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 static struct vring block;
  15
  16 static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  17
  18 static long kvm_hypercall(unsigned long nr, unsigned long param1,
  19                           unsigned long param2)
  20 {
  21     register ulong r_nr asm("1") = nr;
  22     register ulong r_param1 asm("2") = param1;
  23     register ulong r_param2 asm("3") = param2;
  24     register long retval asm("2");
  25
  26     asm volatile ("diag 2,4,0x500"
  27                   : "=d" (retval)
  28                   : "d" (r_nr), "0" (r_param1), "r"(r_param2)
  29                   : "memory", "cc");
  30
  31     return retval;
  32 }
  33
  34 static void virtio_notify(struct subchannel_id schid)
  35 {
  36     kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid, 0);
  37 }
  38
  39 /***********************************************
  40  *             Virtio functions                *
  41  ***********************************************/
  42
  43 static int drain_irqs(struct subchannel_id schid)
  44 {
  45     struct irb irb = {};
  46     int r = 0;
  47
  48     while (1) {
  49         /* FIXME: make use of TPI, for that enable subchannel and isc */
  50         if (tsch(schid, &irb)) {
  51             /* Might want to differentiate error codes later on. */
  52             if (irb.scsw.cstat) {
  53                 r = -EIO;
  54             } else if (irb.scsw.dstat != 0xc) {
  55                 r = -EIO;
  56             }
  57             return r;
  58         }
  59     }
  60 }
  61
  62 static int run_ccw(struct subchannel_id schid, int cmd, void *ptr, int len)
  63 {
  64     struct ccw1 ccw = {};
  65     struct cmd_orb orb = {};
  66     struct schib schib;
  67     int r;
  68
  69     /* start command processing */
  70     stsch_err(schid, &schib);
  71     schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
  72     msch(schid, &schib);
  73
  74     /* start subchannel command */
  75     orb.fmt = 1;
  76     orb.cpa = (u32)(long)&ccw;
  77     orb.lpm = 0x80;
  78
  79     ccw.cmd_code = cmd;
  80     ccw.cda = (long)ptr;
  81     ccw.count = len;
  82
  83     r = ssch(schid, &orb);
  84     /*
  85      * XXX Wait until device is done processing the CCW. For now we can
  86      *     assume that a simple tsch will have finished the CCW processing,
  87      *     but the architecture allows for asynchronous operation
  88      */
  89     if (!r) {
  90         r = drain_irqs(schid);
  91     }
  92     return r;
  93 }
  94
  95 static void virtio_set_status(struct subchannel_id schid,
  96                               unsigned long dev_addr)
  97 {
  98     unsigned char status = dev_addr;
  99     if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
 100         virtio_panic("Could not write status to host!\n");
 101     }
 102 }
 103
 104 static void virtio_reset(struct subchannel_id schid)
 105 {
 106     run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
 107 }
 108
 109 static void vring_init(struct vring *vr, unsigned int num, void *p,
 110                        unsigned long align)
 111 {
 112     debug_print_addr("init p", p);
 113     vr->num = num;
 114     vr->desc = p;
 115     vr->avail = p + num*sizeof(struct vring_desc);
 116     vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
 117                 & ~(align - 1));
 118
 119     /* Zero out all relevant field */
 120     vr->avail->flags = 0;
 121     vr->avail->idx = 0;
 122
 123     /* We're running with interrupts off anyways, so don't bother */
 124     vr->used->flags = VRING_USED_F_NO_NOTIFY;
 125     vr->used->idx = 0;
 126     vr->used_idx = 0;
 127     vr->next_idx = 0;
 128
 129     debug_print_addr("init vr", vr);
 130 }
 131
 132 static void vring_notify(struct subchannel_id schid)
 133 {
 134     virtio_notify(schid);
 135 }
 136
 137 static void vring_send_buf(struct vring *vr, void *p, int len, int flags)
 138 {
 139     /* For follow-up chains we need to keep the first entry point */
 140     if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
 141         vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
 142     }
 143
 144     vr->desc[vr->next_idx].addr = (ulong)p;
 145     vr->desc[vr->next_idx].len = len;
 146     vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
 147     vr->desc[vr->next_idx].next = vr->next_idx;
 148     vr->desc[vr->next_idx].next++;
 149     vr->next_idx++;
 150
 151     /* Chains only have a single ID */
 152     if (!(flags & VRING_DESC_F_NEXT)) {
 153         vr->avail->idx++;
 154     }
 155 }
 156
 157 static u64 get_clock(void)
 158 {
 159     u64 r;
 160
 161     asm volatile("stck %0" : "=Q" (r) : : "cc");
 162     return r;
 163 }
 164
 165 static ulong get_second(void)
 166 {
 167     return (get_clock() >> 12) / 1000000;
 168 }
 169
 170 /*
 171  * Wait for the host to reply.
 172  *
 173  * timeout is in seconds if > 0.
 174  *
 175  * Returns 0 on success, 1 on timeout.
 176  */
 177 static int vring_wait_reply(struct vring *vr, int timeout)
 178 {
 179     ulong target_second = get_second() + timeout;
 180     struct subchannel_id schid = vr->schid;
 181     int r = 0;
 182
 183     /* Wait until the used index has moved. */
 184     while (vr->used->idx == vr->used_idx) {
 185         vring_notify(schid);
 186         if (timeout && (get_second() >= target_second)) {
 187             r = 1;
 188             break;
 189         }
 190         yield();
 191     }
 192
 193     vr->used_idx = vr->used->idx;
 194     vr->next_idx = 0;
 195     vr->desc[0].len = 0;
 196     vr->desc[0].flags = 0;
 197
 198     return r;
 199 }
 200
 201 /***********************************************
 202  *               Virtio block                  *
 203  ***********************************************/
 204
 205 int virtio_read_many(ulong sector, void *load_addr, int sec_num)
 206 {
 207     struct virtio_blk_outhdr out_hdr;
 208     u8 status;
 209     int r;
 210
 211     /* Tell the host we want to read */
 212     out_hdr.type = VIRTIO_BLK_T_IN;
 213     out_hdr.ioprio = 99;
 214     out_hdr.sector = virtio_sector_adjust(sector);
 215
 216     vring_send_buf(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);
 217
 218     /* This is where we want to receive data */
 219     vring_send_buf(&block, load_addr, virtio_get_block_size() * sec_num,
 220                    VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN |
 221                    VRING_DESC_F_NEXT);
 222
 223     /* status field */
 224     vring_send_buf(&block, &status, sizeof(u8), VRING_DESC_F_WRITE |
 225                    VRING_HIDDEN_IS_CHAIN);
 226
 227     /* Now we can tell the host to read */
 228     vring_wait_reply(&block, 0);
 229
 230     r = drain_irqs(block.schid);
 231     if (r) {
 232         /* Well, whatever status is supposed to contain... */
 233         status = 1;
 234     }
 235     return status;
 236 }
 237
 238 unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
 239                                  ulong subchan_id, void *load_addr)
 240 {
 241     u8 status;
 242     int sec = rec_list1;
 243     int sec_num = ((rec_list2 >> 32) & 0xffff) + 1;
 244     int sec_len = rec_list2 >> 48;
 245     ulong addr = (ulong)load_addr;
 246
 247     if (sec_len != virtio_get_block_size()) {
 248         return -1;
 249     }
 250
 251     sclp_print(".");
 252     status = virtio_read_many(sec, (void *)addr, sec_num);
 253     if (status) {
 254         virtio_panic("I/O Error");
 255     }
 256     addr += sec_num * virtio_get_block_size();
 257
 258     return addr;
 259 }
 260
 261 int virtio_read(ulong sector, void *load_addr)
 262 {
 263     return virtio_read_many(sector, load_addr, 1);
 264 }
 265
 266 static VirtioBlkConfig blk_cfg = {};
 267 static bool guessed_disk_nature;
 268
 269 bool virtio_guessed_disk_nature(void)
 270 {
 271     return guessed_disk_nature;
 272 }
 273
 274 void virtio_assume_scsi(void)
 275 {
 276     guessed_disk_nature = true;
 277     blk_cfg.blk_size = 512;
 278     blk_cfg.physical_block_exp = 0;
 279 }
 280
 281 void virtio_assume_iso9660(void)
 282 {
 283     guessed_disk_nature = true;
 284     blk_cfg.blk_size = 2048;
 285     blk_cfg.physical_block_exp = 0;
 286 }
 287
 288 void virtio_assume_eckd(void)
 289 {
 290     guessed_disk_nature = true;
 291     blk_cfg.blk_size = 4096;
 292     blk_cfg.physical_block_exp = 0;
 293
 294     /* this must be here to calculate code segment position */
 295     blk_cfg.geometry.heads = 15;
 296     blk_cfg.geometry.sectors = 12;
 297 }
 298
 299 bool virtio_disk_is_scsi(void)
 300 {
 301     if (guessed_disk_nature) {
 302         return (virtio_get_block_size()  == 512);
 303     }
 304     return (blk_cfg.geometry.heads == 255)
 305         && (blk_cfg.geometry.sectors == 63)
 306         && (virtio_get_block_size()  == 512);
 307 }
 308
 309 /*
 310  * Other supported value pairs, if any, would need to be added here.
 311  * Note: head count is always 15.
 312  */
 313 static inline u8 virtio_eckd_sectors_for_block_size(int size)
 314 {
 315     switch (size) {
 316     case 512:
 317         return 49;
 318     case 1024:
 319         return 33;
 320     case 2048:
 321         return 21;
 322     case 4096:
 323         return 12;
 324     }
 325     return 0;
 326 }
 327
 328 bool virtio_disk_is_eckd(void)
 329 {
 330     const int block_size = virtio_get_block_size();
 331
 332     if (guessed_disk_nature) {
 333         return (block_size  == 4096);
 334     }
 335     return (blk_cfg.geometry.heads == 15)
 336         && (blk_cfg.geometry.sectors ==
 337             virtio_eckd_sectors_for_block_size(block_size));
 338 }
 339
 340 bool virtio_ipl_disk_is_valid(void)
 341 {
 342     return virtio_disk_is_scsi() || virtio_disk_is_eckd();
 343 }
 344
 345 int virtio_get_block_size(void)
 346 {
 347     return blk_cfg.blk_size << blk_cfg.physical_block_exp;
 348 }
 349
 350 uint8_t virtio_get_heads(void)
 351 {
 352     return blk_cfg.geometry.heads;
 353 }
 354
 355 uint8_t virtio_get_sectors(void)
 356 {
 357     return blk_cfg.geometry.sectors;
 358 }
 359
 360 uint64_t virtio_get_blocks(void)
 361 {
 362     return blk_cfg.capacity /
 363            (virtio_get_block_size() / VIRTIO_SECTOR_SIZE);
 364 }
 365
 366 void virtio_setup_block(struct subchannel_id schid)
 367 {
 368     struct vq_info_block info;
 369     struct vq_config_block config = {};
 370
 371     blk_cfg.blk_size = 0; /* mark "illegal" - setup started... */
 372     guessed_disk_nature = false;
 373
 374     virtio_reset(schid);
 375
 376     /*
 377      * Skipping CCW_CMD_READ_FEAT. We're not doing anything fancy, and
 378      * we'll just stop dead anyway if anything does not work like we
 379      * expect it.
 380      */
 381
 382     config.index = 0;
 383     if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
 384         virtio_panic("Could not get block device VQ configuration\n");
 385     }
 386     if (run_ccw(schid, CCW_CMD_READ_CONF, &blk_cfg, sizeof(blk_cfg))) {
 387         virtio_panic("Could not get block device configuration\n");
 388     }
 389     vring_init(&block, config.num, ring_area,
 390                KVM_S390_VIRTIO_RING_ALIGN);
 391
 392     info.queue = (unsigned long long) ring_area;
 393     info.align = KVM_S390_VIRTIO_RING_ALIGN;
 394     info.index = 0;
 395     info.num = config.num;
 396     block.schid = schid;
 397
 398     if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
 399         virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
 400     }
 401
 402     if (!virtio_ipl_disk_is_valid()) {
 403         /* make sure all getters but blocksize return 0 for invalid IPL disk */
 404         memset(&blk_cfg, 0, sizeof(blk_cfg));
 405         virtio_assume_scsi();
 406     }
 407 }
 408
 409 bool virtio_is_blk(struct subchannel_id schid)
 410 {
 411     int r;
 412     struct senseid senseid = {};
 413
 414     /* run sense id command */
 415     r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
 416     if (r) {
 417         return false;
 418     }
 419     if ((senseid.cu_type != 0x3832) || (senseid.cu_model != VIRTIO_ID_BLOCK)) {
 420         return false;
 421     }
 422
 423     return true;
 424 }
 425
 426 int enable_mss_facility(void)
 427 {
 428     int ret;
 429     struct chsc_area_sda *sda_area = (struct chsc_area_sda *) chsc_page;
 430
 431     memset(sda_area, 0, PAGE_SIZE);
 432     sda_area->request.length = 0x0400;
 433     sda_area->request.code = 0x0031;
 434     sda_area->operation_code = 0x2;
 435
 436     ret = chsc(sda_area);
 437     if ((ret == 0) && (sda_area->response.code == 0x0001)) {
 438         return 0;
 439     }
 440     return -EIO;
 441 }