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/s390x/storage-keys.h"
  16 #include "qapi/error.h"
  17 #include "qapi/qapi-commands-misc-target.h"
  18 #include "qapi/qmp/qdict.h"
  19 #include "qemu/error-report.h"
  20 #include "sysemu/memory_mapping.h"
  21 #include "exec/address-spaces.h"
  22 #include "sysemu/kvm.h"
  23 #include "migration/qemu-file-types.h"
  24 #include "migration/register.h"
  25
  26 #define S390_SKEYS_BUFFER_SIZE (128 * KiB)  /* Room for 128k storage keys */
  27 #define S390_SKEYS_SAVE_FLAG_EOS 0x01
  28 #define S390_SKEYS_SAVE_FLAG_SKEYS 0x02
  29 #define S390_SKEYS_SAVE_FLAG_ERROR 0x04
  30
  31 S390SKeysState *s390_get_skeys_device(void)
  32 {
  33     S390SKeysState *ss;
  34
  35     ss = S390_SKEYS(object_resolve_path_type("", TYPE_S390_SKEYS, NULL));
  36     assert(ss);
  37     return ss;
  38 }
  39
  40 void s390_skeys_init(void)
  41 {
  42     Object *obj;
  43
  44     if (kvm_enabled()) {
  45         obj = object_new(TYPE_KVM_S390_SKEYS);
  46     } else {
  47         obj = object_new(TYPE_QEMU_S390_SKEYS);
  48     }
  49     object_property_add_child(qdev_get_machine(), TYPE_S390_SKEYS,
  50                               obj);
  51     object_unref(obj);
  52
  53     qdev_realize(DEVICE(obj), NULL, &error_fatal);
  54 }
  55
  56 static void write_keys(FILE *f, uint8_t *keys, uint64_t startgfn,
  57                        uint64_t count, Error **errp)
  58 {
  59     uint64_t curpage = startgfn;
  60     uint64_t maxpage = curpage + count - 1;
  61
  62     for (; curpage <= maxpage; curpage++) {
  63         uint8_t acc = (*keys & 0xF0) >> 4;
  64         int fp =  (*keys & 0x08);
  65         int ref = (*keys & 0x04);
  66         int ch = (*keys & 0x02);
  67         int res = (*keys & 0x01);
  68
  69         fprintf(f, "page=%03" PRIx64 ": key(%d) => ACC=%X, FP=%d, REF=%d,"
  70                 " ch=%d, reserved=%d\n",
  71                 curpage, *keys, acc, fp, ref, ch, res);
  72         keys++;
  73     }
  74 }
  75
  76 void hmp_info_skeys(Monitor *mon, const QDict *qdict)
  77 {
  78     S390SKeysState *ss = s390_get_skeys_device();
  79     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
  80     uint64_t addr = qdict_get_int(qdict, "addr");
  81     uint8_t key;
  82     int r;
  83
  84     /* Quick check to see if guest is using storage keys*/
  85     if (!skeyclass->skeys_are_enabled(ss)) {
  86         monitor_printf(mon, "Error: This guest is not using storage keys\n");
  87         return;
  88     }
  89
  90     if (!address_space_access_valid(&address_space_memory,
  91                                     addr & TARGET_PAGE_MASK, TARGET_PAGE_SIZE,
  92                                     false, MEMTXATTRS_UNSPECIFIED)) {
  93         monitor_printf(mon, "Error: The given address is not valid\n");
  94         return;
  95     }
  96
  97     r = skeyclass->get_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
  98     if (r < 0) {
  99         monitor_printf(mon, "Error: %s\n", strerror(-r));
 100         return;
 101     }
 102
 103     monitor_printf(mon, "  key: 0x%X\n", key);
 104 }
 105
 106 void hmp_dump_skeys(Monitor *mon, const QDict *qdict)
 107 {
 108     const char *filename = qdict_get_str(qdict, "filename");
 109     Error *err = NULL;
 110
 111     qmp_dump_skeys(filename, &err);
 112     if (err) {
 113         error_report_err(err);
 114     }
 115 }
 116
 117 void qmp_dump_skeys(const char *filename, Error **errp)
 118 {
 119     S390SKeysState *ss = s390_get_skeys_device();
 120     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
 121     GuestPhysBlockList guest_phys_blocks;
 122     GuestPhysBlock *block;
 123     uint64_t pages, gfn;
 124     Error *lerr = NULL;
 125     uint8_t *buf;
 126     int ret;
 127     int fd;
 128     FILE *f;
 129
 130     /* Quick check to see if guest is using storage keys*/
 131     if (!skeyclass->skeys_are_enabled(ss)) {
 132         error_setg(errp, "This guest is not using storage keys - "
 133                          "nothing to dump");
 134         return;
 135     }
 136
 137     fd = qemu_open_old(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
 138     if (fd < 0) {
 139         error_setg_file_open(errp, errno, filename);
 140         return;
 141     }
 142     f = fdopen(fd, "wb");
 143     if (!f) {
 144         close(fd);
 145         error_setg_file_open(errp, errno, filename);
 146         return;
 147     }
 148
 149     buf = g_try_malloc(S390_SKEYS_BUFFER_SIZE);
 150     if (!buf) {
 151         error_setg(errp, "Could not allocate memory");
 152         goto out;
 153     }
 154
 155     assert(qemu_mutex_iothread_locked());
 156     guest_phys_blocks_init(&guest_phys_blocks);
 157     guest_phys_blocks_append(&guest_phys_blocks);
 158
 159     QTAILQ_FOREACH(block, &guest_phys_blocks.head, next) {
 160         assert(QEMU_IS_ALIGNED(block->target_start, TARGET_PAGE_SIZE));
 161         assert(QEMU_IS_ALIGNED(block->target_end, TARGET_PAGE_SIZE));
 162
 163         gfn = block->target_start / TARGET_PAGE_SIZE;
 164         pages = (block->target_end - block->target_start) / TARGET_PAGE_SIZE;
 165
 166         while (pages) {
 167             const uint64_t cur_pages = MIN(pages, S390_SKEYS_BUFFER_SIZE);
 168
 169             ret = skeyclass->get_skeys(ss, gfn, cur_pages, buf);
 170             if (ret < 0) {
 171                 error_setg_errno(errp, -ret, "get_keys error");
 172                 goto out_free;
 173             }
 174
 175             /* write keys to stream */
 176             write_keys(f, buf, gfn, cur_pages, &lerr);
 177             if (lerr) {
 178                 goto out_free;
 179             }
 180
 181             gfn += cur_pages;
 182             pages -= cur_pages;
 183         }
 184     }
 185
 186 out_free:
 187     guest_phys_blocks_free(&guest_phys_blocks);
 188     error_propagate(errp, lerr);
 189     g_free(buf);
 190 out:
 191     fclose(f);
 192 }
 193
 194 static bool qemu_s390_skeys_are_enabled(S390SKeysState *ss)
 195 {
 196     QEMUS390SKeysState *skeys = QEMU_S390_SKEYS(ss);
 197
 198     /* Lockless check is sufficient. */
 199     return !!skeys->keydata;
 200 }
 201
 202 static bool qemu_s390_enable_skeys(S390SKeysState *ss)
 203 {
 204     QEMUS390SKeysState *skeys = QEMU_S390_SKEYS(ss);
 205     static gsize initialized;
 206
 207     if (likely(skeys->keydata)) {
 208         return true;
 209     }
 210
 211     /*
 212      * TODO: Modern Linux doesn't use storage keys unless running KVM guests
 213      *       that use storage keys. Therefore, we keep it simple for now.
 214      *
 215      * 1) We should initialize to "referenced+changed" for an initial
 216      *    over-indication. Let's avoid touching megabytes of data for now and
 217      *    assume that any sane user will issue a storage key instruction before
 218      *    actually relying on this data.
 219      * 2) Relying on ram_size and allocating a big array is ugly. We should
 220      *    allocate and manage storage key data per RAMBlock or optimally using
 221      *    some sparse data structure.
 222      * 3) We only ever have a single S390SKeysState, so relying on
 223      *    g_once_init_enter() is good enough.
 224      */
 225     if (g_once_init_enter(&initialized)) {
 226         MachineState *machine = MACHINE(qdev_get_machine());
 227
 228         skeys->key_count = machine->ram_size / TARGET_PAGE_SIZE;
 229         skeys->keydata = g_malloc0(skeys->key_count);
 230         g_once_init_leave(&initialized, 1);
 231     }
 232     return false;
 233 }
 234
 235 static int qemu_s390_skeys_set(S390SKeysState *ss, uint64_t start_gfn,
 236                               uint64_t count, uint8_t *keys)
 237 {
 238     QEMUS390SKeysState *skeydev = QEMU_S390_SKEYS(ss);
 239     int i;
 240
 241     /* Check for uint64 overflow and access beyond end of key data */
 242     if (unlikely(!skeydev->keydata || start_gfn + count > skeydev->key_count ||
 243                   start_gfn + count < count)) {
 244         error_report("Error: Setting storage keys for pages with unallocated "
 245                      "storage key memory: gfn=%" PRIx64 " count=%" PRId64,
 246                      start_gfn, count);
 247         return -EINVAL;
 248     }
 249
 250     for (i = 0; i < count; i++) {
 251         skeydev->keydata[start_gfn + i] = keys[i];
 252     }
 253     return 0;
 254 }
 255
 256 static int qemu_s390_skeys_get(S390SKeysState *ss, uint64_t start_gfn,
 257                                uint64_t count, uint8_t *keys)
 258 {
 259     QEMUS390SKeysState *skeydev = QEMU_S390_SKEYS(ss);
 260     int i;
 261
 262     /* Check for uint64 overflow and access beyond end of key data */
 263     if (unlikely(!skeydev->keydata || start_gfn + count > skeydev->key_count ||
 264                   start_gfn + count < count)) {
 265         error_report("Error: Getting storage keys for pages with unallocated "
 266                      "storage key memory: gfn=%" PRIx64 " count=%" PRId64,
 267                      start_gfn, count);
 268         return -EINVAL;
 269     }
 270
 271     for (i = 0; i < count; i++) {
 272         keys[i] = skeydev->keydata[start_gfn + i];
 273     }
 274     return 0;
 275 }
 276
 277 static void qemu_s390_skeys_class_init(ObjectClass *oc, void *data)
 278 {
 279     S390SKeysClass *skeyclass = S390_SKEYS_CLASS(oc);
 280     DeviceClass *dc = DEVICE_CLASS(oc);
 281
 282     skeyclass->skeys_are_enabled = qemu_s390_skeys_are_enabled;
 283     skeyclass->enable_skeys = qemu_s390_enable_skeys;
 284     skeyclass->get_skeys = qemu_s390_skeys_get;
 285     skeyclass->set_skeys = qemu_s390_skeys_set;
 286
 287     /* Reason: Internal device (only one skeys device for the whole memory) */
 288     dc->user_creatable = false;
 289 }
 290
 291 static const TypeInfo qemu_s390_skeys_info = {
 292     .name          = TYPE_QEMU_S390_SKEYS,
 293     .parent        = TYPE_S390_SKEYS,
 294     .instance_size = sizeof(QEMUS390SKeysState),
 295     .class_init    = qemu_s390_skeys_class_init,
 296     .class_size    = sizeof(S390SKeysClass),
 297 };
 298
 299 static void s390_storage_keys_save(QEMUFile *f, void *opaque)
 300 {
 301     S390SKeysState *ss = S390_SKEYS(opaque);
 302     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
 303     GuestPhysBlockList guest_phys_blocks;
 304     GuestPhysBlock *block;
 305     uint64_t pages, gfn;
 306     int error = 0;
 307     uint8_t *buf;
 308
 309     if (!skeyclass->skeys_are_enabled(ss)) {
 310         goto end_stream;
 311     }
 312
 313     buf = g_try_malloc(S390_SKEYS_BUFFER_SIZE);
 314     if (!buf) {
 315         error_report("storage key save could not allocate memory");
 316         goto end_stream;
 317     }
 318
 319     guest_phys_blocks_init(&guest_phys_blocks);
 320     guest_phys_blocks_append(&guest_phys_blocks);
 321
 322     /* Send each contiguous physical memory range separately. */
 323     QTAILQ_FOREACH(block, &guest_phys_blocks.head, next) {
 324         assert(QEMU_IS_ALIGNED(block->target_start, TARGET_PAGE_SIZE));
 325         assert(QEMU_IS_ALIGNED(block->target_end, TARGET_PAGE_SIZE));
 326
 327         gfn = block->target_start / TARGET_PAGE_SIZE;
 328         pages = (block->target_end - block->target_start) / TARGET_PAGE_SIZE;
 329         qemu_put_be64(f, block->target_start | S390_SKEYS_SAVE_FLAG_SKEYS);
 330         qemu_put_be64(f, pages);
 331
 332         while (pages) {
 333             const uint64_t cur_pages = MIN(pages, S390_SKEYS_BUFFER_SIZE);
 334
 335             if (!error) {
 336                 error = skeyclass->get_skeys(ss, gfn, cur_pages, buf);
 337                 if (error) {
 338                     /*
 339                      * Create a valid stream with all 0x00 and indicate
 340                      * S390_SKEYS_SAVE_FLAG_ERROR to the destination.
 341                      */
 342                     error_report("S390_GET_KEYS error %d", error);
 343                     memset(buf, 0, S390_SKEYS_BUFFER_SIZE);
 344                 }
 345             }
 346
 347             qemu_put_buffer(f, buf, cur_pages);
 348             gfn += cur_pages;
 349             pages -= cur_pages;
 350         }
 351
 352         if (error) {
 353             break;
 354         }
 355     }
 356
 357     guest_phys_blocks_free(&guest_phys_blocks);
 358     g_free(buf);
 359 end_stream:
 360     if (error) {
 361         qemu_put_be64(f, S390_SKEYS_SAVE_FLAG_ERROR);
 362     } else {
 363         qemu_put_be64(f, S390_SKEYS_SAVE_FLAG_EOS);
 364     }
 365 }
 366
 367 static int s390_storage_keys_load(QEMUFile *f, void *opaque, int version_id)
 368 {
 369     S390SKeysState *ss = S390_SKEYS(opaque);
 370     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
 371     int ret = 0;
 372
 373     /*
 374      * Make sure to lazy-enable if required to be done explicitly. No need to
 375      * flush any TLB as the VM is not running yet.
 376      */
 377     if (skeyclass->enable_skeys) {
 378         skeyclass->enable_skeys(ss);
 379     }
 380
 381     while (!ret) {
 382         ram_addr_t addr;
 383         int flags;
 384
 385         addr = qemu_get_be64(f);
 386         flags = addr & ~TARGET_PAGE_MASK;
 387         addr &= TARGET_PAGE_MASK;
 388
 389         switch (flags) {
 390         case S390_SKEYS_SAVE_FLAG_SKEYS: {
 391             const uint64_t total_count = qemu_get_be64(f);
 392             uint64_t handled_count = 0, cur_count;
 393             uint64_t cur_gfn = addr / TARGET_PAGE_SIZE;
 394             uint8_t *buf = g_try_malloc(S390_SKEYS_BUFFER_SIZE);
 395
 396             if (!buf) {
 397                 error_report("storage key load could not allocate memory");
 398                 ret = -ENOMEM;
 399                 break;
 400             }
 401
 402             while (handled_count < total_count) {
 403                 cur_count = MIN(total_count - handled_count,
 404                                 S390_SKEYS_BUFFER_SIZE);
 405                 qemu_get_buffer(f, buf, cur_count);
 406
 407                 ret = skeyclass->set_skeys(ss, cur_gfn, cur_count, buf);
 408                 if (ret < 0) {
 409                     error_report("S390_SET_KEYS error %d", ret);
 410                     break;
 411                 }
 412                 handled_count += cur_count;
 413                 cur_gfn += cur_count;
 414             }
 415             g_free(buf);
 416             break;
 417         }
 418         case S390_SKEYS_SAVE_FLAG_ERROR: {
 419             error_report("Storage key data is incomplete");
 420             ret = -EINVAL;
 421             break;
 422         }
 423         case S390_SKEYS_SAVE_FLAG_EOS:
 424             /* normal exit */
 425             return 0;
 426         default:
 427             error_report("Unexpected storage key flag data: %#x", flags);
 428             ret = -EINVAL;
 429         }
 430     }
 431
 432     return ret;
 433 }
 434
 435 static inline bool s390_skeys_get_migration_enabled(Object *obj, Error **errp)
 436 {
 437     S390SKeysState *ss = S390_SKEYS(obj);
 438
 439     return ss->migration_enabled;
 440 }
 441
 442 static SaveVMHandlers savevm_s390_storage_keys = {
 443     .save_state = s390_storage_keys_save,
 444     .load_state = s390_storage_keys_load,
 445 };
 446
 447 static inline void s390_skeys_set_migration_enabled(Object *obj, bool value,
 448                                             Error **errp)
 449 {
 450     S390SKeysState *ss = S390_SKEYS(obj);
 451
 452     /* Prevent double registration of savevm handler */
 453     if (ss->migration_enabled == value) {
 454         return;
 455     }
 456
 457     ss->migration_enabled = value;
 458
 459     if (ss->migration_enabled) {
 460         register_savevm_live(TYPE_S390_SKEYS, 0, 1,
 461                              &savevm_s390_storage_keys, ss);
 462     } else {
 463         unregister_savevm(VMSTATE_IF(ss), TYPE_S390_SKEYS, ss);
 464     }
 465 }
 466
 467 static void s390_skeys_instance_init(Object *obj)
 468 {
 469     object_property_add_bool(obj, "migration-enabled",
 470                              s390_skeys_get_migration_enabled,
 471                              s390_skeys_set_migration_enabled);
 472     object_property_set_bool(obj, "migration-enabled", true, NULL);
 473 }
 474
 475 static void s390_skeys_class_init(ObjectClass *oc, void *data)
 476 {
 477     DeviceClass *dc = DEVICE_CLASS(oc);
 478
 479     dc->hotpluggable = false;
 480     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 481 }
 482
 483 static const TypeInfo s390_skeys_info = {
 484     .name          = TYPE_S390_SKEYS,
 485     .parent        = TYPE_DEVICE,
 486     .instance_init = s390_skeys_instance_init,
 487     .instance_size = sizeof(S390SKeysState),
 488     .class_init    = s390_skeys_class_init,
 489     .class_size    = sizeof(S390SKeysClass),
 490     .abstract = true,
 491 };
 492
 493 static void qemu_s390_skeys_register_types(void)
 494 {
 495     type_register_static(&s390_skeys_info);
 496     type_register_static(&qemu_s390_skeys_info);
 497 }
 498
 499 type_init(qemu_s390_skeys_register_types)