hw/block/xen_disk.c

   1 /*
   2  *  xen paravirt block device backend
   3  *
   4  *  (c) Gerd Hoffmann <[email protected]>
   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  *  Contributions after 2012-01-13 are licensed under the terms of the
  19  *  GNU GPL, version 2 or (at your option) any later version.
  20  */
  21
  22 #include "qemu/osdep.h"
  23 #include <sys/ioctl.h>
  24 #include <sys/uio.h>
  25
  26 #include "hw/hw.h"
  27 #include "hw/xen/xen_backend.h"
  28 #include "xen_blkif.h"
  29 #include "sysemu/blockdev.h"
  30 #include "sysemu/block-backend.h"
  31 #include "qapi/error.h"
  32 #include "qapi/qmp/qdict.h"
  33 #include "qapi/qmp/qstring.h"
  34
  35 /* ------------------------------------------------------------- */
  36
  37 static int batch_maps   = 0;
  38
  39 static int max_requests = 32;
  40
  41 /* ------------------------------------------------------------- */
  42
  43 #define BLOCK_SIZE  512
  44 #define IOCB_COUNT  (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
  45
  46 struct PersistentGrant {
  47     void *page;
  48     struct XenBlkDev *blkdev;
  49 };
  50
  51 typedef struct PersistentGrant PersistentGrant;
  52
  53 struct PersistentRegion {
  54     void *addr;
  55     int num;
  56 };
  57
  58 typedef struct PersistentRegion PersistentRegion;
  59
  60 struct ioreq {
  61     blkif_request_t     req;
  62     int16_t             status;
  63
  64     /* parsed request */
  65     off_t               start;
  66     QEMUIOVector        v;
  67     int                 presync;
  68     uint8_t             mapped;
  69
  70     /* grant mapping */
  71     uint32_t            domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  72     uint32_t            refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  73     int                 prot;
  74     void                *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  75     void                *pages;
  76     int                 num_unmap;
  77
  78     /* aio status */
  79     int                 aio_inflight;
  80     int                 aio_errors;
  81
  82     struct XenBlkDev    *blkdev;
  83     QLIST_ENTRY(ioreq)   list;
  84     BlockAcctCookie     acct;
  85 };
  86
  87 struct XenBlkDev {
  88     struct XenDevice    xendev;  /* must be first */
  89     char                *params;
  90     char                *mode;
  91     char                *type;
  92     char                *dev;
  93     char                *devtype;
  94     bool                directiosafe;
  95     const char          *fileproto;
  96     const char          *filename;
  97     int                 ring_ref;
  98     void                *sring;
  99     int64_t             file_blk;
 100     int64_t             file_size;
 101     int                 protocol;
 102     blkif_back_rings_t  rings;
 103     int                 more_work;
 104     int                 cnt_map;
 105
 106     /* request lists */
 107     QLIST_HEAD(inflight_head, ioreq) inflight;
 108     QLIST_HEAD(finished_head, ioreq) finished;
 109     QLIST_HEAD(freelist_head, ioreq) freelist;
 110     int                 requests_total;
 111     int                 requests_inflight;
 112     int                 requests_finished;
 113
 114     /* Persistent grants extension */
 115     gboolean            feature_discard;
 116     gboolean            feature_persistent;
 117     GTree               *persistent_gnts;
 118     GSList              *persistent_regions;
 119     unsigned int        persistent_gnt_count;
 120     unsigned int        max_grants;
 121
 122     /* Grant copy */
 123     gboolean            feature_grant_copy;
 124
 125     /* qemu block driver */
 126     DriveInfo           *dinfo;
 127     BlockBackend        *blk;
 128     QEMUBH              *bh;
 129 };
 130
 131 /* ------------------------------------------------------------- */
 132
 133 static void ioreq_reset(struct ioreq *ioreq)
 134 {
 135     memset(&ioreq->req, 0, sizeof(ioreq->req));
 136     ioreq->status = 0;
 137     ioreq->start = 0;
 138     ioreq->presync = 0;
 139     ioreq->mapped = 0;
 140
 141     memset(ioreq->domids, 0, sizeof(ioreq->domids));
 142     memset(ioreq->refs, 0, sizeof(ioreq->refs));
 143     ioreq->prot = 0;
 144     memset(ioreq->page, 0, sizeof(ioreq->page));
 145     ioreq->pages = NULL;
 146
 147     ioreq->aio_inflight = 0;
 148     ioreq->aio_errors = 0;
 149
 150     ioreq->blkdev = NULL;
 151     memset(&ioreq->list, 0, sizeof(ioreq->list));
 152     memset(&ioreq->acct, 0, sizeof(ioreq->acct));
 153
 154     qemu_iovec_reset(&ioreq->v);
 155 }
 156
 157 static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
 158 {
 159     uint ua = GPOINTER_TO_UINT(a);
 160     uint ub = GPOINTER_TO_UINT(b);
 161     return (ua > ub) - (ua < ub);
 162 }
 163
 164 static void destroy_grant(gpointer pgnt)
 165 {
 166     PersistentGrant *grant = pgnt;
 167     xengnttab_handle *gnt = grant->blkdev->xendev.gnttabdev;
 168
 169     if (xengnttab_unmap(gnt, grant->page, 1) != 0) {
 170         xen_pv_printf(&grant->blkdev->xendev, 0,
 171                       "xengnttab_unmap failed: %s\n",
 172                       strerror(errno));
 173     }
 174     grant->blkdev->persistent_gnt_count--;
 175     xen_pv_printf(&grant->blkdev->xendev, 3,
 176                   "unmapped grant %p\n", grant->page);
 177     g_free(grant);
 178 }
 179
 180 static void remove_persistent_region(gpointer data, gpointer dev)
 181 {
 182     PersistentRegion *region = data;
 183     struct XenBlkDev *blkdev = dev;
 184     xengnttab_handle *gnt = blkdev->xendev.gnttabdev;
 185
 186     if (xengnttab_unmap(gnt, region->addr, region->num) != 0) {
 187         xen_pv_printf(&blkdev->xendev, 0,
 188                       "xengnttab_unmap region %p failed: %s\n",
 189                       region->addr, strerror(errno));
 190     }
 191     xen_pv_printf(&blkdev->xendev, 3,
 192                   "unmapped grant region %p with %d pages\n",
 193                   region->addr, region->num);
 194     g_free(region);
 195 }
 196
 197 static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
 198 {
 199     struct ioreq *ioreq = NULL;
 200
 201     if (QLIST_EMPTY(&blkdev->freelist)) {
 202         if (blkdev->requests_total >= max_requests) {
 203             goto out;
 204         }
 205         /* allocate new struct */
 206         ioreq = g_malloc0(sizeof(*ioreq));
 207         ioreq->blkdev = blkdev;
 208         blkdev->requests_total++;
 209         qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST);
 210     } else {
 211         /* get one from freelist */
 212         ioreq = QLIST_FIRST(&blkdev->freelist);
 213         QLIST_REMOVE(ioreq, list);
 214     }
 215     QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list);
 216     blkdev->requests_inflight++;
 217
 218 out:
 219     return ioreq;
 220 }
 221
 222 static void ioreq_finish(struct ioreq *ioreq)
 223 {
 224     struct XenBlkDev *blkdev = ioreq->blkdev;
 225
 226     QLIST_REMOVE(ioreq, list);
 227     QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list);
 228     blkdev->requests_inflight--;
 229     blkdev->requests_finished++;
 230 }
 231
 232 static void ioreq_release(struct ioreq *ioreq, bool finish)
 233 {
 234     struct XenBlkDev *blkdev = ioreq->blkdev;
 235
 236     QLIST_REMOVE(ioreq, list);
 237     ioreq_reset(ioreq);
 238     ioreq->blkdev = blkdev;
 239     QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list);
 240     if (finish) {
 241         blkdev->requests_finished--;
 242     } else {
 243         blkdev->requests_inflight--;
 244     }
 245 }
 246
 247 /*
 248  * translate request into iovec + start offset
 249  * do sanity checks along the way
 250  */
 251 static int ioreq_parse(struct ioreq *ioreq)
 252 {
 253     struct XenBlkDev *blkdev = ioreq->blkdev;
 254     uintptr_t mem;
 255     size_t len;
 256     int i;
 257
 258     xen_pv_printf(&blkdev->xendev, 3,
 259                   "op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n",
 260                   ioreq->req.operation, ioreq->req.nr_segments,
 261                   ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number);
 262     switch (ioreq->req.operation) {
 263     case BLKIF_OP_READ:
 264         ioreq->prot = PROT_WRITE; /* to memory */
 265         break;
 266     case BLKIF_OP_FLUSH_DISKCACHE:
 267         ioreq->presync = 1;
 268         if (!ioreq->req.nr_segments) {
 269             return 0;
 270         }
 271         /* fall through */
 272     case BLKIF_OP_WRITE:
 273         ioreq->prot = PROT_READ; /* from memory */
 274         break;
 275     case BLKIF_OP_DISCARD:
 276         return 0;
 277     default:
 278         xen_pv_printf(&blkdev->xendev, 0, "error: unknown operation (%d)\n",
 279                       ioreq->req.operation);
 280         goto err;
 281     };
 282
 283     if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') {
 284         xen_pv_printf(&blkdev->xendev, 0, "error: write req for ro device\n");
 285         goto err;
 286     }
 287
 288     ioreq->start = ioreq->req.sector_number * blkdev->file_blk;
 289     for (i = 0; i < ioreq->req.nr_segments; i++) {
 290         if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
 291             xen_pv_printf(&blkdev->xendev, 0, "error: nr_segments too big\n");
 292             goto err;
 293         }
 294         if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) {
 295             xen_pv_printf(&blkdev->xendev, 0, "error: first > last sector\n");
 296             goto err;
 297         }
 298         if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) {
 299             xen_pv_printf(&blkdev->xendev, 0, "error: page crossing\n");
 300             goto err;
 301         }
 302
 303         ioreq->domids[i] = blkdev->xendev.dom;
 304         ioreq->refs[i]   = ioreq->req.seg[i].gref;
 305
 306         mem = ioreq->req.seg[i].first_sect * blkdev->file_blk;
 307         len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk;
 308         qemu_iovec_add(&ioreq->v, (void*)mem, len);
 309     }
 310     if (ioreq->start + ioreq->v.size > blkdev->file_size) {
 311         xen_pv_printf(&blkdev->xendev, 0, "error: access beyond end of file\n");
 312         goto err;
 313     }
 314     return 0;
 315
 316 err:
 317     ioreq->status = BLKIF_RSP_ERROR;
 318     return -1;
 319 }
 320
 321 static void ioreq_unmap(struct ioreq *ioreq)
 322 {
 323     xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
 324     int i;
 325
 326     if (ioreq->num_unmap == 0 || ioreq->mapped == 0) {
 327         return;
 328     }
 329     if (batch_maps) {
 330         if (!ioreq->pages) {
 331             return;
 332         }
 333         if (xengnttab_unmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) {
 334             xen_pv_printf(&ioreq->blkdev->xendev, 0,
 335                           "xengnttab_unmap failed: %s\n",
 336                           strerror(errno));
 337         }
 338         ioreq->blkdev->cnt_map -= ioreq->num_unmap;
 339         ioreq->pages = NULL;
 340     } else {
 341         for (i = 0; i < ioreq->num_unmap; i++) {
 342             if (!ioreq->page[i]) {
 343                 continue;
 344             }
 345             if (xengnttab_unmap(gnt, ioreq->page[i], 1) != 0) {
 346                 xen_pv_printf(&ioreq->blkdev->xendev, 0,
 347                               "xengnttab_unmap failed: %s\n",
 348                               strerror(errno));
 349             }
 350             ioreq->blkdev->cnt_map--;
 351             ioreq->page[i] = NULL;
 352         }
 353     }
 354     ioreq->mapped = 0;
 355 }
 356
 357 static int ioreq_map(struct ioreq *ioreq)
 358 {
 359     xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
 360     uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 361     uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 362     void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 363     int i, j, new_maps = 0;
 364     PersistentGrant *grant;
 365     PersistentRegion *region;
 366     /* domids and refs variables will contain the information necessary
 367      * to map the grants that are needed to fulfill this request.
 368      *
 369      * After mapping the needed grants, the page array will contain the
 370      * memory address of each granted page in the order specified in ioreq
 371      * (disregarding if it's a persistent grant or not).
 372      */
 373
 374     if (ioreq->v.niov == 0 || ioreq->mapped == 1) {
 375         return 0;
 376     }
 377     if (ioreq->blkdev->feature_persistent) {
 378         for (i = 0; i < ioreq->v.niov; i++) {
 379             grant = g_tree_lookup(ioreq->blkdev->persistent_gnts,
 380                                     GUINT_TO_POINTER(ioreq->refs[i]));
 381
 382             if (grant != NULL) {
 383                 page[i] = grant->page;
 384                 xen_pv_printf(&ioreq->blkdev->xendev, 3,
 385                               "using persistent-grant %" PRIu32 "\n",
 386                               ioreq->refs[i]);
 387             } else {
 388                     /* Add the grant to the list of grants that
 389                      * should be mapped
 390                      */
 391                     domids[new_maps] = ioreq->domids[i];
 392                     refs[new_maps] = ioreq->refs[i];
 393                     page[i] = NULL;
 394                     new_maps++;
 395             }
 396         }
 397         /* Set the protection to RW, since grants may be reused later
 398          * with a different protection than the one needed for this request
 399          */
 400         ioreq->prot = PROT_WRITE | PROT_READ;
 401     } else {
 402         /* All grants in the request should be mapped */
 403         memcpy(refs, ioreq->refs, sizeof(refs));
 404         memcpy(domids, ioreq->domids, sizeof(domids));
 405         memset(page, 0, sizeof(page));
 406         new_maps = ioreq->v.niov;
 407     }
 408
 409     if (batch_maps && new_maps) {
 410         ioreq->pages = xengnttab_map_grant_refs
 411             (gnt, new_maps, domids, refs, ioreq->prot);
 412         if (ioreq->pages == NULL) {
 413             xen_pv_printf(&ioreq->blkdev->xendev, 0,
 414                           "can't map %d grant refs (%s, %d maps)\n",
 415                           new_maps, strerror(errno), ioreq->blkdev->cnt_map);
 416             return -1;
 417         }
 418         for (i = 0, j = 0; i < ioreq->v.niov; i++) {
 419             if (page[i] == NULL) {
 420                 page[i] = ioreq->pages + (j++) * XC_PAGE_SIZE;
 421             }
 422         }
 423         ioreq->blkdev->cnt_map += new_maps;
 424     } else if (new_maps)  {
 425         for (i = 0; i < new_maps; i++) {
 426             ioreq->page[i] = xengnttab_map_grant_ref
 427                 (gnt, domids[i], refs[i], ioreq->prot);
 428             if (ioreq->page[i] == NULL) {
 429                 xen_pv_printf(&ioreq->blkdev->xendev, 0,
 430                               "can't map grant ref %d (%s, %d maps)\n",
 431                               refs[i], strerror(errno), ioreq->blkdev->cnt_map);
 432                 ioreq->mapped = 1;
 433                 ioreq_unmap(ioreq);
 434                 return -1;
 435             }
 436             ioreq->blkdev->cnt_map++;
 437         }
 438         for (i = 0, j = 0; i < ioreq->v.niov; i++) {
 439             if (page[i] == NULL) {
 440                 page[i] = ioreq->page[j++];
 441             }
 442         }
 443     }
 444     if (ioreq->blkdev->feature_persistent && new_maps != 0 &&
 445         (!batch_maps || (ioreq->blkdev->persistent_gnt_count + new_maps <=
 446         ioreq->blkdev->max_grants))) {
 447         /*
 448          * If we are using persistent grants and batch mappings only
 449          * add the new maps to the list of persistent grants if the whole
 450          * area can be persistently mapped.
 451          */
 452         if (batch_maps) {
 453             region = g_malloc0(sizeof(*region));
 454             region->addr = ioreq->pages;
 455             region->num = new_maps;
 456             ioreq->blkdev->persistent_regions = g_slist_append(
 457                                             ioreq->blkdev->persistent_regions,
 458                                             region);
 459         }
 460         while ((ioreq->blkdev->persistent_gnt_count < ioreq->blkdev->max_grants)
 461               && new_maps) {
 462             /* Go through the list of newly mapped grants and add as many
 463              * as possible to the list of persistently mapped grants.
 464              *
 465              * Since we start at the end of ioreq->page(s), we only need
 466              * to decrease new_maps to prevent this granted pages from
 467              * being unmapped in ioreq_unmap.
 468              */
 469             grant = g_malloc0(sizeof(*grant));
 470             new_maps--;
 471             if (batch_maps) {
 472                 grant->page = ioreq->pages + (new_maps) * XC_PAGE_SIZE;
 473             } else {
 474                 grant->page = ioreq->page[new_maps];
 475             }
 476             grant->blkdev = ioreq->blkdev;
 477             xen_pv_printf(&ioreq->blkdev->xendev, 3,
 478                           "adding grant %" PRIu32 " page: %p\n",
 479                           refs[new_maps], grant->page);
 480             g_tree_insert(ioreq->blkdev->persistent_gnts,
 481                           GUINT_TO_POINTER(refs[new_maps]),
 482                           grant);
 483             ioreq->blkdev->persistent_gnt_count++;
 484         }
 485         assert(!batch_maps || new_maps == 0);
 486     }
 487     for (i = 0; i < ioreq->v.niov; i++) {
 488         ioreq->v.iov[i].iov_base += (uintptr_t)page[i];
 489     }
 490     ioreq->mapped = 1;
 491     ioreq->num_unmap = new_maps;
 492     return 0;
 493 }
 494
 495 #if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 480
 496
 497 static void ioreq_free_copy_buffers(struct ioreq *ioreq)
 498 {
 499     int i;
 500
 501     for (i = 0; i < ioreq->v.niov; i++) {
 502         ioreq->page[i] = NULL;
 503     }
 504
 505     qemu_vfree(ioreq->pages);
 506 }
 507
 508 static int ioreq_init_copy_buffers(struct ioreq *ioreq)
 509 {
 510     int i;
 511
 512     if (ioreq->v.niov == 0) {
 513         return 0;
 514     }
 515
 516     ioreq->pages = qemu_memalign(XC_PAGE_SIZE, ioreq->v.niov * XC_PAGE_SIZE);
 517
 518     for (i = 0; i < ioreq->v.niov; i++) {
 519         ioreq->page[i] = ioreq->pages + i * XC_PAGE_SIZE;
 520         ioreq->v.iov[i].iov_base = ioreq->page[i];
 521     }
 522
 523     return 0;
 524 }
 525
 526 static int ioreq_grant_copy(struct ioreq *ioreq)
 527 {
 528     xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
 529     xengnttab_grant_copy_segment_t segs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 530     int i, count, rc;
 531     int64_t file_blk = ioreq->blkdev->file_blk;
 532
 533     if (ioreq->v.niov == 0) {
 534         return 0;
 535     }
 536
 537     count = ioreq->v.niov;
 538
 539     for (i = 0; i < count; i++) {
 540         if (ioreq->req.operation == BLKIF_OP_READ) {
 541             segs[i].flags = GNTCOPY_dest_gref;
 542             segs[i].dest.foreign.ref = ioreq->refs[i];
 543             segs[i].dest.foreign.domid = ioreq->domids[i];
 544             segs[i].dest.foreign.offset = ioreq->req.seg[i].first_sect * file_blk;
 545             segs[i].source.virt = ioreq->v.iov[i].iov_base;
 546         } else {
 547             segs[i].flags = GNTCOPY_source_gref;
 548             segs[i].source.foreign.ref = ioreq->refs[i];
 549             segs[i].source.foreign.domid = ioreq->domids[i];
 550             segs[i].source.foreign.offset = ioreq->req.seg[i].first_sect * file_blk;
 551             segs[i].dest.virt = ioreq->v.iov[i].iov_base;
 552         }
 553         segs[i].len = (ioreq->req.seg[i].last_sect
 554                        - ioreq->req.seg[i].first_sect + 1) * file_blk;
 555     }
 556
 557     rc = xengnttab_grant_copy(gnt, count, segs);
 558
 559     if (rc) {
 560         xen_pv_printf(&ioreq->blkdev->xendev, 0,
 561                       "failed to copy data %d\n", rc);
 562         ioreq->aio_errors++;
 563         return -1;
 564     }
 565
 566     for (i = 0; i < count; i++) {
 567         if (segs[i].status != GNTST_okay) {
 568             xen_pv_printf(&ioreq->blkdev->xendev, 3,
 569                           "failed to copy data %d for gref %d, domid %d\n",
 570                           segs[i].status, ioreq->refs[i], ioreq->domids[i]);
 571             ioreq->aio_errors++;
 572             rc = -1;
 573         }
 574     }
 575
 576     return rc;
 577 }
 578 #else
 579 static void ioreq_free_copy_buffers(struct ioreq *ioreq)
 580 {
 581     abort();
 582 }
 583
 584 static int ioreq_init_copy_buffers(struct ioreq *ioreq)
 585 {
 586     abort();
 587 }
 588
 589 static int ioreq_grant_copy(struct ioreq *ioreq)
 590 {
 591     abort();
 592 }
 593 #endif
 594
 595 static int ioreq_runio_qemu_aio(struct ioreq *ioreq);
 596
 597 static void qemu_aio_complete(void *opaque, int ret)
 598 {
 599     struct ioreq *ioreq = opaque;
 600
 601     if (ret != 0) {
 602         xen_pv_printf(&ioreq->blkdev->xendev, 0, "%s I/O error\n",
 603                       ioreq->req.operation == BLKIF_OP_READ ? "read" : "write");
 604         ioreq->aio_errors++;
 605     }
 606
 607     ioreq->aio_inflight--;
 608     if (ioreq->presync) {
 609         ioreq->presync = 0;
 610         ioreq_runio_qemu_aio(ioreq);
 611         return;
 612     }
 613     if (ioreq->aio_inflight > 0) {
 614         return;
 615     }
 616
 617     if (ioreq->blkdev->feature_grant_copy) {
 618         switch (ioreq->req.operation) {
 619         case BLKIF_OP_READ:
 620             /* in case of failure ioreq->aio_errors is increased */
 621             if (ret == 0) {
 622                 ioreq_grant_copy(ioreq);
 623             }
 624             ioreq_free_copy_buffers(ioreq);
 625             break;
 626         case BLKIF_OP_WRITE:
 627         case BLKIF_OP_FLUSH_DISKCACHE:
 628             if (!ioreq->req.nr_segments) {
 629                 break;
 630             }
 631             ioreq_free_copy_buffers(ioreq);
 632             break;
 633         default:
 634             break;
 635         }
 636     }
 637
 638     ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
 639     if (!ioreq->blkdev->feature_grant_copy) {
 640         ioreq_unmap(ioreq);
 641     }
 642     ioreq_finish(ioreq);
 643     switch (ioreq->req.operation) {
 644     case BLKIF_OP_WRITE:
 645     case BLKIF_OP_FLUSH_DISKCACHE:
 646         if (!ioreq->req.nr_segments) {
 647             break;
 648         }
 649     case BLKIF_OP_READ:
 650         if (ioreq->status == BLKIF_RSP_OKAY) {
 651             block_acct_done(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct);
 652         } else {
 653             block_acct_failed(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct);
 654         }
 655         break;
 656     case BLKIF_OP_DISCARD:
 657     default:
 658         break;
 659     }
 660     qemu_bh_schedule(ioreq->blkdev->bh);
 661 }
 662
 663 static bool blk_split_discard(struct ioreq *ioreq, blkif_sector_t sector_number,
 664                               uint64_t nr_sectors)
 665 {
 666     struct XenBlkDev *blkdev = ioreq->blkdev;
 667     int64_t byte_offset;
 668     int byte_chunk;
 669     uint64_t byte_remaining, limit;
 670     uint64_t sec_start = sector_number;
 671     uint64_t sec_count = nr_sectors;
 672
 673     /* Wrap around, or overflowing byte limit? */
 674     if (sec_start + sec_count < sec_count ||
 675         sec_start + sec_count > INT64_MAX >> BDRV_SECTOR_BITS) {
 676         return false;
 677     }
 678
 679     limit = BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS;
 680     byte_offset = sec_start << BDRV_SECTOR_BITS;
 681     byte_remaining = sec_count << BDRV_SECTOR_BITS;
 682
 683     do {
 684         byte_chunk = byte_remaining > limit ? limit : byte_remaining;
 685         ioreq->aio_inflight++;
 686         blk_aio_pdiscard(blkdev->blk, byte_offset, byte_chunk,
 687                          qemu_aio_complete, ioreq);
 688         byte_remaining -= byte_chunk;
 689         byte_offset += byte_chunk;
 690     } while (byte_remaining > 0);
 691
 692     return true;
 693 }
 694
 695 static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
 696 {
 697     struct XenBlkDev *blkdev = ioreq->blkdev;
 698
 699     if (ioreq->blkdev->feature_grant_copy) {
 700         ioreq_init_copy_buffers(ioreq);
 701         if (ioreq->req.nr_segments && (ioreq->req.operation == BLKIF_OP_WRITE ||
 702             ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) &&
 703             ioreq_grant_copy(ioreq)) {
 704                 ioreq_free_copy_buffers(ioreq);
 705                 goto err;
 706         }
 707     } else {
 708         if (ioreq->req.nr_segments && ioreq_map(ioreq)) {
 709             goto err;
 710         }
 711     }
 712
 713     ioreq->aio_inflight++;
 714     if (ioreq->presync) {
 715         blk_aio_flush(ioreq->blkdev->blk, qemu_aio_complete, ioreq);
 716         return 0;
 717     }
 718
 719     switch (ioreq->req.operation) {
 720     case BLKIF_OP_READ:
 721         block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
 722                          ioreq->v.size, BLOCK_ACCT_READ);
 723         ioreq->aio_inflight++;
 724         blk_aio_preadv(blkdev->blk, ioreq->start, &ioreq->v, 0,
 725                        qemu_aio_complete, ioreq);
 726         break;
 727     case BLKIF_OP_WRITE:
 728     case BLKIF_OP_FLUSH_DISKCACHE:
 729         if (!ioreq->req.nr_segments) {
 730             break;
 731         }
 732
 733         block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
 734                          ioreq->v.size,
 735                          ioreq->req.operation == BLKIF_OP_WRITE ?
 736                          BLOCK_ACCT_WRITE : BLOCK_ACCT_FLUSH);
 737         ioreq->aio_inflight++;
 738         blk_aio_pwritev(blkdev->blk, ioreq->start, &ioreq->v, 0,
 739                         qemu_aio_complete, ioreq);
 740         break;
 741     case BLKIF_OP_DISCARD:
 742     {
 743         struct blkif_request_discard *req = (void *)&ioreq->req;
 744         if (!blk_split_discard(ioreq, req->sector_number, req->nr_sectors)) {
 745             goto err;
 746         }
 747         break;
 748     }
 749     default:
 750         /* unknown operation (shouldn't happen -- parse catches this) */
 751         if (!ioreq->blkdev->feature_grant_copy) {
 752             ioreq_unmap(ioreq);
 753         }
 754         goto err;
 755     }
 756
 757     qemu_aio_complete(ioreq, 0);
 758
 759     return 0;
 760
 761 err:
 762     ioreq_finish(ioreq);
 763     ioreq->status = BLKIF_RSP_ERROR;
 764     return -1;
 765 }
 766
 767 static int blk_send_response_one(struct ioreq *ioreq)
 768 {
 769     struct XenBlkDev  *blkdev = ioreq->blkdev;
 770     int               send_notify   = 0;
 771     int               have_requests = 0;
 772     blkif_response_t  resp;
 773     void              *dst;
 774
 775     resp.id        = ioreq->req.id;
 776     resp.operation = ioreq->req.operation;
 777     resp.status    = ioreq->status;
 778
 779     /* Place on the response ring for the relevant domain. */
 780     switch (blkdev->protocol) {
 781     case BLKIF_PROTOCOL_NATIVE:
 782         dst = RING_GET_RESPONSE(&blkdev->rings.native, blkdev->rings.native.rsp_prod_pvt);
 783         break;
 784     case BLKIF_PROTOCOL_X86_32:
 785         dst = RING_GET_RESPONSE(&blkdev->rings.x86_32_part,
 786                                 blkdev->rings.x86_32_part.rsp_prod_pvt);
 787         break;
 788     case BLKIF_PROTOCOL_X86_64:
 789         dst = RING_GET_RESPONSE(&blkdev->rings.x86_64_part,
 790                                 blkdev->rings.x86_64_part.rsp_prod_pvt);
 791         break;
 792     default:
 793         dst = NULL;
 794         return 0;
 795     }
 796     memcpy(dst, &resp, sizeof(resp));
 797     blkdev->rings.common.rsp_prod_pvt++;
 798
 799     RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify);
 800     if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) {
 801         /*
 802          * Tail check for pending requests. Allows frontend to avoid
 803          * notifications if requests are already in flight (lower
 804          * overheads and promotes batching).
 805          */
 806         RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests);
 807     } else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) {
 808         have_requests = 1;
 809     }
 810
 811     if (have_requests) {
 812         blkdev->more_work++;
 813     }
 814     return send_notify;
 815 }
 816
 817 /* walk finished list, send outstanding responses, free requests */
 818 static void blk_send_response_all(struct XenBlkDev *blkdev)
 819 {
 820     struct ioreq *ioreq;
 821     int send_notify = 0;
 822
 823     while (!QLIST_EMPTY(&blkdev->finished)) {
 824         ioreq = QLIST_FIRST(&blkdev->finished);
 825         send_notify += blk_send_response_one(ioreq);
 826         ioreq_release(ioreq, true);
 827     }
 828     if (send_notify) {
 829         xen_pv_send_notify(&blkdev->xendev);
 830     }
 831 }
 832
 833 static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq, RING_IDX rc)
 834 {
 835     switch (blkdev->protocol) {
 836     case BLKIF_PROTOCOL_NATIVE:
 837         memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc),
 838                sizeof(ioreq->req));
 839         break;
 840     case BLKIF_PROTOCOL_X86_32:
 841         blkif_get_x86_32_req(&ioreq->req,
 842                              RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc));
 843         break;
 844     case BLKIF_PROTOCOL_X86_64:
 845         blkif_get_x86_64_req(&ioreq->req,
 846                              RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc));
 847         break;
 848     }
 849     /* Prevent the compiler from accessing the on-ring fields instead. */
 850     barrier();
 851     return 0;
 852 }
 853
 854 static void blk_handle_requests(struct XenBlkDev *blkdev)
 855 {
 856     RING_IDX rc, rp;
 857     struct ioreq *ioreq;
 858
 859     blkdev->more_work = 0;
 860
 861     rc = blkdev->rings.common.req_cons;
 862     rp = blkdev->rings.common.sring->req_prod;
 863     xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
 864
 865     blk_send_response_all(blkdev);
 866     while (rc != rp) {
 867         /* pull request from ring */
 868         if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc)) {
 869             break;
 870         }
 871         ioreq = ioreq_start(blkdev);
 872         if (ioreq == NULL) {
 873             blkdev->more_work++;
 874             break;
 875         }
 876         blk_get_request(blkdev, ioreq, rc);
 877         blkdev->rings.common.req_cons = ++rc;
 878
 879         /* parse them */
 880         if (ioreq_parse(ioreq) != 0) {
 881
 882             switch (ioreq->req.operation) {
 883             case BLKIF_OP_READ:
 884                 block_acct_invalid(blk_get_stats(blkdev->blk),
 885                                    BLOCK_ACCT_READ);
 886                 break;
 887             case BLKIF_OP_WRITE:
 888                 block_acct_invalid(blk_get_stats(blkdev->blk),
 889                                    BLOCK_ACCT_WRITE);
 890                 break;
 891             case BLKIF_OP_FLUSH_DISKCACHE:
 892                 block_acct_invalid(blk_get_stats(blkdev->blk),
 893                                    BLOCK_ACCT_FLUSH);
 894             default:
 895                 break;
 896             };
 897
 898             if (blk_send_response_one(ioreq)) {
 899                 xen_pv_send_notify(&blkdev->xendev);
 900             }
 901             ioreq_release(ioreq, false);
 902             continue;
 903         }
 904
 905         ioreq_runio_qemu_aio(ioreq);
 906     }
 907
 908     if (blkdev->more_work && blkdev->requests_inflight < max_requests) {
 909         qemu_bh_schedule(blkdev->bh);
 910     }
 911 }
 912
 913 /* ------------------------------------------------------------- */
 914
 915 static void blk_bh(void *opaque)
 916 {
 917     struct XenBlkDev *blkdev = opaque;
 918     blk_handle_requests(blkdev);
 919 }
 920
 921 /*
 922  * We need to account for the grant allocations requiring contiguous
 923  * chunks; the worst case number would be
 924  *     max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1,
 925  * but in order to keep things simple just use
 926  *     2 * max_req * max_seg.
 927  */
 928 #define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg))
 929
 930 static void blk_alloc(struct XenDevice *xendev)
 931 {
 932     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 933
 934     QLIST_INIT(&blkdev->inflight);
 935     QLIST_INIT(&blkdev->finished);
 936     QLIST_INIT(&blkdev->freelist);
 937     blkdev->bh = qemu_bh_new(blk_bh, blkdev);
 938     if (xen_mode != XEN_EMULATE) {
 939         batch_maps = 1;
 940     }
 941     if (xengnttab_set_max_grants(xendev->gnttabdev,
 942             MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) {
 943         xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n",
 944                       strerror(errno));
 945     }
 946 }
 947
 948 static void blk_parse_discard(struct XenBlkDev *blkdev)
 949 {
 950     int enable;
 951
 952     blkdev->feature_discard = true;
 953
 954     if (xenstore_read_be_int(&blkdev->xendev, "discard-enable", &enable) == 0) {
 955         blkdev->feature_discard = !!enable;
 956     }
 957
 958     if (blkdev->feature_discard) {
 959         xenstore_write_be_int(&blkdev->xendev, "feature-discard", 1);
 960     }
 961 }
 962
 963 static int blk_init(struct XenDevice *xendev)
 964 {
 965     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
 966     int info = 0;
 967     char *directiosafe = NULL;
 968
 969     /* read xenstore entries */
 970     if (blkdev->params == NULL) {
 971         char *h = NULL;
 972         blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params");
 973         if (blkdev->params != NULL) {
 974             h = strchr(blkdev->params, ':');
 975         }
 976         if (h != NULL) {
 977             blkdev->fileproto = blkdev->params;
 978             blkdev->filename  = h+1;
 979             *h = 0;
 980         } else {
 981             blkdev->fileproto = "<unset>";
 982             blkdev->filename  = blkdev->params;
 983         }
 984     }
 985     if (!strcmp("aio", blkdev->fileproto)) {
 986         blkdev->fileproto = "raw";
 987     }
 988     if (!strcmp("vhd", blkdev->fileproto)) {
 989         blkdev->fileproto = "vpc";
 990     }
 991     if (blkdev->mode == NULL) {
 992         blkdev->mode = xenstore_read_be_str(&blkdev->xendev, "mode");
 993     }
 994     if (blkdev->type == NULL) {
 995         blkdev->type = xenstore_read_be_str(&blkdev->xendev, "type");
 996     }
 997     if (blkdev->dev == NULL) {
 998         blkdev->dev = xenstore_read_be_str(&blkdev->xendev, "dev");
 999     }
1000     if (blkdev->devtype == NULL) {
1001         blkdev->devtype = xenstore_read_be_str(&blkdev->xendev, "device-type");
1002     }
1003     directiosafe = xenstore_read_be_str(&blkdev->xendev, "direct-io-safe");
1004     blkdev->directiosafe = (directiosafe && atoi(directiosafe));
1005
1006     /* do we have all we need? */
1007     if (blkdev->params == NULL ||
1008         blkdev->mode == NULL   ||
1009         blkdev->type == NULL   ||
1010         blkdev->dev == NULL) {
1011         goto out_error;
1012     }
1013
1014     /* read-only ? */
1015     if (strcmp(blkdev->mode, "w")) {
1016         info  |= VDISK_READONLY;
1017     }
1018
1019     /* cdrom ? */
1020     if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom")) {
1021         info  |= VDISK_CDROM;
1022     }
1023
1024     blkdev->file_blk  = BLOCK_SIZE;
1025
1026     /* fill info
1027      * blk_connect supplies sector-size and sectors
1028      */
1029     xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1);
1030     xenstore_write_be_int(&blkdev->xendev, "feature-persistent", 1);
1031     xenstore_write_be_int(&blkdev->xendev, "info", info);
1032
1033     blk_parse_discard(blkdev);
1034
1035     g_free(directiosafe);
1036     return 0;
1037
1038 out_error:
1039     g_free(blkdev->params);
1040     blkdev->params = NULL;
1041     g_free(blkdev->mode);
1042     blkdev->mode = NULL;
1043     g_free(blkdev->type);
1044     blkdev->type = NULL;
1045     g_free(blkdev->dev);
1046     blkdev->dev = NULL;
1047     g_free(blkdev->devtype);
1048     blkdev->devtype = NULL;
1049     g_free(directiosafe);
1050     blkdev->directiosafe = false;
1051     return -1;
1052 }
1053
1054 static int blk_connect(struct XenDevice *xendev)
1055 {
1056     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1057     int pers, index, qflags;
1058     bool readonly = true;
1059     bool writethrough = true;
1060
1061     /* read-only ? */
1062     if (blkdev->directiosafe) {
1063         qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO;
1064     } else {
1065         qflags = 0;
1066         writethrough = false;
1067     }
1068     if (strcmp(blkdev->mode, "w") == 0) {
1069         qflags |= BDRV_O_RDWR;
1070         readonly = false;
1071     }
1072     if (blkdev->feature_discard) {
1073         qflags |= BDRV_O_UNMAP;
1074     }
1075
1076     /* init qemu block driver */
1077     index = (blkdev->xendev.dev - 202 * 256) / 16;
1078     blkdev->dinfo = drive_get(IF_XEN, 0, index);
1079     if (!blkdev->dinfo) {
1080         Error *local_err = NULL;
1081         QDict *options = NULL;
1082
1083         if (strcmp(blkdev->fileproto, "<unset>")) {
1084             options = qdict_new();
1085             qdict_put(options, "driver", qstring_from_str(blkdev->fileproto));
1086         }
1087
1088         /* setup via xenbus -> create new block driver instance */
1089         xen_pv_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");
1090         blkdev->blk = blk_new_open(blkdev->filename, NULL, options,
1091                                    qflags, &local_err);
1092         if (!blkdev->blk) {
1093             xen_pv_printf(&blkdev->xendev, 0, "error: %s\n",
1094                           error_get_pretty(local_err));
1095             error_free(local_err);
1096             return -1;
1097         }
1098         blk_set_enable_write_cache(blkdev->blk, !writethrough);
1099     } else {
1100         /* setup via qemu cmdline -> already setup for us */
1101         xen_pv_printf(&blkdev->xendev, 2,
1102                       "get configured bdrv (cmdline setup)\n");
1103         blkdev->blk = blk_by_legacy_dinfo(blkdev->dinfo);
1104         if (blk_is_read_only(blkdev->blk) && !readonly) {
1105             xen_pv_printf(&blkdev->xendev, 0, "Unexpected read-only drive");
1106             blkdev->blk = NULL;
1107             return -1;
1108         }
1109         /* blkdev->blk is not create by us, we get a reference
1110          * so we can blk_unref() unconditionally */
1111         blk_ref(blkdev->blk);
1112     }
1113     blk_attach_dev_legacy(blkdev->blk, blkdev);
1114     blkdev->file_size = blk_getlength(blkdev->blk);
1115     if (blkdev->file_size < 0) {
1116         BlockDriverState *bs = blk_bs(blkdev->blk);
1117         const char *drv_name = bs ? bdrv_get_format_name(bs) : NULL;
1118         xen_pv_printf(&blkdev->xendev, 1, "blk_getlength: %d (%s) | drv %s\n",
1119                       (int)blkdev->file_size, strerror(-blkdev->file_size),
1120                       drv_name ?: "-");
1121         blkdev->file_size = 0;
1122     }
1123
1124     xen_pv_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\","
1125                   " size %" PRId64 " (%" PRId64 " MB)\n",
1126                   blkdev->type, blkdev->fileproto, blkdev->filename,
1127                   blkdev->file_size, blkdev->file_size >> 20);
1128
1129     /* Fill in number of sector size and number of sectors */
1130     xenstore_write_be_int(&blkdev->xendev, "sector-size", blkdev->file_blk);
1131     xenstore_write_be_int64(&blkdev->xendev, "sectors",
1132                             blkdev->file_size / blkdev->file_blk);
1133
1134     if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev->ring_ref) == -1) {
1135         return -1;
1136     }
1137     if (xenstore_read_fe_int(&blkdev->xendev, "event-channel",
1138                              &blkdev->xendev.remote_port) == -1) {
1139         return -1;
1140     }
1141     if (xenstore_read_fe_int(&blkdev->xendev, "feature-persistent", &pers)) {
1142         blkdev->feature_persistent = FALSE;
1143     } else {
1144         blkdev->feature_persistent = !!pers;
1145     }
1146
1147     if (!blkdev->xendev.protocol) {
1148         blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
1149     } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_NATIVE) == 0) {
1150         blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
1151     } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {
1152         blkdev->protocol = BLKIF_PROTOCOL_X86_32;
1153     } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {
1154         blkdev->protocol = BLKIF_PROTOCOL_X86_64;
1155     } else {
1156         blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
1157     }
1158
1159     blkdev->sring = xengnttab_map_grant_ref(blkdev->xendev.gnttabdev,
1160                                             blkdev->xendev.dom,
1161                                             blkdev->ring_ref,
1162                                             PROT_READ | PROT_WRITE);
1163     if (!blkdev->sring) {
1164         return -1;
1165     }
1166     blkdev->cnt_map++;
1167
1168     switch (blkdev->protocol) {
1169     case BLKIF_PROTOCOL_NATIVE:
1170     {
1171         blkif_sring_t *sring_native = blkdev->sring;
1172         BACK_RING_INIT(&blkdev->rings.native, sring_native, XC_PAGE_SIZE);
1173         break;
1174     }
1175     case BLKIF_PROTOCOL_X86_32:
1176     {
1177         blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring;
1178
1179         BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, XC_PAGE_SIZE);
1180         break;
1181     }
1182     case BLKIF_PROTOCOL_X86_64:
1183     {
1184         blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring;
1185
1186         BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, XC_PAGE_SIZE);
1187         break;
1188     }
1189     }
1190
1191     if (blkdev->feature_persistent) {
1192         /* Init persistent grants */
1193         blkdev->max_grants = max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST;
1194         blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp,
1195                                              NULL, NULL,
1196                                              batch_maps ?
1197                                              (GDestroyNotify)g_free :
1198                                              (GDestroyNotify)destroy_grant);
1199         blkdev->persistent_regions = NULL;
1200         blkdev->persistent_gnt_count = 0;
1201     }
1202
1203     xen_be_bind_evtchn(&blkdev->xendev);
1204
1205     blkdev->feature_grant_copy =
1206                 (xengnttab_grant_copy(blkdev->xendev.gnttabdev, 0, NULL) == 0);
1207
1208     xen_pv_printf(&blkdev->xendev, 3, "grant copy operation %s\n",
1209                   blkdev->feature_grant_copy ? "enabled" : "disabled");
1210
1211     xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, "
1212                   "remote port %d, local port %d\n",
1213                   blkdev->xendev.protocol, blkdev->ring_ref,
1214                   blkdev->xendev.remote_port, blkdev->xendev.local_port);
1215     return 0;
1216 }
1217
1218 static void blk_disconnect(struct XenDevice *xendev)
1219 {
1220     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1221
1222     if (blkdev->blk) {
1223         blk_detach_dev(blkdev->blk, blkdev);
1224         blk_unref(blkdev->blk);
1225         blkdev->blk = NULL;
1226     }
1227     xen_pv_unbind_evtchn(&blkdev->xendev);
1228
1229     if (blkdev->sring) {
1230         xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring, 1);
1231         blkdev->cnt_map--;
1232         blkdev->sring = NULL;
1233     }
1234
1235     /*
1236      * Unmap persistent grants before switching to the closed state
1237      * so the frontend can free them.
1238      *
1239      * In the !batch_maps case g_tree_destroy will take care of unmapping
1240      * the grant, but in the batch_maps case we need to iterate over every
1241      * region in persistent_regions and unmap it.
1242      */
1243     if (blkdev->feature_persistent) {
1244         g_tree_destroy(blkdev->persistent_gnts);
1245         assert(batch_maps || blkdev->persistent_gnt_count == 0);
1246         if (batch_maps) {
1247             blkdev->persistent_gnt_count = 0;
1248             g_slist_foreach(blkdev->persistent_regions,
1249                             (GFunc)remove_persistent_region, blkdev);
1250             g_slist_free(blkdev->persistent_regions);
1251         }
1252         blkdev->feature_persistent = false;
1253     }
1254 }
1255
1256 static int blk_free(struct XenDevice *xendev)
1257 {
1258     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1259     struct ioreq *ioreq;
1260
1261     if (blkdev->blk || blkdev->sring) {
1262         blk_disconnect(xendev);
1263     }
1264
1265     while (!QLIST_EMPTY(&blkdev->freelist)) {
1266         ioreq = QLIST_FIRST(&blkdev->freelist);
1267         QLIST_REMOVE(ioreq, list);
1268         qemu_iovec_destroy(&ioreq->v);
1269         g_free(ioreq);
1270     }
1271
1272     g_free(blkdev->params);
1273     g_free(blkdev->mode);
1274     g_free(blkdev->type);
1275     g_free(blkdev->dev);
1276     g_free(blkdev->devtype);
1277     qemu_bh_delete(blkdev->bh);
1278     return 0;
1279 }
1280
1281 static void blk_event(struct XenDevice *xendev)
1282 {
1283     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1284
1285     qemu_bh_schedule(blkdev->bh);
1286 }
1287
1288 struct XenDevOps xen_blkdev_ops = {
1289     .size       = sizeof(struct XenBlkDev),
1290     .flags      = DEVOPS_FLAG_NEED_GNTDEV,
1291     .alloc      = blk_alloc,
1292     .init       = blk_init,
1293     .initialise    = blk_connect,
1294     .disconnect = blk_disconnect,
1295     .event      = blk_event,
1296     .free       = blk_free,
1297 };