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
  90         private = container_of(work, struct vfio_ccw_private, io_work);
  91         irb = &private->irb;
  92
  93         is_final = !(scsw_actl(&irb->scsw) &
  94                      (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
  95         if (scsw_is_solicited(&irb->scsw)) {
  96                 cp_update_scsw(&private->cp, &irb->scsw);
  97                 if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING)
  98                         cp_free(&private->cp);
  99         }
 100         mutex_lock(&private->io_mutex);
 101         memcpy(private->io_region->irb_area, irb, sizeof(*irb));
 102         mutex_unlock(&private->io_mutex);
 103
 104         if (private->mdev && is_final)
 105                 private->state = VFIO_CCW_STATE_IDLE;
 106
 107         if (private->io_trigger)
 108                 eventfd_signal(private->io_trigger, 1);
 109 }
 110
 111 static void vfio_ccw_crw_todo(struct work_struct *work)
 112 {
 113         struct vfio_ccw_private *private;
 114
 115         private = container_of(work, struct vfio_ccw_private, crw_work);
 116
 117         if (!list_empty(&private->crw) && private->crw_trigger)
 118                 eventfd_signal(private->crw_trigger, 1);
 119 }
 120
 121 /*
 122  * Css driver callbacks
 123  */
 124 static void vfio_ccw_sch_irq(struct subchannel *sch)
 125 {
 126         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 127
 128         inc_irq_stat(IRQIO_CIO);
 129         vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
 130 }
 131
 132 static void vfio_ccw_free_regions(struct vfio_ccw_private *private)
 133 {
 134         if (private->crw_region)
 135                 kmem_cache_free(vfio_ccw_crw_region, private->crw_region);
 136         if (private->schib_region)
 137                 kmem_cache_free(vfio_ccw_schib_region, private->schib_region);
 138         if (private->cmd_region)
 139                 kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
 140         if (private->io_region)
 141                 kmem_cache_free(vfio_ccw_io_region, private->io_region);
 142 }
 143
 144 static int vfio_ccw_sch_probe(struct subchannel *sch)
 145 {
 146         struct pmcw *pmcw = &sch->schib.pmcw;
 147         struct vfio_ccw_private *private;
 148         int ret = -ENOMEM;
 149
 150         if (pmcw->qf) {
 151                 dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
 152                          dev_name(&sch->dev));
 153                 return -ENODEV;
 154         }
 155
 156         private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
 157         if (!private)
 158                 return -ENOMEM;
 159
 160         private->cp.guest_cp = kcalloc(CCWCHAIN_LEN_MAX, sizeof(struct ccw1),
 161                                        GFP_KERNEL);
 162         if (!private->cp.guest_cp)
 163                 goto out_free;
 164
 165         private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
 166                                                GFP_KERNEL | GFP_DMA);
 167         if (!private->io_region)
 168                 goto out_free;
 169
 170         private->cmd_region = kmem_cache_zalloc(vfio_ccw_cmd_region,
 171                                                 GFP_KERNEL | GFP_DMA);
 172         if (!private->cmd_region)
 173                 goto out_free;
 174
 175         private->schib_region = kmem_cache_zalloc(vfio_ccw_schib_region,
 176                                                   GFP_KERNEL | GFP_DMA);
 177
 178         if (!private->schib_region)
 179                 goto out_free;
 180
 181         private->crw_region = kmem_cache_zalloc(vfio_ccw_crw_region,
 182                                                 GFP_KERNEL | GFP_DMA);
 183
 184         if (!private->crw_region)
 185                 goto out_free;
 186
 187         private->sch = sch;
 188         dev_set_drvdata(&sch->dev, private);
 189         mutex_init(&private->io_mutex);
 190
 191         spin_lock_irq(sch->lock);
 192         private->state = VFIO_CCW_STATE_NOT_OPER;
 193         sch->isc = VFIO_CCW_ISC;
 194         ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
 195         spin_unlock_irq(sch->lock);
 196         if (ret)
 197                 goto out_free;
 198
 199         INIT_LIST_HEAD(&private->crw);
 200         INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
 201         INIT_WORK(&private->crw_work, vfio_ccw_crw_todo);
 202         atomic_set(&private->avail, 1);
 203         private->state = VFIO_CCW_STATE_STANDBY;
 204
 205         ret = vfio_ccw_mdev_reg(sch);
 206         if (ret)
 207                 goto out_disable;
 208
 209         if (dev_get_uevent_suppress(&sch->dev)) {
 210                 dev_set_uevent_suppress(&sch->dev, 0);
 211                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 212         }
 213
 214         VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n",
 215                            sch->schid.cssid, sch->schid.ssid,
 216                            sch->schid.sch_no);
 217         return 0;
 218
 219 out_disable:
 220         cio_disable_subchannel(sch);
 221 out_free:
 222         dev_set_drvdata(&sch->dev, NULL);
 223         vfio_ccw_free_regions(private);
 224         kfree(private->cp.guest_cp);
 225         kfree(private);
 226         return ret;
 227 }
 228
 229 static int vfio_ccw_sch_remove(struct subchannel *sch)
 230 {
 231         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 232         struct vfio_ccw_crw *crw, *temp;
 233
 234         vfio_ccw_sch_quiesce(sch);
 235
 236         list_for_each_entry_safe(crw, temp, &private->crw, next) {
 237                 list_del(&crw->next);
 238                 kfree(crw);
 239         }
 240
 241         vfio_ccw_mdev_unreg(sch);
 242
 243         dev_set_drvdata(&sch->dev, NULL);
 244
 245         vfio_ccw_free_regions(private);
 246         kfree(private->cp.guest_cp);
 247         kfree(private);
 248
 249         VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
 250                            sch->schid.cssid, sch->schid.ssid,
 251                            sch->schid.sch_no);
 252         return 0;
 253 }
 254
 255 static void vfio_ccw_sch_shutdown(struct subchannel *sch)
 256 {
 257         vfio_ccw_sch_quiesce(sch);
 258 }
 259
 260 /**
 261  * vfio_ccw_sch_event - process subchannel event
 262  * @sch: subchannel
 263  * @process: non-zero if function is called in process context
 264  *
 265  * An unspecified event occurred for this subchannel. Adjust data according
 266  * to the current operational state of the subchannel. Return zero when the
 267  * event has been handled sufficiently or -EAGAIN when this function should
 268  * be called again in process context.
 269  */
 270 static int vfio_ccw_sch_event(struct subchannel *sch, int process)
 271 {
 272         struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
 273         unsigned long flags;
 274         int rc = -EAGAIN;
 275
 276         spin_lock_irqsave(sch->lock, flags);
 277         if (!device_is_registered(&sch->dev))
 278                 goto out_unlock;
 279
 280         if (work_pending(&sch->todo_work))
 281                 goto out_unlock;
 282
 283         if (cio_update_schib(sch)) {
 284                 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
 285                 rc = 0;
 286                 goto out_unlock;
 287         }
 288
 289         private = dev_get_drvdata(&sch->dev);
 290         if (private->state == VFIO_CCW_STATE_NOT_OPER) {
 291                 private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
 292                                  VFIO_CCW_STATE_STANDBY;
 293         }
 294         rc = 0;
 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");