1686     uint16_t stctl;
1687     uint16_t fctl;
1688     uint16_t actl;
1689 
1690     stctl = schib->scsw.ctrl & SCSW_CTRL_MASK_STCTL;
1691     fctl = schib->scsw.ctrl & SCSW_CTRL_MASK_FCTL;
1692     actl = schib->scsw.ctrl & SCSW_CTRL_MASK_ACTL;
1693 
1694     /* Clear conditions on subchannel, if applicable. */
1695     if (stctl & SCSW_STCTL_STATUS_PEND) {
1696         schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
1697         if ((stctl != (SCSW_STCTL_INTERMEDIATE | SCSW_STCTL_STATUS_PEND)) ||
1698             ((fctl & SCSW_FCTL_HALT_FUNC) &&
1699              (actl & SCSW_ACTL_SUSP))) {
1700             schib->scsw.ctrl &= ~SCSW_CTRL_MASK_FCTL;
1701         }
1702         if (stctl != (SCSW_STCTL_INTERMEDIATE | SCSW_STCTL_STATUS_PEND)) {
1703             schib->scsw.flags &= ~SCSW_FLAGS_MASK_PNO;
1704             schib->scsw.ctrl &= ~(SCSW_ACTL_RESUME_PEND |
1705                          SCSW_ACTL_START_PEND |
1706                          SCSW_ACTL_HALT_PEND |
1707                          SCSW_ACTL_CLEAR_PEND |
1708                          SCSW_ACTL_SUSP);
1709         } else {
1710             if ((actl & SCSW_ACTL_SUSP) &&
1711                 (fctl & SCSW_FCTL_START_FUNC)) {
1712                 schib->scsw.flags &= ~SCSW_FLAGS_MASK_PNO;
1713                 if (fctl & SCSW_FCTL_HALT_FUNC) {
1714                     schib->scsw.ctrl &= ~(SCSW_ACTL_RESUME_PEND |
1715                                  SCSW_ACTL_START_PEND |
1716                                  SCSW_ACTL_HALT_PEND |
1717                                  SCSW_ACTL_CLEAR_PEND |
1718                                  SCSW_ACTL_SUSP);
1719                 } else {
1720                     schib->scsw.ctrl &= ~SCSW_ACTL_RESUME_PEND;
1721                 }
1722             }
1723         }
1724         /* Clear pending sense data. */
1725         if (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE) {
1726             memset(sch->sense_data, 0 , sizeof(sch->sense_data));
1727         }
1728     }
1729 }
1730 
1731 static void copy_crw_to_guest(CRW *dest, const CRW *src)
1732 {
1733     dest->flags = cpu_to_be16(src->flags);
1734     dest->rsid = cpu_to_be16(src->rsid);
1735 }
1736 
1737 int css_do_stcrw(CRW *crw)
1738 {
1739     CrwContainer *crw_cont;
1740     int ret;
1741 
1742     crw_cont = QTAILQ_FIRST(&channel_subsys.pending_crws);
1743     if (crw_cont) {
1744         QTAILQ_REMOVE(&channel_subsys.pending_crws, crw_cont, sibling);
1745         copy_crw_to_guest(crw, &crw_cont->crw);
1746         g_free(crw_cont);
1747         ret = 0;
1748     } else {
1749         /* List was empty, turn crw machine checks on again. */
1750         memset(crw, 0, sizeof(*crw));
1751         channel_subsys.do_crw_mchk = true;
1752         ret = 1;
1753     }
1754 
1755     return ret;
1756 }
1757 
1758 static void copy_crw_from_guest(CRW *dest, const CRW *src)
1759 {
1760     dest->flags = be16_to_cpu(src->flags);
1761     dest->rsid = be16_to_cpu(src->rsid);
1762 }
1763 
1764 void css_undo_stcrw(CRW *crw)
1765 {
1766     CrwContainer *crw_cont;
1767 
1768     crw_cont = g_try_new0(CrwContainer, 1);
1769     if (!crw_cont) {
1770         channel_subsys.crws_lost = true;
1771         return;
1772     }
1773     copy_crw_from_guest(&crw_cont->crw, crw);
1774 
1775     QTAILQ_INSERT_HEAD(&channel_subsys.pending_crws, crw_cont, sibling);
1776 }
1777 
1778 int css_collect_chp_desc(int m, uint8_t cssid, uint8_t f_chpid, uint8_t l_chpid,
1779                          int rfmt, void *buf)
1780 {
1781     int i, desc_size;
1782     uint32_t words[8];
1783     uint32_t chpid_type_word;
1784     CssImage *css;
1785 
1786     if (!m && !cssid) {
1787         css = channel_subsys.css[channel_subsys.default_cssid];
1788     } else {
1789         css = channel_subsys.css[cssid];
1790     }
1791     if (!css) {
1792         return 0;
1793     }
1794     desc_size = 0;
1795     for (i = f_chpid; i <= l_chpid; i++) {
1796         if (css->chpids[i].in_use) {
1797             chpid_type_word = 0x80000000 | (css->chpids[i].type << 8) | i;
1798             if (rfmt == 0) {
1799                 words[0] = cpu_to_be32(chpid_type_word);
1800                 words[1] = 0;
1801                 memcpy(buf + desc_size, words, 8);
1802                 desc_size += 8;
1803             } else if (rfmt == 1) {
1804                 words[0] = cpu_to_be32(chpid_type_word);
1805                 words[1] = 0;
1806                 words[2] = 0;
1807                 words[3] = 0;
1808                 words[4] = 0;
1809                 words[5] = 0;
1810                 words[6] = 0;
1811                 words[7] = 0;
1812                 memcpy(buf + desc_size, words, 32);
1813                 desc_size += 32;
1814             }
1815         }
1816     }
1817     return desc_size;
1818 }
1819 
1820 void css_do_schm(uint8_t mbk, int update, int dct, uint64_t mbo)
1821 {
1822     /* dct is currently ignored (not really meaningful for our devices) */
1823     /* TODO: Don't ignore mbk. */
1824     if (update && !channel_subsys.chnmon_active) {
1825         /* Enable measuring. */
1826         channel_subsys.chnmon_area = mbo;
1827         channel_subsys.chnmon_active = true;
1828     }
1829     if (!update && channel_subsys.chnmon_active) {
1830         /* Disable measuring. */
1831         channel_subsys.chnmon_area = 0;
1832         channel_subsys.chnmon_active = false;
1833     }
1834 }
1835 
1836 IOInstEnding css_do_rsch(SubchDev *sch)
1837 {
1838     SCHIB *schib = &sch->curr_status;
1839 
1840     if (~(schib->pmcw.flags) & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA)) {
1841         return IOINST_CC_NOT_OPERATIONAL;
1842     }
1843 
1844     if (schib->scsw.ctrl & SCSW_STCTL_STATUS_PEND) {
1845         return IOINST_CC_STATUS_PRESENT;
1846     }
1847 
1848     if (((schib->scsw.ctrl & SCSW_CTRL_MASK_FCTL) != SCSW_FCTL_START_FUNC) ||
1849         (schib->scsw.ctrl & SCSW_ACTL_RESUME_PEND) ||
1850         (!(schib->scsw.ctrl & SCSW_ACTL_SUSP))) {
1851         return IOINST_CC_BUSY;
1852     }
1853 
1854     /* If monitoring is active, update counter. */
1855     if (channel_subsys.chnmon_active) {
1856         css_update_chnmon(sch);
1857     }
1858 
1859     schib->scsw.ctrl |= SCSW_ACTL_RESUME_PEND;
1860     return do_subchannel_work(sch);
1861 }
1862 
1863 int css_do_rchp(uint8_t cssid, uint8_t chpid)
1864 {
1865     uint8_t real_cssid;
1866 
1867     if (cssid > channel_subsys.max_cssid) {
1868         return -EINVAL;
1869     }
1870     if (channel_subsys.max_cssid == 0) {
1871         real_cssid = channel_subsys.default_cssid;
1872     } else {
1873         real_cssid = cssid;
1874     }
1875     if (!channel_subsys.css[real_cssid]) {
1876         return -EINVAL;
1877     }
1878 
1879     if (!channel_subsys.css[real_cssid]->chpids[chpid].in_use) {
1880         return -ENODEV;
1881     }
1882 
1883     if (!channel_subsys.css[real_cssid]->chpids[chpid].is_virtual) {
1884         fprintf(stderr,
1885                 "rchp unsupported for non-virtual chpid %x.%02x!\n",
1886                 real_cssid, chpid);
1887         return -ENODEV;
1888     }
1889 
1890     /* We don't really use a channel path, so we're done here. */
1891     css_queue_crw(CRW_RSC_CHP, CRW_ERC_INIT, 1,
1892                   channel_subsys.max_cssid > 0 ? 1 : 0, chpid);
1893     if (channel_subsys.max_cssid > 0) {
1894         css_queue_crw(CRW_RSC_CHP, CRW_ERC_INIT, 1, 0, real_cssid << 8);
1895     }
1896     return 0;
1897 }
1898 
1899 bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid)
1900 {
1901     SubchSet *set;
1902     uint8_t real_cssid;
1903 
1904     real_cssid = (!m && (cssid == 0)) ? channel_subsys.default_cssid : cssid;
1905     if (ssid > MAX_SSID ||
1906         !channel_subsys.css[real_cssid] ||
1907         !channel_subsys.css[real_cssid]->sch_set[ssid]) {
1908         return true;
1909     }
1910     set = channel_subsys.css[real_cssid]->sch_set[ssid];
1911     return schid > find_last_bit(set->schids_used,
1912                                  (MAX_SCHID + 1) / sizeof(unsigned long));
1913 }
1914 
1915 unsigned int css_find_free_chpid(uint8_t cssid)
1916 {
1917     CssImage *css = channel_subsys.css[cssid];
1918     unsigned int chpid;
1919 
1920     if (!css) {
1921         return MAX_CHPID + 1;
1922     }
1923 
1924     for (chpid = 0; chpid <= MAX_CHPID; chpid++) {
1925         /* skip reserved chpid */
1926         if (chpid == VIRTIO_CCW_CHPID) {
1927             continue;
1928         }
1929         if (!css->chpids[chpid].in_use) {
1930             return chpid;
1931         }
1932     }
1933     return MAX_CHPID + 1;
1934 }
1935 
1936 static int css_add_chpid(uint8_t cssid, uint8_t chpid, uint8_t type,
1937                          bool is_virt)
1938 {
1939     CssImage *css;
1940 
1941     trace_css_chpid_add(cssid, chpid, type);
1942     css = channel_subsys.css[cssid];
1943     if (!css) {
1944         return -EINVAL;
1945     }
1946     if (css->chpids[chpid].in_use) {
1947         return -EEXIST;
1948     }
1949     css->chpids[chpid].in_use = 1;
1950     css->chpids[chpid].type = type;
1951     css->chpids[chpid].is_virtual = is_virt;
1952 
1953     css_generate_chp_crws(cssid, chpid);
1954 
1955     return 0;
1956 }
1957 
1958 void css_sch_build_virtual_schib(SubchDev *sch, uint8_t chpid, uint8_t type)
1959 {
1960     SCHIB *schib = &sch->curr_status;
1961     int i;
1962     CssImage *css = channel_subsys.css[sch->cssid];
1963 
1964     assert(css != NULL);
1965     memset(&schib->pmcw, 0, sizeof(PMCW));
1966     schib->pmcw.flags |= PMCW_FLAGS_MASK_DNV;
1967     schib->pmcw.devno = sch->devno;
1968     /* single path */
1969     schib->pmcw.pim = 0x80;
1970     schib->pmcw.pom = 0xff;
1971     schib->pmcw.pam = 0x80;
1972     schib->pmcw.chpid[0] = chpid;
1973     if (!css->chpids[chpid].in_use) {
1974         css_add_chpid(sch->cssid, chpid, type, true);
1975     }
1976 
1977     memset(&schib->scsw, 0, sizeof(SCSW));
1978     schib->mba = 0;
1979     for (i = 0; i < ARRAY_SIZE(schib->mda); i++) {
1980         schib->mda[i] = 0;
1981     }
1982 }
1983 
1984 SubchDev *css_find_subch(uint8_t m, uint8_t cssid, uint8_t ssid, uint16_t schid)
1985 {
1986     uint8_t real_cssid;
1987 
1988     real_cssid = (!m && (cssid == 0)) ? channel_subsys.default_cssid : cssid;
1989 
1990     if (!channel_subsys.css[real_cssid]) {
1991         return NULL;
1992     }
1993 
1994     if (!channel_subsys.css[real_cssid]->sch_set[ssid]) {
1995         return NULL;
1996     }
1997 
1998     return channel_subsys.css[real_cssid]->sch_set[ssid]->sch[schid];
1999 }
2000 
2001 /**
2002  * Return free device number in subchannel set.
2003  *
2004  * Return index of the first free device number in the subchannel set
2005  * identified by @p cssid and @p ssid, beginning the search at @p
2006  * start and wrapping around at MAX_DEVNO. Return a value exceeding
2007  * MAX_SCHID if there are no free device numbers in the subchannel
2008  * set.
2009  */
2010 static uint32_t css_find_free_devno(uint8_t cssid, uint8_t ssid,
2011                                     uint16_t start)
2012 {
2013     uint32_t round;
2014 
2015     for (round = 0; round <= MAX_DEVNO; round++) {
2016         uint16_t devno = (start + round) % MAX_DEVNO;
2017 
2018         if (!css_devno_used(cssid, ssid, devno)) {
2019             return devno;
2020         }
2021     }
2022     return MAX_DEVNO + 1;
2023 }
2024 
2025 /**
2026  * Return first free subchannel (id) in subchannel set.
2027  *
2028  * Return index of the first free subchannel in the subchannel set
2029  * identified by @p cssid and @p ssid, if there is any. Return a value
2030  * exceeding MAX_SCHID if there are no free subchannels in the
2031  * subchannel set.
2032  */
2033 static uint32_t css_find_free_subch(uint8_t cssid, uint8_t ssid)
2034 {
2035     uint32_t schid;
2036 
2037     for (schid = 0; schid <= MAX_SCHID; schid++) {
2038         if (!css_find_subch(1, cssid, ssid, schid)) {
2039             return schid;
2040         }
2041     }
2042     return MAX_SCHID + 1;
2043 }
2044 
2045 /**
2046  * Return first free subchannel (id) in subchannel set for a device number
2047  *
2048  * Verify the device number @p devno is not used yet in the subchannel
2049  * set identified by @p cssid and @p ssid. Set @p schid to the index
2050  * of the first free subchannel in the subchannel set, if there is
2051  * any. Return true if everything succeeded and false otherwise.
2052  */
2053 static bool css_find_free_subch_for_devno(uint8_t cssid, uint8_t ssid,
2054                                           uint16_t devno, uint16_t *schid,
2055                                           Error **errp)
2056 {
2057     uint32_t free_schid;
2058 
2059     assert(schid);
2060     if (css_devno_used(cssid, ssid, devno)) {
2061         error_setg(errp, "Device %x.%x.%04x already exists",
2062                    cssid, ssid, devno);
2063         return false;
2064     }
2065     free_schid = css_find_free_subch(cssid, ssid);
2066     if (free_schid > MAX_SCHID) {
2067         error_setg(errp, "No free subchannel found for %x.%x.%04x",
2068                    cssid, ssid, devno);
2069         return false;
2070     }
2071     *schid = free_schid;
2072     return true;
2073 }
2074 
2075 /**
2076  * Return first free subchannel (id) and device number
2077  *
2078  * Locate the first free subchannel and first free device number in
2079  * any of the subchannel sets of the channel subsystem identified by
2080  * @p cssid. Return false if no free subchannel / device number could
2081  * be found. Otherwise set @p ssid, @p devno and @p schid to identify
2082  * the available subchannel and device number and return true.
2083  *
2084  * May modify @p ssid, @p devno and / or @p schid even if no free
2085  * subchannel / device number could be found.
2086  */
2087 static bool css_find_free_subch_and_devno(uint8_t cssid, uint8_t *ssid,
2088                                           uint16_t *devno, uint16_t *schid,
2089                                           Error **errp)
2090 {
2091     uint32_t free_schid, free_devno;
2092 
2093     assert(ssid && devno && schid);
2094     for (*ssid = 0; *ssid <= MAX_SSID; (*ssid)++) {
2095         free_schid = css_find_free_subch(cssid, *ssid);
2096         if (free_schid > MAX_SCHID) {
2097             continue;
2098         }
2099         free_devno = css_find_free_devno(cssid, *ssid, free_schid);
2100         if (free_devno > MAX_DEVNO) {
2101             continue;
2102         }
2103         *schid = free_schid;
2104         *devno = free_devno;
2105         return true;
2106     }
2107     error_setg(errp, "Virtual channel subsystem is full!");
2108     return false;
2109 }
2110 
2111 bool css_subch_visible(SubchDev *sch)
2112 {
2113     if (sch->ssid > channel_subsys.max_ssid) {
2114         return false;
2115     }
2116 
2117     if (sch->cssid != channel_subsys.default_cssid) {
2118         return (channel_subsys.max_cssid > 0);
2119     }
2120 
2121     return true;
2122 }
2123 
2124 bool css_present(uint8_t cssid)
2125 {
2126     return (channel_subsys.css[cssid] != NULL);
2127 }
2128 
2129 bool css_devno_used(uint8_t cssid, uint8_t ssid, uint16_t devno)
2130 {
2131     if (!channel_subsys.css[cssid]) {
2132         return false;
2133     }
2134     if (!channel_subsys.css[cssid]->sch_set[ssid]) {
2135         return false;
2136     }
2137 
2138     return !!test_bit(devno,
2139                       channel_subsys.css[cssid]->sch_set[ssid]->devnos_used);
2140 }
2141 
2142 void css_subch_assign(uint8_t cssid, uint8_t ssid, uint16_t schid,
2143                       uint16_t devno, SubchDev *sch)
2144 {
2145     CssImage *css;
2146     SubchSet *s_set;
2147 
2148     trace_css_assign_subch(sch ? "assign" : "deassign", cssid, ssid, schid,
2149                            devno);
2150     if (!channel_subsys.css[cssid]) {
2151         fprintf(stderr,
2152                 "Suspicious call to %s (%x.%x.%04x) for non-existing css!\n",
2153                 __func__, cssid, ssid, schid);
2154         return;
2155     }
2156     css = channel_subsys.css[cssid];
2157 
2158     if (!css->sch_set[ssid]) {
2159         css->sch_set[ssid] = g_new0(SubchSet, 1);
2160     }
2161     s_set = css->sch_set[ssid];
2162 
2163     s_set->sch[schid] = sch;
2164     if (sch) {
2165         set_bit(schid, s_set->schids_used);
2166         set_bit(devno, s_set->devnos_used);
2167     } else {
2168         clear_bit(schid, s_set->schids_used);
2169         clear_bit(devno, s_set->devnos_used);
2170     }
2171 }
2172 
2173 void css_crw_add_to_queue(CRW crw)
2174 {
2175     CrwContainer *crw_cont;
2176 
2177     trace_css_crw((crw.flags & CRW_FLAGS_MASK_RSC) >> 8,
2178                   crw.flags & CRW_FLAGS_MASK_ERC,
2179                   crw.rsid,
2180                   (crw.flags & CRW_FLAGS_MASK_C) ? "(chained)" : "");
2181 
2182     /* TODO: Maybe use a static crw pool? */
2183     crw_cont = g_try_new0(CrwContainer, 1);
2184     if (!crw_cont) {
2185         channel_subsys.crws_lost = true;
2186         return;
2187     }
2188 
2189     crw_cont->crw = crw;
2190 
2191     QTAILQ_INSERT_TAIL(&channel_subsys.pending_crws, crw_cont, sibling);
2192 
2193     if (channel_subsys.do_crw_mchk) {
2194         channel_subsys.do_crw_mchk = false;
2195         /* Inject crw pending machine check. */
2196         s390_crw_mchk();
2197     }
2198 }
2199 
2200 void css_queue_crw(uint8_t rsc, uint8_t erc, int solicited,
2201                    int chain, uint16_t rsid)
2202 {
2203     CRW crw;
2204 
2205     crw.flags = (rsc << 8) | erc;
2206     if (solicited) {
2207         crw.flags |= CRW_FLAGS_MASK_S;
2208     }
2209     if (chain) {
2210         crw.flags |= CRW_FLAGS_MASK_C;
2211     }
2212     crw.rsid = rsid;
2213     if (channel_subsys.crws_lost) {
2214         crw.flags |= CRW_FLAGS_MASK_R;
2215         channel_subsys.crws_lost = false;
2216     }
2217 
2218     css_crw_add_to_queue(crw);
2219 }
2220 
2221 void css_generate_sch_crws(uint8_t cssid, uint8_t ssid, uint16_t schid,
2222                            int hotplugged, int add)
2223 {
2224     uint8_t guest_cssid;
2225     bool chain_crw;
2226 
2227     if (add && !hotplugged) {
2228         return;
2229     }
2230     if (channel_subsys.max_cssid == 0) {
2231         /* Default cssid shows up as 0. */
2232         guest_cssid = (cssid == channel_subsys.default_cssid) ? 0 : cssid;
2233     } else {
2234         /* Show real cssid to the guest. */
2235         guest_cssid = cssid;
2236     }
2237     /*
2238      * Only notify for higher subchannel sets/channel subsystems if the
2239      * guest has enabled it.
2240      */
2241     if ((ssid > channel_subsys.max_ssid) ||
2242         (guest_cssid > channel_subsys.max_cssid) ||
2243         ((channel_subsys.max_cssid == 0) &&
2244          (cssid != channel_subsys.default_cssid))) {
2245         return;
2246     }
2247     chain_crw = (channel_subsys.max_ssid > 0) ||
2248             (channel_subsys.max_cssid > 0);
2249     css_queue_crw(CRW_RSC_SUBCH, CRW_ERC_IPI, 0, chain_crw ? 1 : 0, schid);
2250     if (chain_crw) {
2251         css_queue_crw(CRW_RSC_SUBCH, CRW_ERC_IPI, 0, 0,
2252                       (guest_cssid << 8) | (ssid << 4));
2253     }
2254     /* RW_ERC_IPI --> clear pending interrupts */
2255     css_clear_io_interrupt(css_do_build_subchannel_id(cssid, ssid), schid);
2256 }
2257 
2258 void css_generate_chp_crws(uint8_t cssid, uint8_t chpid)
2259 {
2260     /* TODO */
2261 }
2262 
2263 void css_generate_css_crws(uint8_t cssid)
2264 {
2265     if (!channel_subsys.sei_pending) {
2266         css_queue_crw(CRW_RSC_CSS, CRW_ERC_EVENT, 0, 0, cssid);
2267     }
2268     channel_subsys.sei_pending = true;
2269 }
2270 
2271 void css_clear_sei_pending(void)
2272 {
2273     channel_subsys.sei_pending = false;
2274 }
2275 
2276 int css_enable_mcsse(void)
2277 {
2278     trace_css_enable_facility("mcsse");
2279     channel_subsys.max_cssid = MAX_CSSID;
2280     return 0;
2281 }
2282 
2283 int css_enable_mss(void)
2284 {
2285     trace_css_enable_facility("mss");
2286     channel_subsys.max_ssid = MAX_SSID;
2287     return 0;
2288 }
2289 
2290 void css_reset_sch(SubchDev *sch)
2291 {
2292     SCHIB *schib = &sch->curr_status;
2293 
2294     if ((schib->pmcw.flags & PMCW_FLAGS_MASK_ENA) != 0 && sch->disable_cb) {
2295         sch->disable_cb(sch);
2296     }
2297 
2298     schib->pmcw.intparm = 0;
2299     schib->pmcw.flags &= ~(PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |
2300                   PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |
2301                   PMCW_FLAGS_MASK_MP | PMCW_FLAGS_MASK_TF);
2302     schib->pmcw.flags |= PMCW_FLAGS_MASK_DNV;
2303     schib->pmcw.devno = sch->devno;
2304     schib->pmcw.pim = 0x80;
2305     schib->pmcw.lpm = schib->pmcw.pim;
2306     schib->pmcw.pnom = 0;
2307     schib->pmcw.lpum = 0;
2308     schib->pmcw.mbi = 0;
2309     schib->pmcw.pom = 0xff;
2310     schib->pmcw.pam = 0x80;
2311     schib->pmcw.chars &= ~(PMCW_CHARS_MASK_MBFC | PMCW_CHARS_MASK_XMWME |
2312                   PMCW_CHARS_MASK_CSENSE);
2313 
2314     memset(&schib->scsw, 0, sizeof(schib->scsw));
2315     schib->mba = 0;
2316 
2317     sch->channel_prog = 0x0;
2318     sch->last_cmd_valid = false;
2319     sch->thinint_active = false;
2320 }
2321 
2322 void css_reset(void)
2323 {
2324     CrwContainer *crw_cont;
2325 
2326     /* Clean up monitoring. */
2327     channel_subsys.chnmon_active = false;
2328     channel_subsys.chnmon_area = 0;
2329 
2330     /* Clear pending CRWs. */
2331     while ((crw_cont = QTAILQ_FIRST(&channel_subsys.pending_crws))) {
2332         QTAILQ_REMOVE(&channel_subsys.pending_crws, crw_cont, sibling);
2333         g_free(crw_cont);
2334     }
2335     channel_subsys.sei_pending = false;
2336     channel_subsys.do_crw_mchk = true;
2337     channel_subsys.crws_lost = false;
2338 
2339     /* Reset maximum ids. */
2340     channel_subsys.max_cssid = 0;
2341     channel_subsys.max_ssid = 0;
2342 }
2343 
2344 static void get_css_devid(Object *obj, Visitor *v, const char *name,
2345                           void *opaque, Error **errp)
2346 {
2347     DeviceState *dev = DEVICE(obj);
2348     Property *prop = opaque;
2349     CssDevId *dev_id = qdev_get_prop_ptr(dev, prop);
2350     char buffer[] = "xx.x.xxxx";
2351     char *p = buffer;
2352     int r;
2353 
2354     if (dev_id->valid) {
2355 
2356         r = snprintf(buffer, sizeof(buffer), "%02x.%1x.%04x", dev_id->cssid,
2357                      dev_id->ssid, dev_id->devid);
2358         assert(r == sizeof(buffer) - 1);
2359 
2360         /* drop leading zero */
2361         if (dev_id->cssid <= 0xf) {
2362             p++;
2363         }
2364     } else {
2365         snprintf(buffer, sizeof(buffer), "<unset>");
2366     }
2367 
2368     visit_type_str(v, name, &p, errp);
2369 }
2370 
2371 /*
2372  * parse <cssid>.<ssid>.<devid> and assert valid range for cssid/ssid
2373  */
2374 static void set_css_devid(Object *obj, Visitor *v, const char *name,
2375                           void *opaque, Error **errp)
2376 {
2377     DeviceState *dev = DEVICE(obj);
2378     Property *prop = opaque;
2379     CssDevId *dev_id = qdev_get_prop_ptr(dev, prop);
2380     Error *local_err = NULL;
2381     char *str;
2382     int num, n1, n2;
2383     unsigned int cssid, ssid, devid;
2384 
2385     if (dev->realized) {
2386         qdev_prop_set_after_realize(dev, name, errp);
2387         return;
2388     }
2389 
2390     visit_type_str(v, name, &str, &local_err);
2391     if (local_err) {
2392         error_propagate(errp, local_err);
2393         return;
2394     }
2395 
2396     num = sscanf(str, "%2x.%1x%n.%4x%n", &cssid, &ssid, &n1, &devid, &n2);
2397     if (num != 3 || (n2 - n1) != 5 || strlen(str) != n2) {
2398         error_set_from_qdev_prop_error(errp, EINVAL, dev, prop, str);
2399         goto out;
2400     }
2401     if ((cssid > MAX_CSSID) || (ssid > MAX_SSID)) {
2402         error_setg(errp, "Invalid cssid or ssid: cssid %x, ssid %x",
2403                    cssid, ssid);
2404         goto out;
2405     }
2406 
2407     dev_id->cssid = cssid;
2408     dev_id->ssid = ssid;
2409     dev_id->devid = devid;
2410     dev_id->valid = true;
2411 
2412 out:
2413     g_free(str);
2414 }
2415 
2416 const PropertyInfo css_devid_propinfo = {
2417     .name = "str",
2418     .description = "Identifier of an I/O device in the channel "
2419                    "subsystem, example: fe.1.23ab",
2420     .get = get_css_devid,
2421     .set = set_css_devid,
2422 };
2423 
2424 const PropertyInfo css_devid_ro_propinfo = {
2425     .name = "str",
2426     .description = "Read-only identifier of an I/O device in the channel "
2427                    "subsystem, example: fe.1.23ab",
2428     .get = get_css_devid,
2429 };
2430 
2431 SubchDev *css_create_sch(CssDevId bus_id, Error **errp)
2432 {
2433     uint16_t schid = 0;
2434     SubchDev *sch;
2435 
2436     if (bus_id.valid) {
2437         if (!channel_subsys.css[bus_id.cssid]) {
2438             css_create_css_image(bus_id.cssid, false);
2439         }
2440 
2441         if (!css_find_free_subch_for_devno(bus_id.cssid, bus_id.ssid,
2442                                            bus_id.devid, &schid, errp)) {
2443             return NULL;
2444         }
2445     } else {
2446         for (bus_id.cssid = channel_subsys.default_cssid;;) {
2447             if (!channel_subsys.css[bus_id.cssid]) {
2448                 css_create_css_image(bus_id.cssid, false);
2449             }
2450 
2451             if   (css_find_free_subch_and_devno(bus_id.cssid, &bus_id.ssid,
2452                                                 &bus_id.devid, &schid,
2453                                                 NULL)) {
2454                 break;
2455             }
2456             bus_id.cssid = (bus_id.cssid + 1) % MAX_CSSID;
2457             if (bus_id.cssid == channel_subsys.default_cssid) {
2458                 error_setg(errp, "Virtual channel subsystem is full!");
2459                 return NULL;
2460             }
2461         }
2462     }
2463 
2464     sch = g_new0(SubchDev, 1);
2465     sch->cssid = bus_id.cssid;
2466     sch->ssid = bus_id.ssid;
2467     sch->devno = bus_id.devid;
2468     sch->schid = schid;
2469     css_subch_assign(sch->cssid, sch->ssid, schid, sch->devno, sch);
2470     return sch;
2471 }
2472 
2473 static int css_sch_get_chpids(SubchDev *sch, CssDevId *dev_id)
2474 {
2475     char *fid_path;
2476     FILE *fd;
2477     uint32_t chpid[8];
2478     int i;
2479     SCHIB *schib = &sch->curr_status;
2480 
2481     fid_path = g_strdup_printf("/sys/bus/css/devices/%x.%x.%04x/chpids",
2482                                dev_id->cssid, dev_id->ssid, dev_id->devid);
2483     fd = fopen(fid_path, "r");
2484     if (fd == NULL) {
2485         error_report("%s: open %s failed", __func__, fid_path);
2486         g_free(fid_path);
2487         return -EINVAL;
2488     }
2489 
2490     if (fscanf(fd, "%x %x %x %x %x %x %x %x",
2491         &chpid[0], &chpid[1], &chpid[2], &chpid[3],
2492         &chpid[4], &chpid[5], &chpid[6], &chpid[7]) != 8) {
2493         fclose(fd);
2494         g_free(fid_path);
2495         return -EINVAL;
2496     }
2497 
2498     for (i = 0; i < ARRAY_SIZE(schib->pmcw.chpid); i++) {
2499         schib->pmcw.chpid[i] = chpid[i];
2500     }
2501 
2502     fclose(fd);
2503     g_free(fid_path);
2504 
2505     return 0;
2506 }
2507 
2508 static int css_sch_get_path_masks(SubchDev *sch, CssDevId *dev_id)
2509 {
2510     char *fid_path;
2511     FILE *fd;
2512     uint32_t pim, pam, pom;
2513     SCHIB *schib = &sch->curr_status;
2514 
2515     fid_path = g_strdup_printf("/sys/bus/css/devices/%x.%x.%04x/pimpampom",
2516                                dev_id->cssid, dev_id->ssid, dev_id->devid);
2517     fd = fopen(fid_path, "r");
2518     if (fd == NULL) {
2519         error_report("%s: open %s failed", __func__, fid_path);
2520         g_free(fid_path);
2521         return -EINVAL;
2522     }
2523 
2524     if (fscanf(fd, "%x %x %x", &pim, &pam, &pom) != 3) {
2525         fclose(fd);
2526         g_free(fid_path);
2527         return -EINVAL;
2528     }
2529 
2530     schib->pmcw.pim = pim;
2531     schib->pmcw.pam = pam;
2532     schib->pmcw.pom = pom;
2533     fclose(fd);
2534     g_free(fid_path);
2535 
2536     return 0;
2537 }
2538 
2539 static int css_sch_get_chpid_type(uint8_t chpid, uint32_t *type,
2540                                   CssDevId *dev_id)
2541 {
2542     char *fid_path;
2543     FILE *fd;
2544 
2545     fid_path = g_strdup_printf("/sys/devices/css%x/chp0.%02x/type",
2546                                dev_id->cssid, chpid);
2547     fd = fopen(fid_path, "r");
2548     if (fd == NULL) {
2549         error_report("%s: open %s failed", __func__, fid_path);
2550         g_free(fid_path);
2551         return -EINVAL;
2552     }
2553 
2554     if (fscanf(fd, "%x", type) != 1) {
2555         fclose(fd);
2556         g_free(fid_path);
2557         return -EINVAL;
2558     }
2559 
2560     fclose(fd);
2561     g_free(fid_path);
2562 
2563     return 0;
2564 }
2565 
2566 /*
2567  * We currently retrieve the real device information from sysfs to build the
2568  * guest subchannel information block without considering the migration feature.
2569  * We need to revisit this problem when we want to add migration support.
2570  */
2571 int css_sch_build_schib(SubchDev *sch, CssDevId *dev_id)
2572 {
2573     CssImage *css = channel_subsys.css[sch->cssid];
2574     SCHIB *schib = &sch->curr_status;
2575     uint32_t type;
2576     int i, ret;
2577 
2578     assert(css != NULL);
2579     memset(&schib->pmcw, 0, sizeof(PMCW));
2580     schib->pmcw.flags |= PMCW_FLAGS_MASK_DNV;
2581     /* We are dealing with I/O subchannels only. */
2582     schib->pmcw.devno = sch->devno;
2583 
2584     /* Grab path mask from sysfs. */
2585     ret = css_sch_get_path_masks(sch, dev_id);
2586     if (ret) {
2587         return ret;
2588     }
2589 
2590     /* Grab chpids from sysfs. */
2591     ret = css_sch_get_chpids(sch, dev_id);
2592     if (ret) {
2593         return ret;
2594     }
2595 
2596    /* Build chpid type. */
2597     for (i = 0; i < ARRAY_SIZE(schib->pmcw.chpid); i++) {
2598         if (schib->pmcw.chpid[i] && !css->chpids[schib->pmcw.chpid[i]].in_use) {
2599             ret = css_sch_get_chpid_type(schib->pmcw.chpid[i], &type, dev_id);
2600             if (ret) {
2601                 return ret;
2602             }
2603             css_add_chpid(sch->cssid, schib->pmcw.chpid[i], type, false);
2604         }
2605     }
2606 
2607     memset(&schib->scsw, 0, sizeof(SCSW));
2608     schib->mba = 0;
2609     for (i = 0; i < ARRAY_SIZE(schib->mda); i++) {
2610         schib->mda[i] = 0;
2611     }
2612 
2613     return 0;
2614 }
2615