pc-bios/s390-ccw/virtio.c

   1 /*
   2  * Virtio driver bits
   3  *
   4  * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or (at
   7  * your option) any later version. See the COPYING file in the top-level
   8  * directory.
   9  */
  10
  11 #include "s390-ccw.h"
  12 #include "virtio.h"
  13
  14 #define VRING_WAIT_REPLY_TIMEOUT 3
  15
  16 static VRing block[VIRTIO_MAX_VQS];
  17 static char ring_area[VIRTIO_RING_SIZE * VIRTIO_MAX_VQS]
  18                      __attribute__((__aligned__(PAGE_SIZE)));
  19
  20 static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  21
  22 static VDev vdev = {
  23     .nr_vqs = 1,
  24     .vrings = block,
  25     .cmd_vr_idx = 0,
  26     .ring_area = ring_area,
  27     .wait_reply_timeout = VRING_WAIT_REPLY_TIMEOUT,
  28     .schid = { .one = 1 },
  29 };
  30
  31 VDev *virtio_get_device(void)
  32 {
  33     return &vdev;
  34 }
  35
  36 VirtioDevType virtio_get_device_type(void)
  37 {
  38     return vdev.senseid.cu_model;
  39 }
  40
  41 /* virtio spec v1.0 para 4.3.3.2 */
  42 static long kvm_hypercall(unsigned long nr, unsigned long param1,
  43                           unsigned long param2, unsigned long param3)
  44 {
  45     register ulong r_nr asm("1") = nr;
  46     register ulong r_param1 asm("2") = param1;
  47     register ulong r_param2 asm("3") = param2;
  48     register ulong r_param3 asm("4") = param3;
  49     register long retval asm("2");
  50
  51     asm volatile ("diag 2,4,0x500"
  52                   : "=d" (retval)
  53                   : "d" (r_nr), "0" (r_param1), "r"(r_param2), "d"(r_param3)
  54                   : "memory", "cc");
  55
  56     return retval;
  57 }
  58
  59 static long virtio_notify(SubChannelId schid, int vq_idx, long cookie)
  60 {
  61     return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid,
  62                          vq_idx, cookie);
  63 }
  64
  65 /***********************************************
  66  *             Virtio functions                *
  67  ***********************************************/
  68
  69 static int drain_irqs(SubChannelId schid)
  70 {
  71     Irb irb = {};
  72     int r = 0;
  73
  74     while (1) {
  75         /* FIXME: make use of TPI, for that enable subchannel and isc */
  76         if (tsch(schid, &irb)) {
  77             /* Might want to differentiate error codes later on. */
  78             if (irb.scsw.cstat) {
  79                 r = -EIO;
  80             } else if (irb.scsw.dstat != 0xc) {
  81                 r = -EIO;
  82             }
  83             return r;
  84         }
  85     }
  86 }
  87
  88 static int run_ccw(VDev *vdev, int cmd, void *ptr, int len)
  89 {
  90     Ccw1 ccw = {};
  91     CmdOrb orb = {};
  92     Schib schib;
  93     int r;
  94
  95     /* start command processing */
  96     stsch_err(vdev->schid, &schib);
  97     schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
  98     msch(vdev->schid, &schib);
  99
 100     /* start subchannel command */
 101     orb.fmt = 1;
 102     orb.cpa = (u32)(long)&ccw;
 103     orb.lpm = 0x80;
 104
 105     ccw.cmd_code = cmd;
 106     ccw.cda = (long)ptr;
 107     ccw.count = len;
 108
 109     r = ssch(vdev->schid, &orb);
 110     /*
 111      * XXX Wait until device is done processing the CCW. For now we can
 112      *     assume that a simple tsch will have finished the CCW processing,
 113      *     but the architecture allows for asynchronous operation
 114      */
 115     if (!r) {
 116         r = drain_irqs(vdev->schid);
 117     }
 118     return r;
 119 }
 120
 121 static void vring_init(VRing *vr, VqInfo *info)
 122 {
 123     void *p = (void *) info->queue;
 124
 125     debug_print_addr("init p", p);
 126     vr->id = info->index;
 127     vr->num = info->num;
 128     vr->desc = p;
 129     vr->avail = p + info->num * sizeof(VRingDesc);
 130     vr->used = (void *)(((unsigned long)&vr->avail->ring[info->num]
 131                + info->align - 1) & ~(info->align - 1));
 132
 133     /* Zero out all relevant field */
 134     vr->avail->flags = 0;
 135     vr->avail->idx = 0;
 136
 137     /* We're running with interrupts off anyways, so don't bother */
 138     vr->used->flags = VRING_USED_F_NO_NOTIFY;
 139     vr->used->idx = 0;
 140     vr->used_idx = 0;
 141     vr->next_idx = 0;
 142     vr->cookie = 0;
 143
 144     debug_print_addr("init vr", vr);
 145 }
 146
 147 static bool vring_notify(VRing *vr)
 148 {
 149     vr->cookie = virtio_notify(vr->schid, vr->id, vr->cookie);
 150     return vr->cookie >= 0;
 151 }
 152
 153 static void vring_send_buf(VRing *vr, void *p, int len, int flags)
 154 {
 155     /* For follow-up chains we need to keep the first entry point */
 156     if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
 157         vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
 158     }
 159
 160     vr->desc[vr->next_idx].addr = (ulong)p;
 161     vr->desc[vr->next_idx].len = len;
 162     vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
 163     vr->desc[vr->next_idx].next = vr->next_idx;
 164     vr->desc[vr->next_idx].next++;
 165     vr->next_idx++;
 166
 167     /* Chains only have a single ID */
 168     if (!(flags & VRING_DESC_F_NEXT)) {
 169         vr->avail->idx++;
 170     }
 171 }
 172
 173 static u64 get_clock(void)
 174 {
 175     u64 r;
 176
 177     asm volatile("stck %0" : "=Q" (r) : : "cc");
 178     return r;
 179 }
 180
 181 ulong get_second(void)
 182 {
 183     return (get_clock() >> 12) / 1000000;
 184 }
 185
 186 static int vr_poll(VRing *vr)
 187 {
 188     if (vr->used->idx == vr->used_idx) {
 189         vring_notify(vr);
 190         yield();
 191         return 0;
 192     }
 193
 194     vr->used_idx = vr->used->idx;
 195     vr->next_idx = 0;
 196     vr->desc[0].len = 0;
 197     vr->desc[0].flags = 0;
 198     return 1; /* vr has been updated */
 199 }
 200
 201 /*
 202  * Wait for the host to reply.
 203  *
 204  * timeout is in seconds if > 0.
 205  *
 206  * Returns 0 on success, 1 on timeout.
 207  */
 208 static int vring_wait_reply(void)
 209 {
 210     ulong target_second = get_second() + vdev.wait_reply_timeout;
 211
 212     /* Wait for any queue to be updated by the host */
 213     do {
 214         int i, r = 0;
 215
 216         for (i = 0; i < vdev.nr_vqs; i++) {
 217             r += vr_poll(&vdev.vrings[i]);
 218         }
 219         yield();
 220         if (r) {
 221             return 0;
 222         }
 223     } while (!vdev.wait_reply_timeout || (get_second() < target_second));
 224
 225     return 1;
 226 }
 227
 228 /***********************************************
 229  *               Virtio block                  *
 230  ***********************************************/
 231
 232 static int virtio_blk_read_many(VDev *vdev,
 233                                 ulong sector, void *load_addr, int sec_num)
 234 {
 235     VirtioBlkOuthdr out_hdr;
 236     u8 status;
 237     VRing *vr = &vdev->vrings[vdev->cmd_vr_idx];
 238
 239     /* Tell the host we want to read */
 240     out_hdr.type = VIRTIO_BLK_T_IN;
 241     out_hdr.ioprio = 99;
 242     out_hdr.sector = virtio_sector_adjust(sector);
 243
 244     vring_send_buf(vr, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);
 245
 246     /* This is where we want to receive data */
 247     vring_send_buf(vr, load_addr, virtio_get_block_size() * sec_num,
 248                    VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN |
 249                    VRING_DESC_F_NEXT);
 250
 251     /* status field */
 252     vring_send_buf(vr, &status, sizeof(u8),
 253                    VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN);
 254
 255     /* Now we can tell the host to read */
 256     vring_wait_reply();
 257
 258     if (drain_irqs(vr->schid)) {
 259         /* Well, whatever status is supposed to contain... */
 260         status = 1;
 261     }
 262     return status;
 263 }
 264
 265 int virtio_read_many(ulong sector, void *load_addr, int sec_num)
 266 {
 267     switch (vdev.senseid.cu_model) {
 268     case VIRTIO_ID_BLOCK:
 269         return virtio_blk_read_many(&vdev, sector, load_addr, sec_num);
 270     }
 271     panic("\n! No readable IPL device !\n");
 272     return -1;
 273 }
 274
 275 unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
 276                                  ulong subchan_id, void *load_addr)
 277 {
 278     u8 status;
 279     int sec = rec_list1;
 280     int sec_num = ((rec_list2 >> 32) & 0xffff) + 1;
 281     int sec_len = rec_list2 >> 48;
 282     ulong addr = (ulong)load_addr;
 283
 284     if (sec_len != virtio_get_block_size()) {
 285         return -1;
 286     }
 287
 288     sclp_print(".");
 289     status = virtio_read_many(sec, (void *)addr, sec_num);
 290     if (status) {
 291         panic("I/O Error");
 292     }
 293     addr += sec_num * virtio_get_block_size();
 294
 295     return addr;
 296 }
 297
 298 int virtio_read(ulong sector, void *load_addr)
 299 {
 300     return virtio_read_many(sector, load_addr, 1);
 301 }
 302
 303 VirtioGDN virtio_guessed_disk_nature(void)
 304 {
 305     return vdev.guessed_disk_nature;
 306 }
 307
 308 void virtio_assume_scsi(void)
 309 {
 310     vdev.guessed_disk_nature = VIRTIO_GDN_SCSI;
 311     switch (vdev.senseid.cu_model) {
 312     case VIRTIO_ID_BLOCK:
 313         vdev.config.blk.blk_size = 512;
 314         vdev.config.blk.physical_block_exp = 0;
 315         break;
 316     }
 317 }
 318
 319 void virtio_assume_iso9660(void)
 320 {
 321     vdev.guessed_disk_nature = VIRTIO_GDN_CDROM;
 322     switch (vdev.senseid.cu_model) {
 323     case VIRTIO_ID_BLOCK:
 324         vdev.config.blk.blk_size = 2048;
 325         vdev.config.blk.physical_block_exp = 0;
 326         break;
 327     }
 328 }
 329
 330 void virtio_assume_eckd(void)
 331 {
 332     vdev.guessed_disk_nature = VIRTIO_GDN_DASD;
 333     switch (vdev.senseid.cu_model) {
 334     case VIRTIO_ID_BLOCK:
 335         vdev.config.blk.blk_size = 4096;
 336         vdev.config.blk.physical_block_exp = 0;
 337
 338         /* this must be here to calculate code segment position */
 339         vdev.config.blk.geometry.heads = 15;
 340         vdev.config.blk.geometry.sectors = 12;
 341         break;
 342     }
 343 }
 344
 345 bool virtio_disk_is_scsi(void)
 346 {
 347     if (vdev.guessed_disk_nature == VIRTIO_GDN_SCSI) {
 348         return true;
 349     }
 350     switch (vdev.senseid.cu_model) {
 351     case VIRTIO_ID_BLOCK:
 352         return (vdev.config.blk.geometry.heads == 255)
 353             && (vdev.config.blk.geometry.sectors == 63)
 354             && (virtio_get_block_size()  == 512);
 355     }
 356     return false;
 357 }
 358
 359 /*
 360  * Other supported value pairs, if any, would need to be added here.
 361  * Note: head count is always 15.
 362  */
 363 static inline u8 virtio_eckd_sectors_for_block_size(int size)
 364 {
 365     switch (size) {
 366     case 512:
 367         return 49;
 368     case 1024:
 369         return 33;
 370     case 2048:
 371         return 21;
 372     case 4096:
 373         return 12;
 374     }
 375     return 0;
 376 }
 377
 378 bool virtio_disk_is_eckd(void)
 379 {
 380     const int block_size = virtio_get_block_size();
 381
 382     if (vdev.guessed_disk_nature == VIRTIO_GDN_DASD) {
 383         return true;
 384     }
 385     switch (vdev.senseid.cu_model) {
 386     case VIRTIO_ID_BLOCK:
 387         return (vdev.config.blk.geometry.heads == 15)
 388             && (vdev.config.blk.geometry.sectors ==
 389                 virtio_eckd_sectors_for_block_size(block_size));
 390     }
 391     return false;
 392 }
 393
 394 bool virtio_ipl_disk_is_valid(void)
 395 {
 396     return virtio_disk_is_scsi() || virtio_disk_is_eckd();
 397 }
 398
 399 int virtio_get_block_size(void)
 400 {
 401     switch (vdev.senseid.cu_model) {
 402     case VIRTIO_ID_BLOCK:
 403         return vdev.config.blk.blk_size << vdev.config.blk.physical_block_exp;
 404     }
 405     return 0;
 406 }
 407
 408 uint8_t virtio_get_heads(void)
 409 {
 410     switch (vdev.senseid.cu_model) {
 411     case VIRTIO_ID_BLOCK:
 412         return vdev.config.blk.geometry.heads;
 413     }
 414     return 0;
 415 }
 416
 417 uint8_t virtio_get_sectors(void)
 418 {
 419     switch (vdev.senseid.cu_model) {
 420     case VIRTIO_ID_BLOCK:
 421         return vdev.config.blk.geometry.sectors;
 422     }
 423     return 0;
 424 }
 425
 426 uint64_t virtio_get_blocks(void)
 427 {
 428     switch (vdev.senseid.cu_model) {
 429     case VIRTIO_ID_BLOCK:
 430         return vdev.config.blk.capacity /
 431                (virtio_get_block_size() / VIRTIO_SECTOR_SIZE);
 432     }
 433     return 0;
 434 }
 435
 436 static void virtio_setup_ccw(VDev *vdev)
 437 {
 438     int i, cfg_size;
 439     unsigned char status = VIRTIO_CONFIG_S_DRIVER_OK;
 440
 441     vdev->config.blk.blk_size = 0; /* mark "illegal" - setup started... */
 442     vdev->guessed_disk_nature = VIRTIO_GDN_NONE;
 443
 444     run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0);
 445
 446     switch (vdev->senseid.cu_model) {
 447     case VIRTIO_ID_BLOCK:
 448         vdev->nr_vqs = 1;
 449         vdev->cmd_vr_idx = 0;
 450         cfg_size = sizeof(vdev->config.blk);
 451         break;
 452     default:
 453         panic("Unsupported virtio device\n");
 454     }
 455     IPL_assert(run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size) == 0,
 456                "Could not get block device configuration");
 457
 458     /*
 459      * Skipping CCW_CMD_READ_FEAT. We're not doing anything fancy, and
 460      * we'll just stop dead anyway if anything does not work like we
 461      * expect it.
 462      */
 463
 464     for (i = 0; i < vdev->nr_vqs; i++) {
 465         VqInfo info = {
 466             .queue = (unsigned long long) ring_area + (i * VIRTIO_RING_SIZE),
 467             .align = KVM_S390_VIRTIO_RING_ALIGN,
 468             .index = i,
 469             .num = 0,
 470         };
 471         VqConfig config = {
 472             .index = i,
 473             .num = 0,
 474         };
 475
 476         IPL_assert(
 477             run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config)) == 0,
 478             "Could not get block device VQ configuration");
 479         info.num = config.num;
 480         vring_init(&vdev->vrings[i], &info);
 481         vdev->vrings[i].schid = vdev->schid;
 482         IPL_assert(run_ccw(vdev, CCW_CMD_SET_VQ, &info, sizeof(info)) == 0,
 483                    "Cannot set VQ info");
 484     }
 485     IPL_assert(
 486         run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status)) == 0,
 487         "Could not write status to host");
 488 }
 489
 490 void virtio_setup_device(SubChannelId schid)
 491 {
 492     vdev.schid = schid;
 493     virtio_setup_ccw(&vdev);
 494
 495     switch (vdev.senseid.cu_model) {
 496     case VIRTIO_ID_BLOCK:
 497         if (!virtio_ipl_disk_is_valid()) {
 498             /* make sure all getters but blocksize return 0 for
 499              * invalid IPL disk
 500              */
 501             memset(&vdev.config.blk, 0, sizeof(vdev.config.blk));
 502             virtio_assume_scsi();
 503         }
 504         break;
 505     default:
 506         panic("\n! No IPL device available !\n");
 507     }
 508 }
 509
 510 bool virtio_is_supported(SubChannelId schid)
 511 {
 512     vdev.schid = schid;
 513     memset(&vdev.senseid, 0, sizeof(vdev.senseid));
 514     /* run sense id command */
 515     if (run_ccw(&vdev, CCW_CMD_SENSE_ID, &vdev.senseid, sizeof(vdev.senseid))) {
 516         return false;
 517     }
 518     if (vdev.senseid.cu_type == 0x3832) {
 519         switch (vdev.senseid.cu_model) {
 520         case VIRTIO_ID_BLOCK:
 521             return true;
 522         }
 523     }
 524     return false;
 525 }
 526
 527 int enable_mss_facility(void)
 528 {
 529     int ret;
 530     ChscAreaSda *sda_area = (ChscAreaSda *) chsc_page;
 531
 532     memset(sda_area, 0, PAGE_SIZE);
 533     sda_area->request.length = 0x0400;
 534     sda_area->request.code = 0x0031;
 535     sda_area->operation_code = 0x2;
 536
 537     ret = chsc(sda_area);
 538     if ((ret == 0) && (sda_area->response.code == 0x0001)) {
 539         return 0;
 540     }
 541     return -EIO;
 542 }