hw/s390x/s390-skeys.c

   1 /*
   2  * s390 storage key device
   3  *
   4  * Copyright 2015 IBM Corp.
   5  * Author(s): Jason J. Herne <jjherne@linux.vnet.ibm.com>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2 or (at
   8  * your option) any later version. See the COPYING file in the top-level
   9  * directory.
  10  */
  11
  12 #include "qemu/osdep.h"
  13 #include "qemu/units.h"
  14 #include "hw/boards.h"
  15 #include "hw/qdev-properties.h"
  16 #include "hw/s390x/storage-keys.h"
  17 #include "qapi/error.h"
  18 #include "qapi/qapi-commands-misc-target.h"
  19 #include "qapi/qmp/qdict.h"
  20 #include "qemu/error-report.h"
  21 #include "sysemu/memory_mapping.h"
  22 #include "exec/address-spaces.h"
  23 #include "sysemu/kvm.h"
  24 #include "migration/qemu-file-types.h"
  25 #include "migration/register.h"
  26
  27 #define S390_SKEYS_BUFFER_SIZE (128 * KiB)  /* Room for 128k storage keys */
  28 #define S390_SKEYS_SAVE_FLAG_EOS 0x01
  29 #define S390_SKEYS_SAVE_FLAG_SKEYS 0x02
  30 #define S390_SKEYS_SAVE_FLAG_ERROR 0x04
  31
  32 S390SKeysState *s390_get_skeys_device(void)
  33 {
  34     S390SKeysState *ss;
  35
  36     ss = S390_SKEYS(object_resolve_path_type("", TYPE_S390_SKEYS, NULL));
  37     assert(ss);
  38     return ss;
  39 }
  40
  41 void s390_skeys_init(void)
  42 {
  43     Object *obj;
  44
  45     if (kvm_enabled()) {
  46         obj = object_new(TYPE_KVM_S390_SKEYS);
  47     } else {
  48         obj = object_new(TYPE_QEMU_S390_SKEYS);
  49     }
  50     object_property_add_child(qdev_get_machine(), TYPE_S390_SKEYS,
  51                               obj);
  52     object_unref(obj);
  53
  54     qdev_realize(DEVICE(obj), NULL, &error_fatal);
  55 }
  56
  57 static void write_keys(FILE *f, uint8_t *keys, uint64_t startgfn,
  58                        uint64_t count, Error **errp)
  59 {
  60     uint64_t curpage = startgfn;
  61     uint64_t maxpage = curpage + count - 1;
  62
  63     for (; curpage <= maxpage; curpage++) {
  64         uint8_t acc = (*keys & 0xF0) >> 4;
  65         int fp =  (*keys & 0x08);
  66         int ref = (*keys & 0x04);
  67         int ch = (*keys & 0x02);
  68         int res = (*keys & 0x01);
  69
  70         fprintf(f, "page=%03" PRIx64 ": key(%d) => ACC=%X, FP=%d, REF=%d,"
  71                 " ch=%d, reserved=%d\n",
  72                 curpage, *keys, acc, fp, ref, ch, res);
  73         keys++;
  74     }
  75 }
  76
  77 void hmp_info_skeys(Monitor *mon, const QDict *qdict)
  78 {
  79     S390SKeysState *ss = s390_get_skeys_device();
  80     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
  81     uint64_t addr = qdict_get_int(qdict, "addr");
  82     uint8_t key;
  83     int r;
  84
  85     /* Quick check to see if guest is using storage keys*/
  86     if (!skeyclass->skeys_are_enabled(ss)) {
  87         monitor_printf(mon, "Error: This guest is not using storage keys\n");
  88         return;
  89     }
  90
  91     if (!address_space_access_valid(&address_space_memory,
  92                                     addr & TARGET_PAGE_MASK, TARGET_PAGE_SIZE,
  93                                     false, MEMTXATTRS_UNSPECIFIED)) {
  94         monitor_printf(mon, "Error: The given address is not valid\n");
  95         return;
  96     }
  97
  98     r = skeyclass->get_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
  99     if (r < 0) {
 100         monitor_printf(mon, "Error: %s\n", strerror(-r));
 101         return;
 102     }
 103
 104     monitor_printf(mon, "  key: 0x%X\n", key);
 105 }
 106
 107 void hmp_dump_skeys(Monitor *mon, const QDict *qdict)
 108 {
 109     const char *filename = qdict_get_str(qdict, "filename");
 110     Error *err = NULL;
 111
 112     qmp_dump_skeys(filename, &err);
 113     if (err) {
 114         error_report_err(err);
 115     }
 116 }
 117
 118 void qmp_dump_skeys(const char *filename, Error **errp)
 119 {
 120     S390SKeysState *ss = s390_get_skeys_device();
 121     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
 122     GuestPhysBlockList guest_phys_blocks;
 123     GuestPhysBlock *block;
 124     uint64_t pages, gfn;
 125     Error *lerr = NULL;
 126     uint8_t *buf;
 127     int ret;
 128     int fd;
 129     FILE *f;
 130
 131     /* Quick check to see if guest is using storage keys*/
 132     if (!skeyclass->skeys_are_enabled(ss)) {
 133         error_setg(errp, "This guest is not using storage keys - "
 134                          "nothing to dump");
 135         return;
 136     }
 137
 138     fd = qemu_open_old(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
 139     if (fd < 0) {
 140         error_setg_file_open(errp, errno, filename);
 141         return;
 142     }
 143     f = fdopen(fd, "wb");
 144     if (!f) {
 145         close(fd);
 146         error_setg_file_open(errp, errno, filename);
 147         return;
 148     }
 149
 150     buf = g_try_malloc(S390_SKEYS_BUFFER_SIZE);
 151     if (!buf) {
 152         error_setg(errp, "Could not allocate memory");
 153         goto out;
 154     }
 155
 156     assert(bql_locked());
 157     guest_phys_blocks_init(&guest_phys_blocks);
 158     guest_phys_blocks_append(&guest_phys_blocks);
 159
 160     QTAILQ_FOREACH(block, &guest_phys_blocks.head, next) {
 161         assert(QEMU_IS_ALIGNED(block->target_start, TARGET_PAGE_SIZE));
 162         assert(QEMU_IS_ALIGNED(block->target_end, TARGET_PAGE_SIZE));
 163
 164         gfn = block->target_start / TARGET_PAGE_SIZE;
 165         pages = (block->target_end - block->target_start) / TARGET_PAGE_SIZE;
 166
 167         while (pages) {
 168             const uint64_t cur_pages = MIN(pages, S390_SKEYS_BUFFER_SIZE);
 169
 170             ret = skeyclass->get_skeys(ss, gfn, cur_pages, buf);
 171             if (ret < 0) {
 172                 error_setg_errno(errp, -ret, "get_keys error");
 173                 goto out_free;
 174             }
 175
 176             /* write keys to stream */
 177             write_keys(f, buf, gfn, cur_pages, &lerr);
 178             if (lerr) {
 179                 goto out_free;
 180             }
 181
 182             gfn += cur_pages;
 183             pages -= cur_pages;
 184         }
 185     }
 186
 187 out_free:
 188     guest_phys_blocks_free(&guest_phys_blocks);
 189     error_propagate(errp, lerr);
 190     g_free(buf);
 191 out:
 192     fclose(f);
 193 }
 194
 195 static bool qemu_s390_skeys_are_enabled(S390SKeysState *ss)
 196 {
 197     QEMUS390SKeysState *skeys = QEMU_S390_SKEYS(ss);
 198
 199     /* Lockless check is sufficient. */
 200     return !!skeys->keydata;
 201 }
 202
 203 static bool qemu_s390_enable_skeys(S390SKeysState *ss)
 204 {
 205     QEMUS390SKeysState *skeys = QEMU_S390_SKEYS(ss);
 206     static gsize initialized;
 207
 208     if (likely(skeys->keydata)) {
 209         return true;
 210     }
 211
 212     /*
 213      * TODO: Modern Linux doesn't use storage keys unless running KVM guests
 214      *       that use storage keys. Therefore, we keep it simple for now.
 215      *
 216      * 1) We should initialize to "referenced+changed" for an initial
 217      *    over-indication. Let's avoid touching megabytes of data for now and
 218      *    assume that any sane user will issue a storage key instruction before
 219      *    actually relying on this data.
 220      * 2) Relying on ram_size and allocating a big array is ugly. We should
 221      *    allocate and manage storage key data per RAMBlock or optimally using
 222      *    some sparse data structure.
 223      * 3) We only ever have a single S390SKeysState, so relying on
 224      *    g_once_init_enter() is good enough.
 225      */
 226     if (g_once_init_enter(&initialized)) {
 227         MachineState *machine = MACHINE(qdev_get_machine());
 228
 229         skeys->key_count = machine->ram_size / TARGET_PAGE_SIZE;
 230         skeys->keydata = g_malloc0(skeys->key_count);
 231         g_once_init_leave(&initialized, 1);
 232     }
 233     return false;
 234 }
 235
 236 static int qemu_s390_skeys_set(S390SKeysState *ss, uint64_t start_gfn,
 237                               uint64_t count, uint8_t *keys)
 238 {
 239     QEMUS390SKeysState *skeydev = QEMU_S390_SKEYS(ss);
 240     int i;
 241
 242     /* Check for uint64 overflow and access beyond end of key data */
 243     if (unlikely(!skeydev->keydata || start_gfn + count > skeydev->key_count ||
 244                   start_gfn + count < count)) {
 245         error_report("Error: Setting storage keys for pages with unallocated "
 246                      "storage key memory: gfn=%" PRIx64 " count=%" PRId64,
 247                      start_gfn, count);
 248         return -EINVAL;
 249     }
 250
 251     for (i = 0; i < count; i++) {
 252         skeydev->keydata[start_gfn + i] = keys[i];
 253     }
 254     return 0;
 255 }
 256
 257 static int qemu_s390_skeys_get(S390SKeysState *ss, uint64_t start_gfn,
 258                                uint64_t count, uint8_t *keys)
 259 {
 260     QEMUS390SKeysState *skeydev = QEMU_S390_SKEYS(ss);
 261     int i;
 262
 263     /* Check for uint64 overflow and access beyond end of key data */
 264     if (unlikely(!skeydev->keydata || start_gfn + count > skeydev->key_count ||
 265                   start_gfn + count < count)) {
 266         error_report("Error: Getting storage keys for pages with unallocated "
 267                      "storage key memory: gfn=%" PRIx64 " count=%" PRId64,
 268                      start_gfn, count);
 269         return -EINVAL;
 270     }
 271
 272     for (i = 0; i < count; i++) {
 273         keys[i] = skeydev->keydata[start_gfn + i];
 274     }
 275     return 0;
 276 }
 277
 278 static void qemu_s390_skeys_class_init(ObjectClass *oc, void *data)
 279 {
 280     S390SKeysClass *skeyclass = S390_SKEYS_CLASS(oc);
 281     DeviceClass *dc = DEVICE_CLASS(oc);
 282
 283     skeyclass->skeys_are_enabled = qemu_s390_skeys_are_enabled;
 284     skeyclass->enable_skeys = qemu_s390_enable_skeys;
 285     skeyclass->get_skeys = qemu_s390_skeys_get;
 286     skeyclass->set_skeys = qemu_s390_skeys_set;
 287
 288     /* Reason: Internal device (only one skeys device for the whole memory) */
 289     dc->user_creatable = false;
 290 }
 291
 292 static const TypeInfo qemu_s390_skeys_info = {
 293     .name          = TYPE_QEMU_S390_SKEYS,
 294     .parent        = TYPE_S390_SKEYS,
 295     .instance_size = sizeof(QEMUS390SKeysState),
 296     .class_init    = qemu_s390_skeys_class_init,
 297     .class_size    = sizeof(S390SKeysClass),
 298 };
 299
 300 static void s390_storage_keys_save(QEMUFile *f, void *opaque)
 301 {
 302     S390SKeysState *ss = S390_SKEYS(opaque);
 303     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
 304     GuestPhysBlockList guest_phys_blocks;
 305     GuestPhysBlock *block;
 306     uint64_t pages, gfn;
 307     int error = 0;
 308     uint8_t *buf;
 309
 310     if (!skeyclass->skeys_are_enabled(ss)) {
 311         goto end_stream;
 312     }
 313
 314     buf = g_try_malloc(S390_SKEYS_BUFFER_SIZE);
 315     if (!buf) {
 316         error_report("storage key save could not allocate memory");
 317         goto end_stream;
 318     }
 319
 320     guest_phys_blocks_init(&guest_phys_blocks);
 321     guest_phys_blocks_append(&guest_phys_blocks);
 322
 323     /* Send each contiguous physical memory range separately. */
 324     QTAILQ_FOREACH(block, &guest_phys_blocks.head, next) {
 325         assert(QEMU_IS_ALIGNED(block->target_start, TARGET_PAGE_SIZE));
 326         assert(QEMU_IS_ALIGNED(block->target_end, TARGET_PAGE_SIZE));
 327
 328         gfn = block->target_start / TARGET_PAGE_SIZE;
 329         pages = (block->target_end - block->target_start) / TARGET_PAGE_SIZE;
 330         qemu_put_be64(f, block->target_start | S390_SKEYS_SAVE_FLAG_SKEYS);
 331         qemu_put_be64(f, pages);
 332
 333         while (pages) {
 334             const uint64_t cur_pages = MIN(pages, S390_SKEYS_BUFFER_SIZE);
 335
 336             if (!error) {
 337                 error = skeyclass->get_skeys(ss, gfn, cur_pages, buf);
 338                 if (error) {
 339                     /*
 340                      * Create a valid stream with all 0x00 and indicate
 341                      * S390_SKEYS_SAVE_FLAG_ERROR to the destination.
 342                      */
 343                     error_report("S390_GET_KEYS error %d", error);
 344                     memset(buf, 0, S390_SKEYS_BUFFER_SIZE);
 345                 }
 346             }
 347
 348             qemu_put_buffer(f, buf, cur_pages);
 349             gfn += cur_pages;
 350             pages -= cur_pages;
 351         }
 352
 353         if (error) {
 354             break;
 355         }
 356     }
 357
 358     guest_phys_blocks_free(&guest_phys_blocks);
 359     g_free(buf);
 360 end_stream:
 361     if (error) {
 362         qemu_put_be64(f, S390_SKEYS_SAVE_FLAG_ERROR);
 363     } else {
 364         qemu_put_be64(f, S390_SKEYS_SAVE_FLAG_EOS);
 365     }
 366 }
 367
 368 static int s390_storage_keys_load(QEMUFile *f, void *opaque, int version_id)
 369 {
 370     S390SKeysState *ss = S390_SKEYS(opaque);
 371     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
 372     int ret = 0;
 373
 374     /*
 375      * Make sure to lazy-enable if required to be done explicitly. No need to
 376      * flush any TLB as the VM is not running yet.
 377      */
 378     if (skeyclass->enable_skeys) {
 379         skeyclass->enable_skeys(ss);
 380     }
 381
 382     while (!ret) {
 383         ram_addr_t addr;
 384         int flags;
 385
 386         addr = qemu_get_be64(f);
 387         flags = addr & ~TARGET_PAGE_MASK;
 388         addr &= TARGET_PAGE_MASK;
 389
 390         switch (flags) {
 391         case S390_SKEYS_SAVE_FLAG_SKEYS: {
 392             const uint64_t total_count = qemu_get_be64(f);
 393             uint64_t handled_count = 0, cur_count;
 394             uint64_t cur_gfn = addr / TARGET_PAGE_SIZE;
 395             uint8_t *buf = g_try_malloc(S390_SKEYS_BUFFER_SIZE);
 396
 397             if (!buf) {
 398                 error_report("storage key load could not allocate memory");
 399                 ret = -ENOMEM;
 400                 break;
 401             }
 402
 403             while (handled_count < total_count) {
 404                 cur_count = MIN(total_count - handled_count,
 405                                 S390_SKEYS_BUFFER_SIZE);
 406                 qemu_get_buffer(f, buf, cur_count);
 407
 408                 ret = skeyclass->set_skeys(ss, cur_gfn, cur_count, buf);
 409                 if (ret < 0) {
 410                     error_report("S390_SET_KEYS error %d", ret);
 411                     break;
 412                 }
 413                 handled_count += cur_count;
 414                 cur_gfn += cur_count;
 415             }
 416             g_free(buf);
 417             break;
 418         }
 419         case S390_SKEYS_SAVE_FLAG_ERROR: {
 420             error_report("Storage key data is incomplete");
 421             ret = -EINVAL;
 422             break;
 423         }
 424         case S390_SKEYS_SAVE_FLAG_EOS:
 425             /* normal exit */
 426             return 0;
 427         default:
 428             error_report("Unexpected storage key flag data: %#x", flags);
 429             ret = -EINVAL;
 430         }
 431     }
 432
 433     return ret;
 434 }
 435
 436 static SaveVMHandlers savevm_s390_storage_keys = {
 437     .save_state = s390_storage_keys_save,
 438     .load_state = s390_storage_keys_load,
 439 };
 440
 441 static void s390_skeys_realize(DeviceState *dev, Error **errp)
 442 {
 443     S390SKeysState *ss = S390_SKEYS(dev);
 444
 445     if (ss->migration_enabled) {
 446         register_savevm_live(TYPE_S390_SKEYS, 0, 1,
 447                              &savevm_s390_storage_keys, ss);
 448     }
 449 }
 450
 451 static Property s390_skeys_props[] = {
 452     DEFINE_PROP_BOOL("migration-enabled", S390SKeysState, migration_enabled, true),
 453     DEFINE_PROP_END_OF_LIST(),
 454 };
 455
 456 static void s390_skeys_class_init(ObjectClass *oc, void *data)
 457 {
 458     DeviceClass *dc = DEVICE_CLASS(oc);
 459
 460     dc->hotpluggable = false;
 461     dc->realize = s390_skeys_realize;
 462     device_class_set_props(dc, s390_skeys_props);
 463     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 464 }
 465
 466 static const TypeInfo s390_skeys_info = {
 467     .name          = TYPE_S390_SKEYS,
 468     .parent        = TYPE_DEVICE,
 469     .instance_size = sizeof(S390SKeysState),
 470     .class_init    = s390_skeys_class_init,
 471     .class_size    = sizeof(S390SKeysClass),
 472     .abstract = true,
 473 };
 474
 475 static void qemu_s390_skeys_register_types(void)
 476 {
 477     type_register_static(&s390_skeys_info);
 478     type_register_static(&qemu_s390_skeys_info);
 479 }
 480
 481 type_init(qemu_s390_skeys_register_types)