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