hw/vfio/ccw.c

   1 /*
   2  * vfio based subchannel assignment support
   3  *
   4  * Copyright 2017 IBM Corp.
   5  * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
   6  *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
   7  *            Pierre Morel <pmorel@linux.vnet.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or (at
  10  * your option) any later version. See the COPYING file in the top-level
  11  * directory.
  12  */
  13
  14 #include "qemu/osdep.h"
  15 #include <linux/vfio.h>
  16 #include <linux/vfio_ccw.h>
  17 #include <sys/ioctl.h>
  18
  19 #include "qapi/error.h"
  20 #include "hw/sysbus.h"
  21 #include "hw/vfio/vfio.h"
  22 #include "hw/vfio/vfio-common.h"
  23 #include "hw/s390x/s390-ccw.h"
  24 #include "hw/s390x/vfio-ccw.h"
  25 #include "hw/s390x/ccw-device.h"
  26 #include "exec/address-spaces.h"
  27 #include "qemu/error-report.h"
  28 #include "qemu/module.h"
  29
  30 struct VFIOCCWDevice {
  31     S390CCWDevice cdev;
  32     VFIODevice vdev;
  33     uint64_t io_region_size;
  34     uint64_t io_region_offset;
  35     struct ccw_io_region *io_region;
  36     EventNotifier io_notifier;
  37     bool force_orb_pfch;
  38     bool warned_orb_pfch;
  39 };
  40
  41 static inline void warn_once_pfch(VFIOCCWDevice *vcdev, SubchDev *sch,
  42                                   const char *msg)
  43 {
  44     warn_report_once_cond(&vcdev->warned_orb_pfch,
  45                           "vfio-ccw (devno %x.%x.%04x): %s",
  46                           sch->cssid, sch->ssid, sch->devno, msg);
  47 }
  48
  49 static void vfio_ccw_compute_needs_reset(VFIODevice *vdev)
  50 {
  51     vdev->needs_reset = false;
  52 }
  53
  54 /*
  55  * We don't need vfio_hot_reset_multi and vfio_eoi operations for
  56  * vfio_ccw device now.
  57  */
  58 struct VFIODeviceOps vfio_ccw_ops = {
  59     .vfio_compute_needs_reset = vfio_ccw_compute_needs_reset,
  60 };
  61
  62 static IOInstEnding vfio_ccw_handle_request(SubchDev *sch)
  63 {
  64     S390CCWDevice *cdev = sch->driver_data;
  65     VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
  66     struct ccw_io_region *region = vcdev->io_region;
  67     int ret;
  68
  69     if (!(sch->orb.ctrl0 & ORB_CTRL0_MASK_PFCH)) {
  70         if (!(vcdev->force_orb_pfch)) {
  71             warn_once_pfch(vcdev, sch, "requires PFCH flag set");
  72             sch_gen_unit_exception(sch);
  73             css_inject_io_interrupt(sch);
  74             return IOINST_CC_EXPECTED;
  75         } else {
  76             sch->orb.ctrl0 |= ORB_CTRL0_MASK_PFCH;
  77             warn_once_pfch(vcdev, sch, "PFCH flag forced");
  78         }
  79     }
  80
  81     QEMU_BUILD_BUG_ON(sizeof(region->orb_area) != sizeof(ORB));
  82     QEMU_BUILD_BUG_ON(sizeof(region->scsw_area) != sizeof(SCSW));
  83     QEMU_BUILD_BUG_ON(sizeof(region->irb_area) != sizeof(IRB));
  84
  85     memset(region, 0, sizeof(*region));
  86
  87     memcpy(region->orb_area, &sch->orb, sizeof(ORB));
  88     memcpy(region->scsw_area, &sch->curr_status.scsw, sizeof(SCSW));
  89
  90 again:
  91     ret = pwrite(vcdev->vdev.fd, region,
  92                  vcdev->io_region_size, vcdev->io_region_offset);
  93     if (ret != vcdev->io_region_size) {
  94         if (errno == EAGAIN) {
  95             goto again;
  96         }
  97         error_report("vfio-ccw: wirte I/O region failed with errno=%d", errno);
  98         ret = -errno;
  99     } else {
 100         ret = region->ret_code;
 101     }
 102     switch (ret) {
 103     case 0:
 104         return IOINST_CC_EXPECTED;
 105     case -EBUSY:
 106         return IOINST_CC_BUSY;
 107     case -ENODEV:
 108     case -EACCES:
 109         return IOINST_CC_NOT_OPERATIONAL;
 110     case -EFAULT:
 111     default:
 112         sch_gen_unit_exception(sch);
 113         css_inject_io_interrupt(sch);
 114         return IOINST_CC_EXPECTED;
 115     }
 116 }
 117
 118 static void vfio_ccw_reset(DeviceState *dev)
 119 {
 120     CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);
 121     S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj, ccw_dev);
 122     VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
 123
 124     ioctl(vcdev->vdev.fd, VFIO_DEVICE_RESET);
 125 }
 126
 127 static void vfio_ccw_io_notifier_handler(void *opaque)
 128 {
 129     VFIOCCWDevice *vcdev = opaque;
 130     struct ccw_io_region *region = vcdev->io_region;
 131     S390CCWDevice *cdev = S390_CCW_DEVICE(vcdev);
 132     CcwDevice *ccw_dev = CCW_DEVICE(cdev);
 133     SubchDev *sch = ccw_dev->sch;
 134     SCHIB *schib = &sch->curr_status;
 135     SCSW s;
 136     IRB irb;
 137     int size;
 138
 139     if (!event_notifier_test_and_clear(&vcdev->io_notifier)) {
 140         return;
 141     }
 142
 143     size = pread(vcdev->vdev.fd, region, vcdev->io_region_size,
 144                  vcdev->io_region_offset);
 145     if (size == -1) {
 146         switch (errno) {
 147         case ENODEV:
 148             /* Generate a deferred cc 3 condition. */
 149             schib->scsw.flags |= SCSW_FLAGS_MASK_CC;
 150             schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
 151             schib->scsw.ctrl |= (SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND);
 152             goto read_err;
 153         case EFAULT:
 154             /* Memory problem, generate channel data check. */
 155             schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
 156             schib->scsw.cstat = SCSW_CSTAT_DATA_CHECK;
 157             schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
 158             schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
 159                        SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
 160             goto read_err;
 161         default:
 162             /* Error, generate channel program check. */
 163             schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
 164             schib->scsw.cstat = SCSW_CSTAT_PROG_CHECK;
 165             schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
 166             schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
 167                        SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
 168             goto read_err;
 169         }
 170     } else if (size != vcdev->io_region_size) {
 171         /* Information transfer error, generate channel-control check. */
 172         schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
 173         schib->scsw.cstat = SCSW_CSTAT_CHN_CTRL_CHK;
 174         schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
 175         schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
 176                    SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
 177         goto read_err;
 178     }
 179
 180     memcpy(&irb, region->irb_area, sizeof(IRB));
 181
 182     /* Update control block via irb. */
 183     s = schib->scsw;
 184     copy_scsw_to_guest(&s, &irb.scsw);
 185     schib->scsw = s;
 186
 187     /* If a uint check is pending, copy sense data. */
 188     if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) &&
 189         (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) {
 190         memcpy(sch->sense_data, irb.ecw, sizeof(irb.ecw));
 191     }
 192
 193 read_err:
 194     css_inject_io_interrupt(sch);
 195 }
 196
 197 static void vfio_ccw_register_io_notifier(VFIOCCWDevice *vcdev, Error **errp)
 198 {
 199     VFIODevice *vdev = &vcdev->vdev;
 200     struct vfio_irq_info *irq_info;
 201     struct vfio_irq_set *irq_set;
 202     size_t argsz;
 203     int32_t *pfd;
 204
 205     if (vdev->num_irqs < VFIO_CCW_IO_IRQ_INDEX + 1) {
 206         error_setg(errp, "vfio: unexpected number of io irqs %u",
 207                    vdev->num_irqs);
 208         return;
 209     }
 210
 211     argsz = sizeof(*irq_info);
 212     irq_info = g_malloc0(argsz);
 213     irq_info->index = VFIO_CCW_IO_IRQ_INDEX;
 214     irq_info->argsz = argsz;
 215     if (ioctl(vdev->fd, VFIO_DEVICE_GET_IRQ_INFO,
 216               irq_info) < 0 || irq_info->count < 1) {
 217         error_setg_errno(errp, errno, "vfio: Error getting irq info");
 218         goto out_free_info;
 219     }
 220
 221     if (event_notifier_init(&vcdev->io_notifier, 0)) {
 222         error_setg_errno(errp, errno,
 223                          "vfio: Unable to init event notifier for IO");
 224         goto out_free_info;
 225     }
 226
 227     argsz = sizeof(*irq_set) + sizeof(*pfd);
 228     irq_set = g_malloc0(argsz);
 229     irq_set->argsz = argsz;
 230     irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
 231                      VFIO_IRQ_SET_ACTION_TRIGGER;
 232     irq_set->index = VFIO_CCW_IO_IRQ_INDEX;
 233     irq_set->start = 0;
 234     irq_set->count = 1;
 235     pfd = (int32_t *) &irq_set->data;
 236
 237     *pfd = event_notifier_get_fd(&vcdev->io_notifier);
 238     qemu_set_fd_handler(*pfd, vfio_ccw_io_notifier_handler, NULL, vcdev);
 239     if (ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, irq_set)) {
 240         error_setg(errp, "vfio: Failed to set up io notification");
 241         qemu_set_fd_handler(*pfd, NULL, NULL, vcdev);
 242         event_notifier_cleanup(&vcdev->io_notifier);
 243     }
 244
 245     g_free(irq_set);
 246
 247 out_free_info:
 248     g_free(irq_info);
 249 }
 250
 251 static void vfio_ccw_unregister_io_notifier(VFIOCCWDevice *vcdev)
 252 {
 253     struct vfio_irq_set *irq_set;
 254     size_t argsz;
 255     int32_t *pfd;
 256
 257     argsz = sizeof(*irq_set) + sizeof(*pfd);
 258     irq_set = g_malloc0(argsz);
 259     irq_set->argsz = argsz;
 260     irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
 261                      VFIO_IRQ_SET_ACTION_TRIGGER;
 262     irq_set->index = VFIO_CCW_IO_IRQ_INDEX;
 263     irq_set->start = 0;
 264     irq_set->count = 1;
 265     pfd = (int32_t *) &irq_set->data;
 266     *pfd = -1;
 267
 268     if (ioctl(vcdev->vdev.fd, VFIO_DEVICE_SET_IRQS, irq_set)) {
 269         error_report("vfio: Failed to de-assign device io fd: %m");
 270     }
 271
 272     qemu_set_fd_handler(event_notifier_get_fd(&vcdev->io_notifier),
 273                         NULL, NULL, vcdev);
 274     event_notifier_cleanup(&vcdev->io_notifier);
 275
 276     g_free(irq_set);
 277 }
 278
 279 static void vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error **errp)
 280 {
 281     VFIODevice *vdev = &vcdev->vdev;
 282     struct vfio_region_info *info;
 283     int ret;
 284
 285     /* Sanity check device */
 286     if (!(vdev->flags & VFIO_DEVICE_FLAGS_CCW)) {
 287         error_setg(errp, "vfio: Um, this isn't a vfio-ccw device");
 288         return;
 289     }
 290
 291     if (vdev->num_regions < VFIO_CCW_CONFIG_REGION_INDEX + 1) {
 292         error_setg(errp, "vfio: Unexpected number of the I/O region %u",
 293                    vdev->num_regions);
 294         return;
 295     }
 296
 297     ret = vfio_get_region_info(vdev, VFIO_CCW_CONFIG_REGION_INDEX, &info);
 298     if (ret) {
 299         error_setg_errno(errp, -ret, "vfio: Error getting config info");
 300         return;
 301     }
 302
 303     vcdev->io_region_size = info->size;
 304     if (sizeof(*vcdev->io_region) != vcdev->io_region_size) {
 305         error_setg(errp, "vfio: Unexpected size of the I/O region");
 306         g_free(info);
 307         return;
 308     }
 309
 310     vcdev->io_region_offset = info->offset;
 311     vcdev->io_region = g_malloc0(info->size);
 312
 313     g_free(info);
 314 }
 315
 316 static void vfio_ccw_put_region(VFIOCCWDevice *vcdev)
 317 {
 318     g_free(vcdev->io_region);
 319 }
 320
 321 static void vfio_ccw_put_device(VFIOCCWDevice *vcdev)
 322 {
 323     g_free(vcdev->vdev.name);
 324     vfio_put_base_device(&vcdev->vdev);
 325 }
 326
 327 static void vfio_ccw_get_device(VFIOGroup *group, VFIOCCWDevice *vcdev,
 328                                 Error **errp)
 329 {
 330     char *name = g_strdup_printf("%x.%x.%04x", vcdev->cdev.hostid.cssid,
 331                                  vcdev->cdev.hostid.ssid,
 332                                  vcdev->cdev.hostid.devid);
 333     VFIODevice *vbasedev;
 334
 335     QLIST_FOREACH(vbasedev, &group->device_list, next) {
 336         if (strcmp(vbasedev->name, name) == 0) {
 337             error_setg(errp, "vfio: subchannel %s has already been attached",
 338                        name);
 339             goto out_err;
 340         }
 341     }
 342
 343     /*
 344      * All vfio-ccw devices are believed to operate in a way compatible with
 345      * memory ballooning, ie. pages pinned in the host are in the current
 346      * working set of the guest driver and therefore never overlap with pages
 347      * available to the guest balloon driver.  This needs to be set before
 348      * vfio_get_device() for vfio common to handle the balloon inhibitor.
 349      */
 350     vcdev->vdev.balloon_allowed = true;
 351
 352     if (vfio_get_device(group, vcdev->cdev.mdevid, &vcdev->vdev, errp)) {
 353         goto out_err;
 354     }
 355
 356     vcdev->vdev.ops = &vfio_ccw_ops;
 357     vcdev->vdev.type = VFIO_DEVICE_TYPE_CCW;
 358     vcdev->vdev.name = name;
 359     vcdev->vdev.dev = &vcdev->cdev.parent_obj.parent_obj;
 360
 361     return;
 362
 363 out_err:
 364     g_free(name);
 365 }
 366
 367 static VFIOGroup *vfio_ccw_get_group(S390CCWDevice *cdev, Error **errp)
 368 {
 369     char *tmp, group_path[PATH_MAX];
 370     ssize_t len;
 371     int groupid;
 372
 373     tmp = g_strdup_printf("/sys/bus/css/devices/%x.%x.%04x/%s/iommu_group",
 374                           cdev->hostid.cssid, cdev->hostid.ssid,
 375                           cdev->hostid.devid, cdev->mdevid);
 376     len = readlink(tmp, group_path, sizeof(group_path));
 377     g_free(tmp);
 378
 379     if (len <= 0 || len >= sizeof(group_path)) {
 380         error_setg(errp, "vfio: no iommu_group found");
 381         return NULL;
 382     }
 383
 384     group_path[len] = 0;
 385
 386     if (sscanf(basename(group_path), "%d", &groupid) != 1) {
 387         error_setg(errp, "vfio: failed to read %s", group_path);
 388         return NULL;
 389     }
 390
 391     return vfio_get_group(groupid, &address_space_memory, errp);
 392 }
 393
 394 static void vfio_ccw_realize(DeviceState *dev, Error **errp)
 395 {
 396     VFIOGroup *group;
 397     CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);
 398     S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj, ccw_dev);
 399     VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
 400     S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev);
 401     Error *err = NULL;
 402
 403     /* Call the class init function for subchannel. */
 404     if (cdc->realize) {
 405         cdc->realize(cdev, vcdev->vdev.sysfsdev, &err);
 406         if (err) {
 407             goto out_err_propagate;
 408         }
 409     }
 410
 411     group = vfio_ccw_get_group(cdev, &err);
 412     if (!group) {
 413         goto out_group_err;
 414     }
 415
 416     vfio_ccw_get_device(group, vcdev, &err);
 417     if (err) {
 418         goto out_device_err;
 419     }
 420
 421     vfio_ccw_get_region(vcdev, &err);
 422     if (err) {
 423         goto out_region_err;
 424     }
 425
 426     vfio_ccw_register_io_notifier(vcdev, &err);
 427     if (err) {
 428         goto out_notifier_err;
 429     }
 430
 431     return;
 432
 433 out_notifier_err:
 434     vfio_ccw_put_region(vcdev);
 435 out_region_err:
 436     vfio_ccw_put_device(vcdev);
 437 out_device_err:
 438     vfio_put_group(group);
 439 out_group_err:
 440     if (cdc->unrealize) {
 441         cdc->unrealize(cdev, NULL);
 442     }
 443 out_err_propagate:
 444     error_propagate(errp, err);
 445 }
 446
 447 static void vfio_ccw_unrealize(DeviceState *dev, Error **errp)
 448 {
 449     CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);
 450     S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj, ccw_dev);
 451     VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
 452     S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev);
 453     VFIOGroup *group = vcdev->vdev.group;
 454
 455     vfio_ccw_unregister_io_notifier(vcdev);
 456     vfio_ccw_put_region(vcdev);
 457     vfio_ccw_put_device(vcdev);
 458     vfio_put_group(group);
 459
 460     if (cdc->unrealize) {
 461         cdc->unrealize(cdev, errp);
 462     }
 463 }
 464
 465 static Property vfio_ccw_properties[] = {
 466     DEFINE_PROP_STRING("sysfsdev", VFIOCCWDevice, vdev.sysfsdev),
 467     DEFINE_PROP_BOOL("force-orb-pfch", VFIOCCWDevice, force_orb_pfch, false),
 468     DEFINE_PROP_END_OF_LIST(),
 469 };
 470
 471 static const VMStateDescription vfio_ccw_vmstate = {
 472     .name = "vfio-ccw",
 473     .unmigratable = 1,
 474 };
 475
 476 static void vfio_ccw_class_init(ObjectClass *klass, void *data)
 477 {
 478     DeviceClass *dc = DEVICE_CLASS(klass);
 479     S390CCWDeviceClass *cdc = S390_CCW_DEVICE_CLASS(klass);
 480
 481     dc->props = vfio_ccw_properties;
 482     dc->vmsd = &vfio_ccw_vmstate;
 483     dc->desc = "VFIO-based subchannel assignment";
 484     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 485     dc->realize = vfio_ccw_realize;
 486     dc->unrealize = vfio_ccw_unrealize;
 487     dc->reset = vfio_ccw_reset;
 488
 489     cdc->handle_request = vfio_ccw_handle_request;
 490 }
 491
 492 static const TypeInfo vfio_ccw_info = {
 493     .name = TYPE_VFIO_CCW,
 494     .parent = TYPE_S390_CCW,
 495     .instance_size = sizeof(VFIOCCWDevice),
 496     .class_init = vfio_ccw_class_init,
 497 };
 498
 499 static void register_vfio_ccw_type(void)
 500 {
 501     type_register_static(&vfio_ccw_info);
 502 }
 503
 504 type_init(register_vfio_ccw_type)