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 <bjsdjshi@linux.vnet.ibm.com>
   9  *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
  10  *            Cornelia Huck <cohuck@redhat.com>
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/device.h>
  16 #include <linux/slab.h>
  17 #include <linux/uuid.h>
  18 #include <linux/mdev.h>
  19
  20 #include <asm/isc.h>
  21
  22 #include "chp.h"
  23 #include "ioasm.h"
  24 #include "css.h"
  25 #include "vfio_ccw_private.h"
  26
  27 struct workqueue_struct *vfio_ccw_work_q;
  28 static struct kmem_cache *vfio_ccw_io_region;
  29 static struct kmem_cache *vfio_ccw_cmd_region;
  30 static struct kmem_cache *vfio_ccw_schib_region;
  31 static struct kmem_cache *vfio_ccw_crw_region;
  32
  33 debug_info_t *vfio_ccw_debug_msg_id;
  34 debug_info_t *vfio_ccw_debug_trace_id;
  35
  36 /*
  37  * Helpers
  38  */
  39 int vfio_ccw_sch_quiesce(struct subchannel *sch)
  40 {
  41         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
  42         DECLARE_COMPLETION_ONSTACK(completion);
  43         int iretry, ret = 0;
  44
  45         spin_lock_irq(sch->lock);
  46         if (!sch->schib.pmcw.ena)
  47                 goto out_unlock;
  48         ret = cio_disable_subchannel(sch);
  49         if (ret != -EBUSY)
  50                 goto out_unlock;
  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 out_unlock:
  79         private->state = VFIO_CCW_STATE_NOT_OPER;
  80         spin_unlock_irq(sch->lock);
  81         return ret;
  82 }
  83
  84 static void vfio_ccw_sch_io_todo(struct work_struct *work)
  85 {
  86         struct vfio_ccw_private *private;
  87         struct irb *irb;
  88         bool is_final;
  89         bool cp_is_finished = false;
  90
  91         private = container_of(work, struct vfio_ccw_private, io_work);
  92         irb = &private->irb;
  93
  94         is_final = !(scsw_actl(&irb->scsw) &
  95                      (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
  96         if (scsw_is_solicited(&irb->scsw)) {
  97                 cp_update_scsw(&private->cp, &irb->scsw);
  98                 if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING) {
  99                         cp_free(&private->cp);
 100                         cp_is_finished = true;
 101                 }
 102         }
 103         mutex_lock(&private->io_mutex);
 104         memcpy(private->io_region->irb_area, irb, sizeof(*irb));
 105         mutex_unlock(&private->io_mutex);
 106
 107         /*
 108          * Reset to IDLE only if processing of a channel program
 109          * has finished. Do not overwrite a possible processing
 110          * state if the final interrupt was for HSCH or CSCH.
 111          */
 112         if (private->mdev && cp_is_finished)
 113                 private->state = VFIO_CCW_STATE_IDLE;
 114
 115         if (private->io_trigger)
 116                 eventfd_signal(private->io_trigger, 1);
 117 }
 118
 119 static void vfio_ccw_crw_todo(struct work_struct *work)
 120 {
 121         struct vfio_ccw_private *private;
 122
 123         private = container_of(work, struct vfio_ccw_private, crw_work);
 124
 125         if (!list_empty(&private->crw) && private->crw_trigger)
 126                 eventfd_signal(private->crw_trigger, 1);
 127 }
 128
 129 /*
 130  * Css driver callbacks
 131  */
 132 static void vfio_ccw_sch_irq(struct subchannel *sch)
 133 {
 134         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 135
 136         inc_irq_stat(IRQIO_CIO);
 137         vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
 138 }
 139
 140 static void vfio_ccw_free_regions(struct vfio_ccw_private *private)
 141 {
 142         if (private->crw_region)
 143                 kmem_cache_free(vfio_ccw_crw_region, private->crw_region);
 144         if (private->schib_region)
 145                 kmem_cache_free(vfio_ccw_schib_region, private->schib_region);
 146         if (private->cmd_region)
 147                 kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
 148         if (private->io_region)
 149                 kmem_cache_free(vfio_ccw_io_region, private->io_region);
 150 }
 151
 152 static int vfio_ccw_sch_probe(struct subchannel *sch)
 153 {
 154         struct pmcw *pmcw = &sch->schib.pmcw;
 155         struct vfio_ccw_private *private;
 156         int ret = -ENOMEM;
 157
 158         if (pmcw->qf) {
 159                 dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
 160                          dev_name(&sch->dev));
 161                 return -ENODEV;
 162         }
 163
 164         private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
 165         if (!private)
 166                 return -ENOMEM;
 167
 168         private->cp.guest_cp = kcalloc(CCWCHAIN_LEN_MAX, sizeof(struct ccw1),
 169                                        GFP_KERNEL);
 170         if (!private->cp.guest_cp)
 171                 goto out_free;
 172
 173         private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
 174                                                GFP_KERNEL | GFP_DMA);
 175         if (!private->io_region)
 176                 goto out_free;
 177
 178         private->cmd_region = kmem_cache_zalloc(vfio_ccw_cmd_region,
 179                                                 GFP_KERNEL | GFP_DMA);
 180         if (!private->cmd_region)
 181                 goto out_free;
 182
 183         private->schib_region = kmem_cache_zalloc(vfio_ccw_schib_region,
 184                                                   GFP_KERNEL | GFP_DMA);
 185
 186         if (!private->schib_region)
 187                 goto out_free;
 188
 189         private->crw_region = kmem_cache_zalloc(vfio_ccw_crw_region,
 190                                                 GFP_KERNEL | GFP_DMA);
 191
 192         if (!private->crw_region)
 193                 goto out_free;
 194
 195         private->sch = sch;
 196         dev_set_drvdata(&sch->dev, private);
 197         mutex_init(&private->io_mutex);
 198
 199         spin_lock_irq(sch->lock);
 200         private->state = VFIO_CCW_STATE_NOT_OPER;
 201         sch->isc = VFIO_CCW_ISC;
 202         ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
 203         spin_unlock_irq(sch->lock);
 204         if (ret)
 205                 goto out_free;
 206
 207         INIT_LIST_HEAD(&private->crw);
 208         INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
 209         INIT_WORK(&private->crw_work, vfio_ccw_crw_todo);
 210         atomic_set(&private->avail, 1);
 211         private->state = VFIO_CCW_STATE_STANDBY;
 212
 213         ret = vfio_ccw_mdev_reg(sch);
 214         if (ret)
 215                 goto out_disable;
 216
 217         if (dev_get_uevent_suppress(&sch->dev)) {
 218                 dev_set_uevent_suppress(&sch->dev, 0);
 219                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 220         }
 221
 222         VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n",
 223                            sch->schid.cssid, sch->schid.ssid,
 224                            sch->schid.sch_no);
 225         return 0;
 226
 227 out_disable:
 228         cio_disable_subchannel(sch);
 229 out_free:
 230         dev_set_drvdata(&sch->dev, NULL);
 231         vfio_ccw_free_regions(private);
 232         kfree(private->cp.guest_cp);
 233         kfree(private);
 234         return ret;
 235 }
 236
 237 static int vfio_ccw_sch_remove(struct subchannel *sch)
 238 {
 239         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 240         struct vfio_ccw_crw *crw, *temp;
 241
 242         vfio_ccw_sch_quiesce(sch);
 243
 244         list_for_each_entry_safe(crw, temp, &private->crw, next) {
 245                 list_del(&crw->next);
 246                 kfree(crw);
 247         }
 248
 249         vfio_ccw_mdev_unreg(sch);
 250
 251         dev_set_drvdata(&sch->dev, NULL);
 252
 253         vfio_ccw_free_regions(private);
 254         kfree(private->cp.guest_cp);
 255         kfree(private);
 256
 257         VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
 258                            sch->schid.cssid, sch->schid.ssid,
 259                            sch->schid.sch_no);
 260         return 0;
 261 }
 262
 263 static void vfio_ccw_sch_shutdown(struct subchannel *sch)
 264 {
 265         vfio_ccw_sch_quiesce(sch);
 266 }
 267
 268 /**
 269  * vfio_ccw_sch_event - process subchannel event
 270  * @sch: subchannel
 271  * @process: non-zero if function is called in process context
 272  *
 273  * An unspecified event occurred for this subchannel. Adjust data according
 274  * to the current operational state of the subchannel. Return zero when the
 275  * event has been handled sufficiently or -EAGAIN when this function should
 276  * be called again in process context.
 277  */
 278 static int vfio_ccw_sch_event(struct subchannel *sch, int process)
 279 {
 280         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 281         unsigned long flags;
 282         int rc = -EAGAIN;
 283
 284         spin_lock_irqsave(sch->lock, flags);
 285         if (!device_is_registered(&sch->dev))
 286                 goto out_unlock;
 287
 288         if (work_pending(&sch->todo_work))
 289                 goto out_unlock;
 290
 291         rc = 0;
 292
 293         if (cio_update_schib(sch))
 294                 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
 295
 296 out_unlock:
 297         spin_unlock_irqrestore(sch->lock, flags);
 298
 299         return rc;
 300 }
 301
 302 static void vfio_ccw_queue_crw(struct vfio_ccw_private *private,
 303                                unsigned int rsc,
 304                                unsigned int erc,
 305                                unsigned int rsid)
 306 {
 307         struct vfio_ccw_crw *crw;
 308
 309         /*
 310          * If unable to allocate a CRW, just drop the event and
 311          * carry on.  The guest will either see a later one or
 312          * learn when it issues its own store subchannel.
 313          */
 314         crw = kzalloc(sizeof(*crw), GFP_ATOMIC);
 315         if (!crw)
 316                 return;
 317
 318         /*
 319          * Build the CRW based on the inputs given to us.
 320          */
 321         crw->crw.rsc = rsc;
 322         crw->crw.erc = erc;
 323         crw->crw.rsid = rsid;
 324
 325         list_add_tail(&crw->next, &private->crw);
 326         queue_work(vfio_ccw_work_q, &private->crw_work);
 327 }
 328
 329 static int vfio_ccw_chp_event(struct subchannel *sch,
 330                               struct chp_link *link, int event)
 331 {
 332         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 333         int mask = chp_ssd_get_mask(&sch->ssd_info, link);
 334         int retry = 255;
 335
 336         if (!private || !mask)
 337                 return 0;
 338
 339         trace_vfio_ccw_chp_event(private->sch->schid, mask, event);
 340         VFIO_CCW_MSG_EVENT(2, "%pUl (%x.%x.%04x): mask=0x%x event=%d\n",
 341                            mdev_uuid(private->mdev), sch->schid.cssid,
 342                            sch->schid.ssid, sch->schid.sch_no,
 343                            mask, event);
 344
 345         if (cio_update_schib(sch))
 346                 return -ENODEV;
 347
 348         switch (event) {
 349         case CHP_VARY_OFF:
 350                 /* Path logically turned off */
 351                 sch->opm &= ~mask;
 352                 sch->lpm &= ~mask;
 353                 if (sch->schib.pmcw.lpum & mask)
 354                         cio_cancel_halt_clear(sch, &retry);
 355                 break;
 356         case CHP_OFFLINE:
 357                 /* Path is gone */
 358                 if (sch->schib.pmcw.lpum & mask)
 359                         cio_cancel_halt_clear(sch, &retry);
 360                 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_PERRN,
 361                                    link->chpid.id);
 362                 break;
 363         case CHP_VARY_ON:
 364                 /* Path logically turned on */
 365                 sch->opm |= mask;
 366                 sch->lpm |= mask;
 367                 break;
 368         case CHP_ONLINE:
 369                 /* Path became available */
 370                 sch->lpm |= mask & sch->opm;
 371                 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_INIT,
 372                                    link->chpid.id);
 373                 break;
 374         }
 375
 376         return 0;
 377 }
 378
 379 static struct css_device_id vfio_ccw_sch_ids[] = {
 380         { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
 381         { /* end of list */ },
 382 };
 383 MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
 384
 385 static struct css_driver vfio_ccw_sch_driver = {
 386         .drv = {
 387                 .name = "vfio_ccw",
 388                 .owner = THIS_MODULE,
 389         },
 390         .subchannel_type = vfio_ccw_sch_ids,
 391         .irq = vfio_ccw_sch_irq,
 392         .probe = vfio_ccw_sch_probe,
 393         .remove = vfio_ccw_sch_remove,
 394         .shutdown = vfio_ccw_sch_shutdown,
 395         .sch_event = vfio_ccw_sch_event,
 396         .chp_event = vfio_ccw_chp_event,
 397 };
 398
 399 static int __init vfio_ccw_debug_init(void)
 400 {
 401         vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
 402                                                11 * sizeof(long));
 403         if (!vfio_ccw_debug_msg_id)
 404                 goto out_unregister;
 405         debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
 406         debug_set_level(vfio_ccw_debug_msg_id, 2);
 407         vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
 408         if (!vfio_ccw_debug_trace_id)
 409                 goto out_unregister;
 410         debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
 411         debug_set_level(vfio_ccw_debug_trace_id, 2);
 412         return 0;
 413
 414 out_unregister:
 415         debug_unregister(vfio_ccw_debug_msg_id);
 416         debug_unregister(vfio_ccw_debug_trace_id);
 417         return -1;
 418 }
 419
 420 static void vfio_ccw_debug_exit(void)
 421 {
 422         debug_unregister(vfio_ccw_debug_msg_id);
 423         debug_unregister(vfio_ccw_debug_trace_id);
 424 }
 425
 426 static void vfio_ccw_destroy_regions(void)
 427 {
 428         kmem_cache_destroy(vfio_ccw_crw_region);
 429         kmem_cache_destroy(vfio_ccw_schib_region);
 430         kmem_cache_destroy(vfio_ccw_cmd_region);
 431         kmem_cache_destroy(vfio_ccw_io_region);
 432 }
 433
 434 static int __init vfio_ccw_sch_init(void)
 435 {
 436         int ret;
 437
 438         ret = vfio_ccw_debug_init();
 439         if (ret)
 440                 return ret;
 441
 442         vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
 443         if (!vfio_ccw_work_q) {
 444                 ret = -ENOMEM;
 445                 goto out_err;
 446         }
 447
 448         vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
 449                                         sizeof(struct ccw_io_region), 0,
 450                                         SLAB_ACCOUNT, 0,
 451                                         sizeof(struct ccw_io_region), NULL);
 452         if (!vfio_ccw_io_region) {
 453                 ret = -ENOMEM;
 454                 goto out_err;
 455         }
 456
 457         vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
 458                                         sizeof(struct ccw_cmd_region), 0,
 459                                         SLAB_ACCOUNT, 0,
 460                                         sizeof(struct ccw_cmd_region), NULL);
 461         if (!vfio_ccw_cmd_region) {
 462                 ret = -ENOMEM;
 463                 goto out_err;
 464         }
 465
 466         vfio_ccw_schib_region = kmem_cache_create_usercopy("vfio_ccw_schib_region",
 467                                         sizeof(struct ccw_schib_region), 0,
 468                                         SLAB_ACCOUNT, 0,
 469                                         sizeof(struct ccw_schib_region), NULL);
 470
 471         if (!vfio_ccw_schib_region) {
 472                 ret = -ENOMEM;
 473                 goto out_err;
 474         }
 475
 476         vfio_ccw_crw_region = kmem_cache_create_usercopy("vfio_ccw_crw_region",
 477                                         sizeof(struct ccw_crw_region), 0,
 478                                         SLAB_ACCOUNT, 0,
 479                                         sizeof(struct ccw_crw_region), NULL);
 480
 481         if (!vfio_ccw_crw_region) {
 482                 ret = -ENOMEM;
 483                 goto out_err;
 484         }
 485
 486         isc_register(VFIO_CCW_ISC);
 487         ret = css_driver_register(&vfio_ccw_sch_driver);
 488         if (ret) {
 489                 isc_unregister(VFIO_CCW_ISC);
 490                 goto out_err;
 491         }
 492
 493         return ret;
 494
 495 out_err:
 496         vfio_ccw_destroy_regions();
 497         destroy_workqueue(vfio_ccw_work_q);
 498         vfio_ccw_debug_exit();
 499         return ret;
 500 }
 501
 502 static void __exit vfio_ccw_sch_exit(void)
 503 {
 504         css_driver_unregister(&vfio_ccw_sch_driver);
 505         isc_unregister(VFIO_CCW_ISC);
 506         vfio_ccw_destroy_regions();
 507         destroy_workqueue(vfio_ccw_work_q);
 508         vfio_ccw_debug_exit();
 509 }
 510 module_init(vfio_ccw_sch_init);
 511 module_exit(vfio_ccw_sch_exit);
 512
 513 MODULE_LICENSE("GPL v2");