qemu/hw/xen_disk.c
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   1/*
   2 *  xen paravirt block device backend
   3 *
   4 *  (c) Gerd Hoffmann <kraxel@redhat.com>
   5 *
   6 *  This program is free software; you can redistribute it and/or modify
   7 *  it under the terms of the GNU General Public License as published by
   8 *  the Free Software Foundation; under version 2 of the License.
   9 *
  10 *  This program is distributed in the hope that it will be useful,
  11 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 *  GNU General Public License for more details.
  14 *
  15 *  You should have received a copy of the GNU General Public License along
  16 *  with this program; if not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19#include <stdio.h>
  20#include <stdlib.h>
  21#include <stdarg.h>
  22#include <string.h>
  23#include <unistd.h>
  24#include <signal.h>
  25#include <inttypes.h>
  26#include <time.h>
  27#include <fcntl.h>
  28#include <errno.h>
  29#include <sys/ioctl.h>
  30#include <sys/types.h>
  31#include <sys/stat.h>
  32#include <sys/mman.h>
  33#include <sys/uio.h>
  34
  35#include <xs.h>
  36#include <xenctrl.h>
  37#include <xen/io/xenbus.h>
  38
  39#include "hw.h"
  40#include "block_int.h"
  41#include "qemu-char.h"
  42#include "xen_blkif.h"
  43#include "xen_backend.h"
  44
  45/* ------------------------------------------------------------- */
  46
  47static int syncwrite    = 0;
  48static int batch_maps   = 0;
  49
  50static int max_requests = 32;
  51static int use_aio      = 1;
  52
  53/* ------------------------------------------------------------- */
  54
  55#define BLOCK_SIZE  512
  56#define IOCB_COUNT  (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
  57
  58struct ioreq {
  59    blkif_request_t     req;
  60    int16_t             status;
  61
  62    /* parsed request */
  63    off_t               start;
  64    QEMUIOVector        v;
  65    int                 presync;
  66    int                 postsync;
  67
  68    /* grant mapping */
  69    uint32_t            domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  70    uint32_t            refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  71    int                 prot;
  72    void                *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  73    void                *pages;
  74
  75    /* aio status */
  76    int                 aio_inflight;
  77    int                 aio_errors;
  78
  79    struct XenBlkDev    *blkdev;
  80    QLIST_ENTRY(ioreq)   list;
  81};
  82
  83struct XenBlkDev {
  84    struct XenDevice    xendev;  /* must be first */
  85    char                *params;
  86    char                *mode;
  87    char                *type;
  88    char                *dev;
  89    char                *devtype;
  90    const char          *fileproto;
  91    const char          *filename;
  92    int                 ring_ref;
  93    void                *sring;
  94    int64_t             file_blk;
  95    int64_t             file_size;
  96    int                 protocol;
  97    blkif_back_rings_t  rings;
  98    int                 more_work;
  99    int                 cnt_map;
 100
 101    /* request lists */
 102    QLIST_HEAD(inflight_head, ioreq) inflight;
 103    QLIST_HEAD(finished_head, ioreq) finished;
 104    QLIST_HEAD(freelist_head, ioreq) freelist;
 105    int                 requests_total;
 106    int                 requests_inflight;
 107    int                 requests_finished;
 108
 109    /* qemu block driver */
 110    DriveInfo           *dinfo;
 111    BlockDriverState    *bs;
 112    QEMUBH              *bh;
 113};
 114
 115/* ------------------------------------------------------------- */
 116
 117static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
 118{
 119    struct ioreq *ioreq = NULL;
 120
 121    if (QLIST_EMPTY(&blkdev->freelist)) {
 122        if (blkdev->requests_total >= max_requests)
 123            goto out;
 124        /* allocate new struct */
 125        ioreq = qemu_mallocz(sizeof(*ioreq));
 126        ioreq->blkdev = blkdev;
 127        blkdev->requests_total++;
 128        qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST);
 129    } else {
 130        /* get one from freelist */
 131        ioreq = QLIST_FIRST(&blkdev->freelist);
 132        QLIST_REMOVE(ioreq, list);
 133        qemu_iovec_reset(&ioreq->v);
 134    }
 135    QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list);
 136    blkdev->requests_inflight++;
 137
 138out:
 139    return ioreq;
 140}
 141
 142static void ioreq_finish(struct ioreq *ioreq)
 143{
 144    struct XenBlkDev *blkdev = ioreq->blkdev;
 145
 146    QLIST_REMOVE(ioreq, list);
 147    QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list);
 148    blkdev->requests_inflight--;
 149    blkdev->requests_finished++;
 150}
 151
 152static void ioreq_release(struct ioreq *ioreq)
 153{
 154    struct XenBlkDev *blkdev = ioreq->blkdev;
 155
 156    QLIST_REMOVE(ioreq, list);
 157    memset(ioreq, 0, sizeof(*ioreq));
 158    ioreq->blkdev = blkdev;
 159    QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list);
 160    blkdev->requests_finished--;
 161}
 162
 163/*
 164 * translate request into iovec + start offset
 165 * do sanity checks along the way
 166 */
 167static int ioreq_parse(struct ioreq *ioreq)
 168{
 169    struct XenBlkDev *blkdev = ioreq->blkdev;
 170    uintptr_t mem;
 171    size_t len;
 172    int i;
 173
 174    xen_be_printf(&blkdev->xendev, 3,
 175                  "op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n",
 176                  ioreq->req.operation, ioreq->req.nr_segments,
 177                  ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number);
 178    switch (ioreq->req.operation) {
 179    case BLKIF_OP_READ:
 180        ioreq->prot = PROT_WRITE; /* to memory */
 181        break;
 182    case BLKIF_OP_WRITE_BARRIER:
 183        if (!syncwrite)
 184            ioreq->presync = ioreq->postsync = 1;
 185        /* fall through */
 186    case BLKIF_OP_WRITE:
 187        ioreq->prot = PROT_READ; /* from memory */
 188        if (syncwrite)
 189            ioreq->postsync = 1;
 190        break;
 191    default:
 192        xen_be_printf(&blkdev->xendev, 0, "error: unknown operation (%d)\n",
 193                      ioreq->req.operation);
 194        goto err;
 195    };
 196
 197    if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') {
 198        xen_be_printf(&blkdev->xendev, 0, "error: write req for ro device\n");
 199        goto err;
 200    }
 201
 202    ioreq->start = ioreq->req.sector_number * blkdev->file_blk;
 203    for (i = 0; i < ioreq->req.nr_segments; i++) {
 204        if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
 205            xen_be_printf(&blkdev->xendev, 0, "error: nr_segments too big\n");
 206            goto err;
 207        }
 208        if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) {
 209            xen_be_printf(&blkdev->xendev, 0, "error: first > last sector\n");
 210            goto err;
 211        }
 212        if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) {
 213            xen_be_printf(&blkdev->xendev, 0, "error: page crossing\n");
 214            goto err;
 215        }
 216
 217        ioreq->domids[i] = blkdev->xendev.dom;
 218        ioreq->refs[i]   = ioreq->req.seg[i].gref;
 219
 220        mem = ioreq->req.seg[i].first_sect * blkdev->file_blk;
 221        len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk;
 222        qemu_iovec_add(&ioreq->v, (void*)mem, len);
 223    }
 224    if (ioreq->start + ioreq->v.size > blkdev->file_size) {
 225        xen_be_printf(&blkdev->xendev, 0, "error: access beyond end of file\n");
 226        goto err;
 227    }
 228    return 0;
 229
 230err:
 231    ioreq->status = BLKIF_RSP_ERROR;
 232    return -1;
 233}
 234
 235static void ioreq_unmap(struct ioreq *ioreq)
 236{
 237    int gnt = ioreq->blkdev->xendev.gnttabdev;
 238    int i;
 239
 240    if (ioreq->v.niov == 0)
 241        return;
 242    if (batch_maps) {
 243        if (!ioreq->pages)
 244            return;
 245        if (xc_gnttab_munmap(gnt, ioreq->pages, ioreq->v.niov) != 0)
 246            xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n",
 247                          strerror(errno));
 248        ioreq->blkdev->cnt_map -= ioreq->v.niov;
 249        ioreq->pages = NULL;
 250    } else {
 251        for (i = 0; i < ioreq->v.niov; i++) {
 252            if (!ioreq->page[i])
 253                continue;
 254            if (xc_gnttab_munmap(gnt, ioreq->page[i], 1) != 0)
 255                xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n",
 256                              strerror(errno));
 257            ioreq->blkdev->cnt_map--;
 258            ioreq->page[i] = NULL;
 259        }
 260    }
 261}
 262
 263static int ioreq_map(struct ioreq *ioreq)
 264{
 265    int gnt = ioreq->blkdev->xendev.gnttabdev;
 266    int i;
 267
 268    if (ioreq->v.niov == 0)
 269        return 0;
 270    if (batch_maps) {
 271        ioreq->pages = xc_gnttab_map_grant_refs
 272            (gnt, ioreq->v.niov, ioreq->domids, ioreq->refs, ioreq->prot);
 273        if (ioreq->pages == NULL) {
 274            xen_be_printf(&ioreq->blkdev->xendev, 0,
 275                          "can't map %d grant refs (%s, %d maps)\n",
 276                          ioreq->v.niov, strerror(errno), ioreq->blkdev->cnt_map);
 277            return -1;
 278        }
 279        for (i = 0; i < ioreq->v.niov; i++)
 280            ioreq->v.iov[i].iov_base = ioreq->pages + i * XC_PAGE_SIZE +
 281                (uintptr_t)ioreq->v.iov[i].iov_base;
 282        ioreq->blkdev->cnt_map += ioreq->v.niov;
 283    } else  {
 284        for (i = 0; i < ioreq->v.niov; i++) {
 285            ioreq->page[i] = xc_gnttab_map_grant_ref
 286                (gnt, ioreq->domids[i], ioreq->refs[i], ioreq->prot);
 287            if (ioreq->page[i] == NULL) {
 288                xen_be_printf(&ioreq->blkdev->xendev, 0,
 289                              "can't map grant ref %d (%s, %d maps)\n",
 290                              ioreq->refs[i], strerror(errno), ioreq->blkdev->cnt_map);
 291                ioreq_unmap(ioreq);
 292                return -1;
 293            }
 294            ioreq->v.iov[i].iov_base = ioreq->page[i] + (uintptr_t)ioreq->v.iov[i].iov_base;
 295            ioreq->blkdev->cnt_map++;
 296        }
 297    }
 298    return 0;
 299}
 300
 301static int ioreq_runio_qemu_sync(struct ioreq *ioreq)
 302{
 303    struct XenBlkDev *blkdev = ioreq->blkdev;
 304    int i, rc, len = 0;
 305    off_t pos;
 306
 307    if (ioreq_map(ioreq) == -1)
 308        goto err;
 309    if (ioreq->presync)
 310        bdrv_flush(blkdev->bs);
 311
 312    switch (ioreq->req.operation) {
 313    case BLKIF_OP_READ:
 314        pos = ioreq->start;
 315        for (i = 0; i < ioreq->v.niov; i++) {
 316            rc = bdrv_read(blkdev->bs, pos / BLOCK_SIZE,
 317                           ioreq->v.iov[i].iov_base,
 318                           ioreq->v.iov[i].iov_len / BLOCK_SIZE);
 319            if (rc != 0) {
 320                xen_be_printf(&blkdev->xendev, 0, "rd I/O error (%p, len %zd)\n",
 321                              ioreq->v.iov[i].iov_base,
 322                              ioreq->v.iov[i].iov_len);
 323                goto err;
 324            }
 325            len += ioreq->v.iov[i].iov_len;
 326            pos += ioreq->v.iov[i].iov_len;
 327        }
 328        break;
 329    case BLKIF_OP_WRITE:
 330    case BLKIF_OP_WRITE_BARRIER:
 331        pos = ioreq->start;
 332        for (i = 0; i < ioreq->v.niov; i++) {
 333            rc = bdrv_write(blkdev->bs, pos / BLOCK_SIZE,
 334                            ioreq->v.iov[i].iov_base,
 335                            ioreq->v.iov[i].iov_len / BLOCK_SIZE);
 336            if (rc != 0) {
 337                xen_be_printf(&blkdev->xendev, 0, "wr I/O error (%p, len %zd)\n",
 338                              ioreq->v.iov[i].iov_base,
 339                              ioreq->v.iov[i].iov_len);
 340                goto err;
 341            }
 342            len += ioreq->v.iov[i].iov_len;
 343            pos += ioreq->v.iov[i].iov_len;
 344        }
 345        break;
 346    default:
 347        /* unknown operation (shouldn't happen -- parse catches this) */
 348        goto err;
 349    }
 350
 351    if (ioreq->postsync)
 352        bdrv_flush(blkdev->bs);
 353    ioreq->status = BLKIF_RSP_OKAY;
 354
 355    ioreq_unmap(ioreq);
 356    ioreq_finish(ioreq);
 357    return 0;
 358
 359err:
 360    ioreq->status = BLKIF_RSP_ERROR;
 361    return -1;
 362}
 363
 364static void qemu_aio_complete(void *opaque, int ret)
 365{
 366    struct ioreq *ioreq = opaque;
 367
 368    if (ret != 0) {
 369        xen_be_printf(&ioreq->blkdev->xendev, 0, "%s I/O error\n",
 370                      ioreq->req.operation == BLKIF_OP_READ ? "read" : "write");
 371        ioreq->aio_errors++;
 372    }
 373
 374    ioreq->aio_inflight--;
 375    if (ioreq->aio_inflight > 0)
 376        return;
 377
 378    ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
 379    ioreq_unmap(ioreq);
 380    ioreq_finish(ioreq);
 381    qemu_bh_schedule(ioreq->blkdev->bh);
 382}
 383
 384static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
 385{
 386    struct XenBlkDev *blkdev = ioreq->blkdev;
 387
 388    if (ioreq_map(ioreq) == -1)
 389        goto err;
 390
 391    ioreq->aio_inflight++;
 392    if (ioreq->presync)
 393        bdrv_flush(blkdev->bs); /* FIXME: aio_flush() ??? */
 394
 395    switch (ioreq->req.operation) {
 396    case BLKIF_OP_READ:
 397        ioreq->aio_inflight++;
 398        bdrv_aio_readv(blkdev->bs, ioreq->start / BLOCK_SIZE,
 399                       &ioreq->v, ioreq->v.size / BLOCK_SIZE,
 400                       qemu_aio_complete, ioreq);
 401        break;
 402    case BLKIF_OP_WRITE:
 403    case BLKIF_OP_WRITE_BARRIER:
 404        ioreq->aio_inflight++;
 405        bdrv_aio_writev(blkdev->bs, ioreq->start / BLOCK_SIZE,
 406                        &ioreq->v, ioreq->v.size / BLOCK_SIZE,
 407                        qemu_aio_complete, ioreq);
 408        break;
 409    default:
 410        /* unknown operation (shouldn't happen -- parse catches this) */
 411        goto err;
 412    }
 413
 414    if (ioreq->postsync)
 415        bdrv_flush(blkdev->bs); /* FIXME: aio_flush() ??? */
 416    qemu_aio_complete(ioreq, 0);
 417
 418    return 0;
 419
 420err:
 421    ioreq->status = BLKIF_RSP_ERROR;
 422    return -1;
 423}
 424
 425static int blk_send_response_one(struct ioreq *ioreq)
 426{
 427    struct XenBlkDev  *blkdev = ioreq->blkdev;
 428    int               send_notify   = 0;
 429    int               have_requests = 0;
 430    blkif_response_t  resp;
 431    void              *dst;
 432
 433    resp.id        = ioreq->req.id;
 434    resp.operation = ioreq->req.operation;
 435    resp.status    = ioreq->status;
 436
 437    /* Place on the response ring for the relevant domain. */
 438    switch (blkdev->protocol) {
 439    case BLKIF_PROTOCOL_NATIVE:
 440        dst = RING_GET_RESPONSE(&blkdev->rings.native, blkdev->rings.native.rsp_prod_pvt);
 441        break;
 442    case BLKIF_PROTOCOL_X86_32:
 443        dst = RING_GET_RESPONSE(&blkdev->rings.x86_32_part,
 444                                blkdev->rings.x86_32_part.rsp_prod_pvt);
 445        break;
 446    case BLKIF_PROTOCOL_X86_64:
 447        dst = RING_GET_RESPONSE(&blkdev->rings.x86_64_part,
 448                                blkdev->rings.x86_64_part.rsp_prod_pvt);
 449        break;
 450    default:
 451        dst = NULL;
 452    }
 453    memcpy(dst, &resp, sizeof(resp));
 454    blkdev->rings.common.rsp_prod_pvt++;
 455
 456    RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify);
 457    if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) {
 458        /*
 459         * Tail check for pending requests. Allows frontend to avoid
 460         * notifications if requests are already in flight (lower
 461         * overheads and promotes batching).
 462         */
 463        RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests);
 464    } else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) {
 465        have_requests = 1;
 466    }
 467
 468    if (have_requests)
 469        blkdev->more_work++;
 470    return send_notify;
 471}
 472
 473/* walk finished list, send outstanding responses, free requests */
 474static void blk_send_response_all(struct XenBlkDev *blkdev)
 475{
 476    struct ioreq *ioreq;
 477    int send_notify = 0;
 478
 479    while (!QLIST_EMPTY(&blkdev->finished)) {
 480        ioreq = QLIST_FIRST(&blkdev->finished);
 481        send_notify += blk_send_response_one(ioreq);
 482        ioreq_release(ioreq);
 483    }
 484    if (send_notify)
 485        xen_be_send_notify(&blkdev->xendev);
 486}
 487
 488static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq, RING_IDX rc)
 489{
 490    switch (blkdev->protocol) {
 491    case BLKIF_PROTOCOL_NATIVE:
 492        memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc),
 493               sizeof(ioreq->req));
 494        break;
 495    case BLKIF_PROTOCOL_X86_32:
 496        blkif_get_x86_32_req(&ioreq->req,
 497                             RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc));
 498        break;
 499    case BLKIF_PROTOCOL_X86_64:
 500        blkif_get_x86_64_req(&ioreq->req,
 501                             RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc));
 502        break;
 503    }
 504    return 0;
 505}
 506
 507static void blk_handle_requests(struct XenBlkDev *blkdev)
 508{
 509    RING_IDX rc, rp;
 510    struct ioreq *ioreq;
 511
 512    blkdev->more_work = 0;
 513
 514    rc = blkdev->rings.common.req_cons;
 515    rp = blkdev->rings.common.sring->req_prod;
 516    xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
 517
 518    if (use_aio)
 519        blk_send_response_all(blkdev);
 520    while (rc != rp) {
 521        /* pull request from ring */
 522        if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc))
 523            break;
 524        ioreq = ioreq_start(blkdev);
 525        if (ioreq == NULL) {
 526            blkdev->more_work++;
 527            break;
 528        }
 529        blk_get_request(blkdev, ioreq, rc);
 530        blkdev->rings.common.req_cons = ++rc;
 531
 532        /* parse them */
 533        if (ioreq_parse(ioreq) != 0) {
 534            if (blk_send_response_one(ioreq))
 535                xen_be_send_notify(&blkdev->xendev);
 536            ioreq_release(ioreq);
 537            continue;
 538        }
 539
 540        if (use_aio) {
 541            /* run i/o in aio mode */
 542            ioreq_runio_qemu_aio(ioreq);
 543        } else {
 544            /* run i/o in sync mode */
 545            ioreq_runio_qemu_sync(ioreq);
 546        }
 547    }
 548    if (!use_aio)
 549        blk_send_response_all(blkdev);
 550
 551    if (blkdev->more_work && blkdev->requests_inflight < max_requests)
 552        qemu_bh_schedule(blkdev->bh);
 553}
 554
 555/* ------------------------------------------------------------- */
 556
 557static void blk_bh(void *opaque)
 558{
 559    struct XenBlkDev *blkdev = opaque;
 560    blk_handle_requests(blkdev);
 561}
 562
 563static void blk_alloc(struct XenDevice *xendev)
 564{
 565    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 566
 567    QLIST_INIT(&blkdev->inflight);
 568    QLIST_INIT(&blkdev->finished);
 569    QLIST_INIT(&blkdev->freelist);
 570    blkdev->bh = qemu_bh_new(blk_bh, blkdev);
 571    if (xen_mode != XEN_EMULATE)
 572        batch_maps = 1;
 573}
 574
 575static int blk_init(struct XenDevice *xendev)
 576{
 577    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 578    int index, qflags, have_barriers, info = 0;
 579    char *h;
 580
 581    /* read xenstore entries */
 582    if (blkdev->params == NULL) {
 583        blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params");
 584        h = strchr(blkdev->params, ':');
 585        if (h != NULL) {
 586            blkdev->fileproto = blkdev->params;
 587            blkdev->filename  = h+1;
 588            *h = 0;
 589        } else {
 590            blkdev->fileproto = "<unset>";
 591            blkdev->filename  = blkdev->params;
 592        }
 593    }
 594    if (blkdev->mode == NULL)
 595        blkdev->mode = xenstore_read_be_str(&blkdev->xendev, "mode");
 596    if (blkdev->type == NULL)
 597        blkdev->type = xenstore_read_be_str(&blkdev->xendev, "type");
 598    if (blkdev->dev == NULL)
 599        blkdev->dev = xenstore_read_be_str(&blkdev->xendev, "dev");
 600    if (blkdev->devtype == NULL)
 601        blkdev->devtype = xenstore_read_be_str(&blkdev->xendev, "device-type");
 602
 603    /* do we have all we need? */
 604    if (blkdev->params == NULL ||
 605        blkdev->mode == NULL   ||
 606        blkdev->type == NULL   ||
 607        blkdev->dev == NULL)
 608        return -1;
 609
 610    /* read-only ? */
 611    if (strcmp(blkdev->mode, "w") == 0) {
 612        qflags = BDRV_O_RDWR;
 613    } else {
 614        qflags = 0;
 615        info  |= VDISK_READONLY;
 616    }
 617
 618    /* cdrom ? */
 619    if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom"))
 620        info  |= VDISK_CDROM;
 621
 622    /* init qemu block driver */
 623    index = (blkdev->xendev.dev - 202 * 256) / 16;
 624    blkdev->dinfo = drive_get(IF_XEN, 0, index);
 625    if (!blkdev->dinfo) {
 626        /* setup via xenbus -> create new block driver instance */
 627        xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");
 628        blkdev->bs = bdrv_new(blkdev->dev);
 629        if (blkdev->bs) {
 630            if (bdrv_open(blkdev->bs, blkdev->filename, qflags,
 631                           bdrv_find_whitelisted_format(blkdev->fileproto))
 632                != 0) {
 633                bdrv_delete(blkdev->bs);
 634                blkdev->bs = NULL;
 635            }
 636        }
 637        if (!blkdev->bs)
 638            return -1;
 639    } else {
 640        /* setup via qemu cmdline -> already setup for us */
 641        xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline setup)\n");
 642        blkdev->bs = blkdev->dinfo->bdrv;
 643    }
 644    blkdev->file_blk  = BLOCK_SIZE;
 645    blkdev->file_size = bdrv_getlength(blkdev->bs);
 646    if (blkdev->file_size < 0) {
 647        xen_be_printf(&blkdev->xendev, 1, "bdrv_getlength: %d (%s) | drv %s\n",
 648                      (int)blkdev->file_size, strerror(-blkdev->file_size),
 649                      blkdev->bs->drv ? blkdev->bs->drv->format_name : "-");
 650        blkdev->file_size = 0;
 651    }
 652    have_barriers = blkdev->bs->drv && blkdev->bs->drv->bdrv_flush ? 1 : 0;
 653
 654    xen_be_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\","
 655                  " size %" PRId64 " (%" PRId64 " MB)\n",
 656                  blkdev->type, blkdev->fileproto, blkdev->filename,
 657                  blkdev->file_size, blkdev->file_size >> 20);
 658
 659    /* fill info */
 660    xenstore_write_be_int(&blkdev->xendev, "feature-barrier", have_barriers);
 661    xenstore_write_be_int(&blkdev->xendev, "info",            info);
 662    xenstore_write_be_int(&blkdev->xendev, "sector-size",     blkdev->file_blk);
 663    xenstore_write_be_int(&blkdev->xendev, "sectors",
 664                          blkdev->file_size / blkdev->file_blk);
 665    return 0;
 666}
 667
 668static int blk_connect(struct XenDevice *xendev)
 669{
 670    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 671
 672    if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev->ring_ref) == -1)
 673        return -1;
 674    if (xenstore_read_fe_int(&blkdev->xendev, "event-channel",
 675                             &blkdev->xendev.remote_port) == -1)
 676        return -1;
 677
 678    blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
 679    if (blkdev->xendev.protocol) {
 680        if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0)
 681            blkdev->protocol = BLKIF_PROTOCOL_X86_32;
 682        if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0)
 683            blkdev->protocol = BLKIF_PROTOCOL_X86_64;
 684    }
 685
 686    blkdev->sring = xc_gnttab_map_grant_ref(blkdev->xendev.gnttabdev,
 687                                            blkdev->xendev.dom,
 688                                            blkdev->ring_ref,
 689                                            PROT_READ | PROT_WRITE);
 690    if (!blkdev->sring)
 691        return -1;
 692    blkdev->cnt_map++;
 693
 694    switch (blkdev->protocol) {
 695    case BLKIF_PROTOCOL_NATIVE:
 696    {
 697        blkif_sring_t *sring_native = blkdev->sring;
 698        BACK_RING_INIT(&blkdev->rings.native, sring_native, XC_PAGE_SIZE);
 699        break;
 700    }
 701    case BLKIF_PROTOCOL_X86_32:
 702    {
 703        blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring;
 704
 705        BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, XC_PAGE_SIZE);
 706        break;
 707    }
 708    case BLKIF_PROTOCOL_X86_64:
 709    {
 710        blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring;
 711
 712        BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, XC_PAGE_SIZE);
 713        break;
 714    }
 715    }
 716
 717    xen_be_bind_evtchn(&blkdev->xendev);
 718
 719    xen_be_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, "
 720                  "remote port %d, local port %d\n",
 721                  blkdev->xendev.protocol, blkdev->ring_ref,
 722                  blkdev->xendev.remote_port, blkdev->xendev.local_port);
 723    return 0;
 724}
 725
 726static void blk_disconnect(struct XenDevice *xendev)
 727{
 728    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 729
 730    if (blkdev->bs) {
 731        if (!blkdev->dinfo) {
 732            /* close/delete only if we created it ourself */
 733            bdrv_close(blkdev->bs);
 734            bdrv_delete(blkdev->bs);
 735        }
 736        blkdev->bs = NULL;
 737    }
 738    xen_be_unbind_evtchn(&blkdev->xendev);
 739
 740    if (blkdev->sring) {
 741        xc_gnttab_munmap(blkdev->xendev.gnttabdev, blkdev->sring, 1);
 742        blkdev->cnt_map--;
 743        blkdev->sring = NULL;
 744    }
 745}
 746
 747static int blk_free(struct XenDevice *xendev)
 748{
 749    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 750    struct ioreq *ioreq;
 751
 752    while (!QLIST_EMPTY(&blkdev->freelist)) {
 753        ioreq = QLIST_FIRST(&blkdev->freelist);
 754        QLIST_REMOVE(ioreq, list);
 755        qemu_iovec_destroy(&ioreq->v);
 756        qemu_free(ioreq);
 757    }
 758
 759    qemu_free(blkdev->params);
 760    qemu_free(blkdev->mode);
 761    qemu_free(blkdev->type);
 762    qemu_free(blkdev->dev);
 763    qemu_free(blkdev->devtype);
 764    qemu_bh_delete(blkdev->bh);
 765    return 0;
 766}
 767
 768static void blk_event(struct XenDevice *xendev)
 769{
 770    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 771
 772    qemu_bh_schedule(blkdev->bh);
 773}
 774
 775struct XenDevOps xen_blkdev_ops = {
 776    .size       = sizeof(struct XenBlkDev),
 777    .flags      = DEVOPS_FLAG_NEED_GNTDEV,
 778    .alloc      = blk_alloc,
 779    .init       = blk_init,
 780    .connect    = blk_connect,
 781    .disconnect = blk_disconnect,
 782    .event      = blk_event,
 783    .free       = blk_free,
 784};
 785