drivers/s390/cio/vfio_ccw_drv.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * VFIO based Physical Subchannel device driver
   4  *
   5  * Copyright IBM Corp. 2017
   6  * Copyright Red Hat, Inc. 2019
   7  *
   8  * Author(s): Dong Jia Shi <[email protected]>
   9  *            Xiao Feng Ren <[email protected]>
  10  *            Cornelia Huck <[email protected]>
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/slab.h>
  16 #include <linux/mdev.h>
  17
  18 #include <asm/isc.h>
  19
  20 #include "chp.h"
  21 #include "ioasm.h"
  22 #include "css.h"
  23 #include "vfio_ccw_private.h"
  24
  25 struct workqueue_struct *vfio_ccw_work_q;
  26 struct kmem_cache *vfio_ccw_io_region;
  27 struct kmem_cache *vfio_ccw_cmd_region;
  28 struct kmem_cache *vfio_ccw_schib_region;
  29 struct kmem_cache *vfio_ccw_crw_region;
  30
  31 debug_info_t *vfio_ccw_debug_msg_id;
  32 debug_info_t *vfio_ccw_debug_trace_id;
  33
  34 /*
  35  * Helpers
  36  */
  37 int vfio_ccw_sch_quiesce(struct subchannel *sch)
  38 {
  39         struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
  40         struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
  41         DECLARE_COMPLETION_ONSTACK(completion);
  42         int iretry, ret = 0;
  43
  44         /*
  45          * Probably an impossible situation, after being called through
  46          * FSM callbacks. But in the event it did, register a warning
  47          * and return as if things were fine.
  48          */
  49         if (WARN_ON(!private))
  50                 return 0;
  51
  52         iretry = 255;
  53         do {
  54
  55                 ret = cio_cancel_halt_clear(sch, &iretry);
  56
  57                 if (ret == -EIO) {
  58                         pr_err("vfio_ccw: could not quiesce subchannel 0.%x.%04x!\n",
  59                                sch->schid.ssid, sch->schid.sch_no);
  60                         break;
  61                 }
  62
  63                 /*
  64                  * Flush all I/O and wait for
  65                  * cancel/halt/clear completion.
  66                  */
  67                 private->completion = &completion;
  68                 spin_unlock_irq(sch->lock);
  69
  70                 if (ret == -EBUSY)
  71                         wait_for_completion_timeout(&completion, 3*HZ);
  72
  73                 private->completion = NULL;
  74                 flush_workqueue(vfio_ccw_work_q);
  75                 spin_lock_irq(sch->lock);
  76                 ret = cio_disable_subchannel(sch);
  77         } while (ret == -EBUSY);
  78
  79         return ret;
  80 }
  81
  82 void vfio_ccw_sch_io_todo(struct work_struct *work)
  83 {
  84         struct vfio_ccw_private *private;
  85         struct irb *irb;
  86         bool is_final;
  87         bool cp_is_finished = false;
  88
  89         private = container_of(work, struct vfio_ccw_private, io_work);
  90         irb = &private->irb;
  91
  92         is_final = !(scsw_actl(&irb->scsw) &
  93                      (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
  94         if (scsw_is_solicited(&irb->scsw)) {
  95                 cp_update_scsw(&private->cp, &irb->scsw);
  96                 if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING) {
  97                         cp_free(&private->cp);
  98                         cp_is_finished = true;
  99                 }
 100         }
 101         mutex_lock(&private->io_mutex);
 102         memcpy(private->io_region->irb_area, irb, sizeof(*irb));
 103         mutex_unlock(&private->io_mutex);
 104
 105         /*
 106          * Reset to IDLE only if processing of a channel program
 107          * has finished. Do not overwrite a possible processing
 108          * state if the interrupt was unsolicited, or if the final
 109          * interrupt was for HSCH or CSCH.
 110          */
 111         if (cp_is_finished)
 112                 private->state = VFIO_CCW_STATE_IDLE;
 113
 114         if (private->io_trigger)
 115                 eventfd_signal(private->io_trigger, 1);
 116 }
 117
 118 void vfio_ccw_crw_todo(struct work_struct *work)
 119 {
 120         struct vfio_ccw_private *private;
 121
 122         private = container_of(work, struct vfio_ccw_private, crw_work);
 123
 124         if (!list_empty(&private->crw) && private->crw_trigger)
 125                 eventfd_signal(private->crw_trigger, 1);
 126 }
 127
 128 /*
 129  * Css driver callbacks
 130  */
 131 static void vfio_ccw_sch_irq(struct subchannel *sch)
 132 {
 133         struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
 134         struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
 135
 136         /*
 137          * The subchannel should still be disabled at this point,
 138          * so an interrupt would be quite surprising. As with an
 139          * interrupt while the FSM is closed, let's attempt to
 140          * disable the subchannel again.
 141          */
 142         if (!private) {
 143                 VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: unexpected interrupt\n",
 144                                    sch->schid.cssid, sch->schid.ssid,
 145                                    sch->schid.sch_no);
 146
 147                 cio_disable_subchannel(sch);
 148                 return;
 149         }
 150
 151         inc_irq_stat(IRQIO_CIO);
 152         vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
 153 }
 154
 155 static void vfio_ccw_free_parent(struct device *dev)
 156 {
 157         struct vfio_ccw_parent *parent = container_of(dev, struct vfio_ccw_parent, dev);
 158
 159         kfree(parent);
 160 }
 161
 162 static int vfio_ccw_sch_probe(struct subchannel *sch)
 163 {
 164         struct pmcw *pmcw = &sch->schib.pmcw;
 165         struct vfio_ccw_parent *parent;
 166         int ret = -ENOMEM;
 167
 168         if (pmcw->qf) {
 169                 dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
 170                          dev_name(&sch->dev));
 171                 return -ENODEV;
 172         }
 173
 174         parent = kzalloc(struct_size(parent, mdev_types, 1), GFP_KERNEL);
 175         if (!parent)
 176                 return -ENOMEM;
 177
 178         dev_set_name(&parent->dev, "parent");
 179         parent->dev.parent = &sch->dev;
 180         parent->dev.release = &vfio_ccw_free_parent;
 181         ret = device_register(&parent->dev);
 182         if (ret)
 183                 goto out_free;
 184
 185         dev_set_drvdata(&sch->dev, parent);
 186
 187         parent->mdev_type.sysfs_name = "io";
 188         parent->mdev_type.pretty_name = "I/O subchannel (Non-QDIO)";
 189         parent->mdev_types[0] = &parent->mdev_type;
 190         ret = mdev_register_parent(&parent->parent, &sch->dev,
 191                                    &vfio_ccw_mdev_driver,
 192                                    parent->mdev_types, 1);
 193         if (ret)
 194                 goto out_unreg;
 195
 196         VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n",
 197                            sch->schid.cssid, sch->schid.ssid,
 198                            sch->schid.sch_no);
 199         return 0;
 200
 201 out_unreg:
 202         device_del(&parent->dev);
 203 out_free:
 204         put_device(&parent->dev);
 205         dev_set_drvdata(&sch->dev, NULL);
 206         return ret;
 207 }
 208
 209 static void vfio_ccw_sch_remove(struct subchannel *sch)
 210 {
 211         struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
 212
 213         mdev_unregister_parent(&parent->parent);
 214
 215         device_unregister(&parent->dev);
 216         dev_set_drvdata(&sch->dev, NULL);
 217
 218         VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
 219                            sch->schid.cssid, sch->schid.ssid,
 220                            sch->schid.sch_no);
 221 }
 222
 223 static void vfio_ccw_sch_shutdown(struct subchannel *sch)
 224 {
 225         struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
 226         struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
 227
 228         if (!private)
 229                 return;
 230
 231         vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
 232         vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
 233 }
 234
 235 /**
 236  * vfio_ccw_sch_event - process subchannel event
 237  * @sch: subchannel
 238  * @process: non-zero if function is called in process context
 239  *
 240  * An unspecified event occurred for this subchannel. Adjust data according
 241  * to the current operational state of the subchannel. Return zero when the
 242  * event has been handled sufficiently or -EAGAIN when this function should
 243  * be called again in process context.
 244  */
 245 static int vfio_ccw_sch_event(struct subchannel *sch, int process)
 246 {
 247         struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
 248         struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
 249         unsigned long flags;
 250         int rc = -EAGAIN;
 251
 252         spin_lock_irqsave(sch->lock, flags);
 253         if (!device_is_registered(&sch->dev))
 254                 goto out_unlock;
 255
 256         if (work_pending(&sch->todo_work))
 257                 goto out_unlock;
 258
 259         rc = 0;
 260
 261         if (cio_update_schib(sch)) {
 262                 if (private)
 263                         vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
 264         }
 265
 266 out_unlock:
 267         spin_unlock_irqrestore(sch->lock, flags);
 268
 269         return rc;
 270 }
 271
 272 static void vfio_ccw_queue_crw(struct vfio_ccw_private *private,
 273                                unsigned int rsc,
 274                                unsigned int erc,
 275                                unsigned int rsid)
 276 {
 277         struct vfio_ccw_crw *crw;
 278
 279         /*
 280          * If unable to allocate a CRW, just drop the event and
 281          * carry on.  The guest will either see a later one or
 282          * learn when it issues its own store subchannel.
 283          */
 284         crw = kzalloc(sizeof(*crw), GFP_ATOMIC);
 285         if (!crw)
 286                 return;
 287
 288         /*
 289          * Build the CRW based on the inputs given to us.
 290          */
 291         crw->crw.rsc = rsc;
 292         crw->crw.erc = erc;
 293         crw->crw.rsid = rsid;
 294
 295         list_add_tail(&crw->next, &private->crw);
 296         queue_work(vfio_ccw_work_q, &private->crw_work);
 297 }
 298
 299 static int vfio_ccw_chp_event(struct subchannel *sch,
 300                               struct chp_link *link, int event)
 301 {
 302         struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
 303         struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
 304         int mask = chp_ssd_get_mask(&sch->ssd_info, link);
 305         int retry = 255;
 306
 307         if (!private || !mask)
 308                 return 0;
 309
 310         trace_vfio_ccw_chp_event(sch->schid, mask, event);
 311         VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: mask=0x%x event=%d\n",
 312                            sch->schid.cssid,
 313                            sch->schid.ssid, sch->schid.sch_no,
 314                            mask, event);
 315
 316         if (cio_update_schib(sch))
 317                 return -ENODEV;
 318
 319         switch (event) {
 320         case CHP_VARY_OFF:
 321                 /* Path logically turned off */
 322                 sch->opm &= ~mask;
 323                 sch->lpm &= ~mask;
 324                 if (sch->schib.pmcw.lpum & mask)
 325                         cio_cancel_halt_clear(sch, &retry);
 326                 break;
 327         case CHP_OFFLINE:
 328                 /* Path is gone */
 329                 if (sch->schib.pmcw.lpum & mask)
 330                         cio_cancel_halt_clear(sch, &retry);
 331                 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_PERRN,
 332                                    link->chpid.id);
 333                 break;
 334         case CHP_VARY_ON:
 335                 /* Path logically turned on */
 336                 sch->opm |= mask;
 337                 sch->lpm |= mask;
 338                 break;
 339         case CHP_ONLINE:
 340                 /* Path became available */
 341                 sch->lpm |= mask & sch->opm;
 342                 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_INIT,
 343                                    link->chpid.id);
 344                 break;
 345         }
 346
 347         return 0;
 348 }
 349
 350 static struct css_device_id vfio_ccw_sch_ids[] = {
 351         { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
 352         { /* end of list */ },
 353 };
 354 MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
 355
 356 static struct css_driver vfio_ccw_sch_driver = {
 357         .drv = {
 358                 .name = "vfio_ccw",
 359                 .owner = THIS_MODULE,
 360         },
 361         .subchannel_type = vfio_ccw_sch_ids,
 362         .irq = vfio_ccw_sch_irq,
 363         .probe = vfio_ccw_sch_probe,
 364         .remove = vfio_ccw_sch_remove,
 365         .shutdown = vfio_ccw_sch_shutdown,
 366         .sch_event = vfio_ccw_sch_event,
 367         .chp_event = vfio_ccw_chp_event,
 368 };
 369
 370 static int __init vfio_ccw_debug_init(void)
 371 {
 372         vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
 373                                                11 * sizeof(long));
 374         if (!vfio_ccw_debug_msg_id)
 375                 goto out_unregister;
 376         debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
 377         debug_set_level(vfio_ccw_debug_msg_id, 2);
 378         vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
 379         if (!vfio_ccw_debug_trace_id)
 380                 goto out_unregister;
 381         debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
 382         debug_set_level(vfio_ccw_debug_trace_id, 2);
 383         return 0;
 384
 385 out_unregister:
 386         debug_unregister(vfio_ccw_debug_msg_id);
 387         debug_unregister(vfio_ccw_debug_trace_id);
 388         return -1;
 389 }
 390
 391 static void vfio_ccw_debug_exit(void)
 392 {
 393         debug_unregister(vfio_ccw_debug_msg_id);
 394         debug_unregister(vfio_ccw_debug_trace_id);
 395 }
 396
 397 static void vfio_ccw_destroy_regions(void)
 398 {
 399         kmem_cache_destroy(vfio_ccw_crw_region);
 400         kmem_cache_destroy(vfio_ccw_schib_region);
 401         kmem_cache_destroy(vfio_ccw_cmd_region);
 402         kmem_cache_destroy(vfio_ccw_io_region);
 403 }
 404
 405 static int __init vfio_ccw_sch_init(void)
 406 {
 407         int ret;
 408
 409         ret = vfio_ccw_debug_init();
 410         if (ret)
 411                 return ret;
 412
 413         vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
 414         if (!vfio_ccw_work_q) {
 415                 ret = -ENOMEM;
 416                 goto out_regions;
 417         }
 418
 419         vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
 420                                         sizeof(struct ccw_io_region), 0,
 421                                         SLAB_ACCOUNT, 0,
 422                                         sizeof(struct ccw_io_region), NULL);
 423         if (!vfio_ccw_io_region) {
 424                 ret = -ENOMEM;
 425                 goto out_regions;
 426         }
 427
 428         vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
 429                                         sizeof(struct ccw_cmd_region), 0,
 430                                         SLAB_ACCOUNT, 0,
 431                                         sizeof(struct ccw_cmd_region), NULL);
 432         if (!vfio_ccw_cmd_region) {
 433                 ret = -ENOMEM;
 434                 goto out_regions;
 435         }
 436
 437         vfio_ccw_schib_region = kmem_cache_create_usercopy("vfio_ccw_schib_region",
 438                                         sizeof(struct ccw_schib_region), 0,
 439                                         SLAB_ACCOUNT, 0,
 440                                         sizeof(struct ccw_schib_region), NULL);
 441
 442         if (!vfio_ccw_schib_region) {
 443                 ret = -ENOMEM;
 444                 goto out_regions;
 445         }
 446
 447         vfio_ccw_crw_region = kmem_cache_create_usercopy("vfio_ccw_crw_region",
 448                                         sizeof(struct ccw_crw_region), 0,
 449                                         SLAB_ACCOUNT, 0,
 450                                         sizeof(struct ccw_crw_region), NULL);
 451
 452         if (!vfio_ccw_crw_region) {
 453                 ret = -ENOMEM;
 454                 goto out_regions;
 455         }
 456
 457         ret = mdev_register_driver(&vfio_ccw_mdev_driver);
 458         if (ret)
 459                 goto out_regions;
 460
 461         isc_register(VFIO_CCW_ISC);
 462         ret = css_driver_register(&vfio_ccw_sch_driver);
 463         if (ret) {
 464                 isc_unregister(VFIO_CCW_ISC);
 465                 goto out_driver;
 466         }
 467
 468         return ret;
 469
 470 out_driver:
 471         mdev_unregister_driver(&vfio_ccw_mdev_driver);
 472 out_regions:
 473         vfio_ccw_destroy_regions();
 474         destroy_workqueue(vfio_ccw_work_q);
 475         vfio_ccw_debug_exit();
 476         return ret;
 477 }
 478
 479 static void __exit vfio_ccw_sch_exit(void)
 480 {
 481         css_driver_unregister(&vfio_ccw_sch_driver);
 482         mdev_unregister_driver(&vfio_ccw_mdev_driver);
 483         isc_unregister(VFIO_CCW_ISC);
 484         vfio_ccw_destroy_regions();
 485         destroy_workqueue(vfio_ccw_work_q);
 486         vfio_ccw_debug_exit();
 487 }
 488 module_init(vfio_ccw_sch_init);
 489 module_exit(vfio_ccw_sch_exit);
 490
 491 MODULE_LICENSE("GPL v2");